* Re: [PATCH v6 0/3] tracing: Guard __DECLARE_TRACE() use of __DO_TRACE_CALL() with SRCU-fast
From: Steven Rostedt @ 2026-01-27 2:39 UTC (permalink / raw)
To: linux-kernel, linux-trace-kernel, bpf
Cc: Masami Hiramatsu, Mark Rutland, Mathieu Desnoyers, Andrew Morton,
Paul E. McKenney, Sebastian Andrzej Siewior, Alexei Starovoitov
In-Reply-To: <20260126231145.728172709@kernel.org>
On Mon, 26 Jan 2026 18:11:45 -0500
Steven Rostedt <rostedt@kernel.org> wrote:
> The current use of guard(preempt_notrace)() within __DECLARE_TRACE()
> to protect invocation of __DO_TRACE_CALL() means that BPF programs
> attached to tracepoints are non-preemptible. This is unhelpful in
> real-time systems, whose users apparently wish to use BPF while also
> achieving low latencies.
>
> Change the protection of tracepoints to use fast_srcu() instead.
> This will allow the callbacks to be able to be preempted. This also
> means that the callbacks themselves need to be able to handle this
> new found preemption ability.
>
> For perf, add a guard(preempt) inside its handler too keep the old behavior
> of perf events being called with preemption disabled.
>
> For BPF, add a migrate_disable() to its handler. Actually, just replace
> the rcu_read_lock() with rcu_read_lock_dont_migrate() and make it
> cover more of the BPF callback handler.
My tests just triggered this, so I'm removing them from my queue for now.
-- Steve
[ 204.194772] ------------[ cut here ]------------
[ 204.194789] WARNING: kernel/rcu/srcutree.c:792 at __srcu_check_read_flavor+0x5c/0xb0, CPU#1: swapper/1/0
[ 204.194800] Modules linked in:
[ 204.194817] CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Not tainted 6.19.0-rc7-test-00018-g2c774d6ad074-dirty #32 PREEMPT(voluntary)
[ 204.194821] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.17.0-debian-1.17.0-1 04/01/2014
[ 204.194824] RIP: 0010:__srcu_check_read_flavor+0x5c/0xb0
[ 204.194829] Code: 84 c9 74 19 39 f1 74 45 0f 0b 85 c0 74 2e 39 c1 74 45 0f 0b 39 f0 75 3f c3 cc cc cc cc 85 c0 74 16 83 fe 04 75 ee 0f 0b eb ea <0f> 0b 8d 46 ff 85 f0 74 ba 0f 0b eb b6 83
fe 04 74 3a 31 c0 f0 0f
[ 204.194832] RSP: 0018:fffffe4c48325b50 EFLAGS: 00010002
[ 204.194835] RAX: 0000000000000001 RBX: ffffffff8791e5a0 RCX: 0000000000000000
[ 204.194836] RDX: 00000000ffffffff RSI: 0000000000000004 RDI: ffffffff879f1180
[ 204.194838] RBP: ffff8e6453fd2000 R08: 0000000000000001 R09: 0000000000000000
[ 204.194839] R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000001
[ 204.194840] R13: fffffe4c48325ef8 R14: ffffffff85eeae93 R15: ffff8e6453906900
[ 204.194842] FS: 0000000000000000(0000) GS:ffff8e6533593000(0000) knlGS:0000000000000000
[ 204.194844] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 204.194845] CR2: 000055d1e7cf8cc0 CR3: 000000010b0cc004 CR4: 0000000000172ef0
[ 204.194850] Call Trace:
[ 204.194866] <NMI>
[ 204.194868] lock_release+0x215/0x320
[ 204.194886] ? arch_perf_update_userpage+0x6c/0xf0
[ 204.195214] perf_event_update_userpage+0x158/0x2e0
[ 204.195538] x86_perf_event_set_period+0xc1/0x180
[ 204.195811] handle_pmi_common+0x1ac/0x450
[ 204.198605] ? __get_next_timer_interrupt+0x185/0x370
[ 204.198914] intel_pmu_handle_irq+0x10e/0x510
[ 204.199032] ? nmi_handle.part.0+0x30/0x270
[ 204.199197] ? __get_next_timer_interrupt+0x185/0x370
[ 204.199404] perf_event_nmi_handler+0x34/0x60
[ 204.199523] nmi_handle.part.0+0xc9/0x270
^ permalink raw reply
* [PATCH v2] tracing: kprobe-event: Return directly when trace kprobes is empty
From: sunliming @ 2026-01-27 5:38 UTC (permalink / raw)
To: rostedt, mhiramat, mathieu.desnoyers
Cc: linux-kernel, linux-trace-kernel, sunliming
From: sunliming <sunliming@kylinos.cn>
In enable_boot_kprobe_events(), it returns directly when trace kprobes is
empty, thereby reducing the function's execution time. This function may
otherwise wait for the event_mutex lock for tens of milliseconds on certain
machines, which is unnecessary when trace kprobes is empty.
Signed-off-by: sunliming <sunliming@kylinos.cn>
---
v2:
- wrap the the null check for the dyn_event_list with macro trace_kprobe_list_empty
---
kernel/trace/trace_kprobe.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index 9953506370a5..95f2c42603d5 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -82,6 +82,7 @@ static struct trace_kprobe *to_trace_kprobe(struct dyn_event *ev)
#define for_each_trace_kprobe(pos, dpos) \
for_each_dyn_event(dpos) \
if (is_trace_kprobe(dpos) && (pos = to_trace_kprobe(dpos)))
+#define trace_kprobe_list_empty() list_empty(&dyn_event_list)
static nokprobe_inline bool trace_kprobe_is_return(struct trace_kprobe *tk)
{
@@ -1982,6 +1983,9 @@ static __init void enable_boot_kprobe_events(void)
struct trace_kprobe *tk;
struct dyn_event *pos;
+ if (trace_kprobe_list_empty())
+ return;
+
guard(mutex)(&event_mutex);
for_each_trace_kprobe(tk, pos) {
list_for_each_entry(file, &tr->events, list)
--
2.25.1
^ permalink raw reply related
* Re: [PATCH] MAINTAINERS: add Rust files to STATIC BRANCH/CALL and TRACING
From: Peter Zijlstra @ 2026-01-27 8:24 UTC (permalink / raw)
To: Alice Ryhl
Cc: Steven Rostedt, Miguel Ojeda, Masami Hiramatsu, Mathieu Desnoyers,
Josh Poimboeuf, Jason Baron, Ard Biesheuvel, linux-kernel,
linux-trace-kernel, rust-for-linux
In-Reply-To: <CAH5fLggpBodWYv2EQy5sgg5eSp9=7PM9ZqXcKaTuozNKN1eGGg@mail.gmail.com>
On Mon, Jan 26, 2026 at 10:58:24PM +0100, Alice Ryhl wrote:
> > > What about the STATIC BRANCH/CALL subsystem? Should I also leave you or
> > > someone else as 'M:' there? It's unclear to me who usually picks up
> > > patches for STATIC BRANCH/CALL when they are not a dependency to a patch
> > > for somewhere else.
> >
> > I think that'd be me -- I typically do the static branch/call bits.
>
> Ah, thanks for the clarification.
>
> Are you ok with using the approach Steven suggested for STATIC
> BRANCH/CALL subsystem too? That is, add a [RUST] entry below the
> current one, list you and me as M:, and anyone else in the main entry
> as R:, and patches land through the same tree as where they would have
> landed if they were a C patch.
>
> I'm open to whichever setup you prefer, but I think it'd be nice to
> get these files into MAINTAINERS somewhere.
Yeah, I suppose that'll work. That [RUST] entry seems to be the
predominant style in MAINTAINERS.
My only concern is that most of the [RUST] entries don't actually
include the F entries for the !rust part, which means that if the C bits
change the Rust people aren't notified.
So I would suggest having all F duplicated from the main entry and then
add the rust files. Or, like we did with ATOMIC, just add you as M to
the main entry, along with a few rust files.
Some day I might actually learn enough to not see it as line noise :/
See 2387fb2a9b84 ("rust: sync: Add basic atomic operation mapping framework")
^ permalink raw reply
* Re: [PATCH] MAINTAINERS: add Rust files to STATIC BRANCH/CALL and TRACING
From: Alice Ryhl @ 2026-01-27 8:26 UTC (permalink / raw)
To: Peter Zijlstra
Cc: Steven Rostedt, Miguel Ojeda, Masami Hiramatsu, Mathieu Desnoyers,
Josh Poimboeuf, Jason Baron, Ard Biesheuvel, linux-kernel,
linux-trace-kernel, rust-for-linux
In-Reply-To: <20260127082401.GS171111@noisy.programming.kicks-ass.net>
On Tue, Jan 27, 2026 at 9:24 AM Peter Zijlstra <peterz@infradead.org> wrote:
>
> On Mon, Jan 26, 2026 at 10:58:24PM +0100, Alice Ryhl wrote:
>
> > > > What about the STATIC BRANCH/CALL subsystem? Should I also leave you or
> > > > someone else as 'M:' there? It's unclear to me who usually picks up
> > > > patches for STATIC BRANCH/CALL when they are not a dependency to a patch
> > > > for somewhere else.
> > >
> > > I think that'd be me -- I typically do the static branch/call bits.
> >
> > Ah, thanks for the clarification.
> >
> > Are you ok with using the approach Steven suggested for STATIC
> > BRANCH/CALL subsystem too? That is, add a [RUST] entry below the
> > current one, list you and me as M:, and anyone else in the main entry
> > as R:, and patches land through the same tree as where they would have
> > landed if they were a C patch.
> >
> > I'm open to whichever setup you prefer, but I think it'd be nice to
> > get these files into MAINTAINERS somewhere.
>
> Yeah, I suppose that'll work. That [RUST] entry seems to be the
> predominant style in MAINTAINERS.
>
> My only concern is that most of the [RUST] entries don't actually
> include the F entries for the !rust part, which means that if the C bits
> change the Rust people aren't notified.
>
> So I would suggest having all F duplicated from the main entry and then
> add the rust files. Or, like we did with ATOMIC, just add you as M to
> the main entry, along with a few rust files.
Ok, that makes sense to me as well. Let's do that. Sending v2 now ...
> Some day I might actually learn enough to not see it as line noise :/
>
> See 2387fb2a9b84 ("rust: sync: Add basic atomic operation mapping framework")
>
^ permalink raw reply
* [PATCH v2] MAINTAINERS: add Rust files to STATIC BRANCH/CALL and TRACING
From: Alice Ryhl @ 2026-01-27 8:30 UTC (permalink / raw)
To: Steven Rostedt, Peter Zijlstra, Masami Hiramatsu,
Mathieu Desnoyers, Josh Poimboeuf, Jason Baron, Ard Biesheuvel
Cc: linux-kernel, linux-trace-kernel, rust-for-linux, Alice Ryhl
I realized that these files were never listed in MAINTAINERS when they
were added in commit ad37bcd965fd ("rust: add tracepoint support").
Signed-off-by: Alice Ryhl <aliceryhl@google.com>
---
Based on v6.19-rc1.
---
Changes in v2:
- Adjust MAINTAINERS entries as per discussion on v1.
- Link to v1: https://lore.kernel.org/r/20260107-jump-label-rust-maintainers-v1-1-702b03482f2e@google.com
---
MAINTAINERS | 15 +++++++++++++++
1 file changed, 15 insertions(+)
diff --git a/MAINTAINERS b/MAINTAINERS
index 5b11839cba9de1e9e43f63787578edd8c429ca39..d1bc1bd7584896c78e517f80194d5de6828298cf 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -25006,6 +25006,7 @@ STATIC BRANCH/CALL
M: Peter Zijlstra <peterz@infradead.org>
M: Josh Poimboeuf <jpoimboe@kernel.org>
M: Jason Baron <jbaron@akamai.com>
+M: Alice Ryhl <aliceryhl@google.com>
R: Steven Rostedt <rostedt@goodmis.org>
R: Ard Biesheuvel <ardb@kernel.org>
S: Supported
@@ -25017,6 +25018,9 @@ F: include/linux/jump_label*.h
F: include/linux/static_call*.h
F: kernel/jump_label.c
F: kernel/static_call*.c
+F: rust/helpers/jump_label.c
+F: rust/kernel/generated_arch_static_branch_asm.rs.S
+F: rust/kernel/jump_label.rs
STI AUDIO (ASoC) DRIVERS
M: Arnaud Pouliquen <arnaud.pouliquen@foss.st.com>
@@ -26474,6 +26478,17 @@ F: scripts/tracing/
F: scripts/tracepoint-update.c
F: tools/testing/selftests/ftrace/
+TRACING [RUST]
+M: Alice Ryhl <aliceryhl@google.com>
+M: Steven Rostedt <rostedt@goodmis.org>
+R: Masami Hiramatsu <mhiramat@kernel.org>
+R: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+L: linux-trace-kernel@vger.kernel.org
+L: rust-for-linux@vger.kernel.org
+S: Maintained
+T: git git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace.git
+F: rust/kernel/tracepoint.rs
+
TRACING MMIO ACCESSES (MMIOTRACE)
M: Steven Rostedt <rostedt@goodmis.org>
M: Masami Hiramatsu <mhiramat@kernel.org>
---
base-commit: 8f0b4cce4481fb22653697cced8d0d04027cb1e8
change-id: 20260107-jump-label-rust-maintainers-17040992e7db
Best regards,
--
Alice Ryhl <aliceryhl@google.com>
^ permalink raw reply related
* Re: [PATCH v2] MAINTAINERS: add Rust files to STATIC BRANCH/CALL and TRACING
From: Peter Zijlstra @ 2026-01-27 8:35 UTC (permalink / raw)
To: Alice Ryhl
Cc: Steven Rostedt, Masami Hiramatsu, Mathieu Desnoyers,
Josh Poimboeuf, Jason Baron, Ard Biesheuvel, linux-kernel,
linux-trace-kernel, rust-for-linux
In-Reply-To: <20260127-jump-label-rust-maintainers-v2-1-11b7c30b11d9@google.com>
On Tue, Jan 27, 2026 at 08:30:01AM +0000, Alice Ryhl wrote:
> I realized that these files were never listed in MAINTAINERS when they
> were added in commit ad37bcd965fd ("rust: add tracepoint support").
>
> Signed-off-by: Alice Ryhl <aliceryhl@google.com>
Works for me; Steve were you taking this or should I?
In case Steve wants to route this:
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
> ---
> Based on v6.19-rc1.
> ---
> Changes in v2:
> - Adjust MAINTAINERS entries as per discussion on v1.
> - Link to v1: https://lore.kernel.org/r/20260107-jump-label-rust-maintainers-v1-1-702b03482f2e@google.com
> ---
> MAINTAINERS | 15 +++++++++++++++
> 1 file changed, 15 insertions(+)
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 5b11839cba9de1e9e43f63787578edd8c429ca39..d1bc1bd7584896c78e517f80194d5de6828298cf 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -25006,6 +25006,7 @@ STATIC BRANCH/CALL
> M: Peter Zijlstra <peterz@infradead.org>
> M: Josh Poimboeuf <jpoimboe@kernel.org>
> M: Jason Baron <jbaron@akamai.com>
> +M: Alice Ryhl <aliceryhl@google.com>
> R: Steven Rostedt <rostedt@goodmis.org>
> R: Ard Biesheuvel <ardb@kernel.org>
> S: Supported
> @@ -25017,6 +25018,9 @@ F: include/linux/jump_label*.h
> F: include/linux/static_call*.h
> F: kernel/jump_label.c
> F: kernel/static_call*.c
> +F: rust/helpers/jump_label.c
> +F: rust/kernel/generated_arch_static_branch_asm.rs.S
> +F: rust/kernel/jump_label.rs
>
> STI AUDIO (ASoC) DRIVERS
> M: Arnaud Pouliquen <arnaud.pouliquen@foss.st.com>
> @@ -26474,6 +26478,17 @@ F: scripts/tracing/
> F: scripts/tracepoint-update.c
> F: tools/testing/selftests/ftrace/
>
> +TRACING [RUST]
> +M: Alice Ryhl <aliceryhl@google.com>
> +M: Steven Rostedt <rostedt@goodmis.org>
> +R: Masami Hiramatsu <mhiramat@kernel.org>
> +R: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
> +L: linux-trace-kernel@vger.kernel.org
> +L: rust-for-linux@vger.kernel.org
> +S: Maintained
> +T: git git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace.git
> +F: rust/kernel/tracepoint.rs
> +
> TRACING MMIO ACCESSES (MMIOTRACE)
> M: Steven Rostedt <rostedt@goodmis.org>
> M: Masami Hiramatsu <mhiramat@kernel.org>
>
> ---
> base-commit: 8f0b4cce4481fb22653697cced8d0d04027cb1e8
> change-id: 20260107-jump-label-rust-maintainers-17040992e7db
>
> Best regards,
> --
> Alice Ryhl <aliceryhl@google.com>
>
^ permalink raw reply
* Re: [PATCH v2] MAINTAINERS: add Rust files to STATIC BRANCH/CALL and TRACING
From: Alice Ryhl @ 2026-01-27 8:44 UTC (permalink / raw)
To: Peter Zijlstra
Cc: Steven Rostedt, Masami Hiramatsu, Mathieu Desnoyers,
Josh Poimboeuf, Jason Baron, Ard Biesheuvel, linux-kernel,
linux-trace-kernel, rust-for-linux
In-Reply-To: <20260127083543.GU171111@noisy.programming.kicks-ass.net>
On Tue, Jan 27, 2026 at 09:35:43AM +0100, Peter Zijlstra wrote:
> On Tue, Jan 27, 2026 at 08:30:01AM +0000, Alice Ryhl wrote:
> > I realized that these files were never listed in MAINTAINERS when they
> > were added in commit ad37bcd965fd ("rust: add tracepoint support").
