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* [syzbot] WARNING: locking bug in hugetlb_no_page
@ 2022-11-12 14:03 syzbot
  2022-11-13 15:36 ` Dmitry Vyukov
  0 siblings, 1 reply; 6+ messages in thread
From: syzbot @ 2022-11-12 14:03 UTC (permalink / raw)
  To: akpm, linux-kernel, linux-mm, llvm, mike.kravetz, nathan,
	ndesaulniers, songmuchun, syzkaller-bugs, trix

Hello,

syzbot found the following issue on:

HEAD commit:    1621b6eaebf7 Merge branch 'for-next/fixes' into for-kernelci
git tree:       git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci
console output: https://syzkaller.appspot.com/x/log.txt?x=13bd511e880000
kernel config:  https://syzkaller.appspot.com/x/.config?x=606e57fd25c5c6cc
dashboard link: https://syzkaller.appspot.com/bug?extid=d07c65298d2c15eafcb0
compiler:       Debian clang version 13.0.1-++20220126092033+75e33f71c2da-1~exp1~20220126212112.63, GNU ld (GNU Binutils for Debian) 2.35.2
userspace arch: arm64
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=13315856880000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=173614d1880000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/82aa7741098d/disk-1621b6ea.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/f6be08c4e4c2/vmlinux-1621b6ea.xz
kernel image: https://storage.googleapis.com/syzbot-assets/296b6946258a/Image-1621b6ea.gz.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+d07c65298d2c15eafcb0@syzkaller.appspotmail.com

------------[ cut here ]------------
DEBUG_LOCKS_WARN_ON(!test_bit(class_idx, lock_classes_in_use))
WARNING: CPU: 1 PID: 3290 at kernel/locking/lockdep.c:5025 __lock_acquire+0x2758/0x3084
Modules linked in:
CPU: 1 PID: 3290 Comm: syz-executor317 Not tainted 6.1.0-rc4-syzkaller-31872-g1621b6eaebf7 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/30/2022
pstate: 604000c5 (nZCv daIF +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : __lock_acquire+0x2758/0x3084
lr : __lock_acquire+0x2754/0x3084 kernel/locking/lockdep.c:5025
sp : ffff800012e3b3e0
x29: ffff800012e3b4c0 x28: 0000000000000001 x27: ffff0000cb891a68
x26: ffff0000cb892450 x25: ffff0000cb892470 x24: ffff0000cb892470
x23: 00000000000000c0 x22: 0000000000000001 x21: 0000000000000000
x20: ffff0000cb891a40 x19: aaaaaa0000fb22ca x18: 0000000000000358
x17: ffff80000c04d83c x16: 0000000000000000 x15: 0000000000000000
x14: 0000000000000000 x13: 0000000000000012 x12: ffff80000d86ff30
x11: ff808000081c06c8 x10: 0000000000000000 x9 : ddc86c2f228f9600
x8 : ddc86c2f228f9600 x7 : 4e5241575f534b43 x6 : ffff80000c01775c
x5 : 0000000000000000 x4 : 0000000000000001 x3 : 0000000000000000
x2 : 0000000000000000 x1 : 0000000100000000 x0 : 0000000000000000
Call trace:
 __lock_acquire+0x2758/0x3084
 reacquire_held_locks+0x120/0x1c0 kernel/locking/lockdep.c:5193
 __lock_release kernel/locking/lockdep.c:5382 [inline]
 lock_release+0x148/0x2b4 kernel/locking/lockdep.c:5688
 __mutex_unlock_slowpath+0x44/0x1cc kernel/locking/mutex.c:907
 mutex_unlock+0x24/0x30 kernel/locking/mutex.c:543
 hugetlb_no_page+0x284/0xe1c mm/hugetlb.c:5771
 hugetlb_fault+0x3a0/0xdfc mm/hugetlb.c:5874
 handle_mm_fault+0x904/0xa48 mm/memory.c:5216
 __do_page_fault arch/arm64/mm/fault.c:506 [inline]
 do_page_fault+0x428/0x79c arch/arm64/mm/fault.c:606
 do_translation_fault+0x78/0x194 arch/arm64/mm/fault.c:689
 do_mem_abort+0x54/0x130 arch/arm64/mm/fault.c:825
 el1_abort+0x3c/0x5c arch/arm64/kernel/entry-common.c:367
 el1h_64_sync_handler+0x60/0xac arch/arm64/kernel/entry-common.c:427
 el1h_64_sync+0x64/0x68 arch/arm64/kernel/entry.S:579
 __arch_copy_from_user+0x24/0x1f4 arch/arm64/lib/copy_from_user.S:77
 __import_iovec+0x60/0x248 lib/iov_iter.c:1773
 import_iovec+0x6c/0x88 lib/iov_iter.c:1838
 vfs_writev fs/read_write.c:931 [inline]
 do_writev+0xf8/0x234 fs/read_write.c:977
 __do_sys_writev fs/read_write.c:1050 [inline]
 __se_sys_writev fs/read_write.c:1047 [inline]
 __arm64_sys_writev+0x28/0x38 fs/read_write.c:1047
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall arch/arm64/kernel/syscall.c:52 [inline]
 el0_svc_common+0x138/0x220 arch/arm64/kernel/syscall.c:142
 do_el0_svc+0x48/0x164 arch/arm64/kernel/syscall.c:206
 el0_svc+0x58/0x150 arch/arm64/kernel/entry-common.c:637
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
 el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:584
irq event stamp: 941
hardirqs last  enabled at (941): [<ffff80000c01c86c>] __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:159 [inline]
hardirqs last  enabled at (941): [<ffff80000c01c86c>] _raw_spin_unlock_irq+0x3c/0x70 kernel/locking/spinlock.c:202
hardirqs last disabled at (940): [<ffff80000c01c66c>] __raw_spin_lock_irq include/linux/spinlock_api_smp.h:117 [inline]
hardirqs last disabled at (940): [<ffff80000c01c66c>] _raw_spin_lock_irq+0x34/0x9c kernel/locking/spinlock.c:170
softirqs last  enabled at (744): [<ffff80000801c38c>] local_bh_enable+0x10/0x34 include/linux/bottom_half.h:32
softirqs last disabled at (742): [<ffff80000801c358>] local_bh_disable+0x10/0x34 include/linux/bottom_half.h:19
---[ end trace 0000000000000000 ]---


