[moderation] [block?] general protection fault in loop_process_work (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 05d3ef8bba77 Linux 6.6-rc7
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=14701bcd680000
kernel config: https://syzkaller.appspot.com/x/.config?x=174a257c5ae6b4fd
dashboard link: https://syzkaller.appspot.com/bug?extid=fce51a3b98d0fee64fff
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
CC: [ax...@kernel.dk linux...@vger.kernel.org linux-...@vger.kernel.org]

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/ae5bfebab516/disk-05d3ef8b.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/09609d77e6f1/vmlinux-05d3ef8b.xz
kernel image: https://storage.googleapis.com/syzbot-assets/7bf5dc3610a4/bzImage-05d3ef8b.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+fce51a...@syzkaller.appspotmail.com

general protection fault, probably for non-canonical address 0xdffffc0000000032: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000190-0x0000000000000197]
CPU: 0 PID: 14698 Comm: kworker/u4:13 Not tainted 6.6.0-rc7-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/06/2023
Workqueue: loop2 loop_workfn
RIP: 0010:file_inode include/linux/fs.h:1073 [inline]
RIP: 0010:file_start_write include/linux/fs.h:2642 [inline]
RIP: 0010:lo_write_bvec drivers/block/loop.c:248 [inline]
RIP: 0010:lo_write_simple drivers/block/loop.c:271 [inline]
RIP: 0010:do_req_filebacked drivers/block/loop.c:495 [inline]
RIP: 0010:loop_handle_cmd drivers/block/loop.c:1915 [inline]
RIP: 0010:loop_process_work+0x1300/0x22a0 drivers/block/loop.c:1950
Code: 01 00 00 00 48 8d 94 24 40 02 00 00 e8 f9 ff c8 fe 4d 8d bc 24 90 01 00 00 4d 89 fd 49 c1 ed 03 48 b8 00 00 00 00 00 fc ff df <41> 80 7c 05 00 00 74 08 4c 89 ff e8 20 a4 74 fc 4d 8b 37 4c 89 f0
RSP: 0018:ffffc90015067940 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: 0000000000001000 RCX: ffff888065800000
RDX: ffff888065800000 RSI: 0000000000000001 RDI: ffffc90015067b28
RBP: ffffc90015067bf0 R08: ffffffff843d18de R09: 0000000000000000
R10: ffffc90015067b10 R11: fffff52002a0cf67 R12: 0000000000000000
R13: 0000000000000032 R14: ffffc90015067b10 R15: 0000000000000190
FS: 0000000000000000(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f785177f000 CR3: 000000002eedf000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
process_one_work kernel/workqueue.c:2630 [inline]
process_scheduled_works+0x90f/0x1400 kernel/workqueue.c:2703
worker_thread+0xa5f/0xff0 kernel/workqueue.c:2784
kthread+0x2d3/0x370 kernel/kthread.c:388
ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:304
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:file_inode include/linux/fs.h:1073 [inline]
RIP: 0010:file_start_write include/linux/fs.h:2642 [inline]
RIP: 0010:lo_write_bvec drivers/block/loop.c:248 [inline]
RIP: 0010:lo_write_simple drivers/block/loop.c:271 [inline]
RIP: 0010:do_req_filebacked drivers/block/loop.c:495 [inline]
RIP: 0010:loop_handle_cmd drivers/block/loop.c:1915 [inline]
RIP: 0010:loop_process_work+0x1300/0x22a0 drivers/block/loop.c:1950
Code: 01 00 00 00 48 8d 94 24 40 02 00 00 e8 f9 ff c8 fe 4d 8d bc 24 90 01 00 00 4d 89 fd 49 c1 ed 03 48 b8 00 00 00 00 00 fc ff df <41> 80 7c 05 00 00 74 08 4c 89 ff e8 20 a4 74 fc 4d 8b 37 4c 89 f0
RSP: 0018:ffffc90015067940 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: 0000000000001000 RCX: ffff888065800000
RDX: ffff888065800000 RSI: 0000000000000001 RDI: ffffc90015067b28
RBP: ffffc90015067bf0 R08: ffffffff843d18de R09: 0000000000000000
R10: ffffc90015067b10 R11: fffff52002a0cf67 R12: 0000000000000000
R13: 0000000000000032 R14: ffffc90015067b10 R15: 0000000000000190
FS: 0000000000000000(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ff0bd698000 CR3: 000000002ee1f000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
0: 01 00 add %eax,(%rax)
2: 00 00 add %al,(%rax)
4: 48 8d 94 24 40 02 00 lea 0x240(%rsp),%rdx
b: 00
c: e8 f9 ff c8 fe call 0xfec9000a
11: 4d 8d bc 24 90 01 00 lea 0x190(%r12),%r15
18: 00
19: 4d 89 fd mov %r15,%r13
1c: 49 c1 ed 03 shr $0x3,%r13
20: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax
27: fc ff df
* 2a: 41 80 7c 05 00 00 cmpb $0x0,0x0(%r13,%rax,1) <-- trapping instruction
30: 74 08 je 0x3a
32: 4c 89 ff mov %r15,%rdi
35: e8 20 a4 74 fc call 0xfc74a45a
3a: 4d 8b 37 mov (%r15),%r14
3d: 4c 89 f0 mov %r14,%rax


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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.