> >
> > Signed-off-by: Alice Ryhl <aliceryhl@google.com>
>
> Works for me; Steve were you taking this or should I?
>
> In case Steve wants to route this:
>
> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Thanks Peter!
By the way, in case you didn't see it, there is a patch for the STATIC
BRANCH/CALL side:
https://lore.kernel.org/all/20260105-define-rust-helper-v2-9-51da5f454a67@google.com/
Alice
^ permalink raw reply
* [PATCH v2 1/3] powerpc64: make clang cross-build friendly
From: Hari Bathini @ 2026-01-27 8:49 UTC (permalink / raw)
To: linuxppc-dev
Cc: Madhavan Srinivasan, Christophe Leroy, Naveen N. Rao,
Michael Ellerman, linux-trace-kernel, Mark Rutland,
Steven Rostedt, Masami Hiramatsu, llvm, Maryam Moghadas
In-Reply-To: <20260127084926.34497-1-hbathini@linux.ibm.com>
ARCH_USING_PATCHABLE_FUNCTION_ENTRY depends on toolchain support for
-fpatchable-function-entry option. The current script that checks
for this support only handles GCC. Rename the script and extend it
to detect support for -fpatchable-function-entry with Clang as well,
allowing clean cross-compilation with Clang toolchains.
Signed-off-by: Hari Bathini <hbathini@linux.ibm.com>
---
* Changes in v2:
- Use $(CLANG_FLAGS) instead of manually checking CC_IS_CLANG
arch/powerpc/Kconfig | 4 ++--
...e-function-entry.sh => check-fpatchable-function-entry.sh} | 0
2 files changed, 2 insertions(+), 2 deletions(-)
rename arch/powerpc/tools/{gcc-check-fpatchable-function-entry.sh => check-fpatchable-function-entry.sh} (100%)
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index b8d36a261009..dcb9894e2004 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -571,8 +571,8 @@ config ARCH_USING_PATCHABLE_FUNCTION_ENTRY
depends on FUNCTION_TRACER && (PPC32 || PPC64_ELF_ABI_V2)
depends on $(cc-option,-fpatchable-function-entry=2)
def_bool y if PPC32
- def_bool $(success,$(srctree)/arch/powerpc/tools/gcc-check-fpatchable-function-entry.sh $(CC) -mlittle-endian) if PPC64 && CPU_LITTLE_ENDIAN
- def_bool $(success,$(srctree)/arch/powerpc/tools/gcc-check-fpatchable-function-entry.sh $(CC) -mbig-endian) if PPC64 && CPU_BIG_ENDIAN
+ def_bool $(success,$(srctree)/arch/powerpc/tools/check-fpatchable-function-entry.sh $(CC) $(CLANG_FLAGS) -mlittle-endian) if PPC64 && CPU_LITTLE_ENDIAN
+ def_bool $(success,$(srctree)/arch/powerpc/tools/check-fpatchable-function-entry.sh $(CC) -mbig-endian) if PPC64 && CPU_BIG_ENDIAN
config PPC_FTRACE_OUT_OF_LINE
def_bool PPC64 && ARCH_USING_PATCHABLE_FUNCTION_ENTRY
diff --git a/arch/powerpc/tools/gcc-check-fpatchable-function-entry.sh b/arch/powerpc/tools/check-fpatchable-function-entry.sh
similarity index 100%
rename from arch/powerpc/tools/gcc-check-fpatchable-function-entry.sh
rename to arch/powerpc/tools/check-fpatchable-function-entry.sh
--
2.52.0
^ permalink raw reply related
* [PATCH v2 0/3] powerpc64/ftrace: fixes clang build issues
From: Hari Bathini @ 2026-01-27 8:49 UTC (permalink / raw)
To: linuxppc-dev
Cc: Madhavan Srinivasan, Christophe Leroy, Naveen N. Rao,
Michael Ellerman, linux-trace-kernel, Mark Rutland,
Steven Rostedt, Masami Hiramatsu, llvm, Maryam Moghadas
Support for -fpatchable-function-entry on ppc64le was added in Clang
with [1]. Faced a couple of issues while building the linux kernel
with Clang though. Patches 1 & 2 address those issues. The last patch
provides workaround to ensure, an open issue [2] in Clang with
-fpatchable-function-entry support, does not impact the linux
ftrace subsystem.
[1] https://github.com/llvm/llvm-project/pull/151569
[2] https://github.com/llvm/llvm-project/issues/163706
Hari Bathini (3):
powerpc64: make clang cross-build friendly
powerpc64/ftrace: fix OOL stub count with clang
powerpc64/ftrace: workaround clang recording GEP in
__patchable_function_entries
arch/powerpc/Kconfig | 4 +--
arch/powerpc/kernel/trace/ftrace.c | 26 ++++++++++++++++---
....sh => check-fpatchable-function-entry.sh} | 0
arch/powerpc/tools/ftrace-gen-ool-stubs.sh | 4 +--
4 files changed, 26 insertions(+), 8 deletions(-)
rename arch/powerpc/tools/{gcc-check-fpatchable-function-entry.sh => check-fpatchable-function-entry.sh} (100%)
--
2.52.0
^ permalink raw reply
* [PATCH v2 2/3] powerpc64/ftrace: fix OOL stub count with clang
From: Hari Bathini @ 2026-01-27 8:49 UTC (permalink / raw)
To: linuxppc-dev
Cc: Madhavan Srinivasan, Christophe Leroy, Naveen N. Rao,
Michael Ellerman, linux-trace-kernel, Mark Rutland,
Steven Rostedt, Masami Hiramatsu, llvm, Maryam Moghadas
In-Reply-To: <20260127084926.34497-1-hbathini@linux.ibm.com>
The total number of out-of-line (OOL) stubs required for function
tracing is determined using the following command:
$(OBJDUMP) -r -j __patchable_function_entries vmlinux.o
While this works correctly with GNU objdump, llvm-objdump does not
list the expected relocation records for this section. Fix this by
using the -d option and counting R_PPC64_ADDR64 relocation entries.
This works as desired with both objdump and llvm-objdump.
Signed-off-by: Hari Bathini <hbathini@linux.ibm.com>
---
* No changes since v1.
arch/powerpc/tools/ftrace-gen-ool-stubs.sh | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/powerpc/tools/ftrace-gen-ool-stubs.sh b/arch/powerpc/tools/ftrace-gen-ool-stubs.sh
index bac186bdf64a..9218d43aeb54 100755
--- a/arch/powerpc/tools/ftrace-gen-ool-stubs.sh
+++ b/arch/powerpc/tools/ftrace-gen-ool-stubs.sh
@@ -15,9 +15,9 @@ if [ -z "$is_64bit" ]; then
RELOCATION=R_PPC_ADDR32
fi
-num_ool_stubs_total=$($objdump -r -j __patchable_function_entries "$vmlinux_o" |
+num_ool_stubs_total=$($objdump -r -j __patchable_function_entries -d "$vmlinux_o" |
grep -c "$RELOCATION")
-num_ool_stubs_inittext=$($objdump -r -j __patchable_function_entries "$vmlinux_o" |
+num_ool_stubs_inittext=$($objdump -r -j __patchable_function_entries -d "$vmlinux_o" |
grep -e ".init.text" -e ".text.startup" | grep -c "$RELOCATION")
num_ool_stubs_text=$((num_ool_stubs_total - num_ool_stubs_inittext))
--
2.52.0
^ permalink raw reply related
* [PATCH v2 3/3] powerpc64/ftrace: workaround clang recording GEP in __patchable_function_entries
From: Hari Bathini @ 2026-01-27 8:49 UTC (permalink / raw)
To: linuxppc-dev
Cc: Madhavan Srinivasan, Christophe Leroy, Naveen N. Rao,
Michael Ellerman, linux-trace-kernel, Mark Rutland,
Steven Rostedt, Masami Hiramatsu, llvm, Maryam Moghadas
In-Reply-To: <20260127084926.34497-1-hbathini@linux.ibm.com>
Support for -fpatchable-function-entry on ppc64le was added in Clang
with [1]. However, when no prefix NOPs are specified - as is the case
with CONFIG_PPC_FTRACE_OUT_OF_LINE - the first NOP is emitted at LEP,
but Clang records the Global Entry Point (GEP) unlike GCC which does
record the Local Entry Point (LEP). Issue [2] has been raised to align
Clang's behavior with GCC. As a temporary workaround to ensure ftrace
initialization works as expected with Clang, derive the LEP using
ppc_function_entry() for kernel symbols and by looking for the below
module GEP sequence for module addresses, until [2] is resolved:
ld r2, -8(r12)
add r2, r2, r12
[1] https://github.com/llvm/llvm-project/pull/151569
[2] https://github.com/llvm/llvm-project/issues/163706
Cc: Maryam Moghadas <maryammo@ca.ibm.com>
Signed-off-by: Hari Bathini <hbathini@linux.ibm.com>
---
* No changes since v1.
arch/powerpc/kernel/trace/ftrace.c | 26 ++++++++++++++++++++++----
1 file changed, 22 insertions(+), 4 deletions(-)
diff --git a/arch/powerpc/kernel/trace/ftrace.c b/arch/powerpc/kernel/trace/ftrace.c
index 841d077e2825..1b2f293e7dcb 100644
--- a/arch/powerpc/kernel/trace/ftrace.c
+++ b/arch/powerpc/kernel/trace/ftrace.c
@@ -37,11 +37,29 @@ unsigned long ftrace_call_adjust(unsigned long addr)
if (addr >= (unsigned long)__exittext_begin && addr < (unsigned long)__exittext_end)
return 0;
- if (IS_ENABLED(CONFIG_ARCH_USING_PATCHABLE_FUNCTION_ENTRY) &&
- !IS_ENABLED(CONFIG_PPC_FTRACE_OUT_OF_LINE)) {
- addr += MCOUNT_INSN_SIZE;
- if (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_CALL_OPS))
+ if (IS_ENABLED(CONFIG_ARCH_USING_PATCHABLE_FUNCTION_ENTRY)) {
+ if (!IS_ENABLED(CONFIG_PPC_FTRACE_OUT_OF_LINE)) {
addr += MCOUNT_INSN_SIZE;
+ if (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_CALL_OPS))
+ addr += MCOUNT_INSN_SIZE;
+ } else if (IS_ENABLED(CONFIG_CC_IS_CLANG) && IS_ENABLED(CONFIG_PPC64)) {
+ /*
+ * addr points to global entry point though the NOP was emitted at local
+ * entry point due to https://github.com/llvm/llvm-project/issues/163706
+ * Handle that here with ppc_function_entry() for kernel symbols while
+ * adjusting module addresses in the else case, by looking for the below
+ * module global entry point sequence:
+ * ld r2, -8(r12)
+ * add r2, r2, r12
+ */
+ if (is_kernel_text(addr) || is_kernel_inittext(addr))
+ addr = ppc_function_entry((void *)addr);
+ else if ((ppc_inst_val(ppc_inst_read((u32 *)addr)) ==
+ PPC_RAW_LD(_R2, _R12, -8)) &&
+ (ppc_inst_val(ppc_inst_read((u32 *)(addr+4))) ==
+ PPC_RAW_ADD(_R2, _R2, _R12)))
+ addr += 8;
+ }
}
return addr;
--
2.52.0
^ permalink raw reply related
* Re: [PATCH v5 09/15] sched: Add task enqueue/dequeue trace points
From: Gabriele Monaco @ 2026-01-27 9:10 UTC (permalink / raw)
To: Peter Zijlstra
Cc: K Prateek Nayak, Tomas Glozar, Clark Williams, John Kacur,
linux-trace-kernel, Ingo Molnar, Nam Cao, Steven Rostedt,
linux-kernel, Juri Lelli
In-Reply-To: <20260122155500.362683-10-gmonaco@redhat.com>
2026-01-22T15:56:08Z Gabriele Monaco <gmonaco@redhat.com>:
> From: Nam Cao <namcao@linutronix.de>
>
> Add trace points into enqueue_task() and dequeue_task().
>
Peter,
can I have your Ack on this?
(Apologies for the spam, I sent it as HTML by mistake)
Thanks,
Gabriele
> Suggested-by: Peter Zijlstra <peterz@infradead.org>
> Signed-off-by: Nam Cao <namcao@linutronix.de>
> Reviewed-by: K Prateek Nayak <kprateek.nayak@amd.com>
> Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
> ---
>
> Notes:
> V5:
> * Do not fire enqueue tracepoint for delayed enqueues
>
> include/trace/events/sched.h | 13 +++++++++++++
> kernel/sched/core.c | 10 +++++++++-
> kernel/sched/sched.h | 2 ++
> 3 files changed, 24 insertions(+), 1 deletion(-)
>
> diff --git a/include/trace/events/sched.h b/include/trace/events/sched.h
> index 366b2e8ec40c..f4e1d3554e3e 100644
> --- a/include/trace/events/sched.h
> +++ b/include/trace/events/sched.h
> @@ -912,6 +912,19 @@ DECLARE_TRACE(sched_dl_server_stop,
> TP_PROTO(struct sched_dl_entity *dl_se, int cpu),
> TP_ARGS(dl_se, cpu));
>
> +/*
> + * The two trace points below may not work as expected for fair tasks due
> + * to delayed dequeue. See:
> + * https://lore.kernel.org/lkml/179674c6-f82a-4718-ace2-67b5e672fdee@amd.com/
> + */
> +DECLARE_TRACE(sched_enqueue,
> + TP_PROTO(struct task_struct *tsk, int cpu),
> + TP_ARGS(tsk, cpu));
> +
> +DECLARE_TRACE(sched_dequeue,
> + TP_PROTO(struct task_struct *tsk, int cpu),
> + TP_ARGS(tsk, cpu));
> +
> #endif /* _TRACE_SCHED_H */
>
> /* This part must be outside protection */
> diff --git a/kernel/sched/core.c b/kernel/sched/core.c
> index f6293fa02fb7..c885d7885172 100644
> --- a/kernel/sched/core.c
> +++ b/kernel/sched/core.c
> @@ -2087,6 +2087,9 @@ unsigned long get_wchan(struct task_struct *p)
>
> void enqueue_task(struct rq *rq, struct task_struct *p, int flags)
> {
> + if (trace_sched_enqueue_tp_enabled() && !(flags & ENQUEUE_DELAYED))
> + trace_sched_enqueue_tp(p, rq->cpu);
> +
> if (!(flags & ENQUEUE_NOCLOCK))
> update_rq_clock(rq);
>
> @@ -2114,6 +2117,8 @@ void enqueue_task(struct rq *rq, struct task_struct *p, int flags)
> */
> inline bool dequeue_task(struct rq *rq, struct task_struct *p, int flags)
> {
> + int ret;
> +
> if (sched_core_enabled(rq))
> sched_core_dequeue(rq, p, flags);
>
> @@ -2131,7 +2136,10 @@ inline bool dequeue_task(struct rq *rq, struct task_struct *p, int flags)
> */
> uclamp_rq_dec(rq, p);
> rq->queue_mask |= p->sched_class->queue_mask;
> - return p->sched_class->dequeue_task(rq, p, flags);
> + ret = p->sched_class->dequeue_task(rq, p, flags);
> + if (trace_sched_dequeue_tp_enabled() && !(flags & DEQUEUE_SLEEP))
> + trace_sched_dequeue_tp(p, rq->cpu);
> + return ret;
> }
>
> void activate_task(struct rq *rq, struct task_struct *p, int flags)
> diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
> index e885a935b716..8465472b40fa 100644
> --- a/kernel/sched/sched.h
> +++ b/kernel/sched/sched.h
> @@ -2918,6 +2918,8 @@ static inline void sub_nr_running(struct rq *rq, unsigned count)
>
> static inline void __block_task(struct rq *rq, struct task_struct *p)
> {
> + trace_sched_dequeue_tp(p, rq->cpu);
> +
> if (p->sched_contributes_to_load)
> rq->nr_uninterruptible++;
>
> --
> 2.52.0
^ permalink raw reply
* Re: [RFC v4 6/7] ext4: fast commit: add lock_updates tracepoint
From: Li Chen @ 2026-01-27 12:05 UTC (permalink / raw)
To: Steven Rostedt
Cc: Zhang Yi, Theodore Ts'o, Andreas Dilger, Masami Hiramatsu,
Mathieu Desnoyers, linux-ext4, linux-kernel, linux-trace-kernel
In-Reply-To: <20260123125737.2b6ddbbe@gandalf.local.home>
Hi Steven,
> On Tue, 20 Jan 2026 19:25:35 +0800
> Li Chen <me@linux.beauty> wrote:
>
> > Commit-time fast commit snapshots run under jbd2_journal_lock_updates(),
> > so it is useful to quantify the time spent with updates locked and to
> > understand why snapshotting can fail.
> >
> > Add a new tracepoint, ext4_fc_lock_updates, reporting the time spent in
> > the updates-locked window along with the number of snapshotted inodes
> > and ranges. Record the first snapshot failure reason in a stable snap_err
> > field for tooling.
