[syzbot] [mm?] WARNING in shmem_evict_inode (3)

From: syzbot
Date: Fri May 24 2024 - 19:40:36 EST


Hello,

syzbot found the following issue on:

HEAD commit: 6e51b4b5bbc0 Merge tag 'mips_6.10' of git://git.kernel.org..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=12425392980000
kernel config: https://syzkaller.appspot.com/x/.config?x=5d5d254b2919253a
dashboard link: https://syzkaller.appspot.com/bug?extid=d159dee03e75571264d4
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
userspace arch: i386

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

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/7bc7510fe41f/non_bootable_disk-6e51b4b5.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/4a78abf5bef3/vmlinux-6e51b4b5.xz
kernel image: https://storage.googleapis.com/syzbot-assets/283fe971fc00/bzImage-6e51b4b5.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+d159dee03e75571264d4@xxxxxxxxxxxxxxxxxxxxxxxxx

------------[ cut here ]------------
WARNING: CPU: 1 PID: 7029 at mm/shmem.c:1265 shmem_evict_inode+0x8a1/0xbb0 mm/shmem.c:1265
Modules linked in:
CPU: 1 PID: 7029 Comm: syz-executor.1 Not tainted 6.9.0-syzkaller-09868-g6e51b4b5bbc0 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
RIP: 0010:shmem_evict_inode+0x8a1/0xbb0 mm/shmem.c:1265
Code: e6 e8 a3 cc c1 ff 45 85 e4 75 aa e8 99 d1 c1 ff 48 8b 74 24 28 48 8b 7c 24 30 e8 fa 4a 9c ff e9 1a fe ff ff e8 80 d1 c1 ff 90 <0f> 0b 90 e9 9f f9 ff ff e8 72 d1 c1 ff 4c 89 e2 48 b8 00 00 00 00
RSP: 0018:ffffc90006edfb48 EFLAGS: 00010293
RAX: 0000000000000000 RBX: ffff88801be8b600 RCX: ffffffff81cca8ef
RDX: ffff88801955c880 RSI: ffffffff81ccaf50 RDI: 0000000000000007
RBP: ffffc90006edfc78 R08: 0000000000000007 R09: 0000000000000000
R10: 0000000000000008 R11: 0000000000000000 R12: 0000000000000008
R13: 0000000000000000 R14: ffff88801be8b630 R15: 0000000000200000
FS: 0000000000000000(0000) GS:ffff88802c100000(0063) knlGS:0000000057f3e400
CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: 000000c0009b58b4 CR3: 0000000059eb4000 CR4: 0000000000350ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
evict+0x2ed/0x6c0 fs/inode.c:667
iput_final fs/inode.c:1741 [inline]
iput.part.0+0x5a8/0x7f0 fs/inode.c:1767
iput+0x5c/0x80 fs/inode.c:1757
dentry_unlink_inode+0x295/0x440 fs/dcache.c:400
__dentry_kill+0x1d0/0x600 fs/dcache.c:603
dput.part.0+0x4b1/0x9b0 fs/dcache.c:845
dput+0x1f/0x30 fs/dcache.c:835
__fput+0x3bc/0xb80 fs/file_table.c:430
task_work_run+0x14e/0x250 kernel/task_work.c:180
resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
exit_to_user_mode_loop kernel/entry/common.c:114 [inline]
exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
__syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
syscall_exit_to_user_mode+0x278/0x2a0 kernel/entry/common.c:218
__do_fast_syscall_32+0x82/0x120 arch/x86/entry/common.c:389
do_fast_syscall_32+0x32/0x80 arch/x86/entry/common.c:411
entry_SYSENTER_compat_after_hwframe+0x84/0x8e
RIP: 0023:0xf7267579
Code: b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 00 00 00 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00
RSP: 002b:00000000ff8d90e0 EFLAGS: 00000293 ORIG_RAX: 0000000000000006
RAX: 0000000000000000 RBX: 0000000000000005 RCX: 0000000057f3e400
RDX: 0000000000000000 RSI: 00000000f73bdff4 RDI: 000000000001bc8b
RBP: 00000000f73e50c0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
</TASK>
----------------
Code disassembly (best guess), 2 bytes skipped:
0: 10 06 adc %al,(%rsi)
2: 03 74 b4 01 add 0x1(%rsp,%rsi,4),%esi
6: 10 07 adc %al,(%rdi)
8: 03 74 b0 01 add 0x1(%rax,%rsi,4),%esi
c: 10 08 adc %cl,(%rax)
e: 03 74 d8 01 add 0x1(%rax,%rbx,8),%esi
1e: 00 51 52 add %dl,0x52(%rcx)
21: 55 push %rbp
22: 89 e5 mov %esp,%ebp
24: 0f 34 sysenter
26: cd 80 int $0x80
* 28: 5d pop %rbp <-- trapping instruction
29: 5a pop %rdx
2a: 59 pop %rcx
2b: c3 ret
2c: 90 nop
2d: 90 nop
2e: 90 nop
2f: 90 nop
30: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi
37: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi


---
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.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title

If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)

If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report

If you want to undo deduplication, reply with:
#syz undup