[v5.15] BUG: scheduling while atomic in exit_to_user_mode_loop (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 9eec9a14ee10 Linux 5.15.198
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=150cd13a580000
kernel config: https://syzkaller.appspot.com/x/.config?x=353ae28c40b35af5
dashboard link: https://syzkaller.appspot.com/bug?extid=9a2d4d61e9055bfb3418
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/7146a7b4242e/disk-9eec9a14.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/a11468b96c22/vmlinux-9eec9a14.xz
kernel image: https://storage.googleapis.com/syzbot-assets/e7cb8f058e1c/bzImage-9eec9a14.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+9a2d4d...@syzkaller.appspotmail.com

loop6: detected capacity change from 0 to 16
erofs: (device loop6): mounted with root inode @ nid 36.
BUG: scheduling while atomic: syz.6.479/6160/0x00000002
no locks held by syz.6.479/6160.
Modules linked in:
Preemption disabled at:
[<ffffffff83990d27>] kmap_atomic include/linux/highmem-internal.h:196 [inline]
[<ffffffff83990d27>] z_erofs_reload_indexes+0x347/0x590 fs/erofs/zmap.c:146
Kernel panic - not syncing: scheduling while atomic: panic_on_warn set ...
CPU: 1 PID: 6160 Comm: syz.6.479 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
panic+0x2e5/0x810 kernel/panic.c:309
check_panic_on_warn+0x80/0xa0 kernel/panic.c:229
__schedule_bug+0x193/0x1f0 kernel/sched/core.c:5589
schedule_debug kernel/sched/core.c:5618 [inline]
__schedule+0x1324/0x43c0 kernel/sched/core.c:6286
schedule+0x11b/0x1e0 kernel/sched/core.c:6478
exit_to_user_mode_loop+0x47/0x130 kernel/entry/common.c:169
exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:214
__syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline]
syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:307
do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f9f6271bcb9
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:00007f9f609770e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: 0000000000000001 RBX: 00007f9f62996fa8 RCX: 00007f9f6271bcb9
RDX: 00000000000f4240 RSI: 0000000000000081 RDI: 00007f9f62996fac
RBP: 00007f9f62996fa0 R08: 000f0591dc35410a R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f9f62997038 R14: 00007ffcdb1d9220 R15: 00007ffcdb1d9308
</TASK>
Kernel Offset: disabled
Rebooting in 86400 seconds..


---
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[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit: 9eec9a14ee10 Linux 5.15.198
git tree: linux-5.15.y

console output: https://syzkaller.appspot.com/x/log.txt?x=11712bfa580000

kernel config: https://syzkaller.appspot.com/x/.config?x=353ae28c40b35af5
dashboard link: https://syzkaller.appspot.com/bug?extid=9a2d4d61e9055bfb3418
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=17a1305a580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/7146a7b4242e/disk-9eec9a14.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/a11468b96c22/vmlinux-9eec9a14.xz
kernel image: https://storage.googleapis.com/syzbot-assets/e7cb8f058e1c/bzImage-9eec9a14.xz

mounted in repro: https://storage.googleapis.com/syzbot-assets/618d232b2eb0/mount_0.gz
fsck result: failed (log: https://syzkaller.appspot.com/x/fsck.log?x=15f0d244580000)

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+9a2d4d...@syzkaller.appspotmail.com

loop0: detected capacity change from 0 to 16
erofs: (device loop0): mounted with root inode @ nid 36.
BUG: scheduling while atomic: syz.0.17/4351/0x00000002
no locks held by syz.0.17/4351.

Modules linked in:
Preemption disabled at:
[<ffffffff83990d27>] kmap_atomic include/linux/highmem-internal.h:196 [inline]
[<ffffffff83990d27>] z_erofs_reload_indexes+0x347/0x590 fs/erofs/zmap.c:146
Kernel panic - not syncing: scheduling while atomic: panic_on_warn set ...