> >
> > Signed-off-by: Li Chen <me@linux.beauty>
> > ---
> > fs/ext4/fast_commit.c | 86 ++++++++++++++++++++++++++++++-------
> > include/trace/events/ext4.h | 33 ++++++++++++++
> > 2 files changed, 104 insertions(+), 15 deletions(-)
> >
> > diff --git a/fs/ext4/fast_commit.c b/fs/ext4/fast_commit.c
> > index d1eefee60912..d266eb2a4219 100644
> > --- a/fs/ext4/fast_commit.c
> > +++ b/fs/ext4/fast_commit.c
> > @@ -193,6 +193,27 @@ static struct kmem_cache *ext4_fc_range_cachep;
> > #define EXT4_FC_SNAPSHOT_MAX_INODES 1024
> > #define EXT4_FC_SNAPSHOT_MAX_RANGES 2048
> >
> > +/*
> > + * Snapshot failure reasons for ext4_fc_lock_updates tracepoint.
> > + * Keep these stable for tooling.
> > + */
> > +enum ext4_fc_snap_err {
> > + EXT4_FC_SNAP_ERR_NONE = 0,
> > + EXT4_FC_SNAP_ERR_ES_MISS,
> > + EXT4_FC_SNAP_ERR_ES_DELAYED,
> > + EXT4_FC_SNAP_ERR_ES_OTHER,
> > + EXT4_FC_SNAP_ERR_INODES_CAP,
> > + EXT4_FC_SNAP_ERR_RANGES_CAP,
> > + EXT4_FC_SNAP_ERR_NOMEM,
> > + EXT4_FC_SNAP_ERR_INODE_LOC,
> > +};
> > +
> > +static inline void ext4_fc_set_snap_err(int *snap_err, int err)
> > +{
> > + if (snap_err && *snap_err == EXT4_FC_SNAP_ERR_NONE)
> > + *snap_err = err;
> > +}
> > +
>
>
>
> > diff --git a/include/trace/events/ext4.h b/include/trace/events/ext4.h
> > index fd76d14c2776..a1493971821d 100644
> > --- a/include/trace/events/ext4.h
> > +++ b/include/trace/events/ext4.h
> > @@ -2812,6 +2812,39 @@ TRACE_EVENT(ext4_fc_commit_stop,
> > __entry->num_fc_ineligible, __entry->nblks_agg, __entry->tid)
> > );
> >
>
> Why not make the snap_err into a human readable format?
>
> #define TRACE_SNAP_ERR \
> EM(NONE) \
> EM(ES_MISS) \
> EM(ES_DELAYED) \
> EM(ES_OTHER) \
> EM(INODES_CAP) \
> EM(RANGES_CAP) \
> EM(NOMEM) \
> EMe(INODE_LOC) \
>
> #undef EM
> #undef EMe
>
> #define EM(a) TRACE_DEFINE_ENUM(EXT4_FC_SNAP_ERR_##a);
> #define EMe(a) TRACE_DEFINE_ENUM(EXT4_FC_SNAP_ERR_##a);
>
> TRACE_SNAP_ERR
>
> #undef EM
> #undef EMe
>
> #define EM(a) { EXT4_FC_SNAP_ERR_##a, #a },
> #define EM(a) { EXT4_FC_SNAP_ERR_##a, #a }
>
>
> > +TRACE_EVENT(ext4_fc_lock_updates,
> > + TP_PROTO(struct super_block *sb, tid_t commit_tid, u64 locked_ns,
> > + unsigned int nr_inodes, unsigned int nr_ranges, int err,
> > + int snap_err),
> > +
> > + TP_ARGS(sb, commit_tid, locked_ns, nr_inodes, nr_ranges, err, snap_err),
> > +
> > + TP_STRUCT__entry(/* entry */
> > + __field(dev_t, dev)
> > + __field(tid_t, tid)
> > + __field(u64, locked_ns)
> > + __field(unsigned int, nr_inodes)
> > + __field(unsigned int, nr_ranges)
> > + __field(int, err)
> > + __field(int, snap_err)
> > + ),
> > +
> > + TP_fast_assign(/* assign */
> > + __entry->dev = sb->s_dev;
> > + __entry->tid = commit_tid;
> > + __entry->locked_ns = locked_ns;
> > + __entry->nr_inodes = nr_inodes;
> > + __entry->nr_ranges = nr_ranges;
> > + __entry->err = err;
> > + __entry->snap_err = snap_err;
> > + ),
> > +
> > + TP_printk("dev %d,%d tid %u locked_ns %llu nr_inodes %u nr_ranges %u err %d snap_err %d",
> > + MAJOR(__entry->dev), MINOR(__entry->dev), __entry->tid,
> > + __entry->locked_ns, __entry->nr_inodes, __entry->nr_ranges,
> > + __entry->err, __entry->snap_err)
>
> And instead of having the raw value of __entry->snap_err, use:
>
> __entry->err, __print_symbolic(__entry->snap_err, TRACE_SNAP_ERR))
Good point. I'll switch snap_err to __print_symbolic() in v5.
Regards,
Li
^ permalink raw reply
* Re: [PATCH] tracing: kprobe-event: Return directly when trace kprobes is empty
From: Steven Rostedt @ 2026-01-27 14:34 UTC (permalink / raw)
To: sunliming
Cc: ostedt, mhiramat, mathieu.desnoyers, linux-kernel,
linux-trace-kernel, sunliming
In-Reply-To: <20260127020137.90205-1-sunliming@linux.dev>
On Tue, 27 Jan 2026 10:01:37 +0800
sunliming@linux.dev wrote:
> From: sunliming <sunliming@kylinos.cn>
>
> In enable_boot_kprobe_events(), it returns directly when trace kprobes is
> empty, thereby reducing the function's execution time. This function may
> otherwise wait for the event_mutex lock for tens of milliseconds on certain
> machines, which is unnecessary when trace kprobes is empty.
>
> Signed-off-by: sunliming <sunliming@kylinos.cn>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Thanks,
-- Steve
> ---
> kernel/trace/trace_kprobe.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
> index 9953506370a5..95f2c42603d5 100644
> --- a/kernel/trace/trace_kprobe.c
> +++ b/kernel/trace/trace_kprobe.c
> @@ -82,6 +82,7 @@ static struct trace_kprobe *to_trace_kprobe(struct dyn_event *ev)
> #define for_each_trace_kprobe(pos, dpos) \
> for_each_dyn_event(dpos) \
> if (is_trace_kprobe(dpos) && (pos = to_trace_kprobe(dpos)))
> +#define trace_kprobe_list_empty() list_empty(&dyn_event_list)
>
> static nokprobe_inline bool trace_kprobe_is_return(struct trace_kprobe *tk)
> {
> @@ -1982,6 +1983,9 @@ static __init void enable_boot_kprobe_events(void)
> struct trace_kprobe *tk;
> struct dyn_event *pos;
>
> + if (trace_kprobe_list_empty())
> + return;
> +
> guard(mutex)(&event_mutex);
> for_each_trace_kprobe(tk, pos) {
> list_for_each_entry(file, &tr->events, list)
^ permalink raw reply
* [PATCH v13 11/18] unwind_user/sframe: Add .sframe validation option
From: Jens Remus @ 2026-01-27 15:05 UTC (permalink / raw)
To: linux-kernel, linux-trace-kernel, bpf, x86, linux-mm,
Steven Rostedt
Cc: Jens Remus, Josh Poimboeuf, Masami Hiramatsu, Mathieu Desnoyers,
Peter Zijlstra, Ingo Molnar, Jiri Olsa, Arnaldo Carvalho de Melo,
Namhyung Kim, Thomas Gleixner, Andrii Nakryiko, Indu Bhagat,
Jose E. Marchesi, Beau Belgrave, Linus Torvalds, Andrew Morton,
Florian Weimer, Kees Cook, Carlos O'Donell, Sam James,
Dylan Hatch, Borislav Petkov, Dave Hansen, David Hildenbrand,
H. Peter Anvin, Liam R. Howlett, Lorenzo Stoakes, Michal Hocko,
Mike Rapoport, Suren Baghdasaryan, Vlastimil Babka,
Heiko Carstens, Vasily Gorbik, Steven Rostedt (Google)
In-Reply-To: <20260127150554.2760964-1-jremus@linux.ibm.com>
From: Josh Poimboeuf <jpoimboe@kernel.org>
Add a debug feature to validate all .sframe sections when first loading
the file rather than on demand.
[ Jens Remus: Add support for SFrame V3. Add support for PC-relative
FDE function start offset. Adjust to rename of struct sframe_fre to
sframe_fre_internal. Use %#x/%#lx format specifiers. ]
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Indu Bhagat <indu.bhagat@oracle.com>
Cc: "Jose E. Marchesi" <jemarch@gnu.org>
Cc: Beau Belgrave <beaub@linux.microsoft.com>
Cc: Jens Remus <jremus@linux.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Florian Weimer <fweimer@redhat.com>
Cc: Sam James <sam@gentoo.org>
Cc: Kees Cook <kees@kernel.org>
Cc: "Carlos O'Donell" <codonell@redhat.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Jens Remus <jremus@linux.ibm.com>
---
Notes (jremus):
Changes in v13:
- Update to SFrame V3:
- Print struct sframe_fde_internal fields fda_off and info2 in debug
message.
- Adjust to rename of struct sframe_fde_internal field func_start_addr
to func_addr.
- Use format strings "%#x" and "%#lx" instead of "0x%x" and "0x%lx".
- Reword commit message (my changes).
arch/Kconfig | 19 ++++++++
kernel/unwind/sframe.c | 99 ++++++++++++++++++++++++++++++++++++++++++
2 files changed, 118 insertions(+)
diff --git a/arch/Kconfig b/arch/Kconfig
index 2ece3df821b5..dcb553136e0c 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -490,6 +490,25 @@ config HAVE_UNWIND_USER_SFRAME
bool
select UNWIND_USER
+config SFRAME_VALIDATION
+ bool "Enable .sframe section debugging"
+ depends on HAVE_UNWIND_USER_SFRAME
+ depends on DYNAMIC_DEBUG
+ help
+ When adding an .sframe section for a task, validate the entire
+ section immediately rather than on demand.
+
+ This is a debug feature which is helpful for rooting out .sframe
+ section issues. If the .sframe section is corrupt, it will fail to
+ load immediately, with more information provided in dynamic printks.
+
+ This has a significant page cache footprint due to its reading of the
+ entire .sframe section for every loaded executable and shared
+ library. Also, it's done for all processes, even those which don't
+ get stack traced by the kernel. Not recommended for general use.
+
+ If unsure, say N.
+
config HAVE_PERF_REGS
bool
help
diff --git a/kernel/unwind/sframe.c b/kernel/unwind/sframe.c
index 3276aa6d0c77..cf353bdbc907 100644
--- a/kernel/unwind/sframe.c
+++ b/kernel/unwind/sframe.c
@@ -367,6 +367,101 @@ int sframe_find(unsigned long ip, struct unwind_user_frame *frame)
return ret;
}
+#ifdef CONFIG_SFRAME_VALIDATION
+
+static int safe_read_fde(struct sframe_section *sec,
+ unsigned int fde_num, struct sframe_fde_internal *fde)
+{
+ int ret;
+
+ if (!user_read_access_begin((void __user *)sec->sframe_start,
+ sec->sframe_end - sec->sframe_start))
+ return -EFAULT;
+ ret = __read_fde(sec, fde_num, fde);
+ user_read_access_end();
+ return ret;
+}
+
+static int safe_read_fre(struct sframe_section *sec,
+ struct sframe_fde_internal *fde,
+ unsigned long fre_addr,
+ struct sframe_fre_internal *fre)
+{
+ int ret;
+
+ if (!user_read_access_begin((void __user *)sec->sframe_start,
+ sec->sframe_end - sec->sframe_start))
+ return -EFAULT;
+ ret = __read_fre(sec, fde, fre_addr, fre);
+ user_read_access_end();
+ return ret;
+}
+
+static int sframe_validate_section(struct sframe_section *sec)
+{
+ unsigned long prev_ip = 0;
+ unsigned int i;
+
+ for (i = 0; i < sec->num_fdes; i++) {
+ struct sframe_fre_internal *fre, *prev_fre = NULL;
+ unsigned long ip, fre_addr;
+ struct sframe_fde_internal fde;
+ struct sframe_fre_internal fres[2];
+ bool which = false;
+ unsigned int j;
+ int ret;
+
+ ret = safe_read_fde(sec, i, &fde);
+ if (ret)
+ return ret;
+
+ ip = fde.func_addr;
+ if (ip <= prev_ip) {
+ dbg_sec("fde %u not sorted\n", i);
+ return -EFAULT;
+ }
+ prev_ip = ip;
+
+ fre_addr = sec->fres_start + fde.fres_off;
+ for (j = 0; j < fde.fres_num; j++) {
+ int ret;
+
+ fre = which ? fres : fres + 1;
+ which = !which;
+
+ ret = safe_read_fre(sec, &fde, fre_addr, fre);
+ if (ret) {
+ dbg_sec("fde %u: __read_fre(%u) failed\n", i, j);
+ dbg_sec("FDE: func_addr:%#lx func_size:%#x fda_off:%#x fres_off:%#x fres_num:%d info:%u info2:%u rep_size:%u\n",
+ fde.func_addr, fde.func_size,
+ fde.fda_off,
+ fde.fres_off, fde.fres_num,
+ fde.info, fde.info2,
+ fde.rep_size);
+ return ret;
+ }
+
+ fre_addr += fre->size;
+
+ if (prev_fre && fre->ip_off <= prev_fre->ip_off) {
+ dbg_sec("fde %u: fre %u not sorted\n", i, j);
+ return -EFAULT;
+ }
+
+ prev_fre = fre;
+ }
+ }
+
+ return 0;
+}
+
+#else /* !CONFIG_SFRAME_VALIDATION */
+
+static int sframe_validate_section(struct sframe_section *sec) { return 0; }
+
+#endif /* !CONFIG_SFRAME_VALIDATION */
+
+
static void free_section(struct sframe_section *sec)
{
dbg_free(sec);
@@ -476,6 +571,10 @@ int sframe_add_section(unsigned long sframe_start, unsigned long sframe_end,
goto err_free;
}
+ ret = sframe_validate_section(sec);
+ if (ret)
+ goto err_free;
+
ret = mtree_insert_range(sframe_mt, sec->text_start, sec->text_end, sec, GFP_KERNEL);
if (ret) {
dbg_sec("mtree_insert_range failed: text=%lx-%lx\n",
--
2.51.0
^ permalink raw reply related
* [PATCH v13 15/18] unwind_user/sframe: Add support for SFrame V3 flexible FDEs
From: Jens Remus @ 2026-01-27 15:05 UTC (permalink / raw)
To: linux-kernel, linux-trace-kernel, bpf, x86, linux-mm,
Steven Rostedt
Cc: Jens Remus, Josh Poimboeuf, Masami Hiramatsu, Mathieu Desnoyers,
Peter Zijlstra, Ingo Molnar, Jiri Olsa, Arnaldo Carvalho de Melo,
Namhyung Kim, Thomas Gleixner, Andrii Nakryiko, Indu Bhagat,
Jose E. Marchesi, Beau Belgrave, Linus Torvalds, Andrew Morton,
Florian Weimer, Kees Cook, Carlos O'Donell, Sam James,
Dylan Hatch, Borislav Petkov, Dave Hansen, David Hildenbrand,
H. Peter Anvin, Liam R. Howlett, Lorenzo Stoakes, Michal Hocko,
Mike Rapoport, Suren Baghdasaryan, Vlastimil Babka,
Heiko Carstens, Vasily Gorbik
In-Reply-To: <20260127150554.2760964-1-jremus@linux.ibm.com>
SFrame V3 introduces flexible FDEs in addition to the regular FDEs.
The key difference is that flexible FDEs encode the CFA, RA, and FP
tracking information using two FRE data words, a control word and an
offset, or a single padding data word of zero (e.g. to represent FP
without RA tracking information).
The control word contains the following information:
- reg_p: Whether to use the register contents (reg_p=1) specified
by regnum or the CFA (reg_p=0) as base.
- deref_p: Whether to dereference.
- regnum: A DWARF register number.
The offset is added to the base (i.e. CFA or register contents). Then
the resulting address may optionally be dereferenced.
This enables the following flexible CFA and FP/RA recovery rules:
- CFA = register + offset // reg_p=1, deref_p=0
- CFA = *(register + offset) // reg_p=1, deref_p=1
- FP/RA = *(CFA + offset) // reg_p=0, deref_p=0
- FP/RA = register + offset // reg_p=1, deref_p=0
- FP/RA = *(register + offset) // reg_p=1, deref_p=1
Note that for the CFA a rule with reg_p=0 is invalid, as the value of
the CFA cannot be described using itself as base. For FP/RA a rule with
reg_p=0 and deref_p=0 and regnum=0 is invalid, as it that is equal to
the padding data word of zero.
