[syzbot] BUG: sleeping function called from invalid context in __fput

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    ff8744b5 Merge branch '100GbE' of git://git.kernel.org/pub..
git tree:       net-next
console output: https://syzkaller.appspot.com/x/log.txt?x=1338e88c300000
kernel config:  https://syzkaller.appspot.com/x/.config?x=7cf9abab1592f017
dashboard link: https://syzkaller.appspot.com/bug?extid=ecdd08539833605a9399

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

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+ecdd08539833605a9399@xxxxxxxxxxxxxxxxxxxxxxxxx

BUG: sleeping function called from invalid context at fs/file_table.c:264
in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 8392, name: syz-executor.2
no locks held by syz-executor.2/8392.
Preemption disabled at:
[<ffffffff812aa3e4>] kernel_fpu_begin_mask+0x64/0x260 arch/x86/kernel/fpu/core.c:126
CPU: 1 PID: 8392 Comm: syz-executor.2 Not tainted 5.13.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:79 [inline]
 dump_stack+0x141/0x1d7 lib/dump_stack.c:120
 ___might_sleep.cold+0x1f1/0x237 kernel/sched/core.c:8337
 __fput+0xf9/0x920 fs/file_table.c:264
 task_work_run+0xdd/0x1a0 kernel/task_work.c:164
 get_signal+0x1ba2/0x2150 kernel/signal.c:2608
 arch_do_signal_or_restart+0x2a8/0x1eb0 arch/x86/kernel/signal.c:789
 handle_signal_work kernel/entry/common.c:148 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:172 [inline]
 exit_to_user_mode_prepare+0x180/0x290 kernel/entry/common.c:209
 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
 syscall_exit_to_user_mode+0x19/0x60 kernel/entry/common.c:302
 do_syscall_64+0x47/0xb0 arch/x86/entry/common.c:57
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x4665d9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 bc ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ff928e9e188 EFLAGS: 00000246 ORIG_RAX: 000000000000012b
RAX: fffffffffffffff4 RBX: 000000000056bf80 RCX: 00000000004665d9
RDX: 0000000000000001 RSI: 0000000020001f40 RDI: 0000000000000004
RBP: 00007ff928e9e1d0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007ffdfbf7c36f R14: 00007ff928e9e300 R15: 0000000000022000
note: syz-executor.2[8392] exited with preempt_count 1


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