CPU: 1 PID: 4351 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
panic+0x2e5/0x810 kernel/panic.c:309
check_panic_on_warn+0x80/0xa0 kernel/panic.c:229
__schedule_bug+0x193/0x1f0 kernel/sched/core.c:5589
schedule_debug kernel/sched/core.c:5618 [inline]
__schedule+0x1324/0x43c0 kernel/sched/core.c:6286
schedule+0x11b/0x1e0 kernel/sched/core.c:6478
exit_to_user_mode_loop+0x47/0x130 kernel/entry/common.c:169
exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:214
__syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline]
syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:307
do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86
entry_SYSCALL_64_after_hwframe+0x66/0xd0

RIP: 0033:0x7f00b3879cb9

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:00007f00b2edd0e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: 0000000000000001 RBX: 00007f00b3af4fa8 RCX: 00007f00b3879cb9
RDX: 00000000000f4240 RSI: 0000000000000081 RDI: 00007f00b3af4fac
RBP: 00007f00b3af4fa0 R08: 0022d5648d7fe7c2 R09: 0000000000000000

R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000

R13: 00007f00b3af5038 R14: 00007ffe4c35e270 R15: 00007ffe4c35e358

</TASK>
Kernel Offset: disabled
Rebooting in 86400 seconds..


---

If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.

[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit: 9eec9a14ee10 Linux 5.15.198
git tree: linux-5.15.y

console output: https://syzkaller.appspot.com/x/log.txt?x=10ac105a580000

kernel config: https://syzkaller.appspot.com/x/.config?x=353ae28c40b35af5
dashboard link: https://syzkaller.appspot.com/bug?extid=9a2d4d61e9055bfb3418
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=17dcd13a580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=17c92bfa580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/7146a7b4242e/disk-9eec9a14.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/a11468b96c22/vmlinux-9eec9a14.xz
kernel image: https://storage.googleapis.com/syzbot-assets/e7cb8f058e1c/bzImage-9eec9a14.xz

mounted in repro: https://storage.googleapis.com/syzbot-assets/85004be6e0be/mount_0.gz
fsck result: failed (log: https://syzkaller.appspot.com/x/fsck.log?x=11d1305a580000)

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+9a2d4d...@syzkaller.appspotmail.com

loop0: detected capacity change from 0 to 16
erofs: (device loop0): mounted with root inode @ nid 36.
BUG: scheduling while atomic: syz.0.17/4319/0x00000002
no locks held by syz.0.17/4319.

Modules linked in:
Preemption disabled at:
[<ffffffff83990d27>] kmap_atomic include/linux/highmem-internal.h:196 [inline]
[<ffffffff83990d27>] z_erofs_reload_indexes+0x347/0x590 fs/erofs/zmap.c:146
Kernel panic - not syncing: scheduling while atomic: panic_on_warn set ...

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
panic+0x2e5/0x810 kernel/panic.c:309
check_panic_on_warn+0x80/0xa0 kernel/panic.c:229
__schedule_bug+0x193/0x1f0 kernel/sched/core.c:5589
schedule_debug kernel/sched/core.c:5618 [inline]
__schedule+0x1324/0x43c0 kernel/sched/core.c:6286
schedule+0x11b/0x1e0 kernel/sched/core.c:6478
exit_to_user_mode_loop+0x47/0x130 kernel/entry/common.c:169
exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:214
__syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline]
syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:307
do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86
entry_SYSCALL_64_after_hwframe+0x66/0xd0

RIP: 0033:0x7f1a6303ecb9

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:00007f1a626a20e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: 0000000000000001 RBX: 00007f1a632b9fa8 RCX: 00007f1a6303ecb9
RDX: 00000000000f4240 RSI: 0000000000000081 RDI: 00007f1a632b9fac
RBP: 00007f1a632b9fa0 R08: 0039db51fbd66196 R09: 0000000000000000

R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000

R13: 00007f1a632ba038 R14: 00007ffd59d0bca0 R15: 00007ffd59d0bd88

</TASK>
Kernel Offset: disabled
Rebooting in 86400 seconds..


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