Re: BUG: unable to handle kernel paging request in dqput

[Takashi Iwai]

On Sat, 26 Sep 2020 22:48:15 +0200,
syzbot wrote:
> 
> Hello,
> 
> syzbot found the following issue on:
> 
> HEAD commit:    98477740 Merge branch 'rcu/urgent' of git://git.kernel.org..
> git tree:       upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=17930875900000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=af502ec9a451c9fc
> dashboard link: https://syzkaller.appspot.com/bug?extid=f816042a7ae2225f25ba
> compiler:       clang version 10.0.0 (https://github.com/llvm/llvm-project/ c2443155a0fb245c8f17f2c1c72b6ea391e86e81)
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=133783ab900000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=13bb5973900000
> 
> The issue was bisected to:
> 
> commit 1d0f953086f090a022f2c0e1448300c15372db46
> Author: Ioan-Adrian Ratiu <adi@xxxxxxxxxx>
> Date:   Wed Jan 4 22:37:46 2017 +0000
> 
>     ALSA: usb-audio: Fix irq/process data synchronization
> 
> bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=133362c3900000
> final oops:     https://syzkaller.appspot.com/x/report.txt?x=10b362c3900000
> console output: https://syzkaller.appspot.com/x/log.txt?x=173362c3900000

This commit looks really irrelevant from the Oops code path.
It must be a different reason.


