* Re: [PATCH v3 5/7] kernel: Use mutable list iterators
From: bot+bpf-ci @ 2026-06-22 5:22 UTC (permalink / raw)
To: kaitao.cheng, paul, eparis, ast, daniel, andrii, eddyz87, memxor,
davem, kuba, hawk, john.fastabend, tj, hannes, mkoutny, dev,
mripard, natalie.vock, peterz, mingo, acme, namhyung, mhiramat,
oleg, oberpar, akpm, baoquan.he, rppt, pasha.tatashin, pratyush,
naveen, jpoimboe, jikos, mbenes, pmladek, will, boqun, mcgrof,
petr.pavlu, da.gomez, samitolvanen, steffen.klassert,
daniel.m.jordan, rafael, dave, paulmck, josh, frederic,
neeraj.upadhyay, joelagnelf, urezki, juri.lelli, vincent.guittot,
kees, bsingharora, anna-maria, tglx, jstultz, kpsingh,
mattbobrowski, nathan, martin.lau, song, mark.rutland,
mathieu.desnoyers, dietmar.eggemann, void, rostedt
Cc: audit, linux-kernel, bpf, netdev, cgroups, dri-devel,
linux-perf-users, linux-trace-kernel, kexec, live-patching,
linux-modules, linux-crypto, linux-pm, rcu, sched-ext, llvm,
chengkaitao, ast, andrii, daniel, martin.lau, eddyz87,
yonghong.song, clm, ihor.solodrai
In-Reply-To: <20260622042811.31684-1-kaitao.cheng@linux.dev>
[-- Attachment #1: Type: text/plain, Size: 1983 bytes --]
> diff --git a/kernel/trace/trace_dynevent.c b/kernel/trace/trace_dynevent.c
> index c4dfbc293bae..9e076106bee7 100644
> --- a/kernel/trace/trace_dynevent.c
> +++ b/kernel/trace/trace_dynevent.c
[ ... ]
> @@ -100,7 +100,7 @@ int dyn_event_release(const char *raw_command, struct dyn_event_operations *type
> return -EINVAL;
>
> mutex_lock(&event_mutex);
> - for_each_dyn_event_safe(pos, n) {
> + for_each_dyn_event_safe(pos) {
> if (type && type != pos->ops)
> continue;
> if (!pos->ops->match(system, event,
Does this leave the variable n unused? Looking at the function
declaration around line 74, it still has:
struct dyn_event *pos, *n;
but after this change n is no longer passed to for_each_dyn_event_safe().
The macro now hides the temporary cursor internally, so n appears to be
dead code. This would trigger -Wunused-variable warnings and break builds
with CONFIG_WERROR=y.
For comparison, the sibling change at line 219 (dyn_events_release_all)
correctly removed the *tmp variable from its declaration.
> diff --git a/kernel/trace/trace_dynevent.h b/kernel/trace/trace_dynevent.h
> index beee3f8d7544..a4dc0812284f 100644
> --- a/kernel/trace/trace_dynevent.h
> +++ b/kernel/trace/trace_dynevent.h
> @@ -115,10 +115,9 @@ int dyn_event_create(const char *raw_command, struct dyn_event_operations *type)
> /*
> * for_each_dyn_event - iterate over the dyn_event list safely
> * @pos: the struct dyn_event * to use as a loop cursor
> - * @n: the struct dyn_event * to use as temporary storage
> */
> -#define for_each_dyn_event_safe(pos, n) \
> - list_for_each_entry_safe(pos, n, &dyn_event_list, list)
> +#define for_each_dyn_event_safe(pos) \
> + list_for_each_entry_mutable(pos, &dyn_event_list, list)
---
AI reviewed your patch. Please fix the bug or email reply why it's not a bug.
See: https://github.com/kernel-patches/vmtest/blob/master/ci/claude/README.md
CI run summary: https://github.com/kernel-patches/bpf/actions/runs/27930295027
^ permalink raw reply
* Re: [PATCH v3 0/7] Prepare mutable list iterators to cache cursor state
From: Alexei Starovoitov @ 2026-06-22 5:28 UTC (permalink / raw)
To: Kaitao Cheng
Cc: Andrew Morton, David Hildenbrand, Jens Axboe, Tejun Heo,
Alexander Viro, Christian Brauner, Alexei Starovoitov,
Daniel Borkmann, Andrii Nakryiko, Johannes Weiner, Peter Zijlstra,
Ingo Molnar, Arnaldo Carvalho de Melo, Namhyung Kim,
Thomas Gleixner, Juri Lelli, Vincent Guittot, Paul Moore,
Andy Shevchenko, Paul E. McKenney, Shakeel Butt,
Christian König, David Howells, Simona Vetter, Randy Dunlap,
Luca Ceresoli, Philipp Stanner, linux-block, LKML,
open list:CONTROL GROUP (CGROUP), linux-ntfs-dev, Linux-Fsdevel,
io-uring, audit, bpf, Network Development, dri-devel,
linux-perf-use., linux-trace-kernel, kexec, live-patching,
linux-modules, Linux Crypto Mailing List, Linux Power Management,
rcu, sched-ext, linux-mm, virtualization, damon,
clang-built-linux, chengkaitao
In-Reply-To: <20260622040533.29824-1-kaitao.cheng@linux.dev>
On Sun, Jun 21, 2026 at 9:06 PM Kaitao Cheng <kaitao.cheng@linux.dev> wrote:
>
> From: chengkaitao <chengkaitao@kylinos.cn>
>
> The list_for_each*_safe() helpers are used when the loop body may remove
> the current entry. Their current interface, however, forces every caller
> to define a temporary cursor outside the macro and pass it in, even when
> the caller never uses that cursor directly. For most call sites this
> extra cursor is just boilerplate required by the macro implementation.
>
> This is awkward because the saved next pointer is an internal detail of
> the iteration. Callers that only remove or move the current entry do not
> need to spell it out.
>
> The _safe() suffix has also caused confusion. Christian Koenig pointed
> out that the name is easy to read as a thread-safe variant, especially
> for beginners, even though it only means that the iterator keeps enough
> state to tolerate removal of the current entry. He suggested _mutable()
> as a clearer description of what the loop permits.
>
> Add *_mutable() iterator variants for list, hlist and llist. The new
> helpers are variadic and support both forms. In the common case, the
> caller omits the temporary cursor and the macro creates a unique internal
> cursor with typeof(pos) and __UNIQUE_ID(). If a loop really needs an
> explicit temporary cursor, the caller can still pass it and the helper
> keeps the existing *_safe() behaviour.
>
> For example, a call site may use the shorter form:
>
> list_for_each_entry_mutable(pos, head, member)
>
> or keep the explicit temporary cursor form:
>
> list_for_each_entry_mutable(pos, tmp, head, member)
>
> The existing *_safe() helpers remain available for compatibility. This
> series only converts users in mm, block, kernel, init and io_uring. If
> this approach looks acceptable, the remaining users can be converted in
> follow-up series.
>
> Changes in v3 (Christian König, Andy Shevchenko):
> - Convert safe list walks to mutable iterators
>
> Changes in v2 (Muchun Song, Andy Shevchenko):
> - Drop the list_for_each_entry_mutable*() helpers from v1 and make the
> cursor change directly in the existing list_for_each_entry*() helpers.
> - Open-code special list walks that rely on updating the loop cursor in
> the body, preserving their existing traversal semantics.
>
> Link to v2:
> https://lore.kernel.org/all/20260609061347.93688-1-kaitao.cheng@linux.dev/
>
> Link to v1:
> https://lore.kernel.org/all/20260529082149.76764-1-kaitao.cheng@linux.dev/
>
> Kaitao Cheng (7):
> list: Add mutable iterator variants
> llist: Add mutable iterator variants
> mm: Use mutable list iterators
> block: Use mutable list iterators
> kernel: Use mutable list iterators
> initramfs: Use mutable list iterator
> io_uring: Use mutable list iterators
>
> block/bfq-iosched.c | 17 +-
> block/blk-cgroup.c | 12 +-
> block/blk-flush.c | 4 +-
> block/blk-iocost.c | 18 +-
> block/blk-mq.c | 8 +-
> block/blk-throttle.c | 4 +-
> block/kyber-iosched.c | 4 +-
> block/partitions/ldm.c | 8 +-
> block/sed-opal.c | 4 +-
> include/linux/list.h | 269 ++++++++++++++++++++++++----
> include/linux/llist.h | 81 +++++++--
> init/initramfs.c | 5 +-
> io_uring/cancel.c | 6 +-
> io_uring/poll.c | 3 +-
> io_uring/rw.c | 4 +-
> io_uring/timeout.c | 8 +-
> io_uring/uring_cmd.c | 3 +-
> kernel/audit_tree.c | 4 +-
> kernel/audit_watch.c | 16 +-
> kernel/auditfilter.c | 4 +-
> kernel/auditsc.c | 4 +-
> kernel/bpf/arena.c | 10 +-
> kernel/bpf/arraymap.c | 8 +-
> kernel/bpf/bpf_local_storage.c | 3 +-
> kernel/bpf/bpf_lru_list.c | 25 ++-
> kernel/bpf/btf.c | 18 +-
> kernel/bpf/cgroup.c | 7 +-
> kernel/bpf/cpumap.c | 4 +-
> kernel/bpf/devmap.c | 10 +-
> kernel/bpf/helpers.c | 8 +-
> kernel/bpf/local_storage.c | 4 +-
> kernel/bpf/memalloc.c | 16 +-
> kernel/bpf/offload.c | 8 +-
> kernel/bpf/states.c | 4 +-
> kernel/bpf/stream.c | 4 +-
> kernel/bpf/verifier.c | 6 +-
> kernel/cgroup/cgroup-v1.c | 4 +-
> kernel/cgroup/cgroup.c | 54 +++---
> kernel/cgroup/dmem.c | 12 +-
> kernel/cgroup/rdma.c | 8 +-
> kernel/events/core.c | 44 +++--
> kernel/events/uprobes.c | 12 +-
> kernel/exit.c | 8 +-
> kernel/fail_function.c | 4 +-
> kernel/gcov/clang.c | 4 +-
> kernel/irq_work.c | 4 +-
> kernel/kexec_core.c | 4 +-
> kernel/kprobes.c | 16 +-
> kernel/livepatch/core.c | 4 +-
> kernel/livepatch/core.h | 4 +-
> kernel/liveupdate/kho_block.c | 4 +-
> kernel/liveupdate/luo_flb.c | 4 +-
> kernel/locking/rwsem.c | 2 +-
> kernel/locking/test-ww_mutex.c | 2 +-
> kernel/module/main.c | 11 +-
> kernel/padata.c | 4 +-
> kernel/power/snapshot.c | 8 +-
> kernel/power/wakelock.c | 4 +-
> kernel/printk/printk.c | 11 +-
> kernel/ptrace.c | 4 +-
> kernel/rcu/rcutorture.c | 3 +-
> kernel/rcu/tasks.h | 9 +-
> kernel/rcu/tree.c | 6 +-
> kernel/resource.c | 4 +-
> kernel/sched/core.c | 4 +-
> kernel/sched/ext.c | 22 +--
> kernel/sched/fair.c | 28 +--
> kernel/sched/topology.c | 4 +-
> kernel/sched/wait.c | 4 +-
> kernel/seccomp.c | 4 +-
> kernel/signal.c | 11 +-
> kernel/smp.c | 4 +-
> kernel/taskstats.c | 8 +-
> kernel/time/clockevents.c | 6 +-
> kernel/time/clocksource.c | 4 +-
> kernel/time/posix-cpu-timers.c | 4 +-
> kernel/time/posix-timers.c | 3 +-
> kernel/torture.c | 3 +-
> kernel/trace/bpf_trace.c | 4 +-
> kernel/trace/ftrace.c | 49 +++--
> kernel/trace/ring_buffer.c | 25 ++-
> kernel/trace/trace.c | 12 +-
> kernel/trace/trace_dynevent.c | 6 +-
> kernel/trace/trace_dynevent.h | 5 +-
> kernel/trace/trace_events.c | 35 ++--
> kernel/trace/trace_events_filter.c | 4 +-
> kernel/trace/trace_events_hist.c | 8 +-
> kernel/trace/trace_events_trigger.c | 17 +-
> kernel/trace/trace_events_user.c | 16 +-
> kernel/trace/trace_stat.c | 4 +-
> kernel/user-return-notifier.c | 3 +-
> kernel/workqueue.c | 16 +-
> mm/backing-dev.c | 8 +-
> mm/balloon.c | 8 +-
> mm/cma.c | 4 +-
> mm/compaction.c | 4 +-
> mm/damon/core.c | 4 +-
> mm/damon/sysfs-schemes.c | 4 +-
> mm/dmapool.c | 4 +-
> mm/huge_memory.c | 8 +-
> mm/hugetlb.c | 56 +++---
> mm/hugetlb_vmemmap.c | 16 +-
> mm/khugepaged.c | 14 +-
> mm/kmemleak.c | 7 +-
> mm/ksm.c | 25 +--
> mm/list_lru.c | 4 +-
> mm/memcontrol-v1.c | 8 +-
> mm/memory-failure.c | 12 +-
> mm/memory-tiers.c | 4 +-
> mm/migrate.c | 23 ++-
> mm/mmu_notifier.c | 9 +-
> mm/page_alloc.c | 8 +-
> mm/page_reporting.c | 2 +-
> mm/percpu.c | 11 +-
> mm/pgtable-generic.c | 4 +-
> mm/rmap.c | 10 +-
> mm/shmem.c | 9 +-
> mm/slab_common.c | 14 +-
> mm/slub.c | 33 ++--
> mm/swapfile.c | 4 +-
> mm/userfaultfd.c | 12 +-
> mm/vmalloc.c | 24 +--
> mm/vmscan.c | 7 +-
> mm/zsmalloc.c | 4 +-
> 124 files changed, 875 insertions(+), 681 deletions(-)
Not sure what you were thinking, but this diff stat
is not landable.
pw-bot: cr
^ permalink raw reply
* Re: [PATCH v8 24/46] KVM: guest_memfd: Make in-place conversion the default
From: Yan Zhao @ 2026-06-22 4:53 UTC (permalink / raw)
To: ackerleytng
Cc: aik, andrew.jones, binbin.wu, brauner, chao.p.peng, david,
jmattson, jthoughton, michael.roth, oupton, pankaj.gupta, qperret,
rick.p.edgecombe, rientjes, shivankg, steven.price, tabba, willy,
wyihan, forkloop, pratyush, suzuki.poulose, aneesh.kumar, liam,
Paolo Bonzini, Sean Christopherson, Thomas Gleixner, Ingo Molnar,
Borislav Petkov, Dave Hansen, x86, H. Peter Anvin, Steven Rostedt,
Masami Hiramatsu, Mathieu Desnoyers, Jonathan Corbet, Shuah Khan,
Shuah Khan, Vishal Annapurve, Andrew Morton, Chris Li,
Kairui Song, Kemeng Shi, Nhat Pham, Barry Song, Axel Rasmussen,
Yuanchu Xie, Wei Xu, Youngjun Park, Qi Zheng, Shakeel Butt,
Kiryl Shutsemau, Baoquan He, Jason Gunthorpe, Vlastimil Babka,
kvm, linux-kernel, linux-trace-kernel, linux-doc, linux-kselftest,
linux-mm, linux-coco
In-Reply-To: <20260618-gmem-inplace-conversion-v8-24-9d2959357853@google.com>
On Thu, Jun 18, 2026 at 05:32:01PM -0700, Ackerley Tng via B4 Relay wrote:
> From: Ackerley Tng <ackerleytng@google.com>
>
> Make in-place conversion the default if the arch has private mem.
>
> The default can be overridden at compile type by enabling
> CONFIG_KVM_VM_MEMORY_ATTRIBUTES, or at KVM load time through a module
> parameter.
>
> In-place conversion also implies tracking a guest's private/shared state in
> guest_memfd. To avoid inconsistencies in the way memory attributes are
> tracked between the per-VM or by guest_memfd, make the module_param
> read-only (0444).
>
> Document that using per-VM attributes for tracking private/shared state of
> guest memory is deprecated in favor of tracking in guest_memfd.
>
> Warn if the admin sets gmem_in_place_conversion as false when
> CONFIG_KVM_VM_MEMORY_ATTRIBUTES is not enabled. Add warning in the code
> path where guest memory is populated for a CoCo VM, since that's the
> earliest point in a CoCo VM's lifecycle where memory attributes are
> queried. Unlike other query sites, this site is exclusively used by CoCo
> VMs.
>
> Signed-off-by: Sean Christopherson <seanjc@google.com>
> ---
> arch/x86/kvm/Kconfig | 7 ++++++-
> virt/kvm/guest_memfd.c | 5 +++++
> virt/kvm/kvm_main.c | 3 ++-
> 3 files changed, 13 insertions(+), 2 deletions(-)
>
> diff --git a/arch/x86/kvm/Kconfig b/arch/x86/kvm/Kconfig
> index c28393dc664eb..a3c189d765150 100644
> --- a/arch/x86/kvm/Kconfig
> +++ b/arch/x86/kvm/Kconfig
> @@ -85,7 +85,12 @@ config KVM_VM_MEMORY_ATTRIBUTES
> bool "Enable per-VM PRIVATE vs. SHARED attributes (for CoCo VMs)"
> help
> Enable support for tracking PRIVATE vs. SHARED memory using per-VM
> - memory attributes.
> + memory attributes. Using per-VM attributes are deprecated in favor
> + of tracking PRIVATE state in guest_memfd. Select this if you need
> + to run CoCo VMs using a VMM that doesn't support guest_memfd memory
> + attributes.
> +
> + If unsure, say N.
>
> config KVM_SW_PROTECTED_VM
> bool "Enable support for KVM software-protected VMs"
> diff --git a/virt/kvm/guest_memfd.c b/virt/kvm/guest_memfd.c
> index 86c9f5b0863cb..5cb73543c03c8 100644
> --- a/virt/kvm/guest_memfd.c
> +++ b/virt/kvm/guest_memfd.c
> @@ -1193,10 +1193,15 @@ static bool kvm_gmem_range_is_private(struct file *file, pgoff_t index,
> {
> struct maple_tree *mt = &GMEM_I(file_inode(file))->attributes;
>
> +#ifdef CONFIG_KVM_VM_MEMORY_ATTRIBUTES
> if (!gmem_in_place_conversion)
> return kvm_range_has_vm_memory_attributes(kvm, gfn, gfn + nr_pages,
> KVM_MEMORY_ATTRIBUTE_PRIVATE,
> KVM_MEMORY_ATTRIBUTE_PRIVATE);
> +#else
> + if (WARN_ON_ONCE(!gmem_in_place_conversion))
> + return false;
> +#endif
>
> return kvm_gmem_range_has_attributes(mt, index, nr_pages,
> KVM_MEMORY_ATTRIBUTE_PRIVATE);
> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
> index dd1d18a1d2f68..46e92b5dc3804 100644
> --- a/virt/kvm/kvm_main.c
> +++ b/virt/kvm/kvm_main.c
> @@ -102,7 +102,8 @@ static bool __ro_after_init allow_unsafe_mappings;
> module_param(allow_unsafe_mappings, bool, 0444);
>
> #ifdef kvm_arch_has_private_mem
> -bool __ro_after_init gmem_in_place_conversion = false;
> +bool __ro_after_init gmem_in_place_conversion = !IS_ENABLED(CONFIG_KVM_VM_MEMORY_ATTRIBUTES);
> +module_param(gmem_in_place_conversion, bool, 0444);
With gmem_in_place_conversion=true, userspace can create guest_memfd without the
MMAP flag. In such cases, shared memory is allocated from different backends.