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzkaller@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
syzbot can test patches for this issue, for details see:
https://goo.gl/tpsmEJ#testing-patches


^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [syzbot] WARNING: locking bug in hugetlb_no_page
  2022-11-12 14:03 [syzbot] WARNING: locking bug in hugetlb_no_page syzbot
@ 2022-11-13 15:36 ` Dmitry Vyukov
  2022-11-13 18:50   ` Mike Kravetz
  0 siblings, 1 reply; 6+ messages in thread
From: Dmitry Vyukov @ 2022-11-13 15:36 UTC (permalink / raw)
  To: syzbot
  Cc: akpm, linux-kernel, linux-mm, llvm, mike.kravetz, nathan,
	ndesaulniers, songmuchun, syzkaller-bugs, trix, Hillf Danton

On Sat, 12 Nov 2022 at 15:03, syzbot
<syzbot+d07c65298d2c15eafcb0@syzkaller.appspotmail.com> wrote:
>
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit:    1621b6eaebf7 Merge branch 'for-next/fixes' into for-kernelci
> git tree:       git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci
> console output: https://syzkaller.appspot.com/x/log.txt?x=13bd511e880000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=606e57fd25c5c6cc
> dashboard link: https://syzkaller.appspot.com/bug?extid=d07c65298d2c15eafcb0
> compiler:       Debian clang version 13.0.1-++20220126092033+75e33f71c2da-1~exp1~20220126212112.63, GNU ld (GNU Binutils for Debian) 2.35.2
> userspace arch: arm64
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=13315856880000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=173614d1880000
>
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/82aa7741098d/disk-1621b6ea.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/f6be08c4e4c2/vmlinux-1621b6ea.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/296b6946258a/Image-1621b6ea.gz.xz
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+d07c65298d2c15eafcb0@syzkaller.appspotmail.com

This may have the same root cause as:

possible deadlock in hugetlb_fault
https://lore.kernel.org/all/CACT4Y+ZWNV6ApzEv0UrsF2T8JWmXez_-H-EGMii-S_2JbXv07Q@mail.gmail.com/

and there is a potential explanation as to what may be the problem.