Cc: Steven Rostedt <rostedt@kernel.org>
Cc: Josh Poimboeuf <jpoimboe@kernel.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Indu Bhagat <indu.bhagat@oracle.com>
Cc: "Jose E. Marchesi" <jemarch@gnu.org>
Cc: Beau Belgrave <beaub@linux.microsoft.com>
Cc: Jens Remus <jremus@linux.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Florian Weimer <fweimer@redhat.com>
Cc: Sam James <sam@gentoo.org>
Cc: Kees Cook <kees@kernel.org>
Cc: "Carlos O'Donell" <codonell@redhat.com>
Signed-off-by: Jens Remus <jremus@linux.ibm.com>
---
Notes (jremus):
Changes in v13:
- New patch.
kernel/unwind/sframe.c | 249 ++++++++++++++++++++++++++++++++---------
kernel/unwind/sframe.h | 5 +
2 files changed, 204 insertions(+), 50 deletions(-)
diff --git a/kernel/unwind/sframe.c b/kernel/unwind/sframe.c
index 4dfc8cf2075e..ebf2a2905c5c 100644
--- a/kernel/unwind/sframe.c
+++ b/kernel/unwind/sframe.c
@@ -12,6 +12,7 @@
#include <linux/mm.h>
#include <linux/string_helpers.h>
#include <linux/sframe.h>
+#include <asm/unwind_user_sframe.h>
#include <linux/unwind_user_types.h>
#include "sframe.h"
@@ -31,8 +32,11 @@ struct sframe_fde_internal {
struct sframe_fre_internal {
unsigned int size;
u32 ip_off;
+ u32 cfa_ctl;
s32 cfa_off;
+ u32 ra_ctl;
s32 ra_off;
+ u32 fp_ctl;
s32 fp_off;
u8 info;
};
@@ -189,16 +193,147 @@ static __always_inline int __find_fde(struct sframe_section *sec,
s32 : UNSAFE_GET_USER_SIGNED_INC(to, from, size, label), \
s64 : UNSAFE_GET_USER_SIGNED_INC(to, from, size, label))
+static __always_inline int
+__read_regular_fre_datawords(struct sframe_section *sec,
+ struct sframe_fde_internal *fde,
+ unsigned long cur,
+ unsigned char dataword_count,
+ unsigned char dataword_size,
+ struct sframe_fre_internal *fre)
+{
+ s32 cfa_off, ra_off, fp_off;
+ unsigned int cfa_regnum;
+
+ UNSAFE_GET_USER_INC(cfa_off, cur, dataword_size, Efault);
+ dataword_count--;
+
+ ra_off = sec->ra_off;
+ if (!ra_off && dataword_count) {
+ dataword_count--;
+ UNSAFE_GET_USER_INC(ra_off, cur, dataword_size, Efault);
+ }
+
+ fp_off = sec->fp_off;
+ if (!fp_off && dataword_count) {
+ dataword_count--;
+ UNSAFE_GET_USER_INC(fp_off, cur, dataword_size, Efault);
+ }
+
+ if (dataword_count)
+ return -EFAULT;
+
+ cfa_regnum =
+ (SFRAME_V3_FRE_CFA_BASE_REG_ID(fre->info) == SFRAME_BASE_REG_FP) ?
+ SFRAME_REG_FP : SFRAME_REG_SP;
+
+ fre->cfa_ctl = (cfa_regnum << 3) | 1; /* regnum, deref_p=0, reg_p=1 */
+ fre->cfa_off = cfa_off;
+ fre->ra_ctl = ra_off ? 2 : 0; /* regnum=0, deref_p=(ra_off != 0), reg_p=0 */
+ fre->ra_off = ra_off;
+ fre->fp_ctl = fp_off ? 2 : 0; /* regnum=0, deref_p=(fp_off != 0), reg_p=0 */
+ fre->fp_off = fp_off;
+
+ return 0;
+
+Efault:
+ return -EFAULT;
+}
+
+static __always_inline int
+__read_flex_fde_fre_datawords(struct sframe_section *sec,
+ struct sframe_fde_internal *fde,
+ unsigned long cur,
+ unsigned char dataword_count,
+ unsigned char dataword_size,
+ struct sframe_fre_internal *fre)
+{
+ u32 cfa_ctl, ra_ctl, fp_ctl;
+ s32 cfa_off, ra_off, fp_off;
+
+ if (dataword_count < 2)
+ return -EFAULT;
+ UNSAFE_GET_USER_INC(cfa_ctl, cur, dataword_size, Efault);
+ UNSAFE_GET_USER_INC(cfa_off, cur, dataword_size, Efault);
+ dataword_count -= 2;
+
+ ra_off = sec->ra_off;
+ ra_ctl = ra_off ? 2 : 0; /* regnum=0, deref_p=(ra_off != 0), reg_p=0 */
+ if (dataword_count >= 2) {
+ UNSAFE_GET_USER_INC(ra_ctl, cur, dataword_size, Efault);
+ dataword_count--;
+ if (ra_ctl) {
+ UNSAFE_GET_USER_INC(ra_off, cur, dataword_size, Efault);
+ dataword_count--;
+ } else {
+ /* Padding RA location info */
+ ra_ctl = ra_off ? 2 : 0; /* re-deduce (see above) */
+ }
+ }
+
+ fp_off = sec->fp_off;
+ fp_ctl = fp_off ? 2 : 0; /* regnum=0, deref_p=(fp_off != 0), reg_p=0 */
+ if (dataword_count >= 2) {
+ UNSAFE_GET_USER_INC(fp_ctl, cur, dataword_size, Efault);
+ dataword_count--;
+ if (fp_ctl) {
+ UNSAFE_GET_USER_INC(fp_off, cur, dataword_size, Efault);
+ dataword_count--;
+ } else {
+ /* Padding FP location info */
+ fp_ctl = fp_off ? 2 : 0; /* re-deduce (see above) */
+ }
+ }
+
+ if (dataword_count)
+ return -EFAULT;
+
+ fre->cfa_ctl = cfa_ctl;
+ fre->cfa_off = cfa_off;
+ fre->ra_ctl = ra_ctl;
+ fre->ra_off = ra_off;
+ fre->fp_ctl = fp_ctl;
+ fre->fp_off = fp_off;
+
+ return 0;
+
+Efault:
+ return -EFAULT;
+}
+
+static __always_inline int
+__read_fre_datawords(struct sframe_section *sec,
+ struct sframe_fde_internal *fde,
+ unsigned long cur,
+ unsigned char dataword_count,
+ unsigned char dataword_size,
+ struct sframe_fre_internal *fre)
+{
+ unsigned char fde_type = SFRAME_V3_FDE_TYPE(fde->info2);
+
+ switch (fde_type) {
+ case SFRAME_FDE_TYPE_REGULAR:
+ return __read_regular_fre_datawords(sec, fde, cur,
+ dataword_count,
+ dataword_size,
+ fre);
+ case SFRAME_FDE_TYPE_FLEXIBLE:
+ return __read_flex_fde_fre_datawords(sec, fde, cur,
+ dataword_count,
+ dataword_size,
+ fre);
+ default:
+ return -EFAULT;
+ }
+}
+
static __always_inline int __read_fre(struct sframe_section *sec,
struct sframe_fde_internal *fde,
unsigned long fre_addr,
struct sframe_fre_internal *fre)
{
- unsigned char fde_type = SFRAME_V3_FDE_TYPE(fde->info2);
unsigned char fde_pctype = SFRAME_V3_FDE_PCTYPE(fde->info);
unsigned char fre_type = SFRAME_V3_FDE_FRE_TYPE(fde->info);
unsigned char dataword_count, dataword_size;
- s32 cfa_off, ra_off, fp_off;
unsigned long cur = fre_addr;
unsigned char addr_size;
u32 ip_off;
@@ -224,75 +359,88 @@ static __always_inline int __read_fre(struct sframe_section *sec,
if (cur + (dataword_count * dataword_size) > sec->fres_end)
return -EFAULT;
- /* TODO: Support for flexible FDEs not implemented yet. */
- if (fde_type != SFRAME_FDE_TYPE_REGULAR)
- return -EFAULT;
+ fre->size = addr_size + 1 + (dataword_count * dataword_size);
+ fre->ip_off = ip_off;
+ fre->info = info;
if (!dataword_count) {
/*
* A FRE without data words indicates RA undefined /
* outermost frame.
*/
- cfa_off = 0;
- ra_off = 0;
- fp_off = 0;
- goto done;
- }
+ fre->cfa_ctl = 0;
+ fre->cfa_off = 0;
+ fre->ra_ctl = 0;
+ fre->ra_off = 0;
+ fre->fp_ctl = 0;
+ fre->fp_off = 0;
- UNSAFE_GET_USER_INC(cfa_off, cur, dataword_size, Efault);
- dataword_count--;
-
- ra_off = sec->ra_off;
- if (!ra_off && dataword_count) {
- dataword_count--;
- UNSAFE_GET_USER_INC(ra_off, cur, dataword_size, Efault);
- }
-
- fp_off = sec->fp_off;
- if (!fp_off && dataword_count) {
- dataword_count--;
- UNSAFE_GET_USER_INC(fp_off, cur, dataword_size, Efault);
+ return 0;
}
- if (dataword_count)
- return -EFAULT;
-
-done:
- fre->size = addr_size + 1 + (dataword_count * dataword_size);
- fre->ip_off = ip_off;
- fre->cfa_off = cfa_off;
- fre->ra_off = ra_off;
- fre->fp_off = fp_off;
- fre->info = info;
-
- return 0;
+ return __read_fre_datawords(sec, fde, cur, dataword_count, dataword_size, fre);
Efault:
return -EFAULT;
}
-static __always_inline void
+static __always_inline int
sframe_init_cfa_rule_data(struct unwind_user_cfa_rule_data *cfa_rule_data,
- unsigned char fre_info,
- s32 offset)
+ u32 ctlword, s32 offset)
{
- if (SFRAME_V3_FRE_CFA_BASE_REG_ID(fre_info) == SFRAME_BASE_REG_FP)
- cfa_rule_data->rule = UNWIND_USER_CFA_RULE_FP_OFFSET;
- else
- cfa_rule_data->rule = UNWIND_USER_CFA_RULE_SP_OFFSET;
+ bool deref_p = SFRAME_V3_FLEX_FDE_CTLWORD_DEREF_P(ctlword);
+ bool reg_p = SFRAME_V3_FLEX_FDE_CTLWORD_REG_P(ctlword);
+
+ if (reg_p) {
+ unsigned int regnum = SFRAME_V3_FLEX_FDE_CTLWORD_REGNUM(ctlword);
+
+ switch (regnum) {
+ case SFRAME_REG_SP:
+ cfa_rule_data->rule = UNWIND_USER_CFA_RULE_SP_OFFSET;
+ break;
+ case SFRAME_REG_FP:
+ cfa_rule_data->rule = UNWIND_USER_CFA_RULE_FP_OFFSET;
+ break;
+ default:
+ cfa_rule_data->rule = UNWIND_USER_CFA_RULE_REG_OFFSET;
+ cfa_rule_data->regnum = regnum;
+ }
+ } else {
+ return -EINVAL;
+ }
+
+ if (deref_p)
+ cfa_rule_data->rule |= UNWIND_USER_RULE_DEREF;
+
cfa_rule_data->offset = offset;
+
+ return 0;
}
static __always_inline void
sframe_init_rule_data(struct unwind_user_rule_data *rule_data,
- s32 offset)
+ u32 ctlword, s32 offset)
{
- if (offset) {
- rule_data->rule = UNWIND_USER_RULE_CFA_OFFSET_DEREF;
- rule_data->offset = offset;
- } else {
+ bool deref_p = SFRAME_V3_FLEX_FDE_CTLWORD_DEREF_P(ctlword);
+ bool reg_p = SFRAME_V3_FLEX_FDE_CTLWORD_REG_P(ctlword);
+
+ if (!ctlword && !offset) {
rule_data->rule = UNWIND_USER_RULE_RETAIN;
+ return;
+ }
+ if (reg_p) {
+ unsigned int regnum = SFRAME_V3_FLEX_FDE_CTLWORD_REGNUM(ctlword);
+
+ rule_data->rule = UNWIND_USER_RULE_REG_OFFSET;
+ rule_data->regnum = regnum;
+ } else {
+ rule_data->rule = UNWIND_USER_RULE_CFA_OFFSET;
}
+
+ if (deref_p)
+ rule_data->rule |= UNWIND_USER_RULE_DEREF;
+
+ rule_data->offset = offset;
}
static __always_inline int __find_fre(struct sframe_section *sec,
@@ -344,9 +492,10 @@ static __always_inline int __find_fre(struct sframe_section *sec,
return -EINVAL;
fre = prev_fre;
- sframe_init_cfa_rule_data(&frame->cfa, fre->info, fre->cfa_off);
- sframe_init_rule_data(&frame->ra, fre->ra_off);
- sframe_init_rule_data(&frame->fp, fre->fp_off);
+ if (sframe_init_cfa_rule_data(&frame->cfa, fre->cfa_ctl, fre->cfa_off))
+ return -EINVAL;
+ sframe_init_rule_data(&frame->ra, fre->ra_ctl, fre->ra_off);
+ sframe_init_rule_data(&frame->fp, fre->fp_ctl, fre->fp_off);
frame->outermost = SFRAME_V3_FRE_RA_UNDEFINED_P(fre->info);
return 0;
diff --git a/kernel/unwind/sframe.h b/kernel/unwind/sframe.h
index 3fcc15534e5a..5b6112945b6c 100644
--- a/kernel/unwind/sframe.h
+++ b/kernel/unwind/sframe.h
@@ -66,6 +66,7 @@ struct sframe_fda_v3 {
#define SFRAME_V3_AARCH64_FDE_PAUTH_KEY(info) (((info) >> 5) & 0x1)
#define SFRAME_FDE_TYPE_REGULAR 0
+#define SFRAME_FDE_TYPE_FLEXIBLE 1
#define SFRAME_V3_FDE_TYPE_MASK 0x0f
#define SFRAME_V3_FDE_TYPE(info2) ((info2) & SFRAME_V3_FDE_TYPE_MASK)
@@ -79,4 +80,8 @@ struct sframe_fda_v3 {
#define SFRAME_V3_AARCH64_FRE_MANGLED_RA_P(info) (((info) >> 7) & 0x1)
#define SFRAME_V3_FRE_RA_UNDEFINED_P(info) (SFRAME_V3_FRE_DATAWORD_COUNT(info) == 0)
+#define SFRAME_V3_FLEX_FDE_CTLWORD_REGNUM(data) (((data) >> 3) & 0x1f)
+#define SFRAME_V3_FLEX_FDE_CTLWORD_DEREF_P(data) (((data) >> 1) & 0x1)
+#define SFRAME_V3_FLEX_FDE_CTLWORD_REG_P(data) ((data) & 0x1)
+
#endif /* _SFRAME_H */
--
2.51.0
^ permalink raw reply related
* [PATCH v13 09/18] unwind_user/sframe: Remove .sframe section on detected corruption
From: Jens Remus @ 2026-01-27 15:05 UTC (permalink / raw)
To: linux-kernel, linux-trace-kernel, bpf, x86, linux-mm,
Steven Rostedt
Cc: Jens Remus, Josh Poimboeuf, Masami Hiramatsu, Mathieu Desnoyers,
Peter Zijlstra, Ingo Molnar, Jiri Olsa, Arnaldo Carvalho de Melo,
Namhyung Kim, Thomas Gleixner, Andrii Nakryiko, Indu Bhagat,
Jose E. Marchesi, Beau Belgrave, Linus Torvalds, Andrew Morton,
Florian Weimer, Kees Cook, Carlos O'Donell, Sam James,
Dylan Hatch, Borislav Petkov, Dave Hansen, David Hildenbrand,
H. Peter Anvin, Liam R. Howlett, Lorenzo Stoakes, Michal Hocko,
Mike Rapoport, Suren Baghdasaryan, Vlastimil Babka,
Heiko Carstens, Vasily Gorbik, Steven Rostedt (Google)
In-Reply-To: <20260127150554.2760964-1-jremus@linux.ibm.com>
From: Josh Poimboeuf <jpoimboe@kernel.org>
To avoid continued attempted use of a bad .sframe section, remove it
on demand when the first sign of corruption is detected.
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Indu Bhagat <indu.bhagat@oracle.com>
Cc: "Jose E. Marchesi" <jemarch@gnu.org>
Cc: Beau Belgrave <beaub@linux.microsoft.com>
Cc: Jens Remus <jremus@linux.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Florian Weimer <fweimer@redhat.com>
Cc: Sam James <sam@gentoo.org>
Cc: Kees Cook <kees@kernel.org>
Cc: "Carlos O'Donell" <codonell@redhat.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Jens Remus <jremus@linux.ibm.com>
---
kernel/unwind/sframe.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/kernel/unwind/sframe.c b/kernel/unwind/sframe.c
index 6004b43aac34..9a63f8828593 100644
--- a/kernel/unwind/sframe.c
+++ b/kernel/unwind/sframe.c
@@ -358,6 +358,10 @@ int sframe_find(unsigned long ip, struct unwind_user_frame *frame)
ret = __find_fre(sec, &fde, ip, frame);
end:
user_read_access_end();
+
+ if (ret == -EFAULT)
+ WARN_ON_ONCE(sframe_remove_section(sec->sframe_start));
+
return ret;
}
--
2.51.0
^ permalink raw reply related
* [PATCH v13 02/18] unwind_user/sframe: Store .sframe section data in per-mm maple tree
From: Jens Remus @ 2026-01-27 15:05 UTC (permalink / raw)
To: linux-kernel, linux-trace-kernel, bpf, x86, linux-mm,
Steven Rostedt
Cc: Jens Remus, Josh Poimboeuf, Masami Hiramatsu, Mathieu Desnoyers,
Peter Zijlstra, Ingo Molnar, Jiri Olsa, Arnaldo Carvalho de Melo,
Namhyung Kim, Thomas Gleixner, Andrii Nakryiko, Indu Bhagat,
Jose E. Marchesi, Beau Belgrave, Linus Torvalds, Andrew Morton,
Florian Weimer, Kees Cook, Carlos O'Donell, Sam James,
Dylan Hatch, Borislav Petkov, Dave Hansen, David Hildenbrand,
H. Peter Anvin, Liam R. Howlett, Lorenzo Stoakes, Michal Hocko,
Mike Rapoport, Suren Baghdasaryan, Vlastimil Babka,
Heiko Carstens, Vasily Gorbik, Steven Rostedt (Google)
In-Reply-To: <20260127150554.2760964-1-jremus@linux.ibm.com>
From: Josh Poimboeuf <jpoimboe@kernel.org>
Associate an .sframe section with its mm by adding it to a per-mm maple
tree which is indexed by the corresponding text address range. A single
.sframe section can be associated with multiple text ranges.
