kernel panic: corrupted stack end in epoll_pwait

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: a41ba30d Linux 4.14.181
git tree: linux-4.14.y
console output: https://syzkaller.appspot.com/x/log.txt?x=14f50cba100000
kernel config: https://syzkaller.appspot.com/x/.config?x=c5458e9cda81cf95
dashboard link: https://syzkaller.appspot.com/bug?extid=bd992f38e231c32da4ed
compiler: gcc (GCC) 9.0.0 20181231 (experimental)

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

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+bd992f...@syzkaller.appspotmail.com

Kernel panic - not syncing: corrupted stack end detected inside scheduler

CPU: 1 PID: 20829 Comm: syz-fuzzer Not tainted 4.14.181-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:17 [inline]
dump_stack+0x1b2/0x283 lib/dump_stack.c:58
panic+0x1f9/0x42d kernel/panic.c:183
schedule_debug kernel/sched/core.c:3199 [inline]
__schedule+0x1d70/0x1d70 kernel/sched/core.c:3308
schedule+0x8d/0x1b0 kernel/sched/core.c:3428
schedule_hrtimeout_range_clock+0x2ac/0x2f0 kernel/time/hrtimer.c:1707
ep_poll+0x865/0xa50 fs/eventpoll.c:1829
SYSC_epoll_wait fs/eventpoll.c:2203 [inline]
SyS_epoll_wait+0x152/0x1a0 fs/eventpoll.c:2168
SYSC_epoll_pwait fs/eventpoll.c:2234 [inline]
SyS_epoll_pwait+0x246/0x290 fs/eventpoll.c:2214
do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x45b300
RSP: 002b:000000c4204b9860 EFLAGS: 00000246 ORIG_RAX: 0000000000000119
RAX: ffffffffffffffda RBX: 00000000ffffffff RCX: 000000000045b300
RDX: 0000000000000080 RSI: 000000c4204b98a0 RDI: 0000000000000004
RBP: 000000c4204b9ea0 R08: 0000000000000000 R09: 000000c42de28b40
R10: 00000000ffffffff R11: 0000000000000246 R12: 0000000000000000
R13: 00000000000000f1 R14: 0000000000000011 R15: 0000000000000080
Kernel Offset: disabled
Rebooting in 86400 seconds..


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[syzbot]

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