WARNING: suspicious RCU usage in inode

WARNING: suspicious RCU usage in inode_security
Status: upstream: reported on 2021/01/20 03:59
Reported-by: syzbot+37978b81dea56c7a4249@syzkaller.appspotmail.com
First crash: 194d, last: 73d

Sample crash report:

=============================
WARNING: suspicious RCU usage
5.13.0-rc2-syzkaller #0 Not tainted
-----------------------------
kernel/sched/core.c:8304 Illegal context switch in RCU-bh read-side critical section!

other info that might help us debug this:


rcu_scheduler_active = 2, debug_locks = 0
no locks held by sshd/8645.

stack backtrace:
CPU: 2 PID: 8645 Comm: sshd Not tainted 5.13.0-rc2-syzkaller #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-2 04/01/2014
Call Trace:
 __dump_stack lib/dump_stack.c:79 [inline]
 dump_stack+0x141/0x1d7 lib/dump_stack.c:120
 ___might_sleep+0x229/0x2c0 kernel/sched/core.c:8304
 __inode_security_revalidate security/selinux/hooks.c:295 [inline]
 inode_security+0x5d/0x130 security/selinux/hooks.c:332
 selinux_file_permission+0x140/0x520 security/selinux/hooks.c:3712
 security_file_permission+0x56/0x560 security/security.c:1505
 rw_verify_area+0x115/0x350 fs/read_write.c:400
 vfs_read+0x126/0x570 fs/read_write.c:487
 ksys_read+0x1ee/0x250 fs/read_write.c:634
 do_syscall_64+0x3a/0xb0 arch/x86/entry/common.c:47
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7f755772d910
Code: b6 fe ff ff 48 8d 3d 0f be 08 00 48 83 ec 08 e8 06 db 01 00 66 0f 1f 44 00 00 83 3d f9 2d 2c 00 00 75 10 b8 00 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 31 c3 48 83 ec 08 e8 de 9b 01 00 48 89 04 24
RSP: 002b:00007fffbb0a27e8 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f755772d910
RDX: 0000000000004000 RSI: 00007fffbb0a27f0 RDI: 0000000000000003
RBP: 00005640043833b0 R08: 00000000000002cf R09: 00007fffbb157080
R10: 00007fffbb1570f0 R11: 0000000000000246 R12: 0000000000000001
R13: 00007fffbb0a687f R14: 000056400327bbe7 R15: 0000000000000003

Crashes (3):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	VM info	Title
ci-qemu-upstream	2021/05/17 08:41	upstream	d07f6ca923ea	a2eb125d	.config	log	report	info	WARNING: suspicious RCU usage in inode_security
ci-upstream-kasan-gce-selinux-root	2021/03/28 22:25	upstream	81b1d39fd39a	a8529b82	.config	log	report	info	WARNING: suspicious RCU usage in inode_security
ci-qemu-upstream	2021/01/16 03:51	upstream	82821be8a2e1	65a7a854	.config	log	report	info