> ------------[ cut here ]------------
> DEBUG_LOCKS_WARN_ON(!test_bit(class_idx, lock_classes_in_use))
> WARNING: CPU: 1 PID: 3290 at kernel/locking/lockdep.c:5025 __lock_acquire+0x2758/0x3084
> Modules linked in:
> CPU: 1 PID: 3290 Comm: syz-executor317 Not tainted 6.1.0-rc4-syzkaller-31872-g1621b6eaebf7 #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/30/2022
> pstate: 604000c5 (nZCv daIF +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
> pc : __lock_acquire+0x2758/0x3084
> lr : __lock_acquire+0x2754/0x3084 kernel/locking/lockdep.c:5025
> sp : ffff800012e3b3e0
> x29: ffff800012e3b4c0 x28: 0000000000000001 x27: ffff0000cb891a68
> x26: ffff0000cb892450 x25: ffff0000cb892470 x24: ffff0000cb892470
> x23: 00000000000000c0 x22: 0000000000000001 x21: 0000000000000000
> x20: ffff0000cb891a40 x19: aaaaaa0000fb22ca x18: 0000000000000358
> x17: ffff80000c04d83c x16: 0000000000000000 x15: 0000000000000000
> x14: 0000000000000000 x13: 0000000000000012 x12: ffff80000d86ff30
> x11: ff808000081c06c8 x10: 0000000000000000 x9 : ddc86c2f228f9600
> x8 : ddc86c2f228f9600 x7 : 4e5241575f534b43 x6 : ffff80000c01775c
> x5 : 0000000000000000 x4 : 0000000000000001 x3 : 0000000000000000
> x2 : 0000000000000000 x1 : 0000000100000000 x0 : 0000000000000000
> Call trace:
>  __lock_acquire+0x2758/0x3084
>  reacquire_held_locks+0x120/0x1c0 kernel/locking/lockdep.c:5193
>  __lock_release kernel/locking/lockdep.c:5382 [inline]
>  lock_release+0x148/0x2b4 kernel/locking/lockdep.c:5688
>  __mutex_unlock_slowpath+0x44/0x1cc kernel/locking/mutex.c:907
>  mutex_unlock+0x24/0x30 kernel/locking/mutex.c:543
>  hugetlb_no_page+0x284/0xe1c mm/hugetlb.c:5771
>  hugetlb_fault+0x3a0/0xdfc mm/hugetlb.c:5874
>  handle_mm_fault+0x904/0xa48 mm/memory.c:5216
>  __do_page_fault arch/arm64/mm/fault.c:506 [inline]
>  do_page_fault+0x428/0x79c arch/arm64/mm/fault.c:606
>  do_translation_fault+0x78/0x194 arch/arm64/mm/fault.c:689
>  do_mem_abort+0x54/0x130 arch/arm64/mm/fault.c:825
>  el1_abort+0x3c/0x5c arch/arm64/kernel/entry-common.c:367
>  el1h_64_sync_handler+0x60/0xac arch/arm64/kernel/entry-common.c:427
>  el1h_64_sync+0x64/0x68 arch/arm64/kernel/entry.S:579
>  __arch_copy_from_user+0x24/0x1f4 arch/arm64/lib/copy_from_user.S:77
>  __import_iovec+0x60/0x248 lib/iov_iter.c:1773
>  import_iovec+0x6c/0x88 lib/iov_iter.c:1838
>  vfs_writev fs/read_write.c:931 [inline]
>  do_writev+0xf8/0x234 fs/read_write.c:977
>  __do_sys_writev fs/read_write.c:1050 [inline]
>  __se_sys_writev fs/read_write.c:1047 [inline]
>  __arm64_sys_writev+0x28/0x38 fs/read_write.c:1047
>  __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
>  invoke_syscall arch/arm64/kernel/syscall.c:52 [inline]
>  el0_svc_common+0x138/0x220 arch/arm64/kernel/syscall.c:142
>  do_el0_svc+0x48/0x164 arch/arm64/kernel/syscall.c:206
>  el0_svc+0x58/0x150 arch/arm64/kernel/entry-common.c:637
>  el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
>  el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:584
> irq event stamp: 941
> hardirqs last  enabled at (941): [<ffff80000c01c86c>] __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:159 [inline]
> hardirqs last  enabled at (941): [<ffff80000c01c86c>] _raw_spin_unlock_irq+0x3c/0x70 kernel/locking/spinlock.c:202
> hardirqs last disabled at (940): [<ffff80000c01c66c>] __raw_spin_lock_irq include/linux/spinlock_api_smp.h:117 [inline]
> hardirqs last disabled at (940): [<ffff80000c01c66c>] _raw_spin_lock_irq+0x34/0x9c kernel/locking/spinlock.c:170
> softirqs last  enabled at (744): [<ffff80000801c38c>] local_bh_enable+0x10/0x34 include/linux/bottom_half.h:32
> softirqs last disabled at (742): [<ffff80000801c358>] local_bh_disable+0x10/0x34 include/linux/bottom_half.h:19
> ---[ end trace 0000000000000000 ]---
>
>
> ---
> This report is generated by a bot. It may contain errors.
> See https://goo.gl/tpsmEJ for more information about syzbot.
> syzbot engineers can be reached at syzkaller@googlegroups.com.
>
> syzbot will keep track of this issue. See:
> https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
> syzbot can test patches for this issue, for details see:
> https://goo.gl/tpsmEJ#testing-patches