This means this module parameter only enables per-gmem memory attribute and does
not guarantee that gmem in-place conversion will actually occur.
To avoid confusion, could we rename this module parameter to something more
accurate, such as gmem_memory_attribute?
> EXPORT_SYMBOL_FOR_KVM_INTERNAL(gmem_in_place_conversion);
> #endif
>
>
> --
> 2.55.0.rc0.738.g0c8ab3ebcc-goog
>
>
^ permalink raw reply
* Re: [PATCH v3 0/7] Prepare mutable list iterators to cache cursor state
From: Kaitao Cheng @ 2026-06-22 6:15 UTC (permalink / raw)
To: Alexei Starovoitov
Cc: Andrew Morton, David Hildenbrand, Jens Axboe, Tejun Heo,
Alexander Viro, Christian Brauner, Alexei Starovoitov,
Daniel Borkmann, Andrii Nakryiko, Johannes Weiner, Peter Zijlstra,
Ingo Molnar, Arnaldo Carvalho de Melo, Namhyung Kim,
Thomas Gleixner, Juri Lelli, Vincent Guittot, Paul Moore,
Andy Shevchenko, Paul E. McKenney, Shakeel Butt,
Christian König, David Howells, Simona Vetter, Randy Dunlap,
Luca Ceresoli, Philipp Stanner, linux-block, LKML,
open list:CONTROL GROUP (CGROUP), linux-ntfs-dev, Linux-Fsdevel,
io-uring, audit, bpf, Network Development, dri-devel,
linux-perf-use., linux-trace-kernel, kexec, live-patching,
linux-modules, Linux Crypto Mailing List, Linux Power Management,
rcu, sched-ext, linux-mm, virtualization, damon,
clang-built-linux, chengkaitao, Muchun Song
In-Reply-To: <CAADnVQJmPWFT01b7DuLdtafv=8FyB84GYHNZ8zSTck+9Aw0JpA@mail.gmail.com>
在 2026/6/22 13:28, Alexei Starovoitov 写道:
> On Sun, Jun 21, 2026 at 9:06 PM Kaitao Cheng <kaitao.cheng@linux.dev> wrote:
>>
>> From: chengkaitao <chengkaitao@kylinos.cn>
>>
>> The list_for_each*_safe() helpers are used when the loop body may remove
>> the current entry. Their current interface, however, forces every caller
>> to define a temporary cursor outside the macro and pass it in, even when
>> the caller never uses that cursor directly. For most call sites this
>> extra cursor is just boilerplate required by the macro implementation.
>>
>> This is awkward because the saved next pointer is an internal detail of
>> the iteration. Callers that only remove or move the current entry do not
>> need to spell it out.
>>
>> The _safe() suffix has also caused confusion. Christian Koenig pointed
>> out that the name is easy to read as a thread-safe variant, especially
>> for beginners, even though it only means that the iterator keeps enough
>> state to tolerate removal of the current entry. He suggested _mutable()
>> as a clearer description of what the loop permits.
>>
>> Add *_mutable() iterator variants for list, hlist and llist. The new
>> helpers are variadic and support both forms. In the common case, the
>> caller omits the temporary cursor and the macro creates a unique internal
>> cursor with typeof(pos) and __UNIQUE_ID(). If a loop really needs an
>> explicit temporary cursor, the caller can still pass it and the helper
>> keeps the existing *_safe() behaviour.
>>
>> For example, a call site may use the shorter form:
>>
>> list_for_each_entry_mutable(pos, head, member)
>>
>> or keep the explicit temporary cursor form:
>>
>> list_for_each_entry_mutable(pos, tmp, head, member)
>>
>> The existing *_safe() helpers remain available for compatibility. This
>> series only converts users in mm, block, kernel, init and io_uring. If
>> this approach looks acceptable, the remaining users can be converted in
>> follow-up series.
>>
>> Changes in v3 (Christian König, Andy Shevchenko):
>> - Convert safe list walks to mutable iterators
>>
>> Changes in v2 (Muchun Song, Andy Shevchenko):
>> - Drop the list_for_each_entry_mutable*() helpers from v1 and make the
>> cursor change directly in the existing list_for_each_entry*() helpers.
>> - Open-code special list walks that rely on updating the loop cursor in
>> the body, preserving their existing traversal semantics.
>>
>> Link to v2:
>> https://lore.kernel.org/all/20260609061347.93688-1-kaitao.cheng@linux.dev/
>>
>> Link to v1:
>> https://lore.kernel.org/all/20260529082149.76764-1-kaitao.cheng@linux.dev/
>>
>> Kaitao Cheng (7):
>> list: Add mutable iterator variants
>> llist: Add mutable iterator variants
>> mm: Use mutable list iterators
>> block: Use mutable list iterators
>> kernel: Use mutable list iterators
>> initramfs: Use mutable list iterator
>> io_uring: Use mutable list iterators
>>
>> block/bfq-iosched.c | 17 +-
>> block/blk-cgroup.c | 12 +-
>> block/blk-flush.c | 4 +-
>> block/blk-iocost.c | 18 +-
>> block/blk-mq.c | 8 +-
>> block/blk-throttle.c | 4 +-
>> block/kyber-iosched.c | 4 +-
>> block/partitions/ldm.c | 8 +-
>> block/sed-opal.c | 4 +-
>> include/linux/list.h | 269 ++++++++++++++++++++++++----
>> include/linux/llist.h | 81 +++++++--
>> init/initramfs.c | 5 +-
>> io_uring/cancel.c | 6 +-
>> io_uring/poll.c | 3 +-
>> io_uring/rw.c | 4 +-
>> io_uring/timeout.c | 8 +-
>> io_uring/uring_cmd.c | 3 +-
>> kernel/audit_tree.c | 4 +-
>> kernel/audit_watch.c | 16 +-
>> kernel/auditfilter.c | 4 +-
>> kernel/auditsc.c | 4 +-
>> kernel/bpf/arena.c | 10 +-
>> kernel/bpf/arraymap.c | 8 +-
>> kernel/bpf/bpf_local_storage.c | 3 +-
>> kernel/bpf/bpf_lru_list.c | 25 ++-
>> kernel/bpf/btf.c | 18 +-
>> kernel/bpf/cgroup.c | 7 +-
>> kernel/bpf/cpumap.c | 4 +-
>> kernel/bpf/devmap.c | 10 +-
>> kernel/bpf/helpers.c | 8 +-
>> kernel/bpf/local_storage.c | 4 +-
>> kernel/bpf/memalloc.c | 16 +-
>> kernel/bpf/offload.c | 8 +-
>> kernel/bpf/states.c | 4 +-
>> kernel/bpf/stream.c | 4 +-
>> kernel/bpf/verifier.c | 6 +-
>> kernel/cgroup/cgroup-v1.c | 4 +-
>> kernel/cgroup/cgroup.c | 54 +++---
>> kernel/cgroup/dmem.c | 12 +-
>> kernel/cgroup/rdma.c | 8 +-
>> kernel/events/core.c | 44 +++--
>> kernel/events/uprobes.c | 12 +-
>> kernel/exit.c | 8 +-
>> kernel/fail_function.c | 4 +-
>> kernel/gcov/clang.c | 4 +-
>> kernel/irq_work.c | 4 +-
>> kernel/kexec_core.c | 4 +-
>> kernel/kprobes.c | 16 +-
>> kernel/livepatch/core.c | 4 +-
>> kernel/livepatch/core.h | 4 +-
>> kernel/liveupdate/kho_block.c | 4 +-
>> kernel/liveupdate/luo_flb.c | 4 +-
>> kernel/locking/rwsem.c | 2 +-
>> kernel/locking/test-ww_mutex.c | 2 +-
>> kernel/module/main.c | 11 +-
>> kernel/padata.c | 4 +-
>> kernel/power/snapshot.c | 8 +-
>> kernel/power/wakelock.c | 4 +-
>> kernel/printk/printk.c | 11 +-
>> kernel/ptrace.c | 4 +-
>> kernel/rcu/rcutorture.c | 3 +-
>> kernel/rcu/tasks.h | 9 +-
>> kernel/rcu/tree.c | 6 +-
>> kernel/resource.c | 4 +-
>> kernel/sched/core.c | 4 +-
>> kernel/sched/ext.c | 22 +--
>> kernel/sched/fair.c | 28 +--
>> kernel/sched/topology.c | 4 +-
>> kernel/sched/wait.c | 4 +-
>> kernel/seccomp.c | 4 +-
>> kernel/signal.c | 11 +-
>> kernel/smp.c | 4 +-
>> kernel/taskstats.c | 8 +-
>> kernel/time/clockevents.c | 6 +-
>> kernel/time/clocksource.c | 4 +-
>> kernel/time/posix-cpu-timers.c | 4 +-
>> kernel/time/posix-timers.c | 3 +-
>> kernel/torture.c | 3 +-
>> kernel/trace/bpf_trace.c | 4 +-
>> kernel/trace/ftrace.c | 49 +++--
>> kernel/trace/ring_buffer.c | 25 ++-
>> kernel/trace/trace.c | 12 +-
>> kernel/trace/trace_dynevent.c | 6 +-
>> kernel/trace/trace_dynevent.h | 5 +-
>> kernel/trace/trace_events.c | 35 ++--
>> kernel/trace/trace_events_filter.c | 4 +-
>> kernel/trace/trace_events_hist.c | 8 +-
>> kernel/trace/trace_events_trigger.c | 17 +-
>> kernel/trace/trace_events_user.c | 16 +-
>> kernel/trace/trace_stat.c | 4 +-
>> kernel/user-return-notifier.c | 3 +-
>> kernel/workqueue.c | 16 +-
>> mm/backing-dev.c | 8 +-
>> mm/balloon.c | 8 +-
>> mm/cma.c | 4 +-
>> mm/compaction.c | 4 +-
>> mm/damon/core.c | 4 +-
>> mm/damon/sysfs-schemes.c | 4 +-
>> mm/dmapool.c | 4 +-
>> mm/huge_memory.c | 8 +-
>> mm/hugetlb.c | 56 +++---
>> mm/hugetlb_vmemmap.c | 16 +-
>> mm/khugepaged.c | 14 +-
>> mm/kmemleak.c | 7 +-
>> mm/ksm.c | 25 +--
>> mm/list_lru.c | 4 +-
>> mm/memcontrol-v1.c | 8 +-
>> mm/memory-failure.c | 12 +-
>> mm/memory-tiers.c | 4 +-
>> mm/migrate.c | 23 ++-
>> mm/mmu_notifier.c | 9 +-
>> mm/page_alloc.c | 8 +-
>> mm/page_reporting.c | 2 +-
>> mm/percpu.c | 11 +-
>> mm/pgtable-generic.c | 4 +-
>> mm/rmap.c | 10 +-
>> mm/shmem.c | 9 +-
>> mm/slab_common.c | 14 +-
>> mm/slub.c | 33 ++--
>> mm/swapfile.c | 4 +-
>> mm/userfaultfd.c | 12 +-
>> mm/vmalloc.c | 24 +--
>> mm/vmscan.c | 7 +-
>> mm/zsmalloc.c | 4 +-
>> 124 files changed, 875 insertions(+), 681 deletions(-)
>
> Not sure what you were thinking, but this diff stat
> is not landable.
[PATCH v3 1/7] and [PATCH v3 2/7] contain the main logic and can
be merged directly. They are also compatible with the old API.
[PATCH v3 3/7] through [PATCH v3 7/7] are just simple interface
replacements and do not change any functional logic. They can be
left unmerged for now; individual modules can pick them up later
if needed.
In v2, Andy Shevchenko mentioned: "If it's done by Linus himself
during the day when he prepares -rc1, it's fine." Even so, the
changes in this patch series are indeed quite large and touch
almost every subsystem. I have only converted part of them for
now, so I wanted to send this out first and see what people think.
--
Thanks
Kaitao Cheng
^ permalink raw reply
* [syzbot] [trace?] general protection fault in mtree_load
From: syzbot @ 2026-06-22 6:59 UTC (permalink / raw)
To: bp, dave.hansen, hpa, linux-kernel, linux-trace-kernel, mhiramat,
mingo, oleg, peterz, syzkaller-bugs, tglx, x86
Hello,
syzbot found the following issue on:
HEAD commit: 6b5a2b7d9bc1 Merge tag 'trace-tools-v7.2' of git://git.ker..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=16d56986580000
kernel config: https://syzkaller.appspot.com/x/.config?x=ea6584355d75e0cd
dashboard link: https://syzkaller.appspot.com/bug?extid=61ce80689253f42e6d80
compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-6b5a2b7d.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/b3cb0499fbe9/vmlinux-6b5a2b7d.xz
kernel image: https://storage.googleapis.com/syzbot-assets/47cfbe57f6ea/bzImage-6b5a2b7d.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+61ce80689253f42e6d80@syzkaller.appspotmail.com
Oops: general protection fault, probably for non-canonical address 0xdffffc0000000011: 0000 [#1] SMP KASAN NOPTI
KASAN: null-ptr-deref in range [0x0000000000000088-0x000000000000008f]
CPU: 3 UID: 0 PID: 24402 Comm: syz.4.5217 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
RIP: 0010:mas_root lib/maple_tree.c:759 [inline]
RIP: 0010:mas_start lib/maple_tree.c:1179 [inline]
RIP: 0010:mtree_load+0x16d/0xa90 lib/maple_tree.c:5657
Code: 00 00 00 00 48 c7 44 24 78 ff ff ff ff e8 6b bd 84 f6 48 8b 5c 24 50 c6 84 24 9c 00 00 00 00 48 8d 7b 48 48 89 f8 48 c1 e8 03 <42> 80 3c 20 00 0f 85 d6 08 00 00 48 8b 5b 48 e8 6f 1a 08 00 31 ff
RSP: 0018:ffffc900039c76d8 EFLAGS: 00010206
RAX: 0000000000000011 RBX: 0000000000000040 RCX: ffffffff8b848746
RDX: ffff888041b6a540 RSI: ffffffff8b848775 RDI: 0000000000000088
RBP: 0000000000000000 R08: 0000000000000005 R09: 0000000000000001
R10: 0000000000000001 R11: 000000000000751b R12: dffffc0000000000
R13: ffff88802693adc0 R14: 00001fff904365a7 R15: dffffc0000000000
FS: 0000000000000000(0000) GS:ffff8880d665f000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f44aa04f156 CR3: 00000000364d5000 CR4: 0000000000352ef0
Call Trace:
<TASK>
vma_lookup include/linux/mm.h:4204 [inline]
__in_uprobe_trampoline arch/x86/kernel/uprobes.c:766 [inline]
__is_optimized arch/x86/kernel/uprobes.c:1056 [inline]
is_optimized arch/x86/kernel/uprobes.c:1067 [inline]
set_orig_insn+0x1ec/0x2a0 arch/x86/kernel/uprobes.c:1098
remove_breakpoint kernel/events/uprobes.c:1185 [inline]
register_for_each_vma+0xbb7/0xdb0 kernel/events/uprobes.c:1318
uprobe_unregister_nosync+0x12a/0x1c0 kernel/events/uprobes.c:1343
bpf_uprobe_unregister kernel/trace/bpf_trace.c:2936 [inline]
bpf_uprobe_multi_link_release+0xb3/0x1c0 kernel/trace/bpf_trace.c:2947
bpf_link_free+0xec/0x4a0 kernel/bpf/syscall.c:3273
bpf_link_put_direct kernel/bpf/syscall.c:3326 [inline]
bpf_link_release+0x5d/0x80 kernel/bpf/syscall.c:3333
__fput+0x3ff/0xb50 fs/file_table.c:512
task_work_run+0x150/0x240 kernel/task_work.c:233
exit_task_work include/linux/task_work.h:40 [inline]
do_exit+0x951/0x2ae0 kernel/exit.c:1004
do_group_exit+0xd5/0x2a0 kernel/exit.c:1147
get_signal+0x1ec7/0x21e0 kernel/signal.c:3038
arch_do_signal_or_restart+0x91/0x7e0 arch/x86/kernel/signal.c:337
__exit_to_user_mode_loop kernel/entry/common.c:66 [inline]
exit_to_user_mode_loop+0x139/0x6f0 kernel/entry/common.c:101
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline]
ret_from_fork+0x932/0xd50 arch/x86/kernel/process.c:167
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:mas_root lib/maple_tree.c:759 [inline]
RIP: 0010:mas_start lib/maple_tree.c:1179 [inline]
RIP: 0010:mtree_load+0x16d/0xa90 lib/maple_tree.c:5657
Code: 00 00 00 00 48 c7 44 24 78 ff ff ff ff e8 6b bd 84 f6 48 8b 5c 24 50 c6 84 24 9c 00 00 00 00 48 8d 7b 48 48 89 f8 48 c1 e8 03 <42> 80 3c 20 00 0f 85 d6 08 00 00 48 8b 5b 48 e8 6f 1a 08 00 31 ff
RSP: 0018:ffffc900039c76d8 EFLAGS: 00010206
RAX: 0000000000000011 RBX: 0000000000000040 RCX: ffffffff8b848746
RDX: ffff888041b6a540 RSI: ffffffff8b848775 RDI: 0000000000000088
RBP: 0000000000000000 R08: 0000000000000005 R09: 0000000000000001
R10: 0000000000000001 R11: 000000000000751b R12: dffffc0000000000
R13: ffff88802693adc0 R14: 00001fff904365a7 R15: dffffc0000000000
FS: 0000000000000000(0000) GS:ffff8880d665f000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c433cbf CR3: 00000000429b6000 CR4: 0000000000352ef0
----------------
Code disassembly (best guess):
0: 00 00 add %al,(%rax)
2: 00 00 add %al,(%rax)
4: 48 c7 44 24 78 ff ff movq $0xffffffffffffffff,0x78(%rsp)
b: ff ff
d: e8 6b bd 84 f6 call 0xf684bd7d
12: 48 8b 5c 24 50 mov 0x50(%rsp),%rbx
17: c6 84 24 9c 00 00 00 movb $0x0,0x9c(%rsp)
1e: 00
1f: 48 8d 7b 48 lea 0x48(%rbx),%rdi
23: 48 89 f8 mov %rdi,%rax
26: 48 c1 e8 03 shr $0x3,%rax
* 2a: 42 80 3c 20 00 cmpb $0x0,(%rax,%r12,1) <-- trapping instruction
2f: 0f 85 d6 08 00 00 jne 0x90b
35: 48 8b 5b 48 mov 0x48(%rbx),%rbx
39: e8 6f 1a 08 00 call 0x81aad
3e: 31 ff xor %edi,%edi
---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzkaller@googlegroups.com.
syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title
If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)
If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report
If you want to undo deduplication, reply with:
#syz undup
^ permalink raw reply
* [PATCH] f2fs: don't drop the top folio order in the f2fs_iostat tracepoint
From: Zhan Xusheng @ 2026-06-22 7:15 UTC (permalink / raw)
To: Jaegeuk Kim
Cc: Chao Yu, Steven Rostedt, Masami Hiramatsu, linux-kernel,
linux-trace-kernel, Zhan Xusheng
The f2fs_iostat tracepoint stores the per-order read folio counts in a
fixed-size array and prints a fixed number of buckets, both hardcoded to
11. The sysfs iostat accounting array is instead sized by NR_PAGE_ORDERS
(= MAX_PAGE_ORDER + 1), which is not always 11:
arm64 16K pages -> MAX_PAGE_ORDER 11 -> NR_PAGE_ORDERS 12
arm64 64K pages -> MAX_PAGE_ORDER 13 -> NR_PAGE_ORDERS 14
f2fs enables large folios for immutable, non-compressed files, and the
read folio order is bounded by MAX_PAGECACHE_ORDER, i.e.
min(MAX_XAS_ORDER, PREFERRED_MAX_PAGECACHE_ORDER). With THP enabled this
reaches order 11 on 16K/64K base-page kernels (MAX_XAS_ORDER caps it at
11). So an order-11 read folio is possible there and is accounted into
index 11 of the array.
