[v6.1] WARNING in poll_select_finish

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 1a8763b93150 Linux 6.1.188
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=146e0515580000
kernel config: https://syzkaller.appspot.com/x/.config?x=7e5b41322189806a
dashboard link: https://syzkaller.appspot.com/bug?extid=65d3f6312343baf995aa
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
userspace arch: arm64
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=12877005580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/79d582e9ec4f/disk-1a8763b9.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/70e43b512b19/vmlinux-1a8763b9.xz
kernel image: https://storage.googleapis.com/syzbot-assets/7107d5b60093/Image-1a8763b9.gz.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/30edde7b66b8/mount_0.gz
fsck result: OK (log: https://syzkaller.appspot.com/x/fsck.log?x=105294c9580000)

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+65d3f6...@syzkaller.appspotmail.com

------------[ cut here ]------------
WARNING: CPU: 1 PID: 4500 at include/linux/sched/signal.h:558 restore_saved_sigmask_unless include/linux/sched/signal.h:558 [inline]
WARNING: CPU: 1 PID: 4500 at include/linux/sched/signal.h:558 poll_select_finish+0x5b8/0x644 fs/select.c:301
Modules linked in:
CPU: 1 PID: 4500 Comm: syz.0.17 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/14/2026
pstate: 82400005 (Nzcv daif +PAN -UAO +TCO -DIT -SSBS BTYPE=--)
pc : restore_saved_sigmask_unless include/linux/sched/signal.h:558 [inline]
pc : poll_select_finish+0x5b8/0x644 fs/select.c:301
lr : restore_saved_sigmask_unless include/linux/sched/signal.h:558 [inline]
lr : poll_select_finish+0x5b8/0x644 fs/select.c:301
sp : ffff800021047b60
x29: ffff800021047c40 x28: 0000000000000008 x27: dfff800000000000
x26: ffff800021047b80 x25: ffff700004208f70 x24: 0000000000000008
x23: ffff800021047ce0 x22: 0000000000000002 x21: ffff0000d266b800
x20: 0000000000000000 x19: 00000000fffffdfe x18: 1fffe00033e6db7e
x17: ffff8000153bd000 x16: ffff800011bb65f8 x15: 0000000040000000
x14: 0000000000000002 x13: 1ffff00004208f78 x12: 0000000000000000
x11: ff00800008a0a2c0 x10: 0000000000000000 x9 : ffff800008a0a2c0
x8 : ffff0000d266b800 x7 : 0000000000000000 x6 : 000000000000003f
x5 : 0000000000000040 x4 : 0000000000000000 x3 : 0000000000000010
x2 : 0000000000000000 x1 : 0000000000000000 x0 : 0000000000000000
Call trace:
restore_saved_sigmask_unless include/linux/sched/signal.h:558 [inline]
poll_select_finish+0x5b8/0x644 fs/select.c:301
__do_sys_ppoll fs/select.c:1119 [inline]
__se_sys_ppoll fs/select.c:1098 [inline]
__arm64_sys_ppoll+0x240/0x2c8 fs/select.c:1098
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x290 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x13c/0x258 arch/arm64/kernel/syscall.c:140
do_el0_svc+0x5c/0x134 arch/arm64/kernel/syscall.c:204
el0_svc+0x58/0x128 arch/arm64/kernel/entry-common.c:637
el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585
irq event stamp: 746
hardirqs last enabled at (745): [<ffff800011bb47dc>] __exit_to_kernel_mode arch/arm64/kernel/entry-common.c:84 [inline]
hardirqs last enabled at (745): [<ffff800011bb47dc>] exit_to_kernel_mode+0xcc/0xfc arch/arm64/kernel/entry-common.c:94
hardirqs last disabled at (746): [<ffff800011bb2834>] el1_dbg+0x24/0x80 arch/arm64/kernel/entry-common.c:405
softirqs last enabled at (696): [<ffff800008031254>] local_bh_enable+0x10/0x34 include/linux/bottom_half.h:32
softirqs last disabled at (694): [<ffff800008031220>] local_bh_disable+0x10/0x34 include/linux/bottom_half.h:19
---[ end trace 0000000000000000 ]---


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