Re: [syzbot] [ntfs3?] [btrfs?] BUG: unable to handle kernel paging request in clear_user_rep_good

Christoph Hellwig
2023-02-03T16:25:43Z

Where are the ntfs3 and btrfs tags coming from? This seems to clearly
be about ext4 in the call stack.

On Thu, Feb 02, 2023 at 11:54:48PM -0800, syzbot wrote:
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit: ab072681eabe Merge tag 'irq_urgent_for_v6.2_rc6' of git://..
> git tree: upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=15933749480000
> kernel config: https://syzkaller.appspot.com/x/.config?x=23330449ad10b66f
> dashboard link: https://syzkaller.appspot.com/bug?extid=401145a9a237779feb26
> compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=13b3ba9e480000
>
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/a43bbc272cf3/disk-ab072681.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/fec05f5bcfa7/vmlinux-ab072681.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/00b9b0dd9801/bzImage-ab072681.xz
> mounted in repro #1: https://storage.googleapis.com/syzbot-assets/f7ef8856a9ce/mount_0.gz
> mounted in repro #2: https://storage.googleapis.com/syzbot-assets/79f8035a08dd/mount_4.gz
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+401145a9a237779feb26@syzkaller.appspotmail.com
>
> BUG: unable to handle page fault for address: 0000000020081000
> #PF: supervisor write access in kernel mode
> #PF: error_code(0x0002) - not-present page
> PGD 1c9cc067 P4D 1c9cc067 PUD 280e9067 PMD 2a76b067 PTE 0
> Oops: 0002 [#1] PREEMPT SMP KASAN
> CPU: 0 PID: 5441 Comm: syz-executor.1 Not tainted 6.2.0-rc5-syzkaller-00221-gab072681eabe #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/12/2023
> RIP: 0010:clear_user_rep_good+0x1c/0x30 arch/x86/lib/clear_page_64.S:147
> Code: 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 f3 0f 1e fa 48 83 f9 40 72 a6 89 ca 48 c1 e9 03 74 03 f3 48 ab 83 e2 07 74 04 89 d1 <f3> aa 31 c0 c3 48 c1 e1 03 83 e2 07 48 01 d1 eb f1 0f 1f 00 f3 0f
> RSP: 0018:ffffc900056f76d8 EFLAGS: 00050202
> RAX: 0000000000000000 RBX: 0000000000081002 RCX: 0000000000000002
> RDX: 0000000000000002 RSI: ffffffff84098c49 RDI: 0000000020081000
> RBP: 0000000000081002 R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000001 R11: 0000000000094001 R12: ffffc900056f7d70
> R13: 0000000020000000 R14: 000000007ffff000 R15: 0000000000000000
> FS: 00007fc1837f1700(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 0000000020081000 CR3: 000000002b26e000 CR4: 0000000000350ef0
> Call Trace:
> <TASK>
> __clear_user arch/x86/include/asm/uaccess_64.h:103 [inline]
> clear_user arch/x86/include/asm/uaccess_64.h:124 [inline]
> iov_iter_zero+0x709/0x1290 lib/iov_iter.c:800
> iomap_dio_hole_iter fs/iomap/direct-io.c:389 [inline]
> iomap_dio_iter fs/iomap/direct-io.c:440 [inline]
> __iomap_dio_rw+0xe3d/0x1cd0 fs/iomap/direct-io.c:601
> iomap_dio_rw+0x40/0xa0 fs/iomap/direct-io.c:689
> ext4_dio_read_iter fs/ext4/file.c:94 [inline]
> ext4_file_read_iter+0x4be/0x690 fs/ext4/file.c:145