On those configurations the sysfs file reports the order-11 count
correctly, but the tracepoint silently drops it: the memcpy is capped at
min(NR_PAGE_ORDERS, 11), so index 11 is never copied and the trace
disagrees with sysfs. There is no memory-safety issue, only the order-11
bucket missing from the trace; 4K-page kernels (NR_PAGE_ORDERS == 11,
max order <= 9) are unaffected.
Size the array and the printed buckets by a ceiling that covers the
largest possible NR_PAGE_ORDERS (14) with headroom, and add a
BUILD_BUG_ON() so any future growth of NR_PAGE_ORDERS fails the build
loudly instead of silently truncating again. The human-readable
"order=count" output is preserved.
Fixes: cb8ff3ead9a3 ("f2fs: add page-order information for large folio reads in iostat")
Signed-off-by: Zhan Xusheng <zhanxusheng@xiaomi.com>
---
fs/f2fs/iostat.c | 6 ++++++
include/trace/events/f2fs.h | 20 ++++++++++++++++----
2 files changed, 22 insertions(+), 4 deletions(-)
diff --git a/fs/f2fs/iostat.c b/fs/f2fs/iostat.c
index ae265e3e9b2c..cd801bd0b910 100644
--- a/fs/f2fs/iostat.c
+++ b/fs/f2fs/iostat.c
@@ -188,6 +188,12 @@ void f2fs_update_read_folio_count(struct f2fs_sb_info *sbi, struct folio *folio)
unsigned int order = folio_order(folio);
unsigned long flags;
+ /*
+ * The f2fs_iostat tracepoint emits a fixed number of read folio order
+ * buckets. Make sure every order fits so none is silently dropped.
+ */
+ BUILD_BUG_ON(NR_PAGE_ORDERS > F2FS_IOSTAT_RD_FOLIO_ORDERS);
+
if (!sbi->iostat_enable)
return;
diff --git a/include/trace/events/f2fs.h b/include/trace/events/f2fs.h
index b5188d2671d7..3e810690d9de 100644
--- a/include/trace/events/f2fs.h
+++ b/include/trace/events/f2fs.h
@@ -2114,6 +2114,14 @@ DEFINE_EVENT(f2fs_zip_end, f2fs_decompress_pages_end,
);
#ifdef CONFIG_F2FS_IOSTAT
+/*
+ * Number of read folio order buckets emitted by the f2fs_iostat tracepoint.
+ * TP_printk() cannot loop, so the field count is fixed here and must be >=
+ * the largest possible NR_PAGE_ORDERS (14 on arm64 with 64K pages). The
+ * BUILD_BUG_ON() in f2fs_update_read_folio_count() enforces this.
+ */
+#define F2FS_IOSTAT_RD_FOLIO_ORDERS 16
+
TRACE_EVENT(f2fs_iostat,
TP_PROTO(struct f2fs_sb_info *sbi, unsigned long long *iostat,
@@ -2151,7 +2159,7 @@ TRACE_EVENT(f2fs_iostat,
__field(unsigned long long, fs_mrio)
__field(unsigned long long, fs_discard)
__field(unsigned long long, fs_reset_zone)
- __array(unsigned long long, read_folio_count, 11)
+ __array(unsigned long long, read_folio_count, F2FS_IOSTAT_RD_FOLIO_ORDERS)
),
TP_fast_assign(
@@ -2186,7 +2194,8 @@ TRACE_EVENT(f2fs_iostat,
__entry->fs_reset_zone = iostat[FS_ZONE_RESET_IO];
memset(__entry->read_folio_count, 0, sizeof(__entry->read_folio_count));
memcpy(__entry->read_folio_count, read_folio_count,
- sizeof(unsigned long long) * min_t(int, NR_PAGE_ORDERS, 11));
+ sizeof(unsigned long long) *
+ min_t(int, NR_PAGE_ORDERS, F2FS_IOSTAT_RD_FOLIO_ORDERS));
),
TP_printk("dev = (%d,%d), "
@@ -2201,7 +2210,8 @@ TRACE_EVENT(f2fs_iostat,
"fs [data=%llu, (gc_data=%llu, cdata=%llu), "
"node=%llu, meta=%llu], "
"read_folio_count [0=%llu, 1=%llu, 2=%llu, 3=%llu, 4=%llu, "
- "5=%llu, 6=%llu, 7=%llu, 8=%llu, 9=%llu, 10=%llu]",
+ "5=%llu, 6=%llu, 7=%llu, 8=%llu, 9=%llu, 10=%llu, 11=%llu, "
+ "12=%llu, 13=%llu, 14=%llu, 15=%llu]",
show_dev(__entry->dev), __entry->app_wio, __entry->app_dio,
__entry->app_bio, __entry->app_mio, __entry->app_bcdio,
__entry->app_mcdio, __entry->fs_dio, __entry->fs_cdio,
@@ -2218,7 +2228,9 @@ TRACE_EVENT(f2fs_iostat,
__entry->read_folio_count[4], __entry->read_folio_count[5],
__entry->read_folio_count[6], __entry->read_folio_count[7],
__entry->read_folio_count[8], __entry->read_folio_count[9],
- __entry->read_folio_count[10])
+ __entry->read_folio_count[10], __entry->read_folio_count[11],
+ __entry->read_folio_count[12], __entry->read_folio_count[13],
+ __entry->read_folio_count[14], __entry->read_folio_count[15])
);
#ifndef __F2FS_IOSTAT_LATENCY_TYPE
--
2.43.0
^ permalink raw reply related
* Re: [PATCH v8 23/46] KVM: TDX: Make source page optional for KVM_TDX_INIT_MEM_REGION
From: Yan Zhao @ 2026-06-22 6:57 UTC (permalink / raw)
To: ackerleytng
Cc: aik, andrew.jones, binbin.wu, brauner, chao.p.peng, david,
jmattson, jthoughton, michael.roth, oupton, pankaj.gupta, qperret,
rick.p.edgecombe, rientjes, shivankg, steven.price, tabba, willy,
wyihan, forkloop, pratyush, suzuki.poulose, aneesh.kumar, liam,
Paolo Bonzini, Sean Christopherson, Thomas Gleixner, Ingo Molnar,
Borislav Petkov, Dave Hansen, x86, H. Peter Anvin, Steven Rostedt,
Masami Hiramatsu, Mathieu Desnoyers, Jonathan Corbet, Shuah Khan,
Shuah Khan, Vishal Annapurve, Andrew Morton, Chris Li,
Kairui Song, Kemeng Shi, Nhat Pham, Barry Song, Axel Rasmussen,
Yuanchu Xie, Wei Xu, Youngjun Park, Qi Zheng, Shakeel Butt,
Kiryl Shutsemau, Baoquan He, Jason Gunthorpe, Vlastimil Babka,
kvm, linux-kernel, linux-trace-kernel, linux-doc, linux-kselftest,
linux-mm, linux-coco
In-Reply-To: <20260618-gmem-inplace-conversion-v8-23-9d2959357853@google.com>
On Thu, Jun 18, 2026 at 05:32:00PM -0700, Ackerley Tng via B4 Relay wrote:
> From: Ackerley Tng <ackerleytng@google.com>
>
> Update tdx_gmem_post_populate() to handle cases where a source page is
> not explicitly provided. Instead of returning -EOPNOTSUPP when src_page
> is NULL, default to using the page associated with the destination PFN.
>
> This change allows for in-place memory conversion where the data is
> already present in the target PFN, ensuring the TDX module has a valid
> source page reference for the TDH.MEM.PAGE.ADD operation.
>
> Signed-off-by: Ackerley Tng <ackerleytng@google.com>
> Signed-off-by: Sean Christopherson <seanjc@google.com>
> ---
> Documentation/virt/kvm/x86/intel-tdx.rst | 4 ++++
> arch/x86/kvm/vmx/tdx.c | 11 ++++++++---
> 2 files changed, 12 insertions(+), 3 deletions(-)
>
> diff --git a/Documentation/virt/kvm/x86/intel-tdx.rst b/Documentation/virt/kvm/x86/intel-tdx.rst
> index 6a222e9d09541..74357fe87f9ec 100644
> --- a/Documentation/virt/kvm/x86/intel-tdx.rst
> +++ b/Documentation/virt/kvm/x86/intel-tdx.rst
> @@ -158,6 +158,10 @@ KVM_TDX_INIT_MEM_REGION
> Initialize @nr_pages TDX guest private memory starting from @gpa with userspace
> provided data from @source_addr. @source_addr must be PAGE_SIZE-aligned.
>
> +If guest_memfd in-place conversion is enabled, pass NULL for @source_addr to
> +initialize the memory region using memory contents already populated in
> +guest_memfd memory.
> +
> Note, before calling this sub command, memory attribute of the range
> [gpa, gpa + nr_pages] needs to be private. Userspace can use
> KVM_SET_MEMORY_ATTRIBUTES to set the attribute.
> diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c
> index ffe9d0db58c59..56d10333c61a7 100644
> --- a/arch/x86/kvm/vmx/tdx.c
> +++ b/arch/x86/kvm/vmx/tdx.c
> @@ -3198,8 +3198,12 @@ static int tdx_gmem_post_populate(struct kvm *kvm, gfn_t gfn, kvm_pfn_t pfn,
> if (KVM_BUG_ON(kvm_tdx->page_add_src, kvm))
> return -EIO;
>
> - if (!src_page)
> - return -EOPNOTSUPP;
> + if (!src_page) {
> + if (!gmem_in_place_conversion)
When userspace turns on gmem_in_place_conversion while creating guest_memfd
without the MMAP flag, the absence of src_page should still be treated as an
error.
Additionally, to properly enable in-place copying for the TDX initial memory
region, userspace must not only specify source_addr to NULL, but also follow
a specific sequence (where steps 1/2/3/7 are required only for in-place copy):
1. create guest_memfd with MMAP flag
2. mmap the guest_memfd.
3. convert the initial memory range to shared.
4. copy initial content to the source page.
5. convert the initial memory range to private
6. invoke ioctl KVM_TDX_INIT_MEM_REGION.
7. do not unmap the source backend.
So, would it be reasonable to introduce a dedicated flag that allows userspace
to explicitly opt into the in-place copy functionality? e.g.,
diff --git a/arch/x86/include/uapi/asm/kvm.h b/arch/x86/include/uapi/asm/kvm.h
index 1585ec804066..d047a6efc728 100644
--- a/arch/x86/include/uapi/asm/kvm.h
+++ b/arch/x86/include/uapi/asm/kvm.h
@@ -1043,6 +1043,9 @@ struct kvm_tdx_init_vm {
};
#define KVM_TDX_MEASURE_MEMORY_REGION _BITULL(0)
+#define KVM_TDX_IN_PLACE_COPY_INITIAL_MEMORY_REGION _BITULL(1)
+#define KVM_TDX_INIT_MEM_VALID_FLAGS (KVM_TDX_MEASURE_MEMORY_REGION | \
+ KVM_TDX_IN_PLACE_COPY_INITIAL_MEMORY_REGION)
struct kvm_tdx_init_mem_region {
__u64 source_addr;
diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c
index 56d10333c61a..6072b38ceb37 100644
--- a/arch/x86/kvm/vmx/tdx.c
+++ b/arch/x86/kvm/vmx/tdx.c
@@ -3190,6 +3190,7 @@ static int tdx_gmem_post_populate(struct kvm *kvm, gfn_t gfn, kvm_pfn_t pfn,
struct page *src_page, void *_arg)
{
struct tdx_gmem_post_populate_arg *arg = _arg;
+ bool in_place_copy = arg->flags & KVM_TDX_IN_PLACE_COPY_INITIAL_MEMORY_REGION;
struct kvm_tdx *kvm_tdx = to_kvm_tdx(kvm);
u64 err, entry, level_state;
gpa_t gpa = gfn_to_gpa(gfn);
@@ -3199,7 +3200,7 @@ static int tdx_gmem_post_populate(struct kvm *kvm, gfn_t gfn, kvm_pfn_t pfn,
return -EIO;
if (!src_page) {
- if (!gmem_in_place_conversion)
+ if (!in_place_copy)
return -EOPNOTSUPP;
src_page = pfn_to_page(pfn);
@@ -3245,7 +3246,7 @@ static int tdx_vcpu_init_mem_region(struct kvm_vcpu *vcpu, struct kvm_tdx_cmd *c
if (kvm_tdx->state == TD_STATE_RUNNABLE)
return -EINVAL;
- if (cmd->flags & ~KVM_TDX_MEASURE_MEMORY_REGION)
+ if (cmd->flags & ~KVM_TDX_INIT_MEM_VALID_FLAGS)
return -EINVAL;
> + return -EOPNOTSUPP;
> +
> + src_page = pfn_to_page(pfn);
> + }
>
> kvm_tdx->page_add_src = src_page;
> ret = kvm_tdp_mmu_map_private_pfn(arg->vcpu, gfn, pfn);
> @@ -3278,7 +3282,8 @@ static int tdx_vcpu_init_mem_region(struct kvm_vcpu *vcpu, struct kvm_tdx_cmd *c
> break;
> }
>
> - region.source_addr += PAGE_SIZE;
> + if (region.source_addr)
> + region.source_addr += PAGE_SIZE;
> region.gpa += PAGE_SIZE;
> region.nr_pages--;
>
>
> --
> 2.55.0.rc0.738.g0c8ab3ebcc-goog
>
>
^ permalink raw reply related
* Re: [PATCH v8 23/46] KVM: TDX: Make source page optional for KVM_TDX_INIT_MEM_REGION
From: Yan Zhao @ 2026-06-22 7:18 UTC (permalink / raw)
To: Fuad Tabba
Cc: ackerleytng, aik, andrew.jones, binbin.wu, brauner, chao.p.peng,
david, jmattson, jthoughton, michael.roth, oupton, pankaj.gupta,
qperret, rick.p.edgecombe, rientjes, shivankg, steven.price,
willy, wyihan, forkloop, pratyush, suzuki.poulose, aneesh.kumar,
liam, Paolo Bonzini, Sean Christopherson, Thomas Gleixner,
Ingo Molnar, Borislav Petkov, Dave Hansen, x86, H. Peter Anvin,
Steven Rostedt, Masami Hiramatsu, Mathieu Desnoyers,
Jonathan Corbet, Shuah Khan, Shuah Khan, Vishal Annapurve,
Andrew Morton, Chris Li, Kairui Song, Kemeng Shi, Nhat Pham,
Barry Song, Axel Rasmussen, Yuanchu Xie, Wei Xu, Youngjun Park,
Qi Zheng, Shakeel Butt, Kiryl Shutsemau, Baoquan He,
Jason Gunthorpe, Vlastimil Babka, kvm, linux-kernel,
linux-trace-kernel, linux-doc, linux-kselftest, linux-mm,
linux-coco
In-Reply-To: <CA+EHjTyj-JdW8H0ii2j3dayqnT2s3VV+brSG++p335=FGd2GXg@mail.gmail.com>
On Fri, Jun 19, 2026 at 12:09:54PM +0100, Fuad Tabba wrote:
> Sashiko flagged that when src_page = pfn_to_page(pfn),
> tdh_mem_page_add gets identical physical addresses for r8
> (destination) and r9 (source), reading with host KeyID and writing
> with TD KeyID on the same address.
This is allowed :)
See below description in the spec [1].
In-Place Add:
It is allowed to set the TD page HPA in R8 to the same address as the source
page HPA in R9. In this case the source page is converted to be a TD private
page.
[1] https://www.intel.com/content/www/us/en/content-details/853294/intel-trust-domain-extensions-intel-tdx-module-base-architecture-specification.html
^ permalink raw reply
* Re: [PATCH 0/2] tracing: Move trace_printk.h out of kernel.h
From: Christophe Leroy (CS GROUP) @ 2026-06-22 8:05 UTC (permalink / raw)
To: Steven Rostedt, linux-kernel, linux-trace-kernel
Cc: Masami Hiramatsu, Mark Rutland, Mathieu Desnoyers, Andrew Morton,
Linus Torvalds, Sebastian Andrzej Siewior, John Ogness,
Thomas Gleixner, Peter Zijlstra, Julia Lawall, Yury Norov,
linux-doc, linux-kbuild, linuxppc-dev, dri-devel, linux-stm32,
linux-arm-kernel, linux-rdma, linux-usb, linux-ext4, linux-nfs,
kvm, intel-gfx
In-Reply-To: <20260621093430.264983361@kernel.org>
Le 21/06/2026 à 11:34, Steven Rostedt a écrit :
> There's been complaints about trace_printk() being defined in kernel.h as it
> can increase the compilation time. As it is only used by some developers for
> debugging purposes, it should not be in kernel.h causing lots of wasted CPU
> cycles for those that do not ever care about it.
Do we have a measurement of the increased compilation time ?
Christophe
>
> Instead, add a CONFIG_TRACE_PRINTK_DEBUGGING option that developers that do
> use it can set and not have to always remember to add #include <linux/trace_printk.h>
> to the files they add trace_printk() while debugging. It also means that
> those that do not have that config set will not have to worry about wasted
> CPU cycles as it is only include in the CFLAGS when the option is set, and
> its completely ignored otherwise.
>
> Steven Rostedt (2):
> tracing: Move non-trace_printk prototypes back to kernel.h
> tracing: Add CONFIG_TRACE_PRINTK_DEBUGGING to clean up kernel.h
>
> ----
> .../driver_development_debugging_guide.rst | 2 +-
> Makefile | 5 +++++
> arch/powerpc/kvm/book3s_xics.c | 1 +
> drivers/gpu/drm/i915/gt/intel_gtt.h | 1 +
> drivers/gpu/drm/i915/i915_gem.h | 1 +
> drivers/hwtracing/stm/dummy_stm.c | 4 ++++
> drivers/infiniband/hw/hfi1/trace_dbg.h | 1 +
> drivers/usb/early/xhci-dbc.c | 1 +
> fs/ext4/inline.c | 1 +
> include/linux/kernel.h | 19 ++++++++++++++++++-
> include/linux/sunrpc/debug.h | 1 +
> include/linux/trace_printk.h | 22 +++-------------------
> kernel/trace/Kconfig | 10 ++++++++++
> kernel/trace/ring_buffer_benchmark.c | 1 +
> kernel/trace/trace.h | 1 +
> samples/fprobe/fprobe_example.c | 1 +
> samples/ftrace/ftrace-direct-modify.c | 1 +
> samples/ftrace/ftrace-direct-multi-modify.c | 1 +
> samples/ftrace/ftrace-direct-multi.c | 2 +-
> samples/ftrace/ftrace-direct-too.c | 2 +-
> samples/ftrace/ftrace-direct.c | 2 +-
> 21 files changed, 56 insertions(+), 24 deletions(-)
>
^ permalink raw reply
* Re: [PATCH] tracing: Use seq_buf for string concatenation
From: Woradorn Laodhanadhaworn @ 2026-06-22 8:18 UTC (permalink / raw)
To: Jori Koolstra, rostedt
Cc: mhiramat, mathieu.desnoyers, linux-kernel, linux-trace-kernel,
linux-hardening, linux-kernel-mentees, shuah, skhan, me
In-Reply-To: <70408559.2499685.1782062190117@kpc.webmail.kpnmail.nl>
On 22/6/2569 BE 00:16, Jori Koolstra wrote:
>
>> Op 20-06-2026 19:54 CEST schreef Woradorn Laodhanadhaworn <woradorn.laon@gmail.com>:
>>
>>
>> In preparation for removing the strlcat API[1],
>> replace the string concatenation logic with a struct seq_buf,
>> which tracks the current position and the remaining space internally.
