[v5.15] BUG: sleeping function called from invalid context in lookup_one_qstr_excl

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 68efe5a6c16a Linux 5.15.197
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=15516b9a580000
kernel config: https://syzkaller.appspot.com/x/.config?x=30e28339904629ca
dashboard link: https://syzkaller.appspot.com/bug?extid=bcdfb252749b5fbe7e8c
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/a778cfe5926b/disk-68efe5a6.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/d2cfafb4eb48/vmlinux-68efe5a6.xz
kernel image: https://storage.googleapis.com/syzbot-assets/845a4677be47/bzImage-68efe5a6.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+bcdfb2...@syzkaller.appspotmail.com

loop9: detected capacity change from 0 to 16
erofs: (device loop9): mounted with root inode @ nid 36.
erofs: (device loop9): z_erofs_readpage: failed to read, err [-95]
BUG: sleeping function called from invalid context at fs/dcache.c:877
in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 17266, name: syz.9.3221
1 lock held by syz.9.3221/17266:
#0: ffff888040c94c00 (&type->i_mutex_dir_key#11/1){+.+.}-{3:3}, at: inode_lock_nested include/linux/fs.h:822 [inline]
#0: ffff888040c94c00 (&type->i_mutex_dir_key#11/1){+.+.}-{3:3}, at: filename_create+0x208/0x470 fs/namei.c:3843
Preemption disabled at:
[<ffffffff8398fb97>] kmap_atomic include/linux/highmem-internal.h:196 [inline]
[<ffffffff8398fb97>] z_erofs_reload_indexes+0x347/0x590 fs/erofs/zmap.c:146
CPU: 1 PID: 17266 Comm: syz.9.3221 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
<TASK>
dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106
___might_sleep+0x493/0x610 kernel/sched/core.c:9658
dput+0x26/0x1a0 fs/dcache.c:877
lookup_one_qstr_excl+0x1d6/0x240 fs/namei.c:1573
filename_create+0x23a/0x470 fs/namei.c:3844
do_mknodat+0x26f/0x630 fs/namei.c:3989
__do_sys_mknodat fs/namei.c:4030 [inline]
__se_sys_mknodat fs/namei.c:4027 [inline]
__x64_sys_mknodat+0xa5/0xc0 fs/namei.c:4027
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fc56b81ecb9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fc569a7a028 EFLAGS: 00000246 ORIG_RAX: 0000000000000103
RAX: ffffffffffffffda RBX: 00007fc56ba99fa0 RCX: 00007fc56b81ecb9
RDX: 0000000000001000 RSI: 0000200000000040 RDI: ffffffffffffff9c
RBP: 00007fc56b88cbf7 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fc56ba9a038 R14: 00007fc56ba99fa0 R15: 00007ffe55fca5d8
</TASK>
BUG: scheduling while atomic: syz.9.3221/17266/0x00000002
no locks held by syz.9.3221/17266.
Modules linked in:
Preemption disabled at:
[<ffffffff8398fb97>] kmap_atomic include/linux/highmem-internal.h:196 [inline]
[<ffffffff8398fb97>] z_erofs_reload_indexes+0x347/0x590 fs/erofs/zmap.c:146


---
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[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit: 68efe5a6c16a Linux 5.15.197
git tree: linux-5.15.y

console output: https://syzkaller.appspot.com/x/log.txt?x=11e6db9a580000

kernel config: https://syzkaller.appspot.com/x/.config?x=30e28339904629ca
dashboard link: https://syzkaller.appspot.com/bug?extid=bcdfb252749b5fbe7e8c
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1446b3fc580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=11f16b9a580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/a778cfe5926b/disk-68efe5a6.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/d2cfafb4eb48/vmlinux-68efe5a6.xz
kernel image: https://storage.googleapis.com/syzbot-assets/845a4677be47/bzImage-68efe5a6.xz

mounted in repro: https://storage.googleapis.com/syzbot-assets/59bf633e01a8/mount_0.gz
fsck result: failed (log: https://syzkaller.appspot.com/x/fsck.log?x=134ea852580000)

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+bcdfb2...@syzkaller.appspotmail.com

loop0: detected capacity change from 0 to 16
erofs: (device loop0): mounted with root inode @ nid 36.
erofs: (device loop0): z_erofs_readpage: failed to read, err [-95]

BUG: sleeping function called from invalid context at fs/dcache.c:877

in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 4319, name: syz.0.17
1 lock held by syz.0.17/4319:
#0: ffff88805f10c180 (&type->i_mutex_dir_key#8/1){+.+.}-{3:3}, at: inode_lock_nested include/linux/fs.h:822 [inline]
#0: ffff88805f10c180 (&type->i_mutex_dir_key#8/1){+.+.}-{3:3}, at: filename_create+0x208/0x470 fs/namei.c:3843

Preemption disabled at:
[<ffffffff8398fb97>] kmap_atomic include/linux/highmem-internal.h:196 [inline]
[<ffffffff8398fb97>] z_erofs_reload_indexes+0x347/0x590 fs/erofs/zmap.c:146

CPU: 0 PID: 4319 Comm: syz.0.17 Not tainted syzkaller #0

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
<TASK>
dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106
___might_sleep+0x493/0x610 kernel/sched/core.c:9658
dput+0x26/0x1a0 fs/dcache.c:877
lookup_one_qstr_excl+0x1d6/0x240 fs/namei.c:1573
filename_create+0x23a/0x470 fs/namei.c:3844
do_mknodat+0x26f/0x630 fs/namei.c:3989
__do_sys_mknodat fs/namei.c:4030 [inline]
__se_sys_mknodat fs/namei.c:4027 [inline]
__x64_sys_mknodat+0xa5/0xc0 fs/namei.c:4027
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0

RIP: 0033:0x7f3608708cb9

Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 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 e8 ff ff ff f7 d8 64 89 01 48

RSP: 002b:00007ffde2f1bce8 EFLAGS: 00000246 ORIG_RAX: 0000000000000103
RAX: ffffffffffffffda RBX: 00007f3608983fa0 RCX: 00007f3608708cb9

RDX: 0000000000001000 RSI: 0000200000000040 RDI: ffffffffffffff9c

RBP: 00007f3608776bf7 R08: 0000000000000000 R09: 0000000000000000

R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000

R13: 00007f3608983fac R14: 00007f3608983fa0 R15: 00007f3608983fa0
</TASK>
BUG: scheduling while atomic: syz.0.17/4319/0x00000002
no locks held by syz.0.17/4319.

Modules linked in:
Preemption disabled at:
[<ffffffff8398fb97>] kmap_atomic include/linux/highmem-internal.h:196 [inline]
[<ffffffff8398fb97>] z_erofs_reload_indexes+0x347/0x590 fs/erofs/zmap.c:146


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