Re: [syzbot] linux-next boot error: BUG: unable to handle kernel paging request in corrupted

[Dmitry Vyukov]

On Tue, 1 Nov 2022 at 07:31, syzbot
<syzbot+4d9bcd45d5ca0a476cf7@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
>
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit:    e9d267f752f8 Add linux-next specific files for 20221101
> git tree:       linux-next
> console output: https://syzkaller.appspot.com/x/log.txt?x=13c8fdb6880000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=7d67fcb6fc8245f
> dashboard link: https://syzkaller.appspot.com/bug?extid=4d9bcd45d5ca0a476cf7
> compiler:       gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
>
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/a6c3145cf385/disk-e9d267f7.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/3f34d7fed0ff/vmlinux-e9d267f7.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/279836b50e84/bzImage-e9d267f7.xz
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+4d9bcd45d5ca0a476cf7@xxxxxxxxxxxxxxxxxxxxxxxxx
>
> floppy0: no floppy controllers found
> work still pending
> BUG: unable to handle page fault for address: ffffed1018000000
> #PF: supervisor write access in kernel mode
> #PF: error_code(0x0002) - not-present page
> PGD 23ffee067 P4D 23ffee067 PUD 13fff5067 PMD 0
> Oops: 0002 [#1] PREEMPT SMP KASAN
> CPU: 0 PID: 11 Comm: kworker/u4:1 Not tainted 6.1.0-rc3-next-20221101-syzkaller #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/11/2022
> Workqueue: events_unbound async_run_entry_fn

Besides the crash in bioset_exit() there is some issue with kallsyms

\/\/\/\/\/\/

> RIP: 0010:memset_orig-0x7/0xb0

It gives a negative offset from memset_orig. But that's memset_erms symbol:

$ nm -nS vmlinux-6fbda10e | grep ffffffff895869
ffffffff89586900 000000000000002f T __memset
ffffffff89586930 000000000000000f t memset_erms
ffffffff89586940 00000000000000ac t memset_orig
ffffffff895869f0 000000000000006e T num_digits

$ objdump --disassemble=memset_erms vmlinux-6fbda10e
ffffffff89586930 <memset_erms>:
ffffffff89586930: 49 89 f9              mov    %rdi,%r9
ffffffff89586933: 40 88 f0              mov    %sil,%al
ffffffff89586936: 48 89 d1              mov    %rdx,%rcx
ffffffff89586939: f3 aa                rep stos %al,%es:(%rdi)
ffffffff8958693b: 4c 89 c8              mov    %r9,%rax
ffffffff8958693e: c3                    ret