thanks,

Takashi


> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+f816042a7ae2225f25ba@xxxxxxxxxxxxxxxxxxxxxxxxx
> Fixes: 1d0f953086f0 ("ALSA: usb-audio: Fix irq/process data synchronization")
> 
> EXT4-fs (loop0): mounted filesystem without journal. Opts: ,errors=continue
> Quota error (device loop0): qtree_write_dquot: Error -1622674347 occurred while creating quota
> Quota error (device loop0): dq_insert_tree: Quota tree root isn't allocated!
> Quota error (device loop0): qtree_write_dquot: Error -5 occurred while creating quota
> BUG: unable to handle page fault for address: fffffbfff3e8feac
> #PF: supervisor read access in kernel mode
> #PF: error_code(0x0000) - not-present page
> PGD 21ffe5067 P4D 21ffe5067 PUD 21ffe4067 PMD 0 
> Oops: 0000 [#1] PREEMPT SMP KASAN
> CPU: 1 PID: 6845 Comm: syz-executor636 Not tainted 5.9.0-rc6-syzkaller #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
> RIP: 0010:bytes_is_nonzero mm/kasan/generic.c:91 [inline]
> RIP: 0010:memory_is_nonzero mm/kasan/generic.c:108 [inline]
> RIP: 0010:memory_is_poisoned_n mm/kasan/generic.c:134 [inline]
> RIP: 0010:memory_is_poisoned mm/kasan/generic.c:165 [inline]
> RIP: 0010:check_memory_region_inline mm/kasan/generic.c:183 [inline]
> RIP: 0010:check_memory_region+0x80/0x2f0 mm/kasan/generic.c:192
> Code: 01 00 00 00 00 fc ff df 4d 01 ea 4d 89 d6 4d 29 ce 49 83 fe 10 7f 2d 4d 85 f6 0f 84 ab 01 00 00 4c 89 cb 4c 29 d3 0f 1f 40 00 <45> 0f b6 19 45 84 db 0f 85 f3 01 00 00 49 ff c1 48 ff c3 75 eb e9
> RSP: 0018:ffffc90001fdf9d0 EFLAGS: 00010293
> RAX: 2234ff0efb3ccc01 RBX: fffffffffffffffe RCX: ffffffff81e00c97
> RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffffffff9f47f565
> RBP: ffffffff9f47f455 R08: dffffc0000000000 R09: fffffbfff3e8feac
> R10: fffffbfff3e8feae R11: 0000000000000000 R12: 1ffffffff3e8feac
> R13: dffffc0000000001 R14: 0000000000000002 R15: ffffffff9f47f565
> FS:  00000000009ac880(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: fffffbfff3e8feac CR3: 000000009f30a000 CR4: 00000000001506e0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> Call Trace:
>  instrument_atomic_read include/linux/instrumented.h:56 [inline]
>  atomic_read include/asm-generic/atomic-instrumented.h:27 [inline]
>  dqput+0x77/0x770 fs/quota/dquot.c:770
>  dqput_all fs/quota/dquot.c:397 [inline]
>  __dquot_initialize+0x9e6/0xc30 fs/quota/dquot.c:1530
>  ext4_xattr_set+0x9b/0x300 fs/ext4/xattr.c:2474
>  __vfs_setxattr+0x3be/0x400 fs/xattr.c:177
>  __vfs_setxattr_noperm+0x11e/0x4b0 fs/xattr.c:208
>  vfs_setxattr+0xde/0x270 fs/xattr.c:283
>  setxattr+0x167/0x350 fs/xattr.c:548
>  path_setxattr+0x109/0x1c0 fs/xattr.c:567
>  __do_sys_setxattr fs/xattr.c:582 [inline]
>  __se_sys_setxattr fs/xattr.c:578 [inline]
>  __x64_sys_setxattr+0xb7/0xd0 fs/xattr.c:578
>  do_syscall_64+0x31/0x70 arch/x86/entry/common.c:46
>  entry_SYSCALL_64_after_hwframe+0x44/0xa9
> RIP: 0033:0x4447e9
> Code: 8d d7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 5b d7 fb ff c3 66 2e 0f 1f 84 00 00 00 00
> RSP: 002b:00007ffcd4905408 EFLAGS: 00000246 ORIG_RAX: 00000000000000bc
> RAX: ffffffffffffffda RBX: 0030656c69662f2e RCX: 00000000004447e9
> RDX: 0000000000000000 RSI: 0000000020000140 RDI: 00000000200000c0
> RBP: 00000000006cf018 R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000246 R12: 00000000004023d0
> R13: 0000000000402460 R14: 0000000000000000 R15: 0000000000000000
> Modules linked in:
> CR2: fffffbfff3e8feac
> ---[ end trace a52409661d306995 ]---
> RIP: 0010:bytes_is_nonzero mm/kasan/generic.c:91 [inline]
> RIP: 0010:memory_is_nonzero mm/kasan/generic.c:108 [inline]
> RIP: 0010:memory_is_poisoned_n mm/kasan/generic.c:134 [inline]
> RIP: 0010:memory_is_poisoned mm/kasan/generic.c:165 [inline]
> RIP: 0010:check_memory_region_inline mm/kasan/generic.c:183 [inline]
> RIP: 0010:check_memory_region+0x80/0x2f0 mm/kasan/generic.c:192
> Code: 01 00 00 00 00 fc ff df 4d 01 ea 4d 89 d6 4d 29 ce 49 83 fe 10 7f 2d 4d 85 f6 0f 84 ab 01 00 00 4c 89 cb 4c 29 d3 0f 1f 40 00 <45> 0f b6 19 45 84 db 0f 85 f3 01 00 00 49 ff c1 48 ff c3 75 eb e9
> RSP: 0018:ffffc90001fdf9d0 EFLAGS: 00010293
> RAX: 2234ff0efb3ccc01 RBX: fffffffffffffffe RCX: ffffffff81e00c97
> RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffffffff9f47f565
> RBP: ffffffff9f47f455 R08: dffffc0000000000 R09: fffffbfff3e8feac
> R10: fffffbfff3e8feae R11: 0000000000000000 R12: 1ffffffff3e8feac
> R13: dffffc0000000001 R14: 0000000000000002 R15: ffffffff9f47f565
> FS:  00000000009ac880(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: fffffbfff3e8feac CR3: 000000009f30a000 CR4: 00000000001506e0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> 
> 
> ---
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> 
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> For information about bisection process see: https://goo.gl/tpsmEJ#bisection
> syzbot can test patches for this issue, for details see:
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>