[ Jens Remus: Minor cleanups. Reword commit subject/message. ]
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Indu Bhagat <indu.bhagat@oracle.com>
Cc: "Jose E. Marchesi" <jemarch@gnu.org>
Cc: Beau Belgrave <beaub@linux.microsoft.com>
Cc: Jens Remus <jremus@linux.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Florian Weimer <fweimer@redhat.com>
Cc: Sam James <sam@gentoo.org>
Cc: Kees Cook <kees@kernel.org>
Cc: "Carlos O'Donell" <codonell@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: "Liam R. Howlett" <Liam.Howlett@oracle.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: x86@kernel.org
Cc: linux-mm@kvack.org
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Jens Remus <jremus@linux.ibm.com>
---
arch/x86/include/asm/mmu.h | 2 +-
include/linux/mm_types.h | 3 ++
include/linux/sframe.h | 15 ++++++++++
kernel/fork.c | 10 +++++++
kernel/unwind/sframe.c | 56 ++++++++++++++++++++++++++++++++++++--
mm/init-mm.c | 2 ++
6 files changed, 84 insertions(+), 4 deletions(-)
diff --git a/arch/x86/include/asm/mmu.h b/arch/x86/include/asm/mmu.h
index 0fe9c569d171..227a32899a59 100644
--- a/arch/x86/include/asm/mmu.h
+++ b/arch/x86/include/asm/mmu.h
@@ -87,7 +87,7 @@ typedef struct {
.context = { \
.ctx_id = 1, \
.lock = __MUTEX_INITIALIZER(mm.context.lock), \
- }
+ },
void leave_mm(void);
#define leave_mm leave_mm
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 9f6de068295d..c764d00fa522 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -1323,6 +1323,9 @@ struct mm_struct {
#ifdef CONFIG_MM_ID
mm_id_t mm_id;
#endif /* CONFIG_MM_ID */
+#ifdef CONFIG_HAVE_UNWIND_USER_SFRAME
+ struct maple_tree sframe_mt;
+#endif
} __randomize_layout;
/*
diff --git a/include/linux/sframe.h b/include/linux/sframe.h
index 0642595534f9..7ea6a97ed8af 100644
--- a/include/linux/sframe.h
+++ b/include/linux/sframe.h
@@ -2,6 +2,8 @@
#ifndef _LINUX_SFRAME_H
#define _LINUX_SFRAME_H
+#include <linux/mm_types.h>
+
#ifdef CONFIG_HAVE_UNWIND_USER_SFRAME
struct sframe_section {
@@ -19,18 +21,31 @@ struct sframe_section {
signed char fp_off;
};
+#define INIT_MM_SFRAME .sframe_mt = MTREE_INIT(sframe_mt, 0),
+extern void sframe_free_mm(struct mm_struct *mm);
+
extern int sframe_add_section(unsigned long sframe_start, unsigned long sframe_end,
unsigned long text_start, unsigned long text_end);
extern int sframe_remove_section(unsigned long sframe_addr);
+static inline bool current_has_sframe(void)
+{
+ struct mm_struct *mm = current->mm;
+
+ return mm && !mtree_empty(&mm->sframe_mt);
+}
+
#else /* !CONFIG_HAVE_UNWIND_USER_SFRAME */
+#define INIT_MM_SFRAME
+static inline void sframe_free_mm(struct mm_struct *mm) {}
static inline int sframe_add_section(unsigned long sframe_start, unsigned long sframe_end,
unsigned long text_start, unsigned long text_end)
{
return -ENOSYS;
}
static inline int sframe_remove_section(unsigned long sframe_addr) { return -ENOSYS; }
+static inline bool current_has_sframe(void) { return false; }
#endif /* CONFIG_HAVE_UNWIND_USER_SFRAME */
diff --git a/kernel/fork.c b/kernel/fork.c
index b1f3915d5f8e..d8a7a32f8b81 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -107,6 +107,7 @@
#include <linux/tick.h>
#include <linux/unwind_deferred.h>
#include <linux/pgalloc.h>
+#include <linux/sframe.h>
#include <linux/uaccess.h>
#include <asm/mmu_context.h>
@@ -732,6 +733,7 @@ void __mmdrop(struct mm_struct *mm)
mm_pasid_drop(mm);
mm_destroy_cid(mm);
percpu_counter_destroy_many(mm->rss_stat, NR_MM_COUNTERS);
+ sframe_free_mm(mm);
free_mm(mm);
}
@@ -1067,6 +1069,13 @@ static void mmap_init_lock(struct mm_struct *mm)
#endif
}
+static void mm_init_sframe(struct mm_struct *mm)
+{
+#ifdef CONFIG_HAVE_UNWIND_USER_SFRAME
+ mt_init(&mm->sframe_mt);
+#endif
+}
+
static struct mm_struct *mm_init(struct mm_struct *mm, struct task_struct *p,
struct user_namespace *user_ns)
{
@@ -1095,6 +1104,7 @@ static struct mm_struct *mm_init(struct mm_struct *mm, struct task_struct *p,
mm->pmd_huge_pte = NULL;
#endif
mm_init_uprobes_state(mm);
+ mm_init_sframe(mm);
hugetlb_count_init(mm);
mm_flags_clear_all(mm);
diff --git a/kernel/unwind/sframe.c b/kernel/unwind/sframe.c
index c128c1eeaca2..fdb2a4908563 100644
--- a/kernel/unwind/sframe.c
+++ b/kernel/unwind/sframe.c
@@ -81,6 +81,7 @@ static int sframe_read_header(struct sframe_section *sec)
int sframe_add_section(unsigned long sframe_start, unsigned long sframe_end,
unsigned long text_start, unsigned long text_end)
{
+ struct maple_tree *sframe_mt = ¤t->mm->sframe_mt;
struct vm_area_struct *sframe_vma, *text_vma;
struct mm_struct *mm = current->mm;
struct sframe_section *sec;
@@ -122,15 +123,64 @@ int sframe_add_section(unsigned long sframe_start, unsigned long sframe_end,
if (ret)
goto err_free;
- /* TODO nowhere to store it yet - just free it and return an error */
- ret = -ENOSYS;
+ ret = mtree_insert_range(sframe_mt, sec->text_start, sec->text_end, sec, GFP_KERNEL);
+ if (ret) {
+ dbg("mtree_insert_range failed: text=%lx-%lx\n",
+ sec->text_start, sec->text_end);
+ goto err_free;
+ }
+
+ return 0;
err_free:
free_section(sec);
return ret;
}
+static int __sframe_remove_section(struct mm_struct *mm,
+ struct sframe_section *sec)
+{
+ if (!mtree_erase(&mm->sframe_mt, sec->text_start)) {
+ dbg("mtree_erase failed: text=%lx\n", sec->text_start);
+ return -EINVAL;
+ }
+
+ free_section(sec);
+
+ return 0;
+}
+
int sframe_remove_section(unsigned long sframe_start)
{
- return -ENOSYS;
+ struct mm_struct *mm = current->mm;
+ struct sframe_section *sec;
+ unsigned long index = 0;
+ bool found = false;
+ int ret = 0;
+
+ mt_for_each(&mm->sframe_mt, sec, index, ULONG_MAX) {
+ if (sec->sframe_start == sframe_start) {
+ found = true;
+ ret |= __sframe_remove_section(mm, sec);
+ }
+ }
+
+ if (!found || ret)
+ return -EINVAL;
+
+ return 0;
+}
+
+void sframe_free_mm(struct mm_struct *mm)
+{
+ struct sframe_section *sec;
+ unsigned long index = 0;
+
+ if (!mm)
+ return;
+
+ mt_for_each(&mm->sframe_mt, sec, index, ULONG_MAX)
+ free_section(sec);
+
+ mtree_destroy(&mm->sframe_mt);
}
diff --git a/mm/init-mm.c b/mm/init-mm.c
index 4600e7605cab..b32fcf167cc2 100644
--- a/mm/init-mm.c
+++ b/mm/init-mm.c
@@ -11,6 +11,7 @@
#include <linux/atomic.h>
#include <linux/user_namespace.h>
#include <linux/iommu.h>
+#include <linux/sframe.h>
#include <asm/mmu.h>
#ifndef INIT_MM_CONTEXT
@@ -46,6 +47,7 @@ struct mm_struct init_mm = {
.user_ns = &init_user_ns,
.cpu_bitmap = CPU_BITS_NONE,
INIT_MM_CONTEXT(init_mm)
+ INIT_MM_SFRAME
};
void setup_initial_init_mm(void *start_code, void *end_code,
--
2.51.0
^ permalink raw reply related
* [PATCH v13 14/18] unwind_user: Flexible CFA recovery rules
From: Jens Remus @ 2026-01-27 15:05 UTC (permalink / raw)
To: linux-kernel, linux-trace-kernel, bpf, x86, linux-mm,
Steven Rostedt
Cc: Jens Remus, Josh Poimboeuf, Masami Hiramatsu, Mathieu Desnoyers,
Peter Zijlstra, Ingo Molnar, Jiri Olsa, Arnaldo Carvalho de Melo,
Namhyung Kim, Thomas Gleixner, Andrii Nakryiko, Indu Bhagat,
Jose E. Marchesi, Beau Belgrave, Linus Torvalds, Andrew Morton,
Florian Weimer, Kees Cook, Carlos O'Donell, Sam James,
Dylan Hatch, Borislav Petkov, Dave Hansen, David Hildenbrand,
H. Peter Anvin, Liam R. Howlett, Lorenzo Stoakes, Michal Hocko,
Mike Rapoport, Suren Baghdasaryan, Vlastimil Babka,
Heiko Carstens, Vasily Gorbik
In-Reply-To: <20260127150554.2760964-1-jremus@linux.ibm.com>
To enable support for SFrame V3 flexible FDEs with a subsequent patch,
add support for the following flexible Canonical Frame Address (CFA)
recovery rules:
CFA = SP + offset
CFA = FP + offset
CFA = register + offset
CFA = *(register + offset)
Note that CFA recovery rules that use arbitrary register contents are
only valid when in the topmost frame, as their contents are otherwise
unknown.
Cc: Steven Rostedt <rostedt@kernel.org>
Cc: Josh Poimboeuf <jpoimboe@kernel.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Indu Bhagat <indu.bhagat@oracle.com>
Cc: "Jose E. Marchesi" <jemarch@gnu.org>
Cc: Beau Belgrave <beaub@linux.microsoft.com>
Cc: Jens Remus <jremus@linux.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Florian Weimer <fweimer@redhat.com>
Cc: Sam James <sam@gentoo.org>
Cc: Kees Cook <kees@kernel.org>
Cc: "Carlos O'Donell" <codonell@redhat.com>
Signed-off-by: Jens Remus <jremus@linux.ibm.com>
---
Notes (jremus):
Changes in v13:
- New patch.
arch/x86/include/asm/unwind_user.h | 12 ++++++++----
include/linux/unwind_user_types.h | 18 ++++++++++++++++--
kernel/unwind/sframe.c | 15 +++++++++++++--
kernel/unwind/user.c | 22 ++++++++++++++++++----
4 files changed, 55 insertions(+), 12 deletions(-)
diff --git a/arch/x86/include/asm/unwind_user.h b/arch/x86/include/asm/unwind_user.h
index 9c3417be4283..f38f7c5ff1de 100644
--- a/arch/x86/include/asm/unwind_user.h
+++ b/arch/x86/include/asm/unwind_user.h
@@ -20,7 +20,10 @@ static inline int unwind_user_word_size(struct pt_regs *regs)
#ifdef CONFIG_HAVE_UNWIND_USER_FP
#define ARCH_INIT_USER_FP_FRAME(ws) \
- .cfa_off = 2*(ws), \
+ .cfa = { \
+ .rule = UNWIND_USER_CFA_RULE_FP_OFFSET,\
+ .offset = 2*(ws), \
+ }, \
.ra = { \
.rule = UNWIND_USER_RULE_CFA_OFFSET_DEREF,\
.offset = -1*(ws), \
@@ -29,11 +32,13 @@ static inline int unwind_user_word_size(struct pt_regs *regs)
.rule = UNWIND_USER_RULE_CFA_OFFSET_DEREF,\
.offset = -2*(ws), \
}, \
- .use_fp = true, \
.outermost = false,
#define ARCH_INIT_USER_FP_ENTRY_FRAME(ws) \
- .cfa_off = 1*(ws), \
+ .cfa = { \
+ .rule = UNWIND_USER_CFA_RULE_SP_OFFSET,\
+ .offset = 1*(ws), \
+ }, \
.ra = { \
.rule = UNWIND_USER_RULE_CFA_OFFSET_DEREF,\
.offset = -1*(ws), \
@@ -41,7 +46,6 @@ static inline int unwind_user_word_size(struct pt_regs *regs)
.fp = { \
.rule = UNWIND_USER_RULE_RETAIN,\
}, \
- .use_fp = false, \
.outermost = false,
static inline bool unwind_user_at_function_start(struct pt_regs *regs)
diff --git a/include/linux/unwind_user_types.h b/include/linux/unwind_user_types.h
index 0d02714a1b5d..059e5c76f2f3 100644
--- a/include/linux/unwind_user_types.h
+++ b/include/linux/unwind_user_types.h
@@ -29,6 +29,21 @@ struct unwind_stacktrace {
#define UNWIND_USER_RULE_DEREF BIT(31)
+enum unwind_user_cfa_rule {
+ UNWIND_USER_CFA_RULE_SP_OFFSET, /* CFA = SP + offset */
+ UNWIND_USER_CFA_RULE_FP_OFFSET, /* CFA = FP + offset */
+ UNWIND_USER_CFA_RULE_REG_OFFSET, /* CFA = reg + offset */
+ /* DEREF variants */
+ UNWIND_USER_CFA_RULE_REG_OFFSET_DEREF = /* CFA = *(reg + offset) */
+ UNWIND_USER_CFA_RULE_REG_OFFSET | UNWIND_USER_RULE_DEREF,
+};
+
+struct unwind_user_cfa_rule_data {
+ enum unwind_user_cfa_rule rule;
+ s32 offset;
+ unsigned int regnum;
+};
+
enum unwind_user_rule {
UNWIND_USER_RULE_RETAIN, /* entity = entity */
UNWIND_USER_RULE_CFA_OFFSET, /* entity = CFA + offset */
@@ -47,10 +62,9 @@ struct unwind_user_rule_data {
};
struct unwind_user_frame {
- s32 cfa_off;
+ struct unwind_user_cfa_rule_data cfa;
struct unwind_user_rule_data ra;
struct unwind_user_rule_data fp;
- bool use_fp;
bool outermost;
};
diff --git a/kernel/unwind/sframe.c b/kernel/unwind/sframe.c
index b5301fa9dbc8..4dfc8cf2075e 100644
--- a/kernel/unwind/sframe.c
+++ b/kernel/unwind/sframe.c
@@ -271,6 +271,18 @@ static __always_inline int __read_fre(struct sframe_section *sec,
return -EFAULT;
}
+static __always_inline void
+sframe_init_cfa_rule_data(struct unwind_user_cfa_rule_data *cfa_rule_data,
+ unsigned char fre_info,
+ s32 offset)
+{
+ if (SFRAME_V3_FRE_CFA_BASE_REG_ID(fre_info) == SFRAME_BASE_REG_FP)
+ cfa_rule_data->rule = UNWIND_USER_CFA_RULE_FP_OFFSET;
+ else
+ cfa_rule_data->rule = UNWIND_USER_CFA_RULE_SP_OFFSET;
+ cfa_rule_data->offset = offset;
+}
+
static __always_inline void
sframe_init_rule_data(struct unwind_user_rule_data *rule_data,
s32 offset)
@@ -332,10 +344,9 @@ static __always_inline int __find_fre(struct sframe_section *sec,
return -EINVAL;
fre = prev_fre;
- frame->cfa_off = fre->cfa_off;
+ sframe_init_cfa_rule_data(&frame->cfa, fre->info, fre->cfa_off);
sframe_init_rule_data(&frame->ra, fre->ra_off);
sframe_init_rule_data(&frame->fp, fre->fp_off);
- frame->use_fp = SFRAME_V3_FRE_CFA_BASE_REG_ID(fre->info) == SFRAME_BASE_REG_FP;
frame->outermost = SFRAME_V3_FRE_RA_UNDEFINED_P(fre->info);
return 0;
diff --git a/kernel/unwind/user.c b/kernel/unwind/user.c
index 0405922c5c0d..eb7d9489f671 100644
--- a/kernel/unwind/user.c
+++ b/kernel/unwind/user.c
@@ -39,14 +39,28 @@ static int unwind_user_next_common(struct unwind_user_state *state,
}
/* Get the Canonical Frame Address (CFA) */
- if (frame->use_fp) {
+ switch (frame->cfa.rule) {
+ case UNWIND_USER_CFA_RULE_SP_OFFSET:
+ cfa = state->sp;
+ break;
+ case UNWIND_USER_CFA_RULE_FP_OFFSET:
if (state->fp < state->sp)
return -EINVAL;
cfa = state->fp;
- } else {
- cfa = state->sp;
+ break;
+ case UNWIND_USER_CFA_RULE_REG_OFFSET:
+ case UNWIND_USER_CFA_RULE_REG_OFFSET_DEREF:
+ if (!state->topmost || unwind_user_get_reg(&cfa, frame->cfa.regnum))
+ return -EINVAL;
+ break;
+ default:
+ WARN_ON_ONCE(1);
+ return -EINVAL;
}
- cfa += frame->cfa_off;
+ cfa += frame->cfa.offset;
+ if (frame->cfa.rule & UNWIND_USER_RULE_DEREF &&
+ get_user_word(&cfa, cfa, 0, state->ws))
+ return -EINVAL;
/*
* Make sure that stack is not going in wrong direction. Allow SP
--
2.51.0
^ permalink raw reply related
* [PATCH v13 18/18] unwind_user/sframe: Add prctl() interface for registering .sframe sections
From: Jens Remus @ 2026-01-27 15:05 UTC (permalink / raw)
To: linux-kernel, linux-trace-kernel, bpf, x86, linux-mm,
Steven Rostedt
Cc: Jens Remus, Josh Poimboeuf, Masami Hiramatsu, Mathieu Desnoyers,
Peter Zijlstra, Ingo Molnar, Jiri Olsa, Arnaldo Carvalho de Melo,
Namhyung Kim, Thomas Gleixner, Andrii Nakryiko, Indu Bhagat,
Jose E. Marchesi, Beau Belgrave, Linus Torvalds, Andrew Morton,
Florian Weimer, Kees Cook, Carlos O'Donell, Sam James,
Dylan Hatch, Borislav Petkov, Dave Hansen, David Hildenbrand,
H. Peter Anvin, Liam R. Howlett, Lorenzo Stoakes, Michal Hocko,
Mike Rapoport, Suren Baghdasaryan, Vlastimil Babka,
Heiko Carstens, Vasily Gorbik, Steven Rostedt (Google)
In-Reply-To: <20260127150554.2760964-1-jremus@linux.ibm.com>
From: Josh Poimboeuf <jpoimboe@kernel.org>
The kernel doesn't have direct visibility to the ELF contents of shared
libraries. Add some prctl() interfaces which allow glibc to tell the
kernel where to find .sframe sections.
