Re: [PATCH v11 1/4] kasan: support backing vmalloc space with real shadow memory

Dmitry Vyukov
2019-11-29T10:43:50Z

On Tue, Nov 19, 2019 at 10:54 AM Andrey Ryabinin
<aryabinin@virtuozzo.com> wrote:
> On 11/18/19 6:29 AM, Daniel Axtens wrote:
> > Qian Cai <cai@lca.pw> writes:
> >
> >> On Thu, 2019-10-31 at 20:39 +1100, Daniel Axtens wrote:
> >>> /*
> >>> * In this function, newly allocated vm_struct has VM_UNINITIALIZED
> >>> * flag. It means that vm_struct is not fully initialized.
> >>> @@ -3377,6 +3411,9 @@ struct vm_struct **pcpu_get_vm_areas(const unsigned long *offsets,
> >>>
> >>> setup_vmalloc_vm_locked(vms[area], vas[area], VM_ALLOC,
> >>> pcpu_get_vm_areas);
> >>> +
> >>> + /* assume success here */
> >>> + kasan_populate_vmalloc(sizes[area], vms[area]);
> >>> }
> >>> spin_unlock(&vmap_area_lock);
> >>
> >> Here it is all wrong. GFP_KERNEL with in_atomic().
> >
> > I think this fix will work, I will do a v12 with it included.
>
> You can send just the fix. Andrew will fold it into the original patch before sending it to Linus.
>
>
>
> > diff --git a/mm/vmalloc.c b/mm/vmalloc.c
> > index a4b950a02d0b..bf030516258c 100644
> > --- a/mm/vmalloc.c
> > +++ b/mm/vmalloc.c
> > @@ -3417,11 +3417,14 @@ struct vm_struct **pcpu_get_vm_areas(const unsigned long *offsets,
> >
> > setup_vmalloc_vm_locked(vms[area], vas[area], VM_ALLOC,
> > pcpu_get_vm_areas);
> > + }
> > + spin_unlock(&vmap_area_lock);
> >
> > + /* populate the shadow space outside of the lock */
> > + for (area = 0; area < nr_vms; area++) {
> > /* assume success here */
> > kasan_populate_vmalloc(sizes[area], vms[area]);
> > }
> > - spin_unlock(&vmap_area_lock);
> >
> > kfree(vas);
> > return vms;

Hi,

I am testing this support on next-20191129 and seeing the following warnings:

BUG: sleeping function called from invalid context at mm/page_alloc.c:4681
in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 44, name: kworker/1:1
4 locks held by kworker/1:1/44:
#0: ffff888067c26d28 ((wq_completion)events){+.+.}, at:
__write_once_size include/linux/compiler.h:247 [inline]
#0: ffff888067c26d28 ((wq_completion)events){+.+.}, at:
arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
#0: ffff888067c26d28 ((wq_completion)events){+.+.}, at: atomic64_set
include/asm-generic/atomic-instrumented.h:868 [inline]
#0: ffff888067c26d28 ((wq_completion)events){+.+.}, at:
atomic_long_set include/asm-generic/atomic-long.h:40 [inline]
#0: ffff888067c26d28 ((wq_completion)events){+.+.}, at: set_work_data
kernel/workqueue.c:615 [inline]
#0: ffff888067c26d28 ((wq_completion)events){+.+.}, at:
set_work_pool_and_clear_pending kernel/workqueue.c:642 [inline]
#0: ffff888067c26d28 ((wq_completion)events){+.+.}, at:
process_one_work+0x88b/0x1750 kernel/workqueue.c:2235
#1: ffffc900002afdf0 (pcpu_balance_work){+.+.}, at:
process_one_work+0x8c0/0x1750 kernel/workqueue.c:2239
#2: ffffffff8943f080 (pcpu_alloc_mutex){+.+.}, at:
pcpu_balance_workfn+0xcc/0x13e0 mm/percpu.c:1845
#3: ffffffff89450c78 (vmap_area_lock){+.+.}, at: spin_lock
include/linux/spinlock.h:338 [inline]
#3: ffffffff89450c78 (vmap_area_lock){+.+.}, at:
pcpu_get_vm_areas+0x1449/0x3df0 mm/vmalloc.c:3431
Preemption disabled at:
[<ffffffff81a84199>] spin_lock include/linux/spinlock.h:338 [inline]
[<ffffffff81a84199>] pcpu_get_vm_areas+0x1449/0x3df0 mm/vmalloc.c:3431
CPU: 1 PID: 44 Comm: kworker/1:1 Not tainted 5.4.0-next-20191129+ #5
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.12.0-1 04/01/2014
Workqueue: events pcpu_balance_workfn
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x199/0x216 lib/dump_stack.c:118
___might_sleep.cold.97+0x1f5/0x238 kernel/sched/core.c:6800
__might_sleep+0x95/0x190 kernel/sched/core.c:6753
prepare_alloc_pages mm/page_alloc.c:4681 [inline]
__alloc_pages_nodemask+0x3cd/0x890 mm/page_alloc.c:4730
alloc_pages_current+0x10c/0x210 mm/mempolicy.c:2211
alloc_pages include/linux/gfp.h:532 [inline]
__get_free_pages+0xc/0x40 mm/page_alloc.c:4786
kasan_populate_vmalloc_pte mm/kasan/common.c:762 [inline]
kasan_populate_vmalloc_pte+0x2f/0x1b0 mm/kasan/common.c:753
apply_to_pte_range mm/memory.c:2041 [inline]
apply_to_pmd_range mm/memory.c:2068 [inline]
apply_to_pud_range mm/memory.c:2088 [inline]
apply_to_p4d_range mm/memory.c:2108 [inline]
apply_to_page_range+0x5ca/0xa00 mm/memory.c:2133
kasan_populate_vmalloc+0x69/0xa0 mm/kasan/common.c:791
pcpu_get_vm_areas+0x1596/0x3df0 mm/vmalloc.c:3439
pcpu_create_chunk+0x240/0x7f0 mm/percpu-vm.c:340
pcpu_balance_workfn+0x1033/0x13e0 mm/percpu.c:1934
process_one_work+0x9b5/0x1750 kernel/workqueue.c:2264
worker_thread+0x8b/0xd20 kernel/workqueue.c:2410
kthread+0x365/0x450 kernel/kthread.c:255
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352

Not sure if it's the same or not. Is it addressed by something in flight?