^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [syzbot] WARNING: locking bug in hugetlb_no_page
  2022-11-13 15:36 ` Dmitry Vyukov
@ 2022-11-13 18:50   ` Mike Kravetz
  2022-11-14  1:26     ` Hillf Danton
  2022-11-14  2:24     ` Mike Kravetz
  0 siblings, 2 replies; 6+ messages in thread
From: Mike Kravetz @ 2022-11-13 18:50 UTC (permalink / raw)
  To: Dmitry Vyukov
  Cc: syzbot, akpm, linux-kernel, linux-mm, llvm, nathan, ndesaulniers,
	songmuchun, syzkaller-bugs, trix, Hillf Danton

On 11/13/22 16:36, Dmitry Vyukov wrote:
> On Sat, 12 Nov 2022 at 15:03, syzbot
> <syzbot+d07c65298d2c15eafcb0@syzkaller.appspotmail.com> wrote:
> >
> > Hello,
> >
> > syzbot found the following issue on:
> >
> > HEAD commit:    1621b6eaebf7 Merge branch 'for-next/fixes' into for-kernelci
> > git tree:       git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci
> > console output: https://syzkaller.appspot.com/x/log.txt?x=13bd511e880000
> > kernel config:  https://syzkaller.appspot.com/x/.config?x=606e57fd25c5c6cc
> > dashboard link: https://syzkaller.appspot.com/bug?extid=d07c65298d2c15eafcb0
> > compiler:       Debian clang version 13.0.1-++20220126092033+75e33f71c2da-1~exp1~20220126212112.63, GNU ld (GNU Binutils for Debian) 2.35.2
> > userspace arch: arm64
> > syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=13315856880000
> > C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=173614d1880000
> >
> > Downloadable assets:
> > disk image: https://storage.googleapis.com/syzbot-assets/82aa7741098d/disk-1621b6ea.raw.xz
> > vmlinux: https://storage.googleapis.com/syzbot-assets/f6be08c4e4c2/vmlinux-1621b6ea.xz
> > kernel image: https://storage.googleapis.com/syzbot-assets/296b6946258a/Image-1621b6ea.gz.xz
> >
> > IMPORTANT: if you fix the issue, please add the following tag to the commit:
> > Reported-by: syzbot+d07c65298d2c15eafcb0@syzkaller.appspotmail.com
> 
> This may have the same root cause as:
> 
> possible deadlock in hugetlb_fault
> https://lore.kernel.org/all/CACT4Y+ZWNV6ApzEv0UrsF2T8JWmXez_-H-EGMii-S_2JbXv07Q@mail.gmail.com/
> 
> and there is a potential explanation as to what may be the problem.

Thanks Dmitry!

An issue with this new hugetlb locking was previously reported and I have been
working on a solution.  When I look at the reproducer, I see that it is calling
madvise(MADV_DONTNEED).  This triggers the other issue and could certainly
cause the issue reported here.

