[nilfs?] general protection fault in create_empty_buffers (4)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 7d31677bb7b1 gpu: host1x: fix uninitialized variable use
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=14f8b3a6c80000
kernel config: https://syzkaller.appspot.com/x/.config?x=aaa4b45720ca0519
dashboard link: https://syzkaller.appspot.com/bug?extid=3e02ebe38db6514ab209
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
userspace arch: i386
CC: [konishi...@gmail.com linux-...@vger.kernel.org linux-...@vger.kernel.org linux...@vger.kernel.org]

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

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+3e02eb...@syzkaller.appspotmail.com

general protection fault, probably for non-canonical address 0xdffffc000000003d: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x00000000000001e8-0x00000000000001ef]
CPU: 2 PID: 6068 Comm: segctord Not tainted 6.3.0-rc3-syzkaller-00005-g7d31677bb7b1 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-2 04/01/2014
RIP: 0010:__lock_acquire+0xd80/0x5d40 kernel/locking/lockdep.c:4926
Code: 55 0f 41 be 01 00 00 00 0f 86 8e 00 00 00 89 05 36 d2 55 0f e9 83 00 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 da 48 c1 ea 03 <80> 3c 02 00 0f 85 c5 32 00 00 48 81 3b a0 26 11 90 0f 84 52 f3 ff
RSP: 0018:ffffc90002b87600 EFLAGS: 00010002
RAX: dffffc0000000000 RBX: 00000000000001e8 RCX: 0000000000000000
RDX: 000000000000003d RSI: 0000000000000000 RDI: 0000000000000001
RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: ffff88801e163a80 R14: 0000000000000000 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff88802cb00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fcac6a9e150 CR3: 000000004daaf000 CR4: 0000000000152ee0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
lock_acquire kernel/locking/lockdep.c:5669 [inline]
lock_acquire+0x1af/0x520 kernel/locking/lockdep.c:5634
__raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
_raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154
spin_lock include/linux/spinlock.h:350 [inline]
create_empty_buffers+0xc0/0xf30 fs/buffer.c:1595
nilfs_lookup_dirty_data_buffers+0x580/0x6f0 fs/nilfs2/segment.c:711
nilfs_segctor_scan_file+0x1b1/0x6f0 fs/nilfs2/segment.c:1056
nilfs_segctor_collect_blocks fs/nilfs2/segment.c:1178 [inline]
nilfs_segctor_collect fs/nilfs2/segment.c:1505 [inline]
nilfs_segctor_do_construct+0x271b/0x7100 fs/nilfs2/segment.c:2047
nilfs_segctor_construct+0x8e3/0xb30 fs/nilfs2/segment.c:2381
nilfs_segctor_thread_construct fs/nilfs2/segment.c:2489 [inline]
nilfs_segctor_thread+0x3c7/0xf30 fs/nilfs2/segment.c:2572
kthread+0x2e8/0x3a0 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:__lock_acquire+0xd80/0x5d40 kernel/locking/lockdep.c:4926
Code: 55 0f 41 be 01 00 00 00 0f 86 8e 00 00 00 89 05 36 d2 55 0f e9 83 00 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 da 48 c1 ea 03 <80> 3c 02 00 0f 85 c5 32 00 00 48 81 3b a0 26 11 90 0f 84 52 f3 ff
RSP: 0018:ffffc90002b87600 EFLAGS: 00010002
RAX: dffffc0000000000 RBX: 00000000000001e8 RCX: 0000000000000000
RDX: 000000000000003d RSI: 0000000000000000 RDI: 0000000000000001
RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: ffff88801e163a80 R14: 0000000000000000 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff88802cb00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fcac6a9e150 CR3: 000000004daaf000 CR4: 0000000000152ee0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
0: 55 push %rbp
1: 0f 41 be 01 00 00 00 cmovno 0x1(%rsi),%edi
8: 0f 86 8e 00 00 00 jbe 0x9c
e: 89 05 36 d2 55 0f mov %eax,0xf55d236(%rip) # 0xf55d24a
14: e9 83 00 00 00 jmpq 0x9c
19: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax
20: fc ff df
23: 48 89 da mov %rbx,%rdx
26: 48 c1 ea 03 shr $0x3,%rdx
* 2a: 80 3c 02 00 cmpb $0x0,(%rdx,%rax,1) <-- trapping instruction
2e: 0f 85 c5 32 00 00 jne 0x32f9
34: 48 81 3b a0 26 11 90 cmpq $0xffffffff901126a0,(%rbx)
3b: 0f .byte 0xf
3c: 84 52 f3 test %dl,-0xd(%rdx)
3f: ff .byte 0xff


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[syzbot]

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