[
This adds an interface for prctl() for testing loading of sframes for
libraries. But this interface should really be a system call. This patch
is for testing purposes only and should not be applied to mainline.
]
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Indu Bhagat <indu.bhagat@oracle.com>
Cc: "Jose E. Marchesi" <jemarch@gnu.org>
Cc: Beau Belgrave <beaub@linux.microsoft.com>
Cc: Jens Remus <jremus@linux.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Florian Weimer <fweimer@redhat.com>
Cc: Sam James <sam@gentoo.org>
Cc: Kees Cook <kees@kernel.org>
Cc: "Carlos O'Donell" <codonell@redhat.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Jens Remus <jremus@linux.ibm.com>
---
include/uapi/linux/prctl.h | 6 +++++-
kernel/sys.c | 9 +++++++++
2 files changed, 14 insertions(+), 1 deletion(-)
diff --git a/include/uapi/linux/prctl.h b/include/uapi/linux/prctl.h
index 51c4e8c82b1e..91d2c9eb3aa3 100644
--- a/include/uapi/linux/prctl.h
+++ b/include/uapi/linux/prctl.h
@@ -368,7 +368,7 @@ struct prctl_mm_map {
* configuration. All bits may be locked via this call, including
* undefined bits.
*/
-#define PR_LOCK_SHADOW_STACK_STATUS 76
+#define PR_LOCK_SHADOW_STACK_STATUS 76
/*
* Controls the mode of timer_create() for CRIU restore operations.
@@ -386,4 +386,8 @@ struct prctl_mm_map {
# define PR_FUTEX_HASH_SET_SLOTS 1
# define PR_FUTEX_HASH_GET_SLOTS 2
+/* SFRAME management */
+#define PR_ADD_SFRAME 79
+#define PR_REMOVE_SFRAME 80
+
#endif /* _LINUX_PRCTL_H */
diff --git a/kernel/sys.c b/kernel/sys.c
index 8b58eece4e58..ea088b643eb4 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -65,6 +65,7 @@
#include <linux/rcupdate.h>
#include <linux/uidgid.h>
#include <linux/cred.h>
+#include <linux/sframe.h>
#include <linux/nospec.h>
@@ -2868,6 +2869,14 @@ SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
case PR_FUTEX_HASH:
error = futex_hash_prctl(arg2, arg3, arg4);
break;
+ case PR_ADD_SFRAME:
+ error = sframe_add_section(arg2, arg3, arg4, arg5);
+ break;
+ case PR_REMOVE_SFRAME:
+ if (arg3 || arg4 || arg5)
+ return -EINVAL;
+ error = sframe_remove_section(arg2);
+ break;
default:
trace_task_prctl_unknown(option, arg2, arg3, arg4, arg5);
error = -EINVAL;
--
2.51.0
^ permalink raw reply related
* [PATCH v13 13/18] unwind_user: Flexible FP/RA recovery rules
From: Jens Remus @ 2026-01-27 15:05 UTC (permalink / raw)
To: linux-kernel, linux-trace-kernel, bpf, x86, linux-mm,
Steven Rostedt
Cc: Jens Remus, Josh Poimboeuf, Masami Hiramatsu, Mathieu Desnoyers,
Peter Zijlstra, Ingo Molnar, Jiri Olsa, Arnaldo Carvalho de Melo,
Namhyung Kim, Thomas Gleixner, Andrii Nakryiko, Indu Bhagat,
Jose E. Marchesi, Beau Belgrave, Linus Torvalds, Andrew Morton,
Florian Weimer, Kees Cook, Carlos O'Donell, Sam James,
Dylan Hatch, Borislav Petkov, Dave Hansen, David Hildenbrand,
H. Peter Anvin, Liam R. Howlett, Lorenzo Stoakes, Michal Hocko,
Mike Rapoport, Suren Baghdasaryan, Vlastimil Babka,
Heiko Carstens, Vasily Gorbik
In-Reply-To: <20260127150554.2760964-1-jremus@linux.ibm.com>
To enable support for SFrame V3 flexible FDEs with a subsequent patch,
add support for the following flexible frame pointer (FP) and return
address (RA) recovery rules:
FP/RA = *(CFA + offset)
FP/RA = register + offset
FP/RA = *(register + offset)
Note that FP/RA recovery rules that use arbitrary register contents are
only valid when in the topmost frame, as their contents are otherwise
unknown.
This also enables unwinding of user space for architectures, such as
s390, that may save the frame pointer (FP) and/or return address (RA) in
other registers, for instance when in a leaf function.
Cc: Steven Rostedt <rostedt@kernel.org>
Cc: Josh Poimboeuf <jpoimboe@kernel.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Indu Bhagat <indu.bhagat@oracle.com>
Cc: "Jose E. Marchesi" <jemarch@gnu.org>
Cc: Beau Belgrave <beaub@linux.microsoft.com>
Cc: Jens Remus <jremus@linux.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Florian Weimer <fweimer@redhat.com>
Cc: Sam James <sam@gentoo.org>
Cc: Kees Cook <kees@kernel.org>
Cc: "Carlos O'Donell" <codonell@redhat.com>
Signed-off-by: Jens Remus <jremus@linux.ibm.com>
---
Notes (jremus):
Changes in v13:
- New patch. Based on my s390 sframe support series patch
"unwind_user: Enable archs that save RA/FP in other registers":
https://lore.kernel.org/all/20251208171559.2029709-12-jremus@linux.ibm.com/
arch/x86/include/asm/unwind_user.h | 21 ++++++++++---
include/linux/unwind_user.h | 9 ++++++
include/linux/unwind_user_types.h | 23 +++++++++++++--
kernel/unwind/sframe.c | 16 ++++++++--
kernel/unwind/user.c | 47 +++++++++++++++++++++++++-----
5 files changed, 101 insertions(+), 15 deletions(-)
diff --git a/arch/x86/include/asm/unwind_user.h b/arch/x86/include/asm/unwind_user.h
index 2dfb5ef11e36..9c3417be4283 100644
--- a/arch/x86/include/asm/unwind_user.h
+++ b/arch/x86/include/asm/unwind_user.h
@@ -21,15 +21,26 @@ static inline int unwind_user_word_size(struct pt_regs *regs)
#define ARCH_INIT_USER_FP_FRAME(ws) \
.cfa_off = 2*(ws), \
- .ra_off = -1*(ws), \
- .fp_off = -2*(ws), \
+ .ra = { \
+ .rule = UNWIND_USER_RULE_CFA_OFFSET_DEREF,\
+ .offset = -1*(ws), \
+ }, \
+ .fp = { \
+ .rule = UNWIND_USER_RULE_CFA_OFFSET_DEREF,\
+ .offset = -2*(ws), \
+ }, \
.use_fp = true, \
.outermost = false,
#define ARCH_INIT_USER_FP_ENTRY_FRAME(ws) \
.cfa_off = 1*(ws), \
- .ra_off = -1*(ws), \
- .fp_off = 0, \
+ .ra = { \
+ .rule = UNWIND_USER_RULE_CFA_OFFSET_DEREF,\
+ .offset = -1*(ws), \
+ }, \
+ .fp = { \
+ .rule = UNWIND_USER_RULE_RETAIN,\
+ }, \
.use_fp = false, \
.outermost = false,
@@ -41,4 +52,6 @@ static inline bool unwind_user_at_function_start(struct pt_regs *regs)
#endif /* CONFIG_HAVE_UNWIND_USER_FP */
+#include <asm-generic/unwind_user.h>
+
#endif /* _ASM_X86_UNWIND_USER_H */
diff --git a/include/linux/unwind_user.h b/include/linux/unwind_user.h
index bc2edae39955..92cdf38c8ade 100644
--- a/include/linux/unwind_user.h
+++ b/include/linux/unwind_user.h
@@ -32,6 +32,15 @@ static inline int unwind_user_get_ra_reg(unsigned long *val)
#define unwind_user_get_ra_reg unwind_user_get_ra_reg
#endif
+#ifndef unwind_user_get_reg
+static inline int unwind_user_get_reg(unsigned long *val, unsigned int regnum)
+{
+ WARN_ON_ONCE(1);
+ return -EINVAL;
+}
+#define unwind_user_get_reg unwind_user_get_reg
+#endif
+
int unwind_user(struct unwind_stacktrace *trace, unsigned int max_entries);
#endif /* _LINUX_UNWIND_USER_H */
diff --git a/include/linux/unwind_user_types.h b/include/linux/unwind_user_types.h
index 616cc5ee4586..0d02714a1b5d 100644
--- a/include/linux/unwind_user_types.h
+++ b/include/linux/unwind_user_types.h
@@ -27,10 +27,29 @@ struct unwind_stacktrace {
unsigned long *entries;
};
+#define UNWIND_USER_RULE_DEREF BIT(31)
+
+enum unwind_user_rule {
+ UNWIND_USER_RULE_RETAIN, /* entity = entity */
+ UNWIND_USER_RULE_CFA_OFFSET, /* entity = CFA + offset */
+ UNWIND_USER_RULE_REG_OFFSET, /* entity = register + offset */
+ /* DEREF variants */
+ UNWIND_USER_RULE_CFA_OFFSET_DEREF = /* entity = *(CFA + offset) */
+ UNWIND_USER_RULE_CFA_OFFSET | UNWIND_USER_RULE_DEREF,
+ UNWIND_USER_RULE_REG_OFFSET_DEREF = /* entity = *(register + offset) */
+ UNWIND_USER_RULE_REG_OFFSET | UNWIND_USER_RULE_DEREF,
+};
+
+struct unwind_user_rule_data {
+ enum unwind_user_rule rule;
+ s32 offset;
+ unsigned int regnum;
+};
+
struct unwind_user_frame {
s32 cfa_off;
- s32 ra_off;
- s32 fp_off;
+ struct unwind_user_rule_data ra;
+ struct unwind_user_rule_data fp;
bool use_fp;
bool outermost;
};
diff --git a/kernel/unwind/sframe.c b/kernel/unwind/sframe.c
index fc905504ddde..b5301fa9dbc8 100644
--- a/kernel/unwind/sframe.c
+++ b/kernel/unwind/sframe.c
@@ -271,6 +271,18 @@ static __always_inline int __read_fre(struct sframe_section *sec,
return -EFAULT;
}
+static __always_inline void
+sframe_init_rule_data(struct unwind_user_rule_data *rule_data,
+ s32 offset)
+{
+ if (offset) {
+ rule_data->rule = UNWIND_USER_RULE_CFA_OFFSET_DEREF;
+ rule_data->offset = offset;
+ } else {
+ rule_data->rule = UNWIND_USER_RULE_RETAIN;
+ }
+}
+
static __always_inline int __find_fre(struct sframe_section *sec,
struct sframe_fde_internal *fde,
unsigned long ip,
@@ -321,8 +333,8 @@ static __always_inline int __find_fre(struct sframe_section *sec,
fre = prev_fre;
frame->cfa_off = fre->cfa_off;
- frame->ra_off = fre->ra_off;
- frame->fp_off = fre->fp_off;
+ sframe_init_rule_data(&frame->ra, fre->ra_off);
+ sframe_init_rule_data(&frame->fp, fre->fp_off);
frame->use_fp = SFRAME_V3_FRE_CFA_BASE_REG_ID(fre->info) == SFRAME_BASE_REG_FP;
frame->outermost = SFRAME_V3_FRE_RA_UNDEFINED_P(fre->info);
diff --git a/kernel/unwind/user.c b/kernel/unwind/user.c
index 9ceef9b2b8db..0405922c5c0d 100644
--- a/kernel/unwind/user.c
+++ b/kernel/unwind/user.c
@@ -61,22 +61,55 @@ static int unwind_user_next_common(struct unwind_user_state *state,
return -EINVAL;
/* Get the Return Address (RA) */
- if (frame->ra_off) {
- if (get_user_word(&ra, cfa, frame->ra_off, state->ws))
- return -EINVAL;
- } else {
+ switch (frame->ra.rule) {
+ case UNWIND_USER_RULE_RETAIN:
if (!state->topmost || unwind_user_get_ra_reg(&ra))
return -EINVAL;
+ break;
+ /* UNWIND_USER_RULE_CFA_OFFSET not implemented on purpose */
+ case UNWIND_USER_RULE_CFA_OFFSET_DEREF:
+ ra = cfa + frame->ra.offset;
+ break;
+ case UNWIND_USER_RULE_REG_OFFSET:
+ case UNWIND_USER_RULE_REG_OFFSET_DEREF:
+ if (!state->topmost || unwind_user_get_reg(&ra, frame->ra.regnum))
+ return -EINVAL;
+ ra += frame->ra.offset;
+ break;
+ default:
+ WARN_ON_ONCE(1);
+ return -EINVAL;
}
+ if (frame->ra.rule & UNWIND_USER_RULE_DEREF &&
+ get_user_word(&ra, ra, 0, state->ws))
+ return -EINVAL;
/* Get the Frame Pointer (FP) */
- if (frame->fp_off && get_user_word(&fp, cfa, frame->fp_off, state->ws))
+ switch (frame->fp.rule) {
+ case UNWIND_USER_RULE_RETAIN:
+ fp = state->fp;
+ break;
+ /* UNWIND_USER_RULE_CFA_OFFSET not implemented on purpose */
+ case UNWIND_USER_RULE_CFA_OFFSET_DEREF:
+ fp = cfa + frame->fp.offset;
+ break;
+ case UNWIND_USER_RULE_REG_OFFSET:
+ case UNWIND_USER_RULE_REG_OFFSET_DEREF:
+ if (!state->topmost || unwind_user_get_reg(&fp, frame->fp.regnum))
+ return -EINVAL;
+ fp += frame->fp.offset;
+ break;
+ default:
+ WARN_ON_ONCE(1);
+ return -EINVAL;
+ }
+ if (frame->fp.rule & UNWIND_USER_RULE_DEREF &&
+ get_user_word(&fp, fp, 0, state->ws))
return -EINVAL;
state->ip = ra;
state->sp = cfa;
- if (frame->fp_off)
- state->fp = fp;
+ state->fp = fp;
state->topmost = false;
return 0;
}
--
2.51.0
^ permalink raw reply related
* [PATCH v13 12/18] unwind_user: Enable archs that pass RA in a register
From: Jens Remus @ 2026-01-27 15:05 UTC (permalink / raw)
To: linux-kernel, linux-trace-kernel, bpf, x86, linux-mm,
Steven Rostedt
Cc: Jens Remus, Josh Poimboeuf, Masami Hiramatsu, Mathieu Desnoyers,
Peter Zijlstra, Ingo Molnar, Jiri Olsa, Arnaldo Carvalho de Melo,
Namhyung Kim, Thomas Gleixner, Andrii Nakryiko, Indu Bhagat,
Jose E. Marchesi, Beau Belgrave, Linus Torvalds, Andrew Morton,
Florian Weimer, Kees Cook, Carlos O'Donell, Sam James,
Dylan Hatch, Borislav Petkov, Dave Hansen, David Hildenbrand,
H. Peter Anvin, Liam R. Howlett, Lorenzo Stoakes, Michal Hocko,
Mike Rapoport, Suren Baghdasaryan, Vlastimil Babka,
Heiko Carstens, Vasily Gorbik
In-Reply-To: <20260127150554.2760964-1-jremus@linux.ibm.com>
Not all architectures have the return address (RA) in user space saved
on the stack on function entry, such as x86-64 does due to its CALL
instruction pushing the RA onto the stack. Architectures/ABIs, such as
s390, also do not necessarily enforce to save the RA in user space on
the stack in the function prologue or even at all, for instance in leaf
functions.