> call_read_iter include/linux/fs.h:2183 [inline]
> do_iter_readv_writev+0x2e0/0x3b0 fs/read_write.c:733
> do_iter_read+0x2f2/0x750 fs/read_write.c:796
> vfs_readv+0xe5/0x150 fs/read_write.c:916
> do_preadv+0x1b6/0x270 fs/read_write.c:1008
> __do_sys_preadv2 fs/read_write.c:1070 [inline]
> __se_sys_preadv2 fs/read_write.c:1061 [inline]
> __x64_sys_preadv2+0xef/0x150 fs/read_write.c:1061
> do_syscall_x64 arch/x86/entry/common.c:50 [inline]
> do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
> entry_SYSCALL_64_after_hwframe+0x63/0xcd
> RIP: 0033:0x7fc182a8c0c9
> Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 f1 19 00 00 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 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
> RSP: 002b:00007fc1837f1168 EFLAGS: 00000246 ORIG_RAX: 0000000000000147
> RAX: ffffffffffffffda RBX: 00007fc182babf80 RCX: 00007fc182a8c0c9
> RDX: 0000000000000001 RSI: 0000000020000100 RDI: 0000000000000003
> RBP: 00007fc182ae7ae9 R08: 0000000000000000 R09: 0000000000000000
> R10: 000000000007fffe R11: 0000000000000246 R12: 0000000000000000
> R13: 00007ffefd64d1ef R14: 00007fc1837f1300 R15: 0000000000022000
> </TASK>
> Modules linked in:
> CR2: 0000000020081000
> ---[ end trace 0000000000000000 ]---
> RIP: 0010:clear_user_rep_good+0x1c/0x30 arch/x86/lib/clear_page_64.S:147
> Code: 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 f3 0f 1e fa 48 83 f9 40 72 a6 89 ca 48 c1 e9 03 74 03 f3 48 ab 83 e2 07 74 04 89 d1 <f3> aa 31 c0 c3 48 c1 e1 03 83 e2 07 48 01 d1 eb f1 0f 1f 00 f3 0f
> RSP: 0018:ffffc900056f76d8 EFLAGS: 00050202
> RAX: 0000000000000000 RBX: 0000000000081002 RCX: 0000000000000002
> RDX: 0000000000000002 RSI: ffffffff84098c49 RDI: 0000000020081000
> RBP: 0000000000081002 R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000001 R11: 0000000000094001 R12: ffffc900056f7d70
> R13: 0000000020000000 R14: 000000007ffff000 R15: 0000000000000000
> FS: 00007fc1837f1700(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 00007f8294a2a000 CR3: 000000002b26e000 CR4: 0000000000350ef0
> ----------------
> Code disassembly (best guess):
> 0: 66 66 2e 0f 1f 84 00 data16 nopw %cs:0x0(%rax,%rax,1)
> 7: 00 00 00 00
> b: 0f 1f 00 nopl (%rax)
> e: f3 0f 1e fa endbr64
> 12: 48 83 f9 40 cmp $0x40,%rcx
> 16: 72 a6 jb 0xffffffbe
> 18: 89 ca mov %ecx,%edx
> 1a: 48 c1 e9 03 shr $0x3,%rcx
> 1e: 74 03 je 0x23
> 20: f3 48 ab rep stos %rax,%es:(%rdi)
> 23: 83 e2 07 and $0x7,%edx
> 26: 74 04 je 0x2c
> 28: 89 d1 mov %edx,%ecx
> * 2a: f3 aa rep stos %al,%es:(%rdi) <-- trapping instruction
> 2c: 31 c0 xor %eax,%eax
> 2e: c3 retq
> 2f: 48 c1 e1 03 shl $0x3,%rcx
> 33: 83 e2 07 and $0x7,%edx
> 36: 48 01 d1 add %rdx,%rcx
> 39: eb f1 jmp 0x2c
> 3b: 0f 1f 00 nopl (%rax)
> 3e: f3 repz
> 3f: 0f .byte 0xf
>
>
> ---
> 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:
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> syzbot can test patches for this issue, for details see:
> https://goo.gl/tpsmEJ#testing-patches
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