Proposed patches are here and in next-20221111:
https://lore.kernel.org/linux-mm/20221111232628.290160-1-mike.kravetz@oracle.com/

I am currently trying to run the reproducer, but it is not reproducing quickly.
Since this is a timing issue that as expected.  Interesting that this
report is run on arm64 and I am trying to reproduce on x86.  Although, the
issue is not architecture specific in any way.

I'll keep looking, but am fairly confident this is the root cause.
-- 
Mike Kravetz


^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [syzbot] WARNING: locking bug in hugetlb_no_page
  2022-11-13 18:50   ` Mike Kravetz
@ 2022-11-14  1:26     ` Hillf Danton
  2022-11-14  2:24     ` Mike Kravetz
  1 sibling, 0 replies; 6+ messages in thread
From: Hillf Danton @ 2022-11-14  1:26 UTC (permalink / raw)
  To: Mike Kravetz
  Cc: Dmitry Vyukov, syzbot, linux-kernel, linux-mm, syzkaller-bugs

On 13 Nov 2022 10:50:37 -0800 Mike Kravetz <mike.kravetz@oracle.com>
> On 11/13/22 16:36, Dmitry Vyukov wrote:
> > On Sat, 12 Nov 2022 at 15:03, syzbot
> > <syzbot+d07c65298d2c15eafcb0@syzkaller.appspotmail.com> wrote:
> > >
> > > Hello,
> > >
> > > syzbot found the following issue on:
> > >
> > > HEAD commit:    1621b6eaebf7 Merge branch 'for-next/fixes' into for-kernelci
> > > git tree:       git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci
> > > console output: https://syzkaller.appspot.com/x/log.txt?x=13bd511e880000
> > > kernel config:  https://syzkaller.appspot.com/x/.config?x=606e57fd25c5c6cc
> > > dashboard link: https://syzkaller.appspot.com/bug?extid=d07c65298d2c15eafcb0
> > > compiler:       Debian clang version 13.0.1-++20220126092033+75e33f71c2da-1~exp1~20220126212112.63, GNU ld (GNU Binutils for Debian) 2.35.2
> > > userspace arch: arm64
> > > syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=13315856880000
> > > C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=173614d1880000
> > >
> > > Downloadable assets:
> > > disk image: https://storage.googleapis.com/syzbot-assets/82aa7741098d/disk-1621b6ea.raw.xz
> > > vmlinux: https://storage.googleapis.com/syzbot-assets/f6be08c4e4c2/vmlinux-1621b6ea.xz
> > > kernel image: https://storage.googleapis.com/syzbot-assets/296b6946258a/Image-1621b6ea.gz.xz
> > >
> > > IMPORTANT: if you fix the issue, please add the following tag to the commit:
> > > Reported-by: syzbot+d07c65298d2c15eafcb0@syzkaller.appspotmail.com
> > 
> > This may have the same root cause as:
> > 
> > possible deadlock in hugetlb_fault
> > https://lore.kernel.org/all/CACT4Y+ZWNV6ApzEv0UrsF2T8JWmXez_-H-EGMii-S_2JbXv07Q@mail.gmail.com/
> > 
> > and there is a potential explanation as to what may be the problem.
> 
> Thanks Dmitry!
> 
> An issue with this new hugetlb locking was previously reported and I have been
> working on a solution.  When I look at the reproducer, I see that it is calling
> madvise(MADV_DONTNEED).  This triggers the other issue and could certainly
> cause the issue reported here.
> 
> Proposed patches are here and in next-20221111:
> https://lore.kernel.org/linux-mm/20221111232628.290160-1-mike.kravetz@oracle.com/

Thanks for your fix.
> 
> I am currently trying to run the reproducer, but it is not reproducing quickly.
> Since this is a timing issue that as expected.  Interesting that this
> report is run on arm64 and I am trying to reproduce on x86.  Although, the
> issue is not architecture specific in any way.

Syzbot is good at testing patches and take a look at [1,2] for submitting
patch to the bot. Have fun.

[1] https://lore.kernel.org/lkml/YtlbkmVGJyhO4kR6@rowland.harvard.edu/
[2] https://lore.kernel.org/lkml/fa23ffc2-755e-7e04-362d-68fad7d69c85@kernel.dk/

BTW I prefer Alan's way with patch directly attached in response to the report.