Treat a RA offset from CFA of zero as indication that the RA is not
saved (on the stack). For the topmost frame treat it as indication that
the RA is in the link/RA register, such as on arm64 and s390, and obtain
it from there. For non-topmost frames treat it as error, as the RA must
be saved.
Additionally allow the SP to be unchanged in the topmost frame, for
architectures where SP at function entry == SP at call site, such as
arm64 and s390.
Note that treating a RA offset from CFA of zero as indication that
the RA is not saved on the stack additionally allows for architectures,
such as s390, where the frame pointer (FP) may be saved without the RA
being saved as well. Provided that such architectures represent this
in SFrame by encoding the "missing" RA offset using a padding RA offset
with a value of zero.
Cc: Steven Rostedt <rostedt@kernel.org>
Cc: Josh Poimboeuf <jpoimboe@kernel.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Indu Bhagat <indu.bhagat@oracle.com>
Cc: "Jose E. Marchesi" <jemarch@gnu.org>
Cc: Beau Belgrave <beaub@linux.microsoft.com>
Cc: Jens Remus <jremus@linux.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Florian Weimer <fweimer@redhat.com>
Cc: Sam James <sam@gentoo.org>
Cc: Kees Cook <kees@kernel.org>
Cc: "Carlos O'Donell" <codonell@redhat.com>
Signed-off-by: Jens Remus <jremus@linux.ibm.com>
---
Notes (jremus):
Changes in v13:
- New patch. Based on my s390 sframe support series patch
"unwind_user: Enable archs that pass RA in a register":
https://lore.kernel.org/all/20251208171559.2029709-11-jremus@linux.ibm.com/
include/linux/unwind_user.h | 9 +++++++++
kernel/unwind/sframe.c | 6 ++----
kernel/unwind/user.c | 17 +++++++++++++----
3 files changed, 24 insertions(+), 8 deletions(-)
diff --git a/include/linux/unwind_user.h b/include/linux/unwind_user.h
index 64618618febd..bc2edae39955 100644
--- a/include/linux/unwind_user.h
+++ b/include/linux/unwind_user.h
@@ -23,6 +23,15 @@ static inline bool unwind_user_at_function_start(struct pt_regs *regs)
#define unwind_user_at_function_start unwind_user_at_function_start
#endif
+#ifndef unwind_user_get_ra_reg
+static inline int unwind_user_get_ra_reg(unsigned long *val)
+{
+ WARN_ON_ONCE(1);
+ return -EINVAL;
+}
+#define unwind_user_get_ra_reg unwind_user_get_ra_reg
+#endif
+
int unwind_user(struct unwind_stacktrace *trace, unsigned int max_entries);
#endif /* _LINUX_UNWIND_USER_H */
diff --git a/kernel/unwind/sframe.c b/kernel/unwind/sframe.c
index cf353bdbc907..fc905504ddde 100644
--- a/kernel/unwind/sframe.c
+++ b/kernel/unwind/sframe.c
@@ -243,10 +243,8 @@ static __always_inline int __read_fre(struct sframe_section *sec,
dataword_count--;
ra_off = sec->ra_off;
- if (!ra_off) {
- if (!dataword_count--)
- return -EFAULT;
-
+ if (!ra_off && dataword_count) {
+ dataword_count--;
UNSAFE_GET_USER_INC(ra_off, cur, dataword_size, Efault);
}
diff --git a/kernel/unwind/user.c b/kernel/unwind/user.c
index fdb1001e3750..9ceef9b2b8db 100644
--- a/kernel/unwind/user.c
+++ b/kernel/unwind/user.c
@@ -48,8 +48,12 @@ static int unwind_user_next_common(struct unwind_user_state *state,
}
cfa += frame->cfa_off;
- /* Make sure that stack is not going in wrong direction */
- if (cfa <= state->sp)
+ /*
+ * Make sure that stack is not going in wrong direction. Allow SP
+ * to be unchanged for the topmost frame, by subtracting topmost,
+ * which is either 0 or 1.
+ */
+ if (cfa <= state->sp - state->topmost)
return -EINVAL;
/* Make sure that the address is word aligned */
@@ -57,8 +61,13 @@ static int unwind_user_next_common(struct unwind_user_state *state,
return -EINVAL;
/* Get the Return Address (RA) */
- if (get_user_word(&ra, cfa, frame->ra_off, state->ws))
- return -EINVAL;
+ if (frame->ra_off) {
+ if (get_user_word(&ra, cfa, frame->ra_off, state->ws))
+ return -EINVAL;
+ } else {
+ if (!state->topmost || unwind_user_get_ra_reg(&ra))
+ return -EINVAL;
+ }
/* Get the Frame Pointer (FP) */
if (frame->fp_off && get_user_word(&fp, cfa, frame->fp_off, state->ws))
--
2.51.0
^ permalink raw reply related
* [PATCH v13 01/18] unwind_user/sframe: Add support for reading .sframe headers
From: Jens Remus @ 2026-01-27 15:05 UTC (permalink / raw)
To: linux-kernel, linux-trace-kernel, bpf, x86, linux-mm,
Steven Rostedt
Cc: Jens Remus, Josh Poimboeuf, Masami Hiramatsu, Mathieu Desnoyers,
Peter Zijlstra, Ingo Molnar, Jiri Olsa, Arnaldo Carvalho de Melo,
Namhyung Kim, Thomas Gleixner, Andrii Nakryiko, Indu Bhagat,
Jose E. Marchesi, Beau Belgrave, Linus Torvalds, Andrew Morton,
Florian Weimer, Kees Cook, Carlos O'Donell, Sam James,
Dylan Hatch, Borislav Petkov, Dave Hansen, David Hildenbrand,
H. Peter Anvin, Liam R. Howlett, Lorenzo Stoakes, Michal Hocko,
Mike Rapoport, Suren Baghdasaryan, Vlastimil Babka,
Heiko Carstens, Vasily Gorbik, Steven Rostedt (Google)
In-Reply-To: <20260127150554.2760964-1-jremus@linux.ibm.com>
From: Josh Poimboeuf <jpoimboe@kernel.org>
In preparation for unwinding user space stacks with sframe, add basic
sframe compile infrastructure and support for reading the .sframe
section header.
sframe_add_section() reads the header and unconditionally returns an
error, so it's not very useful yet. A subsequent patch will improve
that.
Link: https://lore.kernel.org/all/f27e8463783febfa0dabb0432a3dd6be8ad98412.1737511963.git.jpoimboe@kernel.org/
[ Jens Remus: Add support for SFrame V3. Add support for PC-relative
FDE function start offset. Cleanup includes and indentation. ]
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Indu Bhagat <indu.bhagat@oracle.com>
Cc: "Jose E. Marchesi" <jemarch@gnu.org>
Cc: Beau Belgrave <beaub@linux.microsoft.com>
Cc: Jens Remus <jremus@linux.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Florian Weimer <fweimer@redhat.com>
Cc: Sam James <sam@gentoo.org>
Cc: Kees Cook <kees@kernel.org>
Cc: "Carlos O'Donell" <codonell@redhat.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Jens Remus <jremus@linux.ibm.com>
---
Notes (jremus):
Changes in v13:
- Update to SFrame V3:
- Add and use SFRAME_VERSION_3 definition.
- Add helper macros to access SFrame V3 FDE type.
- Rename SFRAME_FUNC_*() macros to SFRAME_FDE_*().
- Rename SFRAME_FDE_TYPE_PC* defines to SFRAME_FDE_PCTYPE_* and
SFRAME_FUNC_FDE_TYPE() macro to SFRAME_V3_FDE_PCTYPE().
- Reword OFFSET to DATAWORD in SFRAME_FRE_OFFSET_{COUNT|SIZE}()
macros.
- Rename version-specific SFRAME_*() macros to SFRAME_V3_*().
- Update struct sframe_fde and rename to sframe_fde_v3:
- Change field start_addr from s32 to s64 and rename to
func_start_off.
- Change field fres_num from u32 to u16.
- New field u8 info2.
- Remove u16 padding field.
- Split FDE into function descriptor entry (struct sframe_fde_v3) and
attributes (struct sframe_fde_v3).
- Rename macro parameter "data" to "info" to hint at fde/fre info
word and wrap it in parenthesis.
- Group SFRAME_* definitions so that related ones are together.
- Reword commit message (my changes).
MAINTAINERS | 1 +
arch/Kconfig | 3 +
include/linux/sframe.h | 37 +++++++++++
kernel/unwind/Makefile | 3 +-
kernel/unwind/sframe.c | 136 +++++++++++++++++++++++++++++++++++++++++
kernel/unwind/sframe.h | 81 ++++++++++++++++++++++++
6 files changed, 260 insertions(+), 1 deletion(-)
create mode 100644 include/linux/sframe.h
create mode 100644 kernel/unwind/sframe.c
create mode 100644 kernel/unwind/sframe.h
diff --git a/MAINTAINERS b/MAINTAINERS
index 5b11839cba9d..79cff4f4df56 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -27226,6 +27226,7 @@ USERSPACE STACK UNWINDING
M: Josh Poimboeuf <jpoimboe@kernel.org>
M: Steven Rostedt <rostedt@goodmis.org>
S: Maintained
+F: include/linux/sframe.h
F: include/linux/unwind*.h
F: kernel/unwind/
diff --git a/arch/Kconfig b/arch/Kconfig
index 31220f512b16..7d5517364d8b 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -486,6 +486,9 @@ config HAVE_UNWIND_USER_FP
bool
select UNWIND_USER
+config HAVE_UNWIND_USER_SFRAME
+ bool
+
config HAVE_PERF_REGS
bool
help
diff --git a/include/linux/sframe.h b/include/linux/sframe.h
new file mode 100644
index 000000000000..0642595534f9
--- /dev/null
+++ b/include/linux/sframe.h
@@ -0,0 +1,37 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_SFRAME_H
+#define _LINUX_SFRAME_H
+
+#ifdef CONFIG_HAVE_UNWIND_USER_SFRAME
+
+struct sframe_section {
+ unsigned long sframe_start;
+ unsigned long sframe_end;
+ unsigned long text_start;
+ unsigned long text_end;
+
+ unsigned long fdes_start;
+ unsigned long fres_start;
+ unsigned long fres_end;
+ unsigned int num_fdes;
+
+ signed char ra_off;
+ signed char fp_off;
+};
+
+extern int sframe_add_section(unsigned long sframe_start, unsigned long sframe_end,
+ unsigned long text_start, unsigned long text_end);
+extern int sframe_remove_section(unsigned long sframe_addr);
+
+#else /* !CONFIG_HAVE_UNWIND_USER_SFRAME */
+
+static inline int sframe_add_section(unsigned long sframe_start, unsigned long sframe_end,
+ unsigned long text_start, unsigned long text_end)
+{
+ return -ENOSYS;
+}
+static inline int sframe_remove_section(unsigned long sframe_addr) { return -ENOSYS; }
+
+#endif /* CONFIG_HAVE_UNWIND_USER_SFRAME */
+
+#endif /* _LINUX_SFRAME_H */
diff --git a/kernel/unwind/Makefile b/kernel/unwind/Makefile
index eae37bea54fd..146038165865 100644
--- a/kernel/unwind/Makefile
+++ b/kernel/unwind/Makefile
@@ -1 +1,2 @@
- obj-$(CONFIG_UNWIND_USER) += user.o deferred.o
+ obj-$(CONFIG_UNWIND_USER) += user.o deferred.o
+ obj-$(CONFIG_HAVE_UNWIND_USER_SFRAME) += sframe.o
diff --git a/kernel/unwind/sframe.c b/kernel/unwind/sframe.c
new file mode 100644
index 000000000000..c128c1eeaca2
--- /dev/null
+++ b/kernel/unwind/sframe.c
@@ -0,0 +1,136 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Userspace sframe access functions
+ */
+
+#define pr_fmt(fmt) "sframe: " fmt
+
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/srcu.h>
+#include <linux/uaccess.h>
+#include <linux/mm.h>
+#include <linux/string_helpers.h>
+#include <linux/sframe.h>
+#include <linux/unwind_user_types.h>
+
+#include "sframe.h"
+
+#define dbg(fmt, ...) \
+ pr_debug("%s (%d): " fmt, current->comm, current->pid, ##__VA_ARGS__)
+
+static void free_section(struct sframe_section *sec)
+{
+ kfree(sec);
+}
+
+static int sframe_read_header(struct sframe_section *sec)
+{
+ unsigned long header_end, fdes_start, fdes_end, fres_start, fres_end;
+ struct sframe_header shdr;
+ unsigned int num_fdes;
+
+ if (copy_from_user(&shdr, (void __user *)sec->sframe_start, sizeof(shdr))) {
+ dbg("header usercopy failed\n");
+ return -EFAULT;
+ }
+
+ if (shdr.preamble.magic != SFRAME_MAGIC ||
+ shdr.preamble.version != SFRAME_VERSION_3 ||
+ !(shdr.preamble.flags & SFRAME_F_FDE_SORTED) ||
+ !(shdr.preamble.flags & SFRAME_F_FDE_FUNC_START_PCREL) ||
+ shdr.auxhdr_len) {
+ dbg("bad/unsupported sframe header\n");
+ return -EINVAL;
+ }
+
+ if (!shdr.num_fdes || !shdr.num_fres) {
+ dbg("no fde/fre entries\n");
+ return -EINVAL;
+ }
+
+ header_end = sec->sframe_start + SFRAME_HEADER_SIZE(shdr);
+ if (header_end >= sec->sframe_end) {
+ dbg("header doesn't fit in section\n");
+ return -EINVAL;
+ }
+
+ num_fdes = shdr.num_fdes;
+ fdes_start = header_end + shdr.fdes_off;
+ fdes_end = fdes_start + (num_fdes * sizeof(struct sframe_fde_v3));
+
+ fres_start = header_end + shdr.fres_off;
+ fres_end = fres_start + shdr.fre_len;
+
+ if (fres_start < fdes_end || fres_end > sec->sframe_end) {
+ dbg("inconsistent fde/fre offsets\n");
+ return -EINVAL;
+ }
+
+ sec->num_fdes = num_fdes;
+ sec->fdes_start = fdes_start;
+ sec->fres_start = fres_start;
+ sec->fres_end = fres_end;
+
+ sec->ra_off = shdr.cfa_fixed_ra_offset;
+ sec->fp_off = shdr.cfa_fixed_fp_offset;
+
+ return 0;
+}
+
+int sframe_add_section(unsigned long sframe_start, unsigned long sframe_end,
+ unsigned long text_start, unsigned long text_end)
+{
+ struct vm_area_struct *sframe_vma, *text_vma;
+ struct mm_struct *mm = current->mm;
+ struct sframe_section *sec;
+ int ret;
+
+ if (!sframe_start || !sframe_end || !text_start || !text_end) {
+ dbg("zero-length sframe/text address\n");
+ return -EINVAL;
+ }
+
+ scoped_guard(mmap_read_lock, mm) {
+ sframe_vma = vma_lookup(mm, sframe_start);
+ if (!sframe_vma || sframe_end > sframe_vma->vm_end) {
+ dbg("bad sframe address (0x%lx - 0x%lx)\n",
+ sframe_start, sframe_end);
+ return -EINVAL;
+ }
+
+ text_vma = vma_lookup(mm, text_start);
+ if (!text_vma ||
+ !(text_vma->vm_flags & VM_EXEC) ||
+ text_end > text_vma->vm_end) {
+ dbg("bad text address (0x%lx - 0x%lx)\n",
+ text_start, text_end);
+ return -EINVAL;
+ }
+ }
+
+ sec = kzalloc(sizeof(*sec), GFP_KERNEL);
+ if (!sec)
+ return -ENOMEM;
+
+ sec->sframe_start = sframe_start;
+ sec->sframe_end = sframe_end;
+ sec->text_start = text_start;
+ sec->text_end = text_end;
+
+ ret = sframe_read_header(sec);
+ if (ret)
+ goto err_free;
+
+ /* TODO nowhere to store it yet - just free it and return an error */
+ ret = -ENOSYS;
+
+err_free:
+ free_section(sec);
+ return ret;
+}
+
+int sframe_remove_section(unsigned long sframe_start)
+{
+ return -ENOSYS;
+}
diff --git a/kernel/unwind/sframe.h b/kernel/unwind/sframe.h
new file mode 100644
index 000000000000..07a2e99855f9
--- /dev/null
+++ b/kernel/unwind/sframe.h
@@ -0,0 +1,81 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * From https://www.sourceware.org/binutils/docs/sframe-spec.html
+ */
+#ifndef _SFRAME_H
+#define _SFRAME_H
+
+#include <linux/types.h>
+
+#define SFRAME_VERSION_1 1
+#define SFRAME_VERSION_2 2
+#define SFRAME_VERSION_3 3
+#define SFRAME_MAGIC 0xdee2
+
+#define SFRAME_F_FDE_SORTED 0x1
+#define SFRAME_F_FRAME_POINTER 0x2
+#define SFRAME_F_FDE_FUNC_START_PCREL 0x4
+
+#define SFRAME_ABI_AARCH64_ENDIAN_BIG 1
+#define SFRAME_ABI_AARCH64_ENDIAN_LITTLE 2
+#define SFRAME_ABI_AMD64_ENDIAN_LITTLE 3
+
+struct sframe_preamble {
+ u16 magic;
+ u8 version;
+ u8 flags;
+} __packed;
+
+struct sframe_header {
+ struct sframe_preamble preamble;
+ u8 abi_arch;
+ s8 cfa_fixed_fp_offset;
+ s8 cfa_fixed_ra_offset;
+ u8 auxhdr_len;
+ u32 num_fdes;
+ u32 num_fres;
+ u32 fre_len;
+ u32 fdes_off;
+ u32 fres_off;
+} __packed;
+
+#define SFRAME_HEADER_SIZE(header) \
+ ((sizeof(struct sframe_header) + (header).auxhdr_len))
+
+struct sframe_fde_v3 {
+ s64 func_start_off;
+ u32 func_size;
+ u32 fres_off;
+} __packed;
+
+struct sframe_fda_v3 {
+ u16 fres_num;
+ u8 info;
+ u8 info2;
+ u8 rep_size;
+} __packed;
+
+#define SFRAME_FDE_PCTYPE_INC 0
+#define SFRAME_FDE_PCTYPE_MASK 1
+
+#define SFRAME_AARCH64_PAUTH_KEY_A 0
+#define SFRAME_AARCH64_PAUTH_KEY_B 1
+
+#define SFRAME_V3_FDE_FRE_TYPE(info) ((info) & 0xf)
+#define SFRAME_V3_FDE_PCTYPE(info) (((info) >> 4) & 0x1)
+#define SFRAME_V3_AARCH64_FDE_PAUTH_KEY(info) (((info) >> 5) & 0x1)
+
+#define SFRAME_FDE_TYPE_REGULAR 0
+
+#define SFRAME_V3_FDE_TYPE_MASK 0x0f
+#define SFRAME_V3_FDE_TYPE(info2) ((info2) & SFRAME_V3_FDE_TYPE_MASK)
+
+#define SFRAME_BASE_REG_FP 0
+#define SFRAME_BASE_REG_SP 1
+
+#define SFRAME_V3_FRE_CFA_BASE_REG_ID(info) ((info) & 0x1)
+#define SFRAME_V3_FRE_DATAWORD_COUNT(info) (((info) >> 1) & 0xf)
+#define SFRAME_V3_FRE_DATAWORD_SIZE(info) (((info) >> 5) & 0x3)
+#define SFRAME_V3_AARCH64_FRE_MANGLED_RA_P(info) (((info) >> 7) & 0x1)
+
+#endif /* _SFRAME_H */
--
2.51.0
^ permalink raw reply related
* [PATCH v13 03/18] x86/uaccess: Add unsafe_copy_from_user() implementation
From: Jens Remus @ 2026-01-27 15:05 UTC (permalink / raw)
To: linux-kernel, linux-trace-kernel, bpf, x86, linux-mm,
Steven Rostedt
Cc: Jens Remus, Josh Poimboeuf, Masami Hiramatsu, Mathieu Desnoyers,
Peter Zijlstra, Ingo Molnar, Jiri Olsa, Arnaldo Carvalho de Melo,
Namhyung Kim, Thomas Gleixner, Andrii Nakryiko, Indu Bhagat,
Jose E. Marchesi, Beau Belgrave, Linus Torvalds, Andrew Morton,
Florian Weimer, Kees Cook, Carlos O'Donell, Sam James,
Dylan Hatch, Borislav Petkov, Dave Hansen, David Hildenbrand,
H. Peter Anvin, Liam R. Howlett, Lorenzo Stoakes, Michal Hocko,
Mike Rapoport, Suren Baghdasaryan, Vlastimil Babka,
Heiko Carstens, Vasily Gorbik, Steven Rostedt (Google)
In-Reply-To: <20260127150554.2760964-1-jremus@linux.ibm.com>
From: Josh Poimboeuf <jpoimboe@kernel.org>
Add an x86 implementation of unsafe_copy_from_user() similar to the
existing unsafe_copy_to_user().