>>
>> The backing buffer bootup_event_buf allocation is unchanged.
>> Use seq_buf_str() to NUL-terminate before passing to early_enable_events().
>>
>> Link: https://github.com/KSPP/linux/issues/370 [1]
>>
>> Signed-off-by: Woradorn Laodhanadhaworn <woradorn.laon@gmail.com>
>> ---
>> kernel/trace/trace_events.c | 21 ++++++++++++++++-----
>> 1 file changed, 16 insertions(+), 5 deletions(-)
>>
>> diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
>> index c46e623e7e0d..15164723e028 100644
>> --- a/kernel/trace/trace_events.c
>> +++ b/kernel/trace/trace_events.c
>> @@ -22,6 +22,7 @@
>> #include <linux/sort.h>
>> #include <linux/slab.h>
>> #include <linux/delay.h>
>> +#include <linux/seq_buf.h>
>>
>> #include <trace/events/sched.h>
>> #include <trace/syscall.h>
>> @@ -4501,13 +4502,23 @@ extern struct trace_event_call *__start_ftrace_events[];
>> extern struct trace_event_call *__stop_ftrace_events[];
>>
>> static char bootup_event_buf[COMMAND_LINE_SIZE] __initdata;
>
> Isn't this now unused?
>
>> +static struct seq_buf bootup_event_seq;
>> +static bool bootup_event_seq_initialized;
>>
>
> I think this can be refactored to avoid the bool. And should bootup_event_seq not be
> __initdata?
>
>> static __init int setup_trace_event(char *str)
>> {
>> - if (bootup_event_buf[0] != '\0')
>> - strlcat(bootup_event_buf, ",", COMMAND_LINE_SIZE);
>> + if (!bootup_event_seq_initialized) {
>> + seq_buf_init(&bootup_event_seq, bootup_event_buf, COMMAND_LINE_SIZE);
>> + bootup_event_seq_initialized = true;
>> + }
>> +
>> + if (seq_buf_used(&bootup_event_seq) > 0)
>> + seq_buf_puts(&bootup_event_seq, ",");
>>
>> - strlcat(bootup_event_buf, str, COMMAND_LINE_SIZE);
>> + seq_buf_puts(&bootup_event_seq, str);
>> +
>> + if (seq_buf_has_overflowed(&bootup_event_seq))
>> + return -ENOMEM;
>>
>> trace_set_ring_buffer_expanded(NULL);
>> disable_tracing_selftest("running event tracing");
>> @@ -4766,7 +4777,7 @@ static __init int event_trace_enable(void)
>> */
>> __trace_early_add_events(tr);
>>
>> - early_enable_events(tr, bootup_event_buf, false);
>> + early_enable_events(tr, (char *)seq_buf_str(&bootup_event_seq), false);
>
> What if trace_event is empty? Then setup_trace_event does not run AFAIK. See the
> WARN_ON in seq_buf_str too. Have you tested this?
>
>>
>> trace_printk_start_comm();
>>
>> @@ -4794,7 +4805,7 @@ static __init int event_trace_enable_again(void)
>> if (!tr)
>> return -ENODEV;
>>
>> - early_enable_events(tr, bootup_event_buf, true);
>> + early_enable_events(tr, (char *)seq_buf_str(&bootup_event_seq), true);
>>
>> return 0;
>> }
>> --
>> 2.43.0
>
> Thanks,
> Jori.
Thank you, Jori, for your review. I will send v2.
I tested both empty and non-empty trace_event cases with QEMU, and both now boot successfully.
The logs below demonstrate this.
Non-empty trace_event:
qemu-system-x86_64 \
-kernel arch/x86/boot/bzImage \
-initrd initramfs.cpio.gz \
-append "console=ttyS0 trace_event=:mod:rproc_qcom_common,:mod:qrtr,:mod:qcom_aoss trace_event=:mod:rproc_qcom_common" \
-nographic \
-m 512M
[ 0.082316] Kernel command line: console=ttyS0 trace_event=:mod:rproc_qcom_common,:mod:qrtr,:mod:qcom_aoss trace_event=:mod:rproc_qcom_common
[ 0.083324] bootup_event_buf: :mod:rproc_qcom_common,:mod:qrtr,:mod:qcom_aoss
[ 0.083413] bootup_event_buf: :mod:rproc_qcom_common,:mod:qrtr,:mod:qcom_aoss,:mod:rproc_qcom_common
[ 0.083689] printk: log buffer data + meta data: 262144 + 917504 = 1179648 bytes
Empty trace_event:
qemu-system-x86_64 \
-kernel arch/x86/boot/bzImage \
-initrd initramfs.cpio.gz \
-append "console=ttyS0" \
-nographic \
-m 512M
[ 0.085213] Kernel command line: console=ttyS0
[ 0.086458] printk: log buffer data + meta data: 262144 + 917504 = 1179648 bytes
Thanks,
Woradorn
^ permalink raw reply
* Re: [PATCH v3 0/7] Prepare mutable list iterators to cache cursor state
From: Jani Nikula @ 2026-06-22 8:37 UTC (permalink / raw)
To: Kaitao Cheng, Andrew Morton, David Hildenbrand, Jens Axboe,
Tejun Heo, Alexander Viro, Christian Brauner, Alexei Starovoitov,
Daniel Borkmann, Andrii Nakryiko, Johannes Weiner, Peter Zijlstra,
Ingo Molnar, Arnaldo Carvalho de Melo, Namhyung Kim,
Thomas Gleixner, Juri Lelli, Vincent Guittot, Paul Moore,
Andy Shevchenko, Paul E. McKenney, Shakeel Butt,
Christian König
Cc: David Howells, Simona Vetter, Randy Dunlap, Luca Ceresoli,
Philipp Stanner, linux-block, linux-kernel, cgroups,
linux-ntfs-dev, linux-fsdevel, io-uring, audit, bpf, netdev,
dri-devel, linux-perf-users, linux-trace-kernel, kexec,
live-patching, linux-modules, linux-crypto, linux-pm, rcu,
sched-ext, linux-mm, virtualization, damon, llvm, chengkaitao
In-Reply-To: <20260622040533.29824-1-kaitao.cheng@linux.dev>
On Mon, 22 Jun 2026, Kaitao Cheng <kaitao.cheng@linux.dev> wrote:
> Add *_mutable() iterator variants for list, hlist and llist. The new
> helpers are variadic and support both forms. In the common case, the
> caller omits the temporary cursor and the macro creates a unique internal
> cursor with typeof(pos) and __UNIQUE_ID(). If a loop really needs an
> explicit temporary cursor, the caller can still pass it and the helper
> keeps the existing *_safe() behaviour.
>
> For example, a call site may use the shorter form:
>
> list_for_each_entry_mutable(pos, head, member)
>
> or keep the explicit temporary cursor form:
>
> list_for_each_entry_mutable(pos, tmp, head, member)
I'm unconvinced it's a good idea to allow two forms with macro trickery,
*especially* when it's not the last argument you can omit. I think it's
a footgun.
IMO stick with the first form only, and there'll always be the _safe
variant that can be used when the temp pointer is needed.
BR,
Jani.
--
Jani Nikula, Intel
^ permalink raw reply
* Re: [PATCH v3 1/7] list: Add mutable iterator variants
From: David Laight @ 2026-06-22 8:42 UTC (permalink / raw)
To: Kaitao Cheng
Cc: Andrew Morton, David Hildenbrand, Jens Axboe, Tejun Heo,
Alexander Viro, Christian Brauner, Alexei Starovoitov,
Daniel Borkmann, Andrii Nakryiko, Johannes Weiner, Peter Zijlstra,
Ingo Molnar, Arnaldo Carvalho de Melo, Namhyung Kim,
Thomas Gleixner, Juri Lelli, Vincent Guittot, Paul Moore,
Andy Shevchenko, Paul E. McKenney, Shakeel Butt,
Christian König, David Howells, Simona Vetter, Randy Dunlap,
Luca Ceresoli, Philipp Stanner, linux-block, linux-kernel,
cgroups, linux-ntfs-dev, linux-fsdevel, io-uring, audit, bpf,
netdev, dri-devel, linux-perf-users, linux-trace-kernel, kexec,
live-patching, linux-modules, linux-crypto, linux-pm, rcu,
sched-ext, linux-mm, virtualization, damon, llvm, Kaitao Cheng
In-Reply-To: <20260622040533.29824-2-kaitao.cheng@linux.dev>
On Mon, 22 Jun 2026 12:05:31 +0800
Kaitao Cheng <kaitao.cheng@linux.dev> wrote:
> From: Kaitao Cheng <chengkaitao@kylinos.cn>
>
> The list_for_each*_safe() helpers are used when the loop body may
> remove the current entry. Their API exposes the temporary cursor at
> every call site, even though most users only need it for the iterator
> implementation and never reference it in the loop body.
>
> Add *_mutable() variants for list and hlist iteration. The new helpers
> support both forms: callers may keep passing an explicit temporary cursor
> when they need to inspect or reset it, or omit it and let the helper use
> a unique internal cursor.
I'm not really sure 'mutable' means anything either.
It is possible to make it valid for the loop body (or even other threads)
to delete arbitrary list items - but that needs significant extra overheads.
It might be worth doing something that doesn't need the extra variable,
but there is little point doing all the churn just to rename things.
>
> This makes call sites that only mutate the list through the current entry
> less noisy, while keeping the existing *_safe() helpers available for
> compatibility.
>
> Signed-off-by: Kaitao Cheng <chengkaitao@kylinos.cn>
> ---
> include/linux/list.h | 269 +++++++++++++++++++++++++++++++++++++------
> 1 file changed, 231 insertions(+), 38 deletions(-)
>
> diff --git a/include/linux/list.h b/include/linux/list.h
> index 09d979976b3b..1081def7cea9 100644
> --- a/include/linux/list.h
> +++ b/include/linux/list.h
> @@ -7,6 +7,7 @@
> #include <linux/stddef.h>
> #include <linux/poison.h>
> #include <linux/const.h>
> +#include <linux/args.h>
>
> #include <asm/barrier.h>
>
> @@ -763,28 +764,72 @@ static inline void list_splice_tail_init(struct list_head *list,
> #define list_for_each_prev(pos, head) \
> for (pos = (head)->prev; !list_is_head(pos, (head)); pos = pos->prev)
>
> -/**
> - * list_for_each_safe - iterate over a list safe against removal of list entry
> - * @pos: the &struct list_head to use as a loop cursor.
> - * @n: another &struct list_head to use as temporary storage
> - * @head: the head for your list.
> +/*
> + * list_for_each_safe is an old interface, use list_for_each_mutable instead.
> */
> #define list_for_each_safe(pos, n, head) \
> for (pos = (head)->next, n = pos->next; \
> !list_is_head(pos, (head)); \
> pos = n, n = pos->next)
>
> +#define __list_for_each_mutable_internal(pos, tmp, head) \
> + for (typeof(pos) tmp = (pos = (head)->next)->next; \
Use auto
> + !list_is_head(pos, (head)); \
> + pos = tmp, tmp = pos->next)
> +
> +#define __list_for_each_mutable1(pos, head) \
> + __list_for_each_mutable_internal(pos, __UNIQUE_ID(next), head)
> +
> +#define __list_for_each_mutable2(pos, next, head) \
> + list_for_each_safe(pos, next, head)
> +
> /**
> - * list_for_each_prev_safe - iterate over a list backwards safe against removal of list entry
> + * list_for_each_mutable - iterate over a list safe against entry removal
> * @pos: the &struct list_head to use as a loop cursor.
> - * @n: another &struct list_head to use as temporary storage
> - * @head: the head for your list.
> + * @...: either (head) or (next, head)
> + *
> + * next: another &struct list_head to use as optional temporary storage.
> + * The temporary cursor is internal unless explicitly supplied by
> + * the caller.
> + * head: the head for your list.
> + */
> +#define list_for_each_mutable(pos, ...) \
> + CONCATENATE(__list_for_each_mutable, COUNT_ARGS(__VA_ARGS__)) \
> + (pos, __VA_ARGS__)
The variable argument count logic really just slows down compilation.
Maybe there aren't enough copies of this code to make that significant.
But just because you can do it doesn't mean it is a gooD idea.
I'm also not sure it really adds anything to the readability.
And, it you are going to make the middle argument optional there is
no need to change the macro name.
David
^ permalink raw reply
* Re: [PATCH v3 1/7] list: Add mutable iterator variants
From: Christian König @ 2026-06-22 8:51 UTC (permalink / raw)
To: Kaitao Cheng, Andrew Morton, David Hildenbrand, Jens Axboe,
Tejun Heo, Alexander Viro, Christian Brauner, Alexei Starovoitov,
Daniel Borkmann, Andrii Nakryiko, Johannes Weiner, Peter Zijlstra,
Ingo Molnar, Arnaldo Carvalho de Melo, Namhyung Kim,
Thomas Gleixner, Juri Lelli, Vincent Guittot, Paul Moore,
Andy Shevchenko, Paul E. McKenney, Shakeel Butt
Cc: David Howells, Simona Vetter, Randy Dunlap, Luca Ceresoli,
Philipp Stanner, linux-block, linux-kernel, cgroups,
linux-ntfs-dev, linux-fsdevel, io-uring, audit, bpf, netdev,
dri-devel, linux-perf-users, linux-trace-kernel, kexec,
live-patching, linux-modules, linux-crypto, linux-pm, rcu,
sched-ext, linux-mm, virtualization, damon, llvm, Kaitao Cheng
In-Reply-To: <20260622040533.29824-2-kaitao.cheng@linux.dev>
On 6/22/26 06:05, Kaitao Cheng wrote:
> From: Kaitao Cheng <chengkaitao@kylinos.cn>
>
> The list_for_each*_safe() helpers are used when the loop body may
> remove the current entry. Their API exposes the temporary cursor at
> every call site, even though most users only need it for the iterator
> implementation and never reference it in the loop body.
>
> Add *_mutable() variants for list and hlist iteration. The new helpers
> support both forms: callers may keep passing an explicit temporary cursor
> when they need to inspect or reset it, or omit it and let the helper use
> a unique internal cursor.
That sounds like a bad idea to me. The macro should really be doing one job and that as best as it can.
> This makes call sites that only mutate the list through the current entry
> less noisy, while keeping the existing *_safe() helpers available for
> compatibility.
This can be perfectly used for code that which really needs the separate variable for the next entry.
Regards,
Christian.
>
> Signed-off-by: Kaitao Cheng <chengkaitao@kylinos.cn>
> ---
> include/linux/list.h | 269 +++++++++++++++++++++++++++++++++++++------
> 1 file changed, 231 insertions(+), 38 deletions(-)
>
> diff --git a/include/linux/list.h b/include/linux/list.h
> index 09d979976b3b..1081def7cea9 100644
> --- a/include/linux/list.h
> +++ b/include/linux/list.h
> @@ -7,6 +7,7 @@
> #include <linux/stddef.h>
> #include <linux/poison.h>
> #include <linux/const.h>
> +#include <linux/args.h>
>
> #include <asm/barrier.h>
>
> @@ -763,28 +764,72 @@ static inline void list_splice_tail_init(struct list_head *list,
> #define list_for_each_prev(pos, head) \
> for (pos = (head)->prev; !list_is_head(pos, (head)); pos = pos->prev)
>
> -/**
> - * list_for_each_safe - iterate over a list safe against removal of list entry
> - * @pos: the &struct list_head to use as a loop cursor.
> - * @n: another &struct list_head to use as temporary storage
> - * @head: the head for your list.
> +/*
> + * list_for_each_safe is an old interface, use list_for_each_mutable instead.
> */
> #define list_for_each_safe(pos, n, head) \
> for (pos = (head)->next, n = pos->next; \
> !list_is_head(pos, (head)); \
> pos = n, n = pos->next)
>
> +#define __list_for_each_mutable_internal(pos, tmp, head) \
> + for (typeof(pos) tmp = (pos = (head)->next)->next; \
> + !list_is_head(pos, (head)); \
> + pos = tmp, tmp = pos->next)
> +
> +#define __list_for_each_mutable1(pos, head) \
> + __list_for_each_mutable_internal(pos, __UNIQUE_ID(next), head)
> +
> +#define __list_for_each_mutable2(pos, next, head) \
> + list_for_each_safe(pos, next, head)
> +
> /**
> - * list_for_each_prev_safe - iterate over a list backwards safe against removal of list entry
> + * list_for_each_mutable - iterate over a list safe against entry removal
> * @pos: the &struct list_head to use as a loop cursor.
> - * @n: another &struct list_head to use as temporary storage
> - * @head: the head for your list.
> + * @...: either (head) or (next, head)
> + *
> + * next: another &struct list_head to use as optional temporary storage.
> + * The temporary cursor is internal unless explicitly supplied by
> + * the caller.
> + * head: the head for your list.
> + */
> +#define list_for_each_mutable(pos, ...) \
> + CONCATENATE(__list_for_each_mutable, COUNT_ARGS(__VA_ARGS__)) \
> + (pos, __VA_ARGS__)
> +
> +/*
> + * list_for_each_prev_safe is an old interface, use list_for_each_prev_mutable instead.
> */
> #define list_for_each_prev_safe(pos, n, head) \
> for (pos = (head)->prev, n = pos->prev; \
> !list_is_head(pos, (head)); \
> pos = n, n = pos->prev)
>
> +#define __list_for_each_prev_mutable_internal(pos, tmp, head) \
> + for (typeof(pos) tmp = (pos = (head)->prev)->prev; \
> + !list_is_head(pos, (head)); \
> + pos = tmp, tmp = pos->prev)
> +
> +#define __list_for_each_prev_mutable1(pos, head) \
> + __list_for_each_prev_mutable_internal(pos, __UNIQUE_ID(prev), head)
> +
> +#define __list_for_each_prev_mutable2(pos, prev, head) \
> + list_for_each_prev_safe(pos, prev, head)
> +
> +/**
> + * list_for_each_prev_mutable - iterate over a list backwards safe against entry removal
> + * @pos: the &struct list_head to use as a loop cursor.
> + * @...: either (head) or (prev, head)
> + *
> + * prev: another &struct list_head to use as optional temporary storage.
> + * The temporary cursor is internal unless explicitly supplied by
> + * the caller.
> + * head: the head for your list.
> + */
> +#define list_for_each_prev_mutable(pos, ...) \
> + CONCATENATE(__list_for_each_prev_mutable, COUNT_ARGS(__VA_ARGS__)) \
> + (pos, __VA_ARGS__)
> +
> /**
> * list_count_nodes - count nodes in the list
> * @head: the head for your list.
