=============================
WARNING: suspicious RCU usage
5.13.0-rc7-syzkaller #0 Not tainted
-----------------------------
kernel/sched/core.c:8303 Illegal context switch in RCU-sched read-side critical section!

other info that might help us debug this:


rcu_scheduler_active = 2, debug_locks = 0
1 lock held by systemd-udevd/4854:
 #0: ffff88802a3bd228 (&mm->mmap_lock#2){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:136 [inline]
 #0: ffff88802a3bd228 (&mm->mmap_lock#2){++++}-{3:3}, at: do_user_addr_fault+0x285/0x1210 arch/x86/mm/fault.c:1331

stack backtrace:
CPU: 1 PID: 4854 Comm: systemd-udevd Not tainted 5.13.0-rc7-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+0x266/0x2c0 kernel/sched/core.c:8303
 do_user_addr_fault+0x2c2/0x1210 arch/x86/mm/fault.c:1348
 handle_page_fault arch/x86/mm/fault.c:1475 [inline]
 exc_page_fault+0x9e/0x180 arch/x86/mm/fault.c:1531
 asm_exc_page_fault+0x1e/0x30 arch/x86/include/asm/idtentry.h:577
RIP: 0033:0x55990b1a44c9
Code: 00 c7 43 34 ff ff ff ff c7 43 30 ff ff ff ff 5b eb e6 0f 1f 44 00 00 66 2e 0f 1f 84 00 00 00 00 00 48 8b 7f 08 e8 77 ed fc ff <80> 63 2f fb eb b0 90 48 85 ff 0f 84 77 01 00 00 41 56 41 55 41 54
RSP: 002b:00007ffd5fbf5ae0 EFLAGS: 00010202
RAX: 0000000000000001 RBX: 000055990b908e98 RCX: 000055990b8b8820
RDX: 00007efe1c52fb58 RSI: 0000000000000000 RDI: 00007efe1c52fb00
RBP: 000055990b908ea0 R08: 0000000000000045 R09: 0000000000000018
R10: 000055990b8c5e90 R11: 0000000000000293 R12: 000055990b1d99a0
R13: 000055990b8b88e0 R14: 000055990b908e98 R15: 00007ffd5fbf5bb0