Hillf
> 
> I'll keep looking, but am fairly confident this is the root cause.
> -- 
> Mike Kravetz


^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [syzbot] WARNING: locking bug in hugetlb_no_page
  2022-11-13 18:50   ` Mike Kravetz
  2022-11-14  1:26     ` Hillf Danton
@ 2022-11-14  2:24     ` Mike Kravetz
  2022-11-14  9:59       ` Dmitry Vyukov
  1 sibling, 1 reply; 6+ messages in thread
From: Mike Kravetz @ 2022-11-14  2:24 UTC (permalink / raw)
  To: Dmitry Vyukov
  Cc: syzbot, akpm, linux-kernel, linux-mm, llvm, nathan, ndesaulniers,
	songmuchun, syzkaller-bugs, trix, Hillf Danton

On 11/13/22 10:50, Mike Kravetz wrote:
> On 11/13/22 16:36, Dmitry Vyukov wrote:
> > On Sat, 12 Nov 2022 at 15:03, syzbot
> > <syzbot+d07c65298d2c15eafcb0@syzkaller.appspotmail.com> wrote:
> > >
> > > Hello,
> > >
> > > syzbot found the following issue on:
> > >
> > > HEAD commit:    1621b6eaebf7 Merge branch 'for-next/fixes' into for-kernelci
> > > git tree:       git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci
> > > console output: https://syzkaller.appspot.com/x/log.txt?x=13bd511e880000
> > > kernel config:  https://syzkaller.appspot.com/x/.config?x=606e57fd25c5c6cc
> > > dashboard link: https://syzkaller.appspot.com/bug?extid=d07c65298d2c15eafcb0
> > > compiler:       Debian clang version 13.0.1-++20220126092033+75e33f71c2da-1~exp1~20220126212112.63, GNU ld (GNU Binutils for Debian) 2.35.2
> > > userspace arch: arm64
> > > syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=13315856880000
> > > C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=173614d1880000
> > >
> > > Downloadable assets:
> > > disk image: https://storage.googleapis.com/syzbot-assets/82aa7741098d/disk-1621b6ea.raw.xz
> > > vmlinux: https://storage.googleapis.com/syzbot-assets/f6be08c4e4c2/vmlinux-1621b6ea.xz
> > > kernel image: https://storage.googleapis.com/syzbot-assets/296b6946258a/Image-1621b6ea.gz.xz
> > >
> > > IMPORTANT: if you fix the issue, please add the following tag to the commit:
> > > Reported-by: syzbot+d07c65298d2c15eafcb0@syzkaller.appspotmail.com
> > 
> > This may have the same root cause as:
> > 
> > possible deadlock in hugetlb_fault
> > https://lore.kernel.org/all/CACT4Y+ZWNV6ApzEv0UrsF2T8JWmXez_-H-EGMii-S_2JbXv07Q@mail.gmail.com/
> > 
> > and there is a potential explanation as to what may be the problem.
> 
> Thanks Dmitry!
> 
> An issue with this new hugetlb locking was previously reported and I have been
> working on a solution.  When I look at the reproducer, I see that it is calling
> madvise(MADV_DONTNEED).  This triggers the other issue and could certainly
> cause the issue reported here.
> 
> Proposed patches are here and in next-20221111:
> https://lore.kernel.org/linux-mm/20221111232628.290160-1-mike.kravetz@oracle.com/
> 
> I am currently trying to run the reproducer, but it is not reproducing quickly.
> Since this is a timing issue that as expected.  Interesting that this
> report is run on arm64 and I am trying to reproduce on x86.  Although, the
> issue is not architecture specific in any way.

After tweaking my config, I was able to reliably reproduce.

> I'll keep looking, but am fairly confident this is the root cause.

I was also able to verify the series above addresses the issue.