> @@ -895,12 +940,8 @@ static inline size_t list_count_nodes(struct list_head *head)
> for (; !list_entry_is_head(pos, head, member); \
> pos = list_prev_entry(pos, member))
>
> -/**
> - * list_for_each_entry_safe - iterate over list of given type safe against removal of list entry
> - * @pos: the type * to use as a loop cursor.
> - * @n: another type * to use as temporary storage
> - * @head: the head for your list.
> - * @member: the name of the list_head within the struct.
> +/*
> + * list_for_each_entry_safe is an old interface, use list_for_each_entry_mutable instead.
> */
> #define list_for_each_entry_safe(pos, n, head, member) \
> for (pos = list_first_entry(head, typeof(*pos), member), \
> @@ -908,15 +949,36 @@ static inline size_t list_count_nodes(struct list_head *head)
> !list_entry_is_head(pos, head, member); \
> pos = n, n = list_next_entry(n, member))
>
> +#define __list_for_each_entry_mutable_internal(pos, tmp, head, member) \
> + for (typeof(pos) tmp = list_next_entry(pos = \
> + list_first_entry(head, typeof(*pos), member), member); \
> + !list_entry_is_head(pos, head, member); \
> + pos = tmp, tmp = list_next_entry(tmp, member))
> +
> +#define __list_for_each_entry_mutable2(pos, head, member) \
> + __list_for_each_entry_mutable_internal(pos, __UNIQUE_ID(next), head, member)
> +
> +#define __list_for_each_entry_mutable3(pos, next, head, member) \
> + list_for_each_entry_safe(pos, next, head, member)
> +
> /**
> - * list_for_each_entry_safe_continue - continue list iteration safe against removal
> + * list_for_each_entry_mutable - iterate over a list safe against entry removal
> * @pos: the type * to use as a loop cursor.
> - * @n: another type * to use as temporary storage
> - * @head: the head for your list.
> - * @member: the name of the list_head within the struct.
> + * @...: either (head, member) or (next, head, member)
> *
> - * Iterate over list of given type, continuing after current point,
> - * safe against removal of list entry.
> + * next: another type * to use as optional temporary storage. The
> + * temporary cursor is internal unless explicitly supplied by the
> + * caller.
> + * head: the head for your list.
> + * member: the name of the list_head within the struct.
> + */
> +#define list_for_each_entry_mutable(pos, ...) \
> + CONCATENATE(__list_for_each_entry_mutable, COUNT_ARGS(__VA_ARGS__)) \
> + (pos, __VA_ARGS__)
> +
> +/*
> + * list_for_each_entry_safe_continue is an old interface,
> + * use list_for_each_entry_mutable_continue instead.
> */
> #define list_for_each_entry_safe_continue(pos, n, head, member) \
> for (pos = list_next_entry(pos, member), \
> @@ -924,30 +986,79 @@ static inline size_t list_count_nodes(struct list_head *head)
> !list_entry_is_head(pos, head, member); \
> pos = n, n = list_next_entry(n, member))
>
> +#define __list_for_each_entry_mutable_continue_internal(pos, tmp, head, member) \
> + for (typeof(pos) tmp = list_next_entry(pos = \
> + list_next_entry(pos, member), member); \
> + !list_entry_is_head(pos, head, member); \
> + pos = tmp, tmp = list_next_entry(tmp, member))
> +
> +#define __list_for_each_entry_mutable_continue2(pos, head, member) \
> + __list_for_each_entry_mutable_continue_internal(pos, \
> + __UNIQUE_ID(next), head, member)
> +
> +#define __list_for_each_entry_mutable_continue3(pos, next, head, member) \
> + list_for_each_entry_safe_continue(pos, next, head, member)
> +
> /**
> - * list_for_each_entry_safe_from - iterate over list from current point safe against removal
> + * list_for_each_entry_mutable_continue - continue list iteration safe against removal
> * @pos: the type * to use as a loop cursor.
> - * @n: another type * to use as temporary storage
> - * @head: the head for your list.
> - * @member: the name of the list_head within the struct.
> + * @...: either (head, member) or (next, head, member)
> *
> - * Iterate over list of given type from current point, safe against
> - * removal of list entry.
> + * next: another type * to use as optional temporary storage. The
> + * temporary cursor is internal unless explicitly supplied by the
> + * caller.
> + * head: the head for your list.
> + * member: the name of the list_head within the struct.
> + *
> + * Iterate over list of given type, continuing after current point,
> + * safe against removal of list entry.
> + */
> +#define list_for_each_entry_mutable_continue(pos, ...) \
> + CONCATENATE(__list_for_each_entry_mutable_continue, \
> + COUNT_ARGS(__VA_ARGS__))(pos, __VA_ARGS__)
> +
> +/*
> + * list_for_each_entry_safe_from is an old interface,
> + * use list_for_each_entry_mutable_from instead.
> */
> #define list_for_each_entry_safe_from(pos, n, head, member) \
> for (n = list_next_entry(pos, member); \
> !list_entry_is_head(pos, head, member); \
> pos = n, n = list_next_entry(n, member))
>
> +#define __list_for_each_entry_mutable_from_internal(pos, tmp, head, member) \
> + for (typeof(pos) tmp = list_next_entry(pos, member); \
> + !list_entry_is_head(pos, head, member); \
> + pos = tmp, tmp = list_next_entry(tmp, member))
> +
> +#define __list_for_each_entry_mutable_from2(pos, head, member) \
> + __list_for_each_entry_mutable_from_internal(pos, \
> + __UNIQUE_ID(next), head, member)
> +
> +#define __list_for_each_entry_mutable_from3(pos, next, head, member) \
> + list_for_each_entry_safe_from(pos, next, head, member)
> +
> /**
> - * list_for_each_entry_safe_reverse - iterate backwards over list safe against removal
> + * list_for_each_entry_mutable_from - iterate over list from current point safe against removal
> * @pos: the type * to use as a loop cursor.
> - * @n: another type * to use as temporary storage
> - * @head: the head for your list.
> - * @member: the name of the list_head within the struct.
> + * @...: either (head, member) or (next, head, member)
> *
> - * Iterate backwards over list of given type, safe against removal
> - * of list entry.
> + * next: another type * to use as optional temporary storage. The
> + * temporary cursor is internal unless explicitly supplied by the
> + * caller.
> + * head: the head for your list.
> + * member: the name of the list_head within the struct.
> + *
> + * Iterate over list of given type from current point, safe against
> + * removal of list entry.
> + */
> +#define list_for_each_entry_mutable_from(pos, ...) \
> + CONCATENATE(__list_for_each_entry_mutable_from, \
> + COUNT_ARGS(__VA_ARGS__))(pos, __VA_ARGS__)
> +
> +/*
> + * list_for_each_entry_safe_reverse is an old interface,
> + * use list_for_each_entry_mutable_reverse instead.
> */
> #define list_for_each_entry_safe_reverse(pos, n, head, member) \
> for (pos = list_last_entry(head, typeof(*pos), member), \
> @@ -955,6 +1066,37 @@ static inline size_t list_count_nodes(struct list_head *head)
> !list_entry_is_head(pos, head, member); \
> pos = n, n = list_prev_entry(n, member))
>
> +#define __list_for_each_entry_mutable_reverse_internal(pos, tmp, head, member) \
> + for (typeof(pos) tmp = list_prev_entry(pos = \
> + list_last_entry(head, typeof(*pos), member), member); \
> + !list_entry_is_head(pos, head, member); \
> + pos = tmp, tmp = list_prev_entry(tmp, member))
> +
> +#define __list_for_each_entry_mutable_reverse2(pos, head, member) \
> + __list_for_each_entry_mutable_reverse_internal(pos, \
> + __UNIQUE_ID(prev), head, member)
> +
> +#define __list_for_each_entry_mutable_reverse3(pos, prev, head, member) \
> + list_for_each_entry_safe_reverse(pos, prev, head, member)
> +
> +/**
> + * list_for_each_entry_mutable_reverse - iterate backwards over list safe against removal
> + * @pos: the type * to use as a loop cursor.
> + * @...: either (head, member) or (prev, head, member)
> + *
> + * prev: another type * to use as optional temporary storage. The
> + * temporary cursor is internal unless explicitly supplied by the
> + * caller.
> + * head: the head for your list.
> + * member: the name of the list_head within the struct.
> + *
> + * Iterate backwards over list of given type, safe against removal
> + * of list entry.
> + */
> +#define list_for_each_entry_mutable_reverse(pos, ...) \
> + CONCATENATE(__list_for_each_entry_mutable_reverse, \
> + COUNT_ARGS(__VA_ARGS__))(pos, __VA_ARGS__)
> +
> /**
> * list_safe_reset_next - reset a stale list_for_each_entry_safe loop
> * @pos: the loop cursor used in the list_for_each_entry_safe loop
> @@ -1189,6 +1331,31 @@ static inline void hlist_splice_init(struct hlist_head *from,
> for (pos = (head)->first; pos && ({ n = pos->next; 1; }); \
> pos = n)
>
> +#define __hlist_for_each_mutable_internal(pos, tmp, head) \
> + for (typeof(pos) tmp = (pos = (head)->first) ? pos->next : NULL; \
> + pos; \
> + pos = tmp, tmp = pos ? pos->next : NULL)
> +
> +#define __hlist_for_each_mutable1(pos, head) \
> + __hlist_for_each_mutable_internal(pos, __UNIQUE_ID(next), head)
> +
> +#define __hlist_for_each_mutable2(pos, next, head) \
> + hlist_for_each_safe(pos, next, head)
> +
> +/**
> + * hlist_for_each_mutable - iterate over a hlist safe against entry removal
> + * @pos: the &struct hlist_node to use as a loop cursor.
> + * @...: either (head) or (next, head)
> + *
> + * next: another &struct hlist_node to use as optional temporary storage.
> + * The temporary cursor is internal unless explicitly supplied by
> + * the caller.
> + * head: the head for your hlist.
> + */
> +#define hlist_for_each_mutable(pos, ...) \
> + CONCATENATE(__hlist_for_each_mutable, COUNT_ARGS(__VA_ARGS__)) \
> + (pos, __VA_ARGS__)
> +
> #define hlist_entry_safe(ptr, type, member) \
> ({ typeof(ptr) ____ptr = (ptr); \
> ____ptr ? hlist_entry(____ptr, type, member) : NULL; \
> @@ -1224,18 +1391,44 @@ static inline void hlist_splice_init(struct hlist_head *from,
> for (; pos; \
> pos = hlist_entry_safe((pos)->member.next, typeof(*(pos)), member))
>
> -/**
> - * hlist_for_each_entry_safe - iterate over list of given type safe against removal of list entry
> - * @pos: the type * to use as a loop cursor.
> - * @n: a &struct hlist_node to use as temporary storage
> - * @head: the head for your list.
> - * @member: the name of the hlist_node within the struct.
> +/*
> + * hlist_for_each_entry_safe is an old interface, use hlist_for_each_entry_mutable instead.
> */
> #define hlist_for_each_entry_safe(pos, n, head, member) \
> for (pos = hlist_entry_safe((head)->first, typeof(*pos), member);\
> pos && ({ n = pos->member.next; 1; }); \
> pos = hlist_entry_safe(n, typeof(*pos), member))
>
> +#define __hlist_for_each_entry_mutable_internal(pos, tmp, head, member) \
> + for (struct hlist_node *tmp = (pos = \
> + hlist_entry_safe((head)->first, typeof(*pos), member)) ? \
> + pos->member.next : NULL; \
> + pos; \
> + pos = hlist_entry_safe((tmp), typeof(*pos), member), \
> + tmp = pos ? pos->member.next : NULL)
> +
> +#define __hlist_for_each_entry_mutable2(pos, head, member) \
> + __hlist_for_each_entry_mutable_internal(pos, \
> + __UNIQUE_ID(next), head, member)
> +
> +#define __hlist_for_each_entry_mutable3(pos, next, head, member) \
> + hlist_for_each_entry_safe(pos, next, head, member)
> +
> +/**
> + * hlist_for_each_entry_mutable - iterate over hlist safe against entry removal
> + * @pos: the type * to use as a loop cursor.
> + * @...: either (head, member) or (next, head, member)
> + *
> + * next: a &struct hlist_node to use as optional temporary storage. The
> + * temporary cursor is internal unless explicitly supplied by the
> + * caller.
> + * head: the head for your hlist.
> + * member: the name of the hlist_node within the struct.
> + */
> +#define hlist_for_each_entry_mutable(pos, ...) \
> + CONCATENATE(__hlist_for_each_entry_mutable, \
> + COUNT_ARGS(__VA_ARGS__))(pos, __VA_ARGS__)
> +
> /**
> * hlist_count_nodes - count nodes in the hlist
> * @head: the head for your hlist.
^ permalink raw reply
* Re: [PATCH 0/2] tracing: Move trace_printk.h out of kernel.h
From: Steven Rostedt @ 2026-06-22 8:53 UTC (permalink / raw)
To: Peter Zijlstra
Cc: linux-kernel, linux-trace-kernel, Masami Hiramatsu, Mark Rutland,
Mathieu Desnoyers, Andrew Morton, Linus Torvalds,
Sebastian Andrzej Siewior, John Ogness, Thomas Gleixner,
Julia Lawall, Yury Norov, linux-doc, linux-kbuild, linuxppc-dev,
dri-devel, linux-stm32, linux-arm-kernel, linux-rdma, linux-usb,
linux-ext4, linux-nfs, kvm, intel-gfx
In-Reply-To: <20260622083440.GX49951@noisy.programming.kicks-ass.net>
On Mon, 22 Jun 2026 10:34:40 +0200
Peter Zijlstra <peterz@infradead.org> wrote:
> Did you forget your C 101 class? If you use a function, you gotta
> include the relevant header.
If this was the way it was back in 2009, yeah sure. But the header
wasn't need for 17 years. Now it suddenly will be.
-- Steve
^ permalink raw reply
* Re: [PATCH 0/2] tracing: Move trace_printk.h out of kernel.h
From: Peter Zijlstra @ 2026-06-22 8:34 UTC (permalink / raw)
To: Steven Rostedt
Cc: linux-kernel, linux-trace-kernel, Masami Hiramatsu, Mark Rutland,
Mathieu Desnoyers, Andrew Morton, Linus Torvalds,
Sebastian Andrzej Siewior, John Ogness, Thomas Gleixner,
Julia Lawall, Yury Norov, linux-doc, linux-kbuild, linuxppc-dev,
dri-devel, linux-stm32, linux-arm-kernel, linux-rdma, linux-usb,
linux-ext4, linux-nfs, kvm, intel-gfx
In-Reply-To: <20260621093430.264983361@kernel.org>
On Sun, Jun 21, 2026 at 05:34:30AM -0400, Steven Rostedt wrote:
> There's been complaints about trace_printk() being defined in kernel.h as it
> can increase the compilation time. As it is only used by some developers for
> debugging purposes, it should not be in kernel.h causing lots of wasted CPU
> cycles for those that do not ever care about it.
>
> Instead, add a CONFIG_TRACE_PRINTK_DEBUGGING option that developers that do
> use it can set and not have to always remember to add #include <linux/trace_printk.h>
> to the files they add trace_printk() while debugging. It also means that
> those that do not have that config set will not have to worry about wasted
> CPU cycles as it is only include in the CFLAGS when the option is set, and
> its completely ignored otherwise.
Did you forget your C 101 class? If you use a function, you gotta
include the relevant header.
You don't see userspace saying: 'Hey, you know what, perhaps we should
add stdio.h to every other header, just in case someone wants to
printf()' either.
I really don't understand your argument. Yes, maybe someone will forget
and then either their editor (if they have a halfway modern setup with
LSP enabled) or their build will complain, but so what? This is all
trivial stuff, surely we have more pressing matters to concern outselves
with?
^ permalink raw reply
* Re: [PATCH v8 01/46] KVM: guest_memfd: Introduce per-gmem attributes, use to guard user mappings
From: Binbin Wu @ 2026-06-22 9:08 UTC (permalink / raw)
To: ackerleytng
Cc: aik, andrew.jones, brauner, chao.p.peng, david, jmattson,
jthoughton, michael.roth, oupton, pankaj.gupta, qperret,
rick.p.edgecombe, rientjes, shivankg, steven.price, tabba, willy,
wyihan, yan.y.zhao, forkloop, pratyush, suzuki.poulose,
aneesh.kumar, liam, Paolo Bonzini, Sean Christopherson,
Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen, x86,
H. Peter Anvin, Steven Rostedt, Masami Hiramatsu,
Mathieu Desnoyers, Jonathan Corbet, Shuah Khan, Shuah Khan,
Vishal Annapurve, Andrew Morton, Chris Li, Kairui Song,
Kemeng Shi, Nhat Pham, Barry Song, Axel Rasmussen, Yuanchu Xie,
Wei Xu, Youngjun Park, Qi Zheng, Shakeel Butt, Kiryl Shutsemau,
Baoquan He, Jason Gunthorpe, Vlastimil Babka, kvm, linux-kernel,
linux-trace-kernel, linux-doc, linux-kselftest, linux-mm,
linux-coco
In-Reply-To: <20260618-gmem-inplace-conversion-v8-1-9d2959357853@google.com>
On 6/19/2026 8:31 AM, Ackerley Tng via B4 Relay wrote:
[...]
>
> +static u64 kvm_gmem_get_attributes(struct inode *inode, pgoff_t index)
> +{
> + struct maple_tree *mt = &GMEM_I(inode)->attributes;
> + void *entry = mtree_load(mt, index);
> +
> + return WARN_ON_ONCE(!entry) ? 0 : xa_to_value(entry);
If the entry is unexpectedly missing, returning 0 means the attribute would be treated as shared.
And then in kvm_gmem_fault_user_mapping(), it would allow the userspace to fault in the folio.
Should gmem deny such edge case?
> +}
> +
> +static bool kvm_gmem_is_private_mem(struct inode *inode, pgoff_t index)
> +{
> + return kvm_gmem_get_attributes(inode, index) & KVM_MEMORY_ATTRIBUTE_PRIVATE;
> +}
> +
> +static bool kvm_gmem_is_shared_mem(struct inode *inode, pgoff_t index)
> +{
> + return !kvm_gmem_is_private_mem(inode, index);
> +}
> +
> static int __kvm_gmem_prepare_folio(struct kvm *kvm, struct kvm_memory_slot *slot,
> pgoff_t index, struct folio *folio)
> {
> @@ -397,10 +423,13 @@ static vm_fault_t kvm_gmem_fault_user_mapping(struct vm_fault *vmf)
> if (((loff_t)vmf->pgoff << PAGE_SHIFT) >= i_size_read(inode))
> return VM_FAULT_SIGBUS;
>
> - if (!(GMEM_I(inode)->flags & GUEST_MEMFD_FLAG_INIT_SHARED))
> - return VM_FAULT_SIGBUS;
> + filemap_invalidate_lock_shared(inode->i_mapping);
> + if (kvm_gmem_is_shared_mem(inode, vmf->pgoff))
> + folio = kvm_gmem_get_folio(inode, vmf->pgoff);
> + else
> + folio = ERR_PTR(-EACCES);
> + filemap_invalidate_unlock_shared(inode->i_mapping);
>
> - folio = kvm_gmem_get_folio(inode, vmf->pgoff);
> if (IS_ERR(folio)) {
> if (PTR_ERR(folio) == -EAGAIN)
> return VM_FAULT_RETRY;
> @@ -557,6 +586,51 @@ bool __weak kvm_arch_supports_gmem_init_shared(struct kvm *kvm)
> return true;
> }
>
^ permalink raw reply
* Re: [PATCH v3 9/9] selftests/verification: add tlob selftests
From: Gabriele Monaco @ 2026-06-22 9:26 UTC (permalink / raw)
To: wen.yang; +Cc: Steven Rostedt, linux-trace-kernel, linux-kernel
In-Reply-To: <4aeb668c8446a9f6366d92e218df386bef7bc965.1780847473.git.wen.yang@linux.dev>
On Mon, 2026-06-08 at 00:13 +0800, wen.yang@linux.dev wrote:
> From: Wen Yang <wen.yang@linux.dev>
>
> +grep -qE "^p ${UPROBE_TARGET}:0x[0-9a-f]+ 0x[0-9a-f]+ threshold=[0-
> 9]+$" "$TLOB_MONITOR"
> +grep -q "threshold=5000000000" "$TLOB_MONITOR"
> +
> +! echo "p ${UPROBE_TARGET}:${busy_offset} ${stop_offset}
> threshold=9999000" > "$TLOB_MONITOR" 2>/dev/null
> +
> +echo "-${UPROBE_TARGET}:${busy_offset}" > "$TLOB_MONITOR"
> +! grep -q "^p .*:0x${busy_offset#0x} " "$TLOB_MONITOR"
...