> Code: c1 e9 03 40 0f b6 f6 48 b8 01 01 01 01 01 01 01 01 48 0f af c6 f3 48 ab 89 d1 f3 aa 4c 89 c8 c3 90 49 89 f9 40 88 f0 48 89 d1 <f3> aa 4c 89 c8 c3 90 49 89 fa 40 0f b6 ce 48 b8 01 01 01 01 01 01
> RSP: 0000:ffffc90000107a48 EFLAGS: 00010287
> RAX: dffffc0000000000 RBX: ffff88801cd34100 RCX: fffff11014430738
> RDX: fffff11028a89f18 RSI: 0000000000000000 RDI: ffffed1018000000
> RBP: ffff88814544f8c0 R08: 0000000000000005 R09: ffffed10039a6820
> R10: 0000000000000001 R11: 0000000000000000 R12: ffffffff81a702a0
> R13: ffff88814544f8c0 R14: 0000000000000007 R15: ffff88801cd34100
> FS:  0000000000000000(0000) GS:ffff8880b9a00000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: ffffed1018000000 CR3: 000000000bc8e000 CR4: 00000000003506f0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> Call Trace:
>  <TASK>
>  kasan_unpoison mm/kasan/shadow.c:138 [inline]
>  kasan_unpoison+0x40/0x70 mm/kasan/shadow.c:115
>  kasan_unpoison_range include/linux/kasan.h:112 [inline]
>  kasan_unpoison_element mm/mempool.c:115 [inline]
>  remove_element mm/mempool.c:134 [inline]
>  mempool_exit+0x1c4/0x320 mm/mempool.c:153
>  bioset_exit+0x2d3/0x640 block/bio.c:1655
>  disk_release+0x143/0x480 block/genhd.c:1169
>  device_release+0x9f/0x240 drivers/base/core.c:2330
>  kobject_cleanup lib/kobject.c:673 [inline]
>  kobject_release lib/kobject.c:704 [inline]
>  kref_put include/linux/kref.h:65 [inline]
>  kobject_put+0x1be/0x4c0 lib/kobject.c:721
>  put_device+0x1b/0x30 drivers/base/core.c:3624
>  blk_mark_disk_dead-0xf/0x60
>  do_floppy_init drivers/block/floppy.c:4756 [inline]
>  floppy_async_init+0x2169/0x21ca drivers/block/floppy.c:4765
>  async_run_entry_fn+0x98/0x530 kernel/async.c:127
>  process_one_work+0x9bf/0x1710 kernel/workqueue.c:2289
>  worker_thread+0x665/0x1080 kernel/workqueue.c:2436
>  kthread+0x2e4/0x3a0 kernel/kthread.c:376
>  ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308
>  </TASK>
> Modules linked in:
> CR2: ffffed1018000000
> ---[ end trace 0000000000000000 ]---
> RIP: 0010:memset_orig-0x7/0xb0
> Code: c1 e9 03 40 0f b6 f6 48 b8 01 01 01 01 01 01 01 01 48 0f af c6 f3 48 ab 89 d1 f3 aa 4c 89 c8 c3 90 49 89 f9 40 88 f0 48 89 d1 <f3> aa 4c 89 c8 c3 90 49 89 fa 40 0f b6 ce 48 b8 01 01 01 01 01 01
> RSP: 0000:ffffc90000107a48 EFLAGS: 00010287
> RAX: dffffc0000000000 RBX: ffff88801cd34100 RCX: fffff11014430738
> RDX: fffff11028a89f18 RSI: 0000000000000000 RDI: ffffed1018000000
> RBP: ffff88814544f8c0 R08: 0000000000000005 R09: ffffed10039a6820
> R10: 0000000000000001 R11: 0000000000000000 R12: ffffffff81a702a0
> R13: ffff88814544f8c0 R14: 0000000000000007 R15: ffff88801cd34100
> FS:  0000000000000000(0000) GS:ffff8880b9a00000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: ffffed1018000000 CR3: 000000000bc8e000 CR4: 00000000003506f0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> ----------------
> Code disassembly (best guess):
>    0:   c1 e9 03                shr    $0x3,%ecx
>    3:   40 0f b6 f6             movzbl %sil,%esi
>    7:   48 b8 01 01 01 01 01    movabs $0x101010101010101,%rax
>    e:   01 01 01
>   11:   48 0f af c6             imul   %rsi,%rax
>   15:   f3 48 ab                rep stos %rax,%es:(%rdi)
>   18:   89 d1                   mov    %edx,%ecx
>   1a:   f3 aa                   rep stos %al,%es:(%rdi)
>   1c:   4c 89 c8                mov    %r9,%rax
>   1f:   c3                      retq
>   20:   90                      nop
>   21:   49 89 f9                mov    %rdi,%r9
>   24:   40 88 f0                mov    %sil,%al
>   27:   48 89 d1                mov    %rdx,%rcx
> * 2a:   f3 aa                   rep stos %al,%es:(%rdi) <-- trapping instruction
>   2c:   4c 89 c8                mov    %r9,%rax
>   2f:   c3                      retq
>   30:   90                      nop
>   31:   49 89 fa                mov    %rdi,%r10
>   34:   40 0f b6 ce             movzbl %sil,%ecx
>   38:   48                      rex.W
>   39:   b8 01 01 01 01          mov    $0x1010101,%eax
>   3e:   01 01                   add    %eax,(%rcx)
>
>
> ---
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>
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