-- 
Mike Kravetz


^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [syzbot] WARNING: locking bug in hugetlb_no_page
  2022-11-14  2:24     ` Mike Kravetz
@ 2022-11-14  9:59       ` Dmitry Vyukov
  0 siblings, 0 replies; 6+ messages in thread
From: Dmitry Vyukov @ 2022-11-14  9:59 UTC (permalink / raw)
  To: Mike Kravetz
  Cc: syzbot, akpm, linux-kernel, linux-mm, llvm, nathan, ndesaulniers,
	songmuchun, syzkaller-bugs, trix, Hillf Danton

On Mon, 14 Nov 2022 at 03:24, Mike Kravetz <mike.kravetz@oracle.com> wrote:
>
> On 11/13/22 10:50, Mike Kravetz wrote:
> > On 11/13/22 16:36, Dmitry Vyukov wrote:
> > > On Sat, 12 Nov 2022 at 15:03, syzbot
> > > <syzbot+d07c65298d2c15eafcb0@syzkaller.appspotmail.com> wrote:
> > > >
> > > > Hello,
> > > >
> > > > syzbot found the following issue on:
> > > >
> > > > HEAD commit:    1621b6eaebf7 Merge branch 'for-next/fixes' into for-kernelci
> > > > git tree:       git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci
> > > > console output: https://syzkaller.appspot.com/x/log.txt?x=13bd511e880000
> > > > kernel config:  https://syzkaller.appspot.com/x/.config?x=606e57fd25c5c6cc
> > > > dashboard link: https://syzkaller.appspot.com/bug?extid=d07c65298d2c15eafcb0
> > > > compiler:       Debian clang version 13.0.1-++20220126092033+75e33f71c2da-1~exp1~20220126212112.63, GNU ld (GNU Binutils for Debian) 2.35.2
> > > > userspace arch: arm64
> > > > syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=13315856880000
> > > > C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=173614d1880000
> > > >
> > > > Downloadable assets:
> > > > disk image: https://storage.googleapis.com/syzbot-assets/82aa7741098d/disk-1621b6ea.raw.xz
> > > > vmlinux: https://storage.googleapis.com/syzbot-assets/f6be08c4e4c2/vmlinux-1621b6ea.xz
> > > > kernel image: https://storage.googleapis.com/syzbot-assets/296b6946258a/Image-1621b6ea.gz.xz
> > > >
> > > > IMPORTANT: if you fix the issue, please add the following tag to the commit:
> > > > Reported-by: syzbot+d07c65298d2c15eafcb0@syzkaller.appspotmail.com
> > >
> > > This may have the same root cause as:
> > >
> > > possible deadlock in hugetlb_fault
> > > https://lore.kernel.org/all/CACT4Y+ZWNV6ApzEv0UrsF2T8JWmXez_-H-EGMii-S_2JbXv07Q@mail.gmail.com/
> > >
> > > and there is a potential explanation as to what may be the problem.
> >
> > Thanks Dmitry!
> >
> > An issue with this new hugetlb locking was previously reported and I have been
> > working on a solution.  When I look at the reproducer, I see that it is calling
> > madvise(MADV_DONTNEED).  This triggers the other issue and could certainly
> > cause the issue reported here.
> >
> > Proposed patches are here and in next-20221111:
> > https://lore.kernel.org/linux-mm/20221111232628.290160-1-mike.kravetz@oracle.com/
> >
> > I am currently trying to run the reproducer, but it is not reproducing quickly.
> > Since this is a timing issue that as expected.  Interesting that this
> > report is run on arm64 and I am trying to reproduce on x86.  Although, the
> > issue is not architecture specific in any way.
>
> After tweaking my config, I was able to reliably reproduce.
>
> > I'll keep looking, but am fairly confident this is the root cause.
>
> I was also able to verify the series above addresses the issue.

Let's tell syzbot about the fix so that it reports similar issues in future:

#syz fix:
hugetlb: don't delete vma_lock in hugetlb MADV_DONTNEED processing


^ permalink raw reply	[flat|nested] 6+ messages in thread

end of thread, other threads:[~2022-11-14  9:59 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-11-12 14:03 [syzbot] WARNING: locking bug in hugetlb_no_page syzbot
2022-11-13 15:36 ` Dmitry Vyukov
2022-11-13 18:50   ` Mike Kravetz
2022-11-14  1:26     ` Hillf Danton
2022-11-14  2:24     ` Mike Kravetz
2022-11-14  9:59       ` Dmitry Vyukov

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