> +! grep -q "error_env_tlob" /sys/kernel/tracing/trace
There is a widespread misconception under selftests that ! cmd with set -e
fails if the command succeeds, so you can use it to expect a program failure.
That isn't the case though [1], errexit (what set -e does), skips commands starting
with ! where the result isn't checked.
Essentially if you want to say exit if the command succeeds, you can do:
cmd && exit 1 # explicit
! cmd || exit 1 # explicit
or still exploiting errexit
cmd && false
! cmd || false
I'm going to fix it in existing selftests using the last variant, but keep
this in mind in your selftests as well. (Variants with ! are preferred because
they also return 0 if cmd fails, as you'd expect, I personally prefer to use
false instead of explicit exit, but that's up to you).
Thanks,
Gabriele
[1] - https://www.shellcheck.net/wiki/SC2251
> +echo 0 > monitors/tlob/enable
> +echo 0 > /sys/kernel/tracing/events/rv/error_env_tlob/enable
> +echo > /sys/kernel/tracing/trace
> diff --git
> a/tools/testing/selftests/verification/test.d/tlob/uprobe_violation.t
> c
> b/tools/testing/selftests/verification/test.d/tlob/uprobe_violation.t
> c
> new file mode 100644
> index 000000000000..d210d9c3a92d
> --- /dev/null
> +++
> b/tools/testing/selftests/verification/test.d/tlob/uprobe_violation.t
> c
> @@ -0,0 +1,67 @@
> +#!/bin/sh
> +# SPDX-License-Identifier: GPL-2.0-or-later
> +# description: Test tlob monitor budget violation (error_env_tlob
> and detail_env_tlob fire with correct fields)
> +# requires: tlob:monitor
> +
> +RV_BINDIR="${RV_BINDIR:-$(realpath "$(dirname "${1:-$0}")")}"
> +UPROBE_TARGET="${RV_BINDIR}/tlob_target"
> +TLOB_SYM="${RV_BINDIR}/tlob_sym"
> +[ -x "$UPROBE_TARGET" ] || exit_unsupported
> +[ -x "$TLOB_SYM" ] || exit_unsupported
> +TLOB_MONITOR=monitors/tlob/monitor
> +
> +busy_offset=$("$TLOB_SYM" sym_offset "$UPROBE_TARGET" tlob_busy_work
> 2>/dev/null)
> +stop_offset=$("$TLOB_SYM" sym_offset "$UPROBE_TARGET"
> tlob_busy_work_done 2>/dev/null)
> +[ -n "$busy_offset" ] || exit_unsupported
> +[ -n "$stop_offset" ] || exit_unsupported
> +
> +"$UPROBE_TARGET" 30000 &
> +busy_pid=$!
> +sleep 0.05
> +
> +echo 1 > /sys/kernel/tracing/events/rv/error_env_tlob/enable
> +echo 1 > /sys/kernel/tracing/events/rv/detail_env_tlob/enable
> +echo 1 > /sys/kernel/tracing/tracing_on
> +echo 1 > monitors/tlob/enable
> +echo > /sys/kernel/tracing/trace
> +
> +# 10 µs budget - fires almost immediately; task is busy-spinning on-
> CPU.
> +echo "p ${UPROBE_TARGET}:${busy_offset} ${stop_offset}
> threshold=10000" > "$TLOB_MONITOR"
> +
> +# wait up to 2 s for detail_env_tlob
> +found=0; i=0
> +while [ "$i" -lt 20 ]; do
> + sleep 0.1
> + grep -q "detail_env_tlob" /sys/kernel/tracing/trace && {
> found=1; break; }
> + i=$((i+1))
> +done
> +
> +echo "-${UPROBE_TARGET}:${busy_offset}" > "$TLOB_MONITOR"
> 2>/dev/null
> +kill "$busy_pid" 2>/dev/null || true; wait "$busy_pid" 2>/dev/null
> || true
> +echo 0 > /sys/kernel/tracing/events/rv/error_env_tlob/enable
> +echo 0 > /sys/kernel/tracing/events/rv/detail_env_tlob/enable
> +echo 0 > monitors/tlob/enable
> +
> +[ "$found" = "1" ]
> +
> +# error_env_tlob must carry the clk_elapsed environment field.
> +# The event label is "budget_exceeded" when detected by the hrtimer
> callback,
> +# or the triggering sched event name when detected by the constraint
> path on a
> +# preemption that races with the timer (common on PREEMPT_RT / VM).
> Both are
> +# valid detections; check the env field instead of the label.
> +grep "error_env_tlob" /sys/kernel/tracing/trace | head -n 1 | grep -
> q "clk_elapsed="
> +
> +# detail_env_tlob must have all five fields with the correct
> threshold
> +line=$(grep "detail_env_tlob" /sys/kernel/tracing/trace | head -n 1)
> +echo "$line" | grep -q "pid="
> +echo "$line" | grep -q "threshold_ns=10000"
> +echo "$line" | grep -q "running_ns="
> +echo "$line" | grep -q "waiting_ns="
> +echo "$line" | grep -q "sleeping_ns="
> +
> +# Busy-spin keeps the task on-CPU: running_ns must exceed
> sleeping_ns.
> +running=$(echo "$line" | sed 's/.*running_ns=\([0-9]*\).*/\1/')
> +sleeping=$(echo "$line" | sed 's/.*sleeping_ns=\([0-9]*\).*/\1/')
> +[ "$running" -gt "$sleeping" ]
> +
> +echo > /sys/kernel/tracing/trace
^ permalink raw reply
* [PATCH v2] tracing: Use seq_buf for string concatenation
From: Woradorn Laodhanadhaworn @ 2026-06-22 9:46 UTC (permalink / raw)
To: rostedt
Cc: mhiramat, mathieu.desnoyers, linux-kernel, linux-trace-kernel,
linux-hardening, linux-kernel-mentees, shuah, skhan, me,
jkoolstra, woradorn.laon
In preparation for removing the strlcat API[1],
replace the string concatenation logic with a struct seq_buf,
which tracks the current position and the remaining space internally.
Use seq_buf_str() to NUL-terminate before passing to early_enable_events().
Link: https://github.com/KSPP/linux/issues/370 [1]
Signed-off-by: Woradorn Laodhanadhaworn <woradorn.laon@gmail.com>
---
v1 -> v2: Fixed WARN_ON when booting with empty trace_event.
v1: https://lore.kernel.org/all/20260620175441.223342-1-woradorn.laon@gmail.com
kernel/trace/trace_events.c | 19 +++++++++++++------
1 file changed, 13 insertions(+), 6 deletions(-)
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index c46e623e7e0d..1be62a46e49a 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -22,6 +22,7 @@
#include <linux/sort.h>
#include <linux/slab.h>
#include <linux/delay.h>
+#include <linux/seq_buf.h>
#include <trace/events/sched.h>
#include <trace/syscall.h>
@@ -4500,14 +4501,20 @@ static void __add_event_to_tracers(struct trace_event_call *call)
extern struct trace_event_call *__start_ftrace_events[];
extern struct trace_event_call *__stop_ftrace_events[];
-static char bootup_event_buf[COMMAND_LINE_SIZE] __initdata;
+static struct seq_buf bootup_event_buf __initdata = {
+ .buffer = (char[COMMAND_LINE_SIZE]) {},
+ .size = COMMAND_LINE_SIZE,
+};
static __init int setup_trace_event(char *str)
{
- if (bootup_event_buf[0] != '\0')
- strlcat(bootup_event_buf, ",", COMMAND_LINE_SIZE);
+ if (seq_buf_used(&bootup_event_buf) > 0)
+ seq_buf_puts(&bootup_event_buf, ",");
+
+ seq_buf_puts(&bootup_event_buf, str);
- strlcat(bootup_event_buf, str, COMMAND_LINE_SIZE);
+ if (seq_buf_has_overflowed(&bootup_event_buf))
+ return -ENOMEM;
trace_set_ring_buffer_expanded(NULL);
disable_tracing_selftest("running event tracing");
@@ -4766,7 +4773,7 @@ static __init int event_trace_enable(void)
*/
__trace_early_add_events(tr);
- early_enable_events(tr, bootup_event_buf, false);
+ early_enable_events(tr, (char *)seq_buf_str(&bootup_event_buf), false);
trace_printk_start_comm();
@@ -4794,7 +4801,7 @@ static __init int event_trace_enable_again(void)
if (!tr)
return -ENODEV;
- early_enable_events(tr, bootup_event_buf, true);
+ early_enable_events(tr, (char *)seq_buf_str(&bootup_event_buf), true);
return 0;
}
--
2.43.0
^ permalink raw reply related
* Re: [RFC PATCH 1/3] mm/compaction: skip isolate mlocked folios when compact_unevictable_allowed=0
From: Vlastimil Babka (SUSE) @ 2026-06-22 9:55 UTC (permalink / raw)
To: Wandun, linux-mm, linux-kernel, linux-trace-kernel,
linux-rt-devel
Cc: akpm, surenb, mhocko, jackmanb, hannes, ziy, rostedt, mhiramat,
mathieu.desnoyers, david, ljs, liam, rppt, bigeasy, clrkwllms,
Alexander.Krabler, Hugh Dickins
In-Reply-To: <040788a9-e0d5-478e-bb48-3d22b8b41020@gmail.com>
On 6/18/26 13:43, Wandun wrote:
>
>
> On 6/18/26 02:52, Vlastimil Babka (SUSE) wrote:
>> On 6/4/26 04:38, Wandun Chen wrote:
>>> From: Wandun Chen <chenwandun@lixiang.com>
>>>
>>> compact_unevictable_allowed is default 0 under PREEMPT_RT,
>>> isolate_migratepages_block() skips folios with PG_unevictable set.
>>> However, mlock_folio() sets PG_mlocked immediately but defers
>>> PG_unevictable to mlock_folio_batch(), result in a folio with
>>> PG_mlocked=1 but PG_unevictable=0. Compaction will isolate such a
>>> folio.
>>>
>>> Fix by checking folio_test_mlocked() together with the existing
>>> folio_test_unevictable() check.
>>>
>>> A similar issue has been reported by Alexander Krabler on a 6.12-rt
>>> aarch64 system. Vlastimil suggested to check the mlocked flag [1].
>>>
>>> Reported-by: Alexander Krabler <Alexander.Krabler@kuka.com>
>>> Closes: https://lore.kernel.org/all/DU0PR01MB10385345F7153F334100981888259A@DU0PR01MB10385.eurprd01.prod.exchangelabs.com/
>>> Suggested-by: Vlastimil Babka <vbabka@suse.cz>
>>> Signed-off-by: Wandun Chen <chenwandun@lixiang.com>
>>> Link: https://lore.kernel.org/all/33275585-f2db-4779-89f0-3ae24b455a67@suse.cz/ [1]
>>
>> Well in that thread, Hugh doubted my suggestion and then it seems we didn't
>> concluded anything. Did you actually in practice observe the issue that
>> Alexander had, and that this patch fixed it, or is that theoretical?
>>
> Yes, I wrote a test case that can reproduce it in a few second.
>
> The test case contains 3 steps:
> 1. mlockall
> 2. mmap file(2GB) + trigger file write page fault;
> 3. during step 1, trigger compact via /proc/sys/vm/compact_memory
>
>
> My reproduction environment is qemu with 4GB ram, 8 core, aarch64,
> preempt_rt and includes the tracepoint in patch 02.
> After running the reproduction program for a few seconds, the
> following output appears.
Ah, nice.
> repro-403 [004] ....1 101.270505: mm_compaction_isolate_folio: pfn=0x71e3a mode=0x0 flags=referenced|uptodate|mlocked
> repro-403 [004] ....1 101.270507: mm_compaction_isolate_folio: pfn=0x71e3b mode=0x0 flags=referenced|uptodate|mlocked
> repro-403 [004] ....1 101.270513: mm_compaction_isolate_folio: pfn=0x71e3c mode=0x0 flags=referenced|uptodate|mlocked
> repro-403 [004] ....1 101.270515: mm_compaction_isolate_folio: pfn=0x71e3d mode=0x0 flags=uptodate|mlocked
> repro-403 [004] ....1 101.270517: mm_compaction_isolate_folio: pfn=0x71e3e mode=0x0 flags=uptodate|mlocked
> repro-403 [004] ....1 101.270520: mm_compaction_isolate_folio: pfn=0x71e3f mode=0x0 flags=uptodate|mlocked
>
>
> Unfortunately, I recently found that there is still a bug in the
> fix patch. Setting mlocked in the mlock_folio function could happen
> even after the page is successfully isolated, so it still cannot
> prevent migration. Because of this, I need to think more about how
> to fix it.
>
> Perhaps we should double-check whether the page is mlocked during
> the actual migration phase.
So IIUC the isolation+migration might be started between the folio is
allocated, and mlocked? In that case the check during migration could still
be racy, and if the page is isolated, it's already bad for the RT process.
So this would only be a short-term problem after the mlockall, but we don't
have a way for the RT process to know the moment it's all settled, right?
Probably the proper solution would be for mlock[all]() itself to wait for an
isolated page, and only continue once it knows it can't be isolated anymore.
This might howver would go against some of the folio batching optimizations?
> What do you think of this best-effort approach?
>
>
> Best regards,
> Wandun
>
>
>
>
>
> The full reproducer is as below:
>
> /* gcc repro.c -o repro -lpthread */
>
> #define _GNU_SOURCE
> #include <fcntl.h>
> #include <pthread.h>
> #include <stdio.h>
> #include <stdlib.h>
> #include <sys/mman.h>
> #include <unistd.h>
>
> #define PAGE_SIZE 4096
> #define NR_PAGES 32
> #define FILE_SIZE (2ULL * 1024 * 1024 * 1024)
>
> static void *worker_fn(void *arg)
> {
> int fd = (long)arg;
> size_t len = (size_t)FILE_SIZE;
> char *p = mmap(NULL, len, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
> if (p == MAP_FAILED)
> return NULL;
>
> for (size_t off = 0; off + NR_PAGES * PAGE_SIZE <= len;
> off += NR_PAGES * PAGE_SIZE) {
> for (int i = 0; i < NR_PAGES; i++)
> p[off + i * PAGE_SIZE] = 1;
> usleep(200);
> }
>
> munmap(p, len);
> return NULL;
> }
>
> static void *compact_fn(void *arg)
> {
> (void)arg;
> int fd = open("/proc/sys/vm/compact_memory", O_WRONLY);
> if (fd < 0)
> return NULL;
>
> while (1) {
> if (write(fd, "1", 1) < 0) {}
> usleep(5000);
> }
> }
>
> int main(void)
> {
> mlockall(MCL_CURRENT | MCL_FUTURE);
>
> int fd = open("./repro_largefile.dat", O_RDWR | O_CREAT, 0600);
> if (fd < 0)
> return 1;
> unlink("./repro_largefile.dat");
> if (ftruncate(fd, (off_t)FILE_SIZE) < 0)
> return 1;
>
> printf("repro_largefile: 1 worker, %d pages/batch, Ctrl-C to stop\n",
> NR_PAGES);
>
> pthread_t compact, worker;
> pthread_create(&compact, NULL, compact_fn, NULL);
> pthread_create(&worker, NULL, worker_fn, (void *)(long)fd);
>
> pthread_join(worker, NULL);
> return 0;
> }
>
>>> ---
>>> mm/compaction.c | 3 ++-
>>> 1 file changed, 2 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/mm/compaction.c b/mm/compaction.c
>>> index b776f35ad020..7e07b792bcb5 100644
>>> --- a/mm/compaction.c
>>> +++ b/mm/compaction.c
>>> @@ -1116,7 +1116,8 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn,
>>> is_unevictable = folio_test_unevictable(folio);
>>>
>>> /* Compaction might skip unevictable pages but CMA takes them */
>>> - if (!(mode & ISOLATE_UNEVICTABLE) && is_unevictable)
>>> + if (!(mode & ISOLATE_UNEVICTABLE) &&
>>> + (is_unevictable || folio_test_mlocked(folio)))
>>> goto isolate_fail_put;
>>>
>>> /*
>>
>
^ permalink raw reply
* Re: [PATCH v3 0/7] Prepare mutable list iterators to cache cursor state
From: Andy Shevchenko @ 2026-06-22 10:46 UTC (permalink / raw)
To: Kaitao Cheng
Cc: Alexei Starovoitov, Andrew Morton, David Hildenbrand, Jens Axboe,
Tejun Heo, Alexander Viro, Christian Brauner, Alexei Starovoitov,
Daniel Borkmann, Andrii Nakryiko, Johannes Weiner, Peter Zijlstra,
Ingo Molnar, Arnaldo Carvalho de Melo, Namhyung Kim,
Thomas Gleixner, Juri Lelli, Vincent Guittot, Paul Moore,
Paul E. McKenney, Shakeel Butt, Christian König,
David Howells, Simona Vetter, Randy Dunlap, Luca Ceresoli,
Philipp Stanner, linux-block, LKML,
open list:CONTROL GROUP (CGROUP), linux-ntfs-dev, Linux-Fsdevel,
io-uring, audit, bpf, Network Development, dri-devel,
linux-perf-use., linux-trace-kernel, kexec, live-patching,
linux-modules, Linux Crypto Mailing List, Linux Power Management,
rcu, sched-ext, linux-mm, virtualization, damon,
clang-built-linux, chengkaitao, Muchun Song
In-Reply-To: <8c8f1849-86d3-4c69-be27-30bbdffdf616@linux.dev>
On Mon, Jun 22, 2026 at 02:15:01PM +0800, Kaitao Cheng wrote:
> 在 2026/6/22 13:28, Alexei Starovoitov 写道:
> > On Sun, Jun 21, 2026 at 9:06 PM Kaitao Cheng <kaitao.cheng@linux.dev> wrote:
...