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Indu Bhagat <indu.bhagat@oracle.com>
Cc: "Jose E. Marchesi" <jemarch@gnu.org>
Cc: Beau Belgrave <beaub@linux.microsoft.com>
Cc: Jens Remus <jremus@linux.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Florian Weimer <fweimer@redhat.com>
Cc: Sam James <sam@gentoo.org>
Cc: Kees Cook <kees@kernel.org>
Cc: "Carlos O'Donell" <codonell@redhat.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Jens Remus <jremus@linux.ibm.com>
---
arch/x86/include/asm/uaccess.h | 39 +++++++++++++++++++++++++---------
1 file changed, 29 insertions(+), 10 deletions(-)
diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h
index 367297b188c3..dfe143235967 100644
--- a/arch/x86/include/asm/uaccess.h
+++ b/arch/x86/include/asm/uaccess.h
@@ -598,7 +598,7 @@ _label: \
* We want the unsafe accessors to always be inlined and use
* the error labels - thus the macro games.
*/
-#define unsafe_copy_loop(dst, src, len, type, label) \
+#define unsafe_copy_to_user_loop(dst, src, len, type, label) \
while (len >= sizeof(type)) { \
unsafe_put_user(*(type *)(src),(type __user *)(dst),label); \
dst += sizeof(type); \
@@ -606,15 +606,34 @@ _label: \
len -= sizeof(type); \
}
-#define unsafe_copy_to_user(_dst,_src,_len,label) \
-do { \
- char __user *__ucu_dst = (_dst); \
- const char *__ucu_src = (_src); \
- size_t __ucu_len = (_len); \
- unsafe_copy_loop(__ucu_dst, __ucu_src, __ucu_len, u64, label); \
- unsafe_copy_loop(__ucu_dst, __ucu_src, __ucu_len, u32, label); \
- unsafe_copy_loop(__ucu_dst, __ucu_src, __ucu_len, u16, label); \
- unsafe_copy_loop(__ucu_dst, __ucu_src, __ucu_len, u8, label); \
+#define unsafe_copy_to_user(_dst, _src, _len, label) \
+do { \
+ void __user *__dst = (_dst); \
+ const void *__src = (_src); \
+ size_t __len = (_len); \
+ unsafe_copy_to_user_loop(__dst, __src, __len, u64, label); \
+ unsafe_copy_to_user_loop(__dst, __src, __len, u32, label); \
+ unsafe_copy_to_user_loop(__dst, __src, __len, u16, label); \
+ unsafe_copy_to_user_loop(__dst, __src, __len, u8, label); \
+} while (0)
+
+#define unsafe_copy_from_user_loop(dst, src, len, type, label) \
+ while (len >= sizeof(type)) { \
+ unsafe_get_user(*(type *)(dst), (type __user *)(src), label); \
+ dst += sizeof(type); \
+ src += sizeof(type); \
+ len -= sizeof(type); \
+ }
+
+#define unsafe_copy_from_user(_dst, _src, _len, label) \
+do { \
+ void *__dst = (_dst); \
+ void __user *__src = (_src); \
+ size_t __len = (_len); \
+ unsafe_copy_from_user_loop(__dst, __src, __len, u64, label); \
+ unsafe_copy_from_user_loop(__dst, __src, __len, u32, label); \
+ unsafe_copy_from_user_loop(__dst, __src, __len, u16, label); \
+ unsafe_copy_from_user_loop(__dst, __src, __len, u8, label); \
} while (0)
#ifdef CONFIG_CC_HAS_ASM_GOTO_OUTPUT
--
2.51.0
^ permalink raw reply related
* [PATCH v13 10/18] unwind_user/sframe: Show file name in debug output
From: Jens Remus @ 2026-01-27 15:05 UTC (permalink / raw)
To: linux-kernel, linux-trace-kernel, bpf, x86, linux-mm,
Steven Rostedt
Cc: Jens Remus, Josh Poimboeuf, Masami Hiramatsu, Mathieu Desnoyers,
Peter Zijlstra, Ingo Molnar, Jiri Olsa, Arnaldo Carvalho de Melo,
Namhyung Kim, Thomas Gleixner, Andrii Nakryiko, Indu Bhagat,
Jose E. Marchesi, Beau Belgrave, Linus Torvalds, Andrew Morton,
Florian Weimer, Kees Cook, Carlos O'Donell, Sam James,
Dylan Hatch, Borislav Petkov, Dave Hansen, David Hildenbrand,
H. Peter Anvin, Liam R. Howlett, Lorenzo Stoakes, Michal Hocko,
Mike Rapoport, Suren Baghdasaryan, Vlastimil Babka,
Heiko Carstens, Vasily Gorbik, Steven Rostedt (Google)
In-Reply-To: <20260127150554.2760964-1-jremus@linux.ibm.com>
From: Josh Poimboeuf <jpoimboe@kernel.org>
When debugging sframe issues, the error messages aren't all that helpful
without knowing what file a corresponding .sframe section belongs to.
Prefix debug output strings with the file name.
[ Jens Remus: Fix checkpatch error "space prohibited before that close
parenthesis ')'". ]
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Indu Bhagat <indu.bhagat@oracle.com>
Cc: "Jose E. Marchesi" <jemarch@gnu.org>
Cc: Beau Belgrave <beaub@linux.microsoft.com>
Cc: Jens Remus <jremus@linux.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Florian Weimer <fweimer@redhat.com>
Cc: Sam James <sam@gentoo.org>
Cc: Kees Cook <kees@kernel.org>
Cc: "Carlos O'Donell" <codonell@redhat.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Jens Remus <jremus@linux.ibm.com>
---
include/linux/sframe.h | 4 +++-
kernel/unwind/sframe.c | 23 ++++++++++--------
kernel/unwind/sframe_debug.h | 45 +++++++++++++++++++++++++++++++-----
3 files changed, 56 insertions(+), 16 deletions(-)
diff --git a/include/linux/sframe.h b/include/linux/sframe.h
index 9a72209696f9..b79c5ec09229 100644
--- a/include/linux/sframe.h
+++ b/include/linux/sframe.h
@@ -10,7 +10,9 @@
struct sframe_section {
struct rcu_head rcu;
-
+#ifdef CONFIG_DYNAMIC_DEBUG
+ const char *filename;
+#endif
unsigned long sframe_start;
unsigned long sframe_end;
unsigned long text_start;
diff --git a/kernel/unwind/sframe.c b/kernel/unwind/sframe.c
index 9a63f8828593..3276aa6d0c77 100644
--- a/kernel/unwind/sframe.c
+++ b/kernel/unwind/sframe.c
@@ -359,14 +359,17 @@ int sframe_find(unsigned long ip, struct unwind_user_frame *frame)
end:
user_read_access_end();
- if (ret == -EFAULT)
+ if (ret == -EFAULT) {
+ dbg_sec("removing bad .sframe section\n");
WARN_ON_ONCE(sframe_remove_section(sec->sframe_start));
+ }
return ret;
}
static void free_section(struct sframe_section *sec)
{
+ dbg_free(sec);
kfree(sec);
}
@@ -377,7 +380,7 @@ static int sframe_read_header(struct sframe_section *sec)
unsigned int num_fdes;
if (copy_from_user(&shdr, (void __user *)sec->sframe_start, sizeof(shdr))) {
- dbg("header usercopy failed\n");
+ dbg_sec("header usercopy failed\n");
return -EFAULT;
}
@@ -386,18 +389,18 @@ static int sframe_read_header(struct sframe_section *sec)
!(shdr.preamble.flags & SFRAME_F_FDE_SORTED) ||
!(shdr.preamble.flags & SFRAME_F_FDE_FUNC_START_PCREL) ||
shdr.auxhdr_len) {
- dbg("bad/unsupported sframe header\n");
+ dbg_sec("bad/unsupported sframe header\n");
return -EINVAL;
}
if (!shdr.num_fdes || !shdr.num_fres) {
- dbg("no fde/fre entries\n");
+ dbg_sec("no fde/fre entries\n");
return -EINVAL;
}
header_end = sec->sframe_start + SFRAME_HEADER_SIZE(shdr);
if (header_end >= sec->sframe_end) {
- dbg("header doesn't fit in section\n");
+ dbg_sec("header doesn't fit in section\n");
return -EINVAL;
}
@@ -409,7 +412,7 @@ static int sframe_read_header(struct sframe_section *sec)
fres_end = fres_start + shdr.fre_len;
if (fres_start < fdes_end || fres_end > sec->sframe_end) {
- dbg("inconsistent fde/fre offsets\n");
+ dbg_sec("inconsistent fde/fre offsets\n");
return -EINVAL;
}
@@ -465,6 +468,8 @@ int sframe_add_section(unsigned long sframe_start, unsigned long sframe_end,
sec->text_start = text_start;
sec->text_end = text_end;
+ dbg_init(sec);
+
ret = sframe_read_header(sec);
if (ret) {
dbg_print_header(sec);
@@ -473,8 +478,8 @@ int sframe_add_section(unsigned long sframe_start, unsigned long sframe_end,
ret = mtree_insert_range(sframe_mt, sec->text_start, sec->text_end, sec, GFP_KERNEL);
if (ret) {
- dbg("mtree_insert_range failed: text=%lx-%lx\n",
- sec->text_start, sec->text_end);
+ dbg_sec("mtree_insert_range failed: text=%lx-%lx\n",
+ sec->text_start, sec->text_end);
goto err_free;
}
@@ -496,7 +501,7 @@ static int __sframe_remove_section(struct mm_struct *mm,
struct sframe_section *sec)
{
if (!mtree_erase(&mm->sframe_mt, sec->text_start)) {
- dbg("mtree_erase failed: text=%lx\n", sec->text_start);
+ dbg_sec("mtree_erase failed: text=%lx\n", sec->text_start);
return -EINVAL;
}
diff --git a/kernel/unwind/sframe_debug.h b/kernel/unwind/sframe_debug.h
index 36352124cde8..e568be4172b1 100644
--- a/kernel/unwind/sframe_debug.h
+++ b/kernel/unwind/sframe_debug.h
@@ -10,26 +10,59 @@
#define dbg(fmt, ...) \
pr_debug("%s (%d): " fmt, current->comm, current->pid, ##__VA_ARGS__)
+#define dbg_sec(fmt, ...) \
+ dbg("%s: " fmt, sec->filename, ##__VA_ARGS__)
+
static __always_inline void dbg_print_header(struct sframe_section *sec)
{
unsigned long fdes_end;
fdes_end = sec->fdes_start + (sec->num_fdes * sizeof(struct sframe_fde_v3));
- dbg("SEC: sframe:0x%lx-0x%lx text:0x%lx-0x%lx "
- "fdes:0x%lx-0x%lx fres:0x%lx-0x%lx "
- "ra_off:%d fp_off:%d\n",
- sec->sframe_start, sec->sframe_end, sec->text_start, sec->text_end,
- sec->fdes_start, fdes_end, sec->fres_start, sec->fres_end,
- sec->ra_off, sec->fp_off);
+ dbg_sec("SEC: sframe:0x%lx-0x%lx text:0x%lx-0x%lx "
+ "fdes:0x%lx-0x%lx fres:0x%lx-0x%lx "
+ "ra_off:%d fp_off:%d\n",
+ sec->sframe_start, sec->sframe_end, sec->text_start, sec->text_end,
+ sec->fdes_start, fdes_end, sec->fres_start, sec->fres_end,
+ sec->ra_off, sec->fp_off);
+}
+
+static inline void dbg_init(struct sframe_section *sec)
+{
+ struct mm_struct *mm = current->mm;
+ struct vm_area_struct *vma;
+
+ guard(mmap_read_lock)(mm);
+ vma = vma_lookup(mm, sec->sframe_start);
+ if (!vma)
+ sec->filename = kstrdup("(vma gone???)", GFP_KERNEL);
+ else if (vma->vm_file)
+ sec->filename = kstrdup_quotable_file(vma->vm_file, GFP_KERNEL);
+ else if (vma->vm_ops && vma->vm_ops->name)
+ sec->filename = kstrdup(vma->vm_ops->name(vma), GFP_KERNEL);
+ else if (arch_vma_name(vma))
+ sec->filename = kstrdup(arch_vma_name(vma), GFP_KERNEL);
+ else if (!vma->vm_mm)
+ sec->filename = kstrdup("(vdso)", GFP_KERNEL);
+ else
+ sec->filename = kstrdup("(anonymous)", GFP_KERNEL);
+}
+
+static inline void dbg_free(struct sframe_section *sec)
+{
+ kfree(sec->filename);
}
#else /* !CONFIG_DYNAMIC_DEBUG */
#define dbg(args...) no_printk(args)
+#define dbg_sec(args...) no_printk(args)
static inline void dbg_print_header(struct sframe_section *sec) {}
+static inline void dbg_init(struct sframe_section *sec) {}
+static inline void dbg_free(struct sframe_section *sec) {}
+
#endif /* !CONFIG_DYNAMIC_DEBUG */
#endif /* _SFRAME_DEBUG_H */
--
2.51.0
^ permalink raw reply related
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