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

[Dmitry Vyukov]

On Fri, Nov 29, 2019 at 1:09 PM Daniel Axtens <dja@xxxxxxxxxx> wrote:
>
> Hi Dmitry,
>
> >> 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?
>
> It looks like this one is the same.
>
> There is a patch to fix it:
> https://lore.kernel.org/linux-mm/20191120052719.7201-1-dja@xxxxxxxxxx/
>
> Andrew said he had picked it up on the 22nd:
> https://marc.info/?l=linux-mm-commits&m=157438241512561&w=2
> It's landed in mmots but not mmotm, so hopefully that will happen and
> then it will land in -next very soon!
>
> I will look into your other bug report shortly.

Thanks for the quick responses, Andrey, Daniel.


> Regards,
> Daniel
>
> >>
> >> My config:
> >> https://gist.githubusercontent.com/dvyukov/36c7be311fdec9cd51c649f7c3cb2ddb/raw/39c6f864fdd0ffc53f0822b14c354a73c1695fa1/gistfile1.txt
> >
> >
> > I've tried this fix for pcpu_get_vm_areas:
> > https://groups.google.com/d/msg/kasan-dev/t_F2X1MWKwk/h152Z3q2AgAJ
> > and it helps. But this will break syzbot on linux-next soon.