> >> block/bfq-iosched.c | 17 +-
> >> block/blk-cgroup.c | 12 +-
> >> block/blk-flush.c | 4 +-
> >> block/blk-iocost.c | 18 +-
> >> block/blk-mq.c | 8 +-
> >> block/blk-throttle.c | 4 +-
> >> block/kyber-iosched.c | 4 +-
> >> block/partitions/ldm.c | 8 +-
> >> block/sed-opal.c | 4 +-
> >> include/linux/list.h | 269 ++++++++++++++++++++++++----
> >> include/linux/llist.h | 81 +++++++--
> >> init/initramfs.c | 5 +-
> >> io_uring/cancel.c | 6 +-
> >> io_uring/poll.c | 3 +-
> >> io_uring/rw.c | 4 +-
> >> io_uring/timeout.c | 8 +-
> >> io_uring/uring_cmd.c | 3 +-
> >> kernel/audit_tree.c | 4 +-
> >> kernel/audit_watch.c | 16 +-
> >> kernel/auditfilter.c | 4 +-
> >> kernel/auditsc.c | 4 +-
> >> kernel/bpf/arena.c | 10 +-
> >> kernel/bpf/arraymap.c | 8 +-
> >> kernel/bpf/bpf_local_storage.c | 3 +-
> >> kernel/bpf/bpf_lru_list.c | 25 ++-
> >> kernel/bpf/btf.c | 18 +-
> >> kernel/bpf/cgroup.c | 7 +-
> >> kernel/bpf/cpumap.c | 4 +-
> >> kernel/bpf/devmap.c | 10 +-
> >> kernel/bpf/helpers.c | 8 +-
> >> kernel/bpf/local_storage.c | 4 +-
> >> kernel/bpf/memalloc.c | 16 +-
> >> kernel/bpf/offload.c | 8 +-
> >> kernel/bpf/states.c | 4 +-
> >> kernel/bpf/stream.c | 4 +-
> >> kernel/bpf/verifier.c | 6 +-
> >> kernel/cgroup/cgroup-v1.c | 4 +-
> >> kernel/cgroup/cgroup.c | 54 +++---
> >> kernel/cgroup/dmem.c | 12 +-
> >> kernel/cgroup/rdma.c | 8 +-
> >> kernel/events/core.c | 44 +++--
> >> kernel/events/uprobes.c | 12 +-
> >> kernel/exit.c | 8 +-
> >> kernel/fail_function.c | 4 +-
> >> kernel/gcov/clang.c | 4 +-
> >> kernel/irq_work.c | 4 +-
> >> kernel/kexec_core.c | 4 +-
> >> kernel/kprobes.c | 16 +-
> >> kernel/livepatch/core.c | 4 +-
> >> kernel/livepatch/core.h | 4 +-
> >> kernel/liveupdate/kho_block.c | 4 +-
> >> kernel/liveupdate/luo_flb.c | 4 +-
> >> kernel/locking/rwsem.c | 2 +-
> >> kernel/locking/test-ww_mutex.c | 2 +-
> >> kernel/module/main.c | 11 +-
> >> kernel/padata.c | 4 +-
> >> kernel/power/snapshot.c | 8 +-
> >> kernel/power/wakelock.c | 4 +-
> >> kernel/printk/printk.c | 11 +-
> >> kernel/ptrace.c | 4 +-
> >> kernel/rcu/rcutorture.c | 3 +-
> >> kernel/rcu/tasks.h | 9 +-
> >> kernel/rcu/tree.c | 6 +-
> >> kernel/resource.c | 4 +-
> >> kernel/sched/core.c | 4 +-
> >> kernel/sched/ext.c | 22 +--
> >> kernel/sched/fair.c | 28 +--
> >> kernel/sched/topology.c | 4 +-
> >> kernel/sched/wait.c | 4 +-
> >> kernel/seccomp.c | 4 +-
> >> kernel/signal.c | 11 +-
> >> kernel/smp.c | 4 +-
> >> kernel/taskstats.c | 8 +-
> >> kernel/time/clockevents.c | 6 +-
> >> kernel/time/clocksource.c | 4 +-
> >> kernel/time/posix-cpu-timers.c | 4 +-
> >> kernel/time/posix-timers.c | 3 +-
> >> kernel/torture.c | 3 +-
> >> kernel/trace/bpf_trace.c | 4 +-
> >> kernel/trace/ftrace.c | 49 +++--
> >> kernel/trace/ring_buffer.c | 25 ++-
> >> kernel/trace/trace.c | 12 +-
> >> kernel/trace/trace_dynevent.c | 6 +-
> >> kernel/trace/trace_dynevent.h | 5 +-
> >> kernel/trace/trace_events.c | 35 ++--
> >> kernel/trace/trace_events_filter.c | 4 +-
> >> kernel/trace/trace_events_hist.c | 8 +-
> >> kernel/trace/trace_events_trigger.c | 17 +-
> >> kernel/trace/trace_events_user.c | 16 +-
> >> kernel/trace/trace_stat.c | 4 +-
> >> kernel/user-return-notifier.c | 3 +-
> >> kernel/workqueue.c | 16 +-
> >> mm/backing-dev.c | 8 +-
> >> mm/balloon.c | 8 +-
> >> mm/cma.c | 4 +-
> >> mm/compaction.c | 4 +-
> >> mm/damon/core.c | 4 +-
> >> mm/damon/sysfs-schemes.c | 4 +-
> >> mm/dmapool.c | 4 +-
> >> mm/huge_memory.c | 8 +-
> >> mm/hugetlb.c | 56 +++---
> >> mm/hugetlb_vmemmap.c | 16 +-
> >> mm/khugepaged.c | 14 +-
> >> mm/kmemleak.c | 7 +-
> >> mm/ksm.c | 25 +--
> >> mm/list_lru.c | 4 +-
> >> mm/memcontrol-v1.c | 8 +-
> >> mm/memory-failure.c | 12 +-
> >> mm/memory-tiers.c | 4 +-
> >> mm/migrate.c | 23 ++-
> >> mm/mmu_notifier.c | 9 +-
> >> mm/page_alloc.c | 8 +-
> >> mm/page_reporting.c | 2 +-
> >> mm/percpu.c | 11 +-
> >> mm/pgtable-generic.c | 4 +-
> >> mm/rmap.c | 10 +-
> >> mm/shmem.c | 9 +-
> >> mm/slab_common.c | 14 +-
> >> mm/slub.c | 33 ++--
> >> mm/swapfile.c | 4 +-
> >> mm/userfaultfd.c | 12 +-
> >> mm/vmalloc.c | 24 +--
> >> mm/vmscan.c | 7 +-
> >> mm/zsmalloc.c | 4 +-
> >> 124 files changed, 875 insertions(+), 681 deletions(-)
> >
> > Not sure what you were thinking, but this diff stat
> > is not landable.
>
> [PATCH v3 1/7] and [PATCH v3 2/7] contain the main logic and can
> be merged directly. They are also compatible with the old API.
> [PATCH v3 3/7] through [PATCH v3 7/7] are just simple interface
> replacements and do not change any functional logic. They can be
> left unmerged for now; individual modules can pick them up later
> if needed.
>
> In v2, Andy Shevchenko mentioned: "If it's done by Linus himself
> during the day when he prepares -rc1, it's fine."
Yes, but you need to get his blessing first to go with this.
Have you communicated with him on this?
> Even so, the
> changes in this patch series are indeed quite large and touch
> almost every subsystem. I have only converted part of them for
> now, so I wanted to send this out first and see what people think.
That's why it's better to provide a script to convert (e.g., coccinelle)
instead of tons of patches.
--
With Best Regards,
Andy Shevchenko
^ permalink raw reply
* Re: [PATCH v3 0/7] Prepare mutable list iterators to cache cursor state
From: David Hildenbrand (Arm) @ 2026-06-22 11:27 UTC (permalink / raw)
To: Alexei Starovoitov, Kaitao Cheng
Cc: Andrew Morton, Jens Axboe, Tejun Heo, Alexander Viro,
Christian Brauner, Alexei Starovoitov, Daniel Borkmann,
Andrii Nakryiko, Johannes Weiner, Peter Zijlstra, Ingo Molnar,
Arnaldo Carvalho de Melo, Namhyung Kim, Thomas Gleixner,
Juri Lelli, Vincent Guittot, Paul Moore, Andy Shevchenko,
Paul E. McKenney, Shakeel Butt, Christian König,
David Howells, Simona Vetter, Randy Dunlap, Luca Ceresoli,
Philipp Stanner, linux-block, LKML,
open list:CONTROL GROUP (CGROUP), linux-ntfs-dev, Linux-Fsdevel,
io-uring, audit, bpf, Network Development, dri-devel,
linux-perf-use., linux-trace-kernel, kexec, live-patching,
linux-modules, Linux Crypto Mailing List, Linux Power Management,
rcu, sched-ext, linux-mm, virtualization, damon,
clang-built-linux, chengkaitao
In-Reply-To: <CAADnVQJmPWFT01b7DuLdtafv=8FyB84GYHNZ8zSTck+9Aw0JpA@mail.gmail.com>
On 6/22/26 07:28, Alexei Starovoitov wrote:
> On Sun, Jun 21, 2026 at 9:06 PM Kaitao Cheng <kaitao.cheng@linux.dev> wrote:
>>
>> From: chengkaitao <chengkaitao@kylinos.cn>
>>
>> The list_for_each*_safe() helpers are used when the loop body may remove
>> the current entry. Their current interface, however, forces every caller
>> to define a temporary cursor outside the macro and pass it in, even when
>> the caller never uses that cursor directly. For most call sites this
>> extra cursor is just boilerplate required by the macro implementation.
>>
>> This is awkward because the saved next pointer is an internal detail of
>> the iteration. Callers that only remove or move the current entry do not
>> need to spell it out.
>>
>> The _safe() suffix has also caused confusion. Christian Koenig pointed
>> out that the name is easy to read as a thread-safe variant, especially
>> for beginners, even though it only means that the iterator keeps enough
>> state to tolerate removal of the current entry. He suggested _mutable()
>> as a clearer description of what the loop permits.
>>
>> Add *_mutable() iterator variants for list, hlist and llist. The new
>> helpers are variadic and support both forms. In the common case, the
>> caller omits the temporary cursor and the macro creates a unique internal
>> cursor with typeof(pos) and __UNIQUE_ID(). If a loop really needs an
>> explicit temporary cursor, the caller can still pass it and the helper
>> keeps the existing *_safe() behaviour.
>>
>> For example, a call site may use the shorter form:
>>
>> list_for_each_entry_mutable(pos, head, member)
>>
>> or keep the explicit temporary cursor form:
>>
>> list_for_each_entry_mutable(pos, tmp, head, member)
>>
>> The existing *_safe() helpers remain available for compatibility. This
>> series only converts users in mm, block, kernel, init and io_uring. If
>> this approach looks acceptable, the remaining users can be converted in
>> follow-up series.
>>
>> Changes in v3 (Christian König, Andy Shevchenko):
>> - Convert safe list walks to mutable iterators
>>
>> Changes in v2 (Muchun Song, Andy Shevchenko):
>> - Drop the list_for_each_entry_mutable*() helpers from v1 and make the
>> cursor change directly in the existing list_for_each_entry*() helpers.
>> - Open-code special list walks that rely on updating the loop cursor in
>> the body, preserving their existing traversal semantics.
>>
>> Link to v2:
>> https://lore.kernel.org/all/20260609061347.93688-1-kaitao.cheng@linux.dev/
>>
>> Link to v1:
>> https://lore.kernel.org/all/20260529082149.76764-1-kaitao.cheng@linux.dev/
>>
>> Kaitao Cheng (7):
>> list: Add mutable iterator variants
>> llist: Add mutable iterator variants
>> mm: Use mutable list iterators
>> block: Use mutable list iterators
>> kernel: Use mutable list iterators
>> initramfs: Use mutable list iterator
>> io_uring: Use mutable list iterators
>>
>> block/bfq-iosched.c | 17 +-
>> block/blk-cgroup.c | 12 +-
>> block/blk-flush.c | 4 +-
>> block/blk-iocost.c | 18 +-
>> block/blk-mq.c | 8 +-
>> block/blk-throttle.c | 4 +-
>> block/kyber-iosched.c | 4 +-
>> block/partitions/ldm.c | 8 +-
>> block/sed-opal.c | 4 +-
>> include/linux/list.h | 269 ++++++++++++++++++++++++----
>> include/linux/llist.h | 81 +++++++--
>> init/initramfs.c | 5 +-
>> io_uring/cancel.c | 6 +-
>> io_uring/poll.c | 3 +-
>> io_uring/rw.c | 4 +-
>> io_uring/timeout.c | 8 +-
>> io_uring/uring_cmd.c | 3 +-
>> kernel/audit_tree.c | 4 +-
>> kernel/audit_watch.c | 16 +-
>> kernel/auditfilter.c | 4 +-
>> kernel/auditsc.c | 4 +-
>> kernel/bpf/arena.c | 10 +-
>> kernel/bpf/arraymap.c | 8 +-
>> kernel/bpf/bpf_local_storage.c | 3 +-
>> kernel/bpf/bpf_lru_list.c | 25 ++-
>> kernel/bpf/btf.c | 18 +-
>> kernel/bpf/cgroup.c | 7 +-
>> kernel/bpf/cpumap.c | 4 +-
>> kernel/bpf/devmap.c | 10 +-
>> kernel/bpf/helpers.c | 8 +-
>> kernel/bpf/local_storage.c | 4 +-
>> kernel/bpf/memalloc.c | 16 +-
>> kernel/bpf/offload.c | 8 +-
>> kernel/bpf/states.c | 4 +-
>> kernel/bpf/stream.c | 4 +-
>> kernel/bpf/verifier.c | 6 +-
>> kernel/cgroup/cgroup-v1.c | 4 +-
>> kernel/cgroup/cgroup.c | 54 +++---
>> kernel/cgroup/dmem.c | 12 +-
>> kernel/cgroup/rdma.c | 8 +-
>> kernel/events/core.c | 44 +++--
>> kernel/events/uprobes.c | 12 +-
>> kernel/exit.c | 8 +-
>> kernel/fail_function.c | 4 +-
>> kernel/gcov/clang.c | 4 +-
>> kernel/irq_work.c | 4 +-
>> kernel/kexec_core.c | 4 +-
>> kernel/kprobes.c | 16 +-
>> kernel/livepatch/core.c | 4 +-
>> kernel/livepatch/core.h | 4 +-
>> kernel/liveupdate/kho_block.c | 4 +-
>> kernel/liveupdate/luo_flb.c | 4 +-
>> kernel/locking/rwsem.c | 2 +-
>> kernel/locking/test-ww_mutex.c | 2 +-
>> kernel/module/main.c | 11 +-
>> kernel/padata.c | 4 +-
>> kernel/power/snapshot.c | 8 +-
>> kernel/power/wakelock.c | 4 +-
>> kernel/printk/printk.c | 11 +-
>> kernel/ptrace.c | 4 +-
>> kernel/rcu/rcutorture.c | 3 +-
>> kernel/rcu/tasks.h | 9 +-
>> kernel/rcu/tree.c | 6 +-
>> kernel/resource.c | 4 +-
>> kernel/sched/core.c | 4 +-
>> kernel/sched/ext.c | 22 +--
>> kernel/sched/fair.c | 28 +--
>> kernel/sched/topology.c | 4 +-
>> kernel/sched/wait.c | 4 +-
>> kernel/seccomp.c | 4 +-
>> kernel/signal.c | 11 +-
>> kernel/smp.c | 4 +-
>> kernel/taskstats.c | 8 +-
>> kernel/time/clockevents.c | 6 +-
>> kernel/time/clocksource.c | 4 +-
>> kernel/time/posix-cpu-timers.c | 4 +-
>> kernel/time/posix-timers.c | 3 +-
>> kernel/torture.c | 3 +-
>> kernel/trace/bpf_trace.c | 4 +-
>> kernel/trace/ftrace.c | 49 +++--
>> kernel/trace/ring_buffer.c | 25 ++-
>> kernel/trace/trace.c | 12 +-
>> kernel/trace/trace_dynevent.c | 6 +-
>> kernel/trace/trace_dynevent.h | 5 +-
>> kernel/trace/trace_events.c | 35 ++--
>> kernel/trace/trace_events_filter.c | 4 +-
>> kernel/trace/trace_events_hist.c | 8 +-
>> kernel/trace/trace_events_trigger.c | 17 +-
>> kernel/trace/trace_events_user.c | 16 +-
>> kernel/trace/trace_stat.c | 4 +-
>> kernel/user-return-notifier.c | 3 +-
>> kernel/workqueue.c | 16 +-
>> mm/backing-dev.c | 8 +-
>> mm/balloon.c | 8 +-
>> mm/cma.c | 4 +-
>> mm/compaction.c | 4 +-
>> mm/damon/core.c | 4 +-
>> mm/damon/sysfs-schemes.c | 4 +-
>> mm/dmapool.c | 4 +-
>> mm/huge_memory.c | 8 +-
>> mm/hugetlb.c | 56 +++---
>> mm/hugetlb_vmemmap.c | 16 +-
>> mm/khugepaged.c | 14 +-
>> mm/kmemleak.c | 7 +-
>> mm/ksm.c | 25 +--
>> mm/list_lru.c | 4 +-
>> mm/memcontrol-v1.c | 8 +-
>> mm/memory-failure.c | 12 +-
>> mm/memory-tiers.c | 4 +-
>> mm/migrate.c | 23 ++-
>> mm/mmu_notifier.c | 9 +-
>> mm/page_alloc.c | 8 +-
>> mm/page_reporting.c | 2 +-
>> mm/percpu.c | 11 +-
>> mm/pgtable-generic.c | 4 +-
>> mm/rmap.c | 10 +-
>> mm/shmem.c | 9 +-
>> mm/slab_common.c | 14 +-
>> mm/slub.c | 33 ++--
>> mm/swapfile.c | 4 +-
>> mm/userfaultfd.c | 12 +-
>> mm/vmalloc.c | 24 +--
>> mm/vmscan.c | 7 +-
>> mm/zsmalloc.c | 4 +-
>> 124 files changed, 875 insertions(+), 681 deletions(-)
>
> Not sure what you were thinking, but this diff stat
> is not landable.
Agreed. If we decide we want this, I guess we should target per-subsystem
conversions.
If this goes through the MM tree, I would even appreciate doing this on a per-MM
component granularity.
(unless we have some magic "Linus converts all of them" script, which I doubt we
will have)
Is there a way forward to replace list_for_each_*_safe entirely, possibly just
reusing the old name but simply the parameter?
--
Cheers,
David
^ permalink raw reply
* Re: [PATCH v4 6/7] Documentation: bootconfig: document build-time cmdline rendering
From: Breno Leitao @ 2026-06-22 12:30 UTC (permalink / raw)
To: Masami Hiramatsu
Cc: Andrew Morton, Nathan Chancellor, paulmck, Nicolas Schier,
Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen, x86,
H. Peter Anvin, linux-kernel, linux-trace-kernel, linux-kbuild,
bpf, kernel-team
In-Reply-To: <20260618094719.17bf5448351adc2e56c267fb@kernel.org>
On Thu, Jun 18, 2026 at 09:47:19AM +0900, Masami Hiramatsu wrote:
> On Wed, 17 Jun 2026 02:56:23 -0700
> Breno Leitao <leitao@debian.org> wrote:
>
> > On Wed, Jun 10, 2026 at 07:58:10AM -0700, Breno Leitao wrote:
> > > On Wed, Jun 10, 2026 at 11:37:20PM +0900, Masami Hiramatsu wrote:
> > > > To avoid confusion, when this option is used, shouldn't we treat it
> > > > the same way as if embedded command lines were enabled, and either
> > > > not display it in /proc/bootconfig (or always display it, by merging
> > > > the rendered string)?
> > >
> > > You're right that EMBED_CMDLINE breaks it: the embedded kernel.* keys
> > > are already in boot_command_line before setup_boot_config() ever sees
> > > the initrd bconf, so a user reading /proc/bootconfig would see only
> > > the initrd keys while parse_early_param() acted on the embedded ones.
