Re: [syzbot] [io-uring?] kernel BUG in __io_remove_buffers

[Pavel Begunkov]

On 4/2/24 18:54, syzbot wrote:
> Hello,
>
> syzbot found the following issue on:

Got into spam again as with the last one, replying
just for folks to see.

> HEAD commit:    c0b832517f62 Add linux-next specific files for 20240402
> git tree:       linux-next
> console+strace: https://syzkaller.appspot.com/x/log.txt?x=12d5def9180000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=afcaf46d374cec8c
> dashboard link: https://syzkaller.appspot.com/bug?extid=beb5226eef6218124e9d
> compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=1155ccc5180000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=14b06795180000
>
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/0d36ec76edc7/disk-c0b83251.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/6f9bb4e37dd0/vmlinux-c0b83251.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/2349287b14b7/bzImage-c0b83251.xz
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+beb5226eef6218124e9d@xxxxxxxxxxxxxxxxxxxxxxxxx
>
>   ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
>   ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:243
> ------------[ cut here ]------------
> kernel BUG at include/linux/mm.h:1135!
> Oops: invalid opcode: 0000 [#1] PREEMPT SMP KASAN PTI
> CPU: 0 PID: 12 Comm: kworker/u8:1 Not tainted 6.9.0-rc2-next-20240402-syzkaller #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
> Workqueue: events_unbound io_ring_exit_work
> RIP: 0010:put_page_testzero include/linux/mm.h:1135 [inline]
> RIP: 0010:folio_put_testzero include/linux/mm.h:1141 [inline]
> RIP: 0010:folio_put include/linux/mm.h:1508 [inline]
> RIP: 0010:put_page include/linux/mm.h:1581 [inline]
> RIP: 0010:__io_remove_buffers+0x8ee/0x8f0 io_uring/kbuf.c:196
> Code: ff fb ff ff 48 c7 c7 3c 68 a9 8f e8 fc b6 56 fd e9 ee fb ff ff e8 12 dc f1 fc 48 89 ef 48 c7 c6 60 ff 1e 8c e8 13 20 3b fd 90 <0f> 0b 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa
> RSP: 0018:ffffc90000117830 EFLAGS: 00010246
> RAX: 12798bbc5474ca00 RBX: 0000000000000000 RCX: 0000000000000001
> RDX: dffffc0000000000 RSI: ffffffff8bcad5c0 RDI: 0000000000000001
> RBP: ffffea0000880c40 R08: ffffffff92f3a5ef R09: 1ffffffff25e74bd
> R10: dffffc0000000000 R11: fffffbfff25e74be R12: 0000000000000008
> R13: 0000000000000002 R14: ffff88802d20d280 R15: ffffea0000880c74
> FS:  0000000000000000(0000) GS:ffff8880b9400000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 00000000200020c4 CR3: 000000007d97a000 CR4: 00000000003506f0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> Call Trace:
>   <TASK>
>   io_put_bl io_uring/kbuf.c:229 [inline]
>   io_destroy_buffers+0x14e/0x490 io_uring/kbuf.c:243
>   io_ring_ctx_free+0x818/0xe70 io_uring/io_uring.c:2710
>   io_ring_exit_work+0x7c7/0x850 io_uring/io_uring.c:2941
>   process_one_work kernel/workqueue.c:3218 [inline]
>   process_scheduled_works+0xa2c/0x1830 kernel/workqueue.c:3299
>   worker_thread+0x86d/0xd70 kernel/workqueue.c:3380
>   kthread+0x2f0/0x390 kernel/kthread.c:388
>   ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
>   ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:243
>   </TASK>
> Modules linked in:
> ---[ end trace 0000000000000000 ]---
> RIP: 0010:put_page_testzero include/linux/mm.h:1135 [inline]
> RIP: 0010:folio_put_testzero include/linux/mm.h:1141 [inline]
> RIP: 0010:folio_put include/linux/mm.h:1508 [inline]
> RIP: 0010:put_page include/linux/mm.h:1581 [inline]
> RIP: 0010:__io_remove_buffers+0x8ee/0x8f0 io_uring/kbuf.c:196
> Code: ff fb ff ff 48 c7 c7 3c 68 a9 8f e8 fc b6 56 fd e9 ee fb ff ff e8 12 dc f1 fc 48 89 ef 48 c7 c6 60 ff 1e 8c e8 13 20 3b fd 90 <0f> 0b 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa
> RSP: 0018:ffffc90000117830 EFLAGS: 00010246
> RAX: 12798bbc5474ca00 RBX: 0000000000000000 RCX: 0000000000000001
> RDX: dffffc0000000000 RSI: ffffffff8bcad5c0 RDI: 0000000000000001
> RBP: ffffea0000880c40 R08: ffffffff92f3a5ef R09: 1ffffffff25e74bd
> R10: dffffc0000000000 R11: fffffbfff25e74be R12: 0000000000000008
> R13: 0000000000000002 R14: ffff88802d20d280 R15: ffffea0000880c74
> FS:  0000000000000000(0000) GS:ffff8880b9500000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 00007f31a71870f0 CR3: 000000007930c000 CR4: 00000000003506f0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
>
>
> ---
> 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@xxxxxxxxxxxxxxxx.
>
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>
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>
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--
Pavel Begunkov