> > > That's exactly the split-state Sashiko was circling around.
> > >
> > > Both options you suggest work for me, but they pull in opposite
> > > directions and I'd rather not guess wrong on the user-facing
> > > contract. Which do you prefer for v5?
> > >
> > > (a) Don't display embedded in /proc/bootconfig -- keep the current
> > > "file shows the active bootconfig source" behavior and document
> > > that with EMBED_CMDLINE=y, the kernel.* subtree may have been
> > > applied separately via the cmdline.
> > >
> > > (b) Always display embedded by merging the rendered string into
> > > /proc/bootconfig when EMBED_CMDLINE=y, so the file reflects
> > > what was actually applied.
> > >
> > > Happy to go either way
> >
> > Following up on my own mail rather than leaving it fully open: after
> > looking at the code more, I'd like to recommend (a).
>
> Agreed. Sorry for replying late.
No problem, thanks. Quick heads-up: v5 already went out and crossed with
this mail. It takes (a) and extends bootconfig.rst to walk through the
four sources (bootloader cmdline, embedded cmdline, initrd bootconfig,
embedded bootconfig), so that part is already in flight:
https://lore.kernel.org/r/20260617-bootconfig_using_tools-v5-0-fd589a9cc5e3@debian.org
The naming/mutual-exclusion rework below I'll fold into v6.
> Indeed. So I think this EMBED_CMDLINE is more like CMDLINE set by
> bootconfig file, instead of embedded string. That is useful for reusing
> the boot options. We need to change the explanation and clarify it.
Agreed, that's a much clearer model. v6 will reframe the Kconfig help and
bootconfig.rst around "this is CONFIG_CMDLINE, sourced from a bootconfig
file at build time" rather than "an embedded bootconfig that also feeds
the cmdline".
It also matches what the code already does precedence-wise: the rendered
"kernel" string is prepended to boot_command_line in setup_arch(), so it
sits in front of the bootloader args and parse_args() last-wins lets the
bootloader override it -- i.e. exactly CONFIG_CMDLINE without _OVERRIDE.
So this is mostly a rename + dependency + docs change, not a behavioral
one. (A _FORCE/_EXTEND-style variant could come later if there's demand;
the current behavior is the plain "overridable default" one.)
> Thus we should those configs mutual exclusive. If user already sets the
> CONFIG_CMDLINE, EMBED_CMDLINE should not be enabled.
Makes sense -- two built-in cmdline sources at once is confusing. I'll
make them mutually exclusive in v6. I'm thinking:
depends on CMDLINE = ""
on the new symbol. On x86 CONFIG_CMDLINE is a string that depends on
CMDLINE_BOOL and defaults to "", so this reads as "only offer the
bootconfig-rendered cmdline when no static CONFIG_CMDLINE is configured",
and it works the same on other arches that define CMDLINE as a string.
Does that match what you had in mind, or would you rather gate it the
other way (CMDLINE depends on !the-new-symbol)?
> So you can see CONFIG_BOOT_CONFIG_EMBED_CMDLINE is a bit special.
> I think it maybe natual that we call it CONFIG_CMDLINE_BOOT_CONFIG.
> In this case, we render the cmdline string from bootconfig build-time
> and set CONFIG_CMDLINE with the rendered cmdline string.
> So you can see CONFIG_BOOT_CONFIG_EMBED_CMDLINE is a bit special.
> I think it maybe natual that we call it CONFIG_CMDLINE_BOOT_CONFIG.
> In this case, we render the cmdline string from bootconfig build-time
> and set CONFIG_CMDLINE with the rendered cmdline string.
I'll rename it for v6. One nit: the arch opt-in symbol is already
ARCH_SUPPORTS_CMDLINE_FROM_BOOTCONFIG, so CONFIG_CMDLINE_FROM_BOOTCONFIG would
pair with it verbatim. I'll use CONFIG_CMDLINE_FROM_BOOTCONFIG I'll rename it
for v6.
Another nit: the arch opt-in symbol is already
ARCH_SUPPORTS_CMDLINE_FROM_BOOTCONFIG, so CONFIG_CMDLINE_FROM_BOOTCONFIG would
pair with it verbatim. I'll use CONFIG_CMDLINE_FROM_BOOTCONFIG unless you'd
rather keep CONFIG_CMDLINE_BOOT_CONFIG -- either is fine by me.
One clarification on "set CONFIG_CMDLINE with the rendered string":
CONFIG_CMDLINE is a Kconfig string fixed when .config is read, while the
render happens later during the build, so we can't literally store the
rendered text into CONFIG_CMDLINE. The mechanism stays "render into
.init.rodata, merge into boot_command_line in setup_arch()"; what changes
is how we name and document it, plus the mutual exclusion above. Let me
> So you can see CONFIG_BOOT_CONFIG_EMBED_CMDLINE is a bit special.
> I think it maybe natual that we call it CONFIG_CMDLINE_BOOT_CONFIG.
I'll rename it for v6. One nit: the arch opt-in symbol is already
ARCH_SUPPORTS_CMDLINE_FROM_BOOTCONFIG, so CONFIG_CMDLINE_FROM_BOOTCONFIG
would pair with it verbatim. I'll use CONFIG_CMDLINE_FROM_BOOTCONFIG
> In this case, we render the cmdline string from bootconfig build-time
> and set CONFIG_CMDLINE with the rendered cmdline string.
CONFIG_CMDLINE is a Kconfig string fixed when .config is read, while the
render happens later during the build, so we can't literally store the
rendered text into CONFIG_CMDLINE? let me know if you can envision a way to
get it done.
> I think we can proceed it without rendering it in /proc/bootconfig
> at this point. And later we find the way to detect early parameters
> correctly, we can fix it.
Sounds good. I'll document the sharp edge (with both an embedded cmdline and an
initrd bootconfig, early params reflect the embedded values because the initrd
isn't parsed yet) and leave the early-param-aware override detection as the
follow-up you describe.
> (BTW, early parameter problem is a bit complicated. It is not hard
> to distinguish early parameters, but kernel accepts the same key
> for early parameter and normal parameter. e.g. "console=")
Right, console= being both is the awkward case. Agreed that's better as
its own series once we have a reliable way to detect early params.
So the v6 plan:
- rename CONFIG_BOOT_CONFIG_EMBED_CMDLINE -> CONFIG_CMDLINE_FROM_BOOTCONFIG
(or _BOOT_CONFIG, your call)
- make it mutually exclusive with CONFIG_CMDLINE (depends on CMDLINE = "")
- reframe the Kconfig help + bootconfig.rst as "CONFIG_CMDLINE from a
bootconfig file"
- keep (a): no rendering in /proc/bootconfig; document the early-param
sharp edge
- defer early-param-aware override detection to a follow-up
Thanks for the direction,
--breno
^ permalink raw reply
* Re: [Lsf-pc] [LSF/MM/BPF TOPIC][RFC PATCH v4 00/27] Private Memory Nodes (w/ Compressed RAM)
From: Vlastimil Babka (SUSE) @ 2026-06-22 12:31 UTC (permalink / raw)
To: Gregory Price
Cc: David Hildenbrand (Arm), Balbir Singh, lsf-pc, linux-kernel,
linux-cxl, cgroups, linux-mm, linux-trace-kernel, damon,
kernel-team, gregkh, rafael, dakr, dave, jonathan.cameron,
dave.jiang, alison.schofield, vishal.l.verma, ira.weiny,
dan.j.williams, longman, akpm, lorenzo.stoakes, Liam.Howlett,
vbabka, rppt, surenb, mhocko, osalvador, ziy, matthew.brost,
joshua.hahnjy, rakie.kim, byungchul, ying.huang, apopple,
axelrasmussen, yuanchu, weixugc, yury.norov, linux, mhiramat,
mathieu.desnoyers, tj, hannes, mkoutny, jackmanb, sj, baolin.wang,
npache, ryan.roberts, dev.jain, baohua, lance.yang, muchun.song,
xu.xin16, chengming.zhou, jannh, linmiaohe, nao.horiguchi,
pfalcato, rientjes, shakeel.butt, riel, harry.yoo, cl,
roman.gushchin, chrisl, kasong, shikemeng, nphamcs, bhe,
zhengqi.arch, terry.bowman, Matthew Wilcox
In-Reply-To: <ajPS3AKrZEbZbXBw@gourry-fedora-PF4VCD3F>
On 6/18/26 13:13, Gregory Price wrote:
> On Thu, Jun 18, 2026 at 10:21:30AM +0200, Vlastimil Babka (SUSE) wrote:
>> On 6/15/26 17:37, Gregory Price wrote:
>> >
>> > One thought would be a way to switch what fallback list is used, and
>> > then have specific fallback lists for certain contexts.
>> >
>> > Right now there is a single example of this: __GFP_THISNODE
>> > |= __GFP_THISNODE => NOFALLBACK
>> > &= ~__GFP_THISNODE => FALLBACK
>> >
>> > We could add an interface with the desired fallback list based as an
>> > argument, and let get_page_from_freelist to prefer that over the default
>> > global lists.
>>
>> Does it mean a new argument in a number of functions in the page allocator,
>> or can it be mapped to alloc_flags (at least internally?), because the
>> number of possible fallback lists is small enough?
>>
>
> What I ended up with was adding a single page_alloc.c external interface
> that allows you define the zonelist via an enum, and then an internal
> selector resolution in prepare_alloc_pages() stored in alloc_context
OK. Since it's in alloc_context then there should be no parameter bloat
inside page allocator. And for the single external entry point it's better
to be explicit.
>
> eg:
>
> static inline bool prepare_alloc_pages(gfp_t gfp_mask, unsigned int order,
> int preferred_nid, nodemask_t *nodemask,
> struct alloc_context *ac, gfp_t *alloc_gfp,
> unsigned int *alloc_flags)
> {
> ac->highest_zoneidx = gfp_zone(gfp_mask);
> ac->zonelist = select_zonelist(preferred_nid, gfp_mask, ac->zlsel);
> ... snip ...
> }
>
> struct folio *__folio_alloc_zonelist_noprof(gfp_t gfp, unsigned int order,
> int preferred_nid, nodemask_t *nodemask,
> enum alloc_zonelist zlsel);
>
>
> The original __folio_alloc* functions just add a DEFAULT - which tells
> select_zonelist() to base the decision on __GFP_THISNODE.
>
>
> struct folio *__folio_alloc_noprof(gfp_t gfp, unsigned int order, int preferred_nid,
> nodemask_t *nodemask)
> {
> return __folio_alloc_core(gfp, order, preferred_nid, nodemask,
> ALLOC_ZONELIST_DEFAULT);
> }
> EXPORT_SYMBOL(__folio_alloc_noprof);
>
>
> This does a few things
> - The isolation is structural, there is no way to accidentally
> allocate private memory without passing ALLOC_ZONELIST_PRIVATE
>
> - The isolation forces folios - there are no non-folio interfaces
> which allow zonelist selection
>
> - The zonelist selection is confined to this allocation context,
> so no inheritence is possible.
>
Ack.
>
> I tried to avoid using an ALLOC_ flag so we can avoid yet another flag
> crunch, but there certainly are few enough zonelists that we could
> encode it there and expose it. I know Brendan was looking at plumbing
> alloc flags out to an interface, so i'm open to that.
>
> Externally the way I determine what zonelist to use is a lookup based on
> reason - letting the node filter. This is really only needed in a
> couple spots:
>
> mm/khugepaged.c: enum alloc_zonelist zlsel = alloc_zonelist_for_node(node, NODE_ALLOC_RECLAIM);
> mm/vmscan.c: mtc->zlsel = alloc_zonelist_for_nodemask(mtc->nmask, NODE_ALLOC_TIERING);
> mm/migrate.c: .zlsel = alloc_zonelist_for_node(node, NODE_ALLOC_USER_MIGRATE),
>
> static inline enum alloc_zonelist
> alloc_zonelist_for_node(int nid, enum node_alloc_reason reason)
> {
> bool ok;
>
> if (!node_state(nid, N_MEMORY_PRIVATE))
> return ALLOC_ZONELIST_DEFAULT;
> switch (reason) {
> case NODE_ALLOC_RECLAIM:
> ok = node_is_reclaimable(nid);
> break;
> case NODE_ALLOC_TIERING:
> ok = node_allows_tiering(nid);
> break;
> case NODE_ALLOC_USER_MIGRATE:
> ok = node_allows_user_migrate(nid);
> break;
> default:
> ok = false;
> }
> return ok ? ALLOC_ZONELIST_PRIVATE : ALLOC_ZONELIST_DEFAULT;
> }
>
> Otherwise... everything is now a mempolicy w/ MPOL_F_BIND and all the
> handling goes through the normal fault-paths :]
>
> static struct page *__alloc_pages_mpol(gfp_t gfp, unsigned int order,
> struct mempolicy *pol, pgoff_t ilx, int nid)
> {
> nodemask_t *nodemask;
> struct page *page;
> enum alloc_zonelist zlsel = (pol->flags & MPOL_F_PRIVATE) ?
> ALLOC_ZONELIST_PRIVATE : ALLOC_ZONELIST_DEFAULT;
> ...
> if (pol->mode == MPOL_PREFERRED_MANY)
> return alloc_pages_preferred_many(gfp, order, nid, nodemask,
> zlsel);
> ...
> }
>
>
> Switching to an alloc_flag would probably be trivially if that's really
> wanted
I guess not. Thanks for the explanation!
> ~Gregory
^ permalink raw reply
* Re: [syzbot] [trace?] general protection fault in mtree_load
From: Oleg Nesterov @ 2026-06-22 13:04 UTC (permalink / raw)
To: syzbot
Cc: bp, dave.hansen, hpa, linux-kernel, linux-trace-kernel, mhiramat,
mingo, peterz, syzkaller-bugs, tglx, x86
In-Reply-To: <6a38dd47.713c5d62.148f7.000c.GAE@google.com>
On 06/21, syzbot wrote:
>
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit: 6b5a2b7d9bc1 Merge tag 'trace-tools-v7.2' of git://git.ker..
> git tree: upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=16d56986580000
> kernel config: https://syzkaller.appspot.com/x/.config?x=ea6584355d75e0cd
> dashboard link: https://syzkaller.appspot.com/bug?extid=61ce80689253f42e6d80
> compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44
>
> Unfortunately, I don't have any reproducer for this issue yet.
>
> Downloadable assets:
> disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-6b5a2b7d.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/b3cb0499fbe9/vmlinux-6b5a2b7d.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/47cfbe57f6ea/bzImage-6b5a2b7d.xz
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+61ce80689253f42e6d80@syzkaller.appspotmail.com
>
> Oops: general protection fault, probably for non-canonical address 0xdffffc0000000011: 0000 [#1] SMP KASAN NOPTI
> KASAN: null-ptr-deref in range [0x0000000000000088-0x000000000000008f]
> CPU: 3 UID: 0 PID: 24402 Comm: syz.4.5217 Tainted: G L syzkaller #0 PREEMPT(full)
> Tainted: [L]=SOFTLOCKUP
> Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
> RIP: 0010:mas_root lib/maple_tree.c:759 [inline]
> RIP: 0010:mas_start lib/maple_tree.c:1179 [inline]
> RIP: 0010:mtree_load+0x16d/0xa90 lib/maple_tree.c:5657
> Code: 00 00 00 00 48 c7 44 24 78 ff ff ff ff e8 6b bd 84 f6 48 8b 5c 24 50 c6 84 24 9c 00 00 00 00 48 8d 7b 48 48 89 f8 48 c1 e8 03 <42> 80 3c 20 00 0f 85 d6 08 00 00 48 8b 5b 48 e8 6f 1a 08 00 31 ff
> RSP: 0018:ffffc900039c76d8 EFLAGS: 00010206
> RAX: 0000000000000011 RBX: 0000000000000040 RCX: ffffffff8b848746
> RDX: ffff888041b6a540 RSI: ffffffff8b848775 RDI: 0000000000000088
> RBP: 0000000000000000 R08: 0000000000000005 R09: 0000000000000001
> R10: 0000000000000001 R11: 000000000000751b R12: dffffc0000000000
> R13: ffff88802693adc0 R14: 00001fff904365a7 R15: dffffc0000000000
> FS: 0000000000000000(0000) GS:ffff8880d665f000(0000) knlGS:0000000000000000
> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 00007f44aa04f156 CR3: 00000000364d5000 CR4: 0000000000352ef0
> Call Trace:
> <TASK>
> vma_lookup include/linux/mm.h:4204 [inline]
> __in_uprobe_trampoline arch/x86/kernel/uprobes.c:766 [inline]
> __is_optimized arch/x86/kernel/uprobes.c:1056 [inline]
> is_optimized arch/x86/kernel/uprobes.c:1067 [inline]
> set_orig_insn+0x1ec/0x2a0 arch/x86/kernel/uprobes.c:1098
> remove_breakpoint kernel/events/uprobes.c:1185 [inline]
> register_for_each_vma+0xbb7/0xdb0 kernel/events/uprobes.c:1318
> uprobe_unregister_nosync+0x12a/0x1c0 kernel/events/uprobes.c:1343
> bpf_uprobe_unregister kernel/trace/bpf_trace.c:2936 [inline]
> bpf_uprobe_multi_link_release+0xb3/0x1c0 kernel/trace/bpf_trace.c:2947
> bpf_link_free+0xec/0x4a0 kernel/bpf/syscall.c:3273
> bpf_link_put_direct kernel/bpf/syscall.c:3326 [inline]
> bpf_link_release+0x5d/0x80 kernel/bpf/syscall.c:3333
> __fput+0x3ff/0xb50 fs/file_table.c:512
> task_work_run+0x150/0x240 kernel/task_work.c:233
> exit_task_work include/linux/task_work.h:40 [inline]
current->mm is already NULL, the exiting task has already passed exit_mm().
Hopefully
[PATCHv4 01/13] uprobes/x86: Use proper mm_struct in __in_uprobe_trampoline
https://lore.kernel.org/all/20260526205840.173790-2-jolsa@kernel.org/
should help...
Oleg.
^ permalink raw reply
* Re: [PATCH 0/2] tracing: Move trace_printk.h out of kernel.h
From: Steven Rostedt @ 2026-06-22 13:08 UTC (permalink / raw)
To: Christophe Leroy (CS GROUP)
Cc: linux-kernel, linux-trace-kernel, Masami Hiramatsu, Mark Rutland,
Mathieu Desnoyers, Andrew Morton, Linus Torvalds,
Sebastian Andrzej Siewior, John Ogness, Thomas Gleixner,
Peter Zijlstra, Julia Lawall, Yury Norov, linux-doc, linux-kbuild,
linuxppc-dev, dri-devel, linux-stm32, linux-arm-kernel,
linux-rdma, linux-usb, linux-ext4, linux-nfs, kvm, intel-gfx
In-Reply-To: <dbb5915e-6587-4de9-87f3-76bea5024da8@kernel.org>
On Mon, 22 Jun 2026 10:05:13 +0200
"Christophe Leroy (CS GROUP)" <chleroy@kernel.org> wrote:
> > There's been complaints about trace_printk() being defined in kernel.h as it
> > can increase the compilation time. As it is only used by some developers for
> > debugging purposes, it should not be in kernel.h causing lots of wasted CPU
> > cycles for those that do not ever care about it.
>
> Do we have a measurement of the increased compilation time ?
I believe Yury does.
-- Steve
^ permalink raw reply
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