=============================
WARNING: suspicious RCU usage
5.13.0-rc3-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
1 lock held by syz-executor.0/15306:
 #0: 
ffff8880846e0f58
 (
&mm->mmap_lock
#2
){++++}-{3:3}
, at: mmap_read_trylock include/linux/mmap_lock.h:136 [inline]
, at: do_user_addr_fault+0x2d8/0x1120 arch/x86/mm/fault.c:1331

stack backtrace:
CPU: 1 PID: 15306 Comm: syz-executor.0 Not tainted 5.13.0-rc3-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+0x202/0x31e lib/dump_stack.c:120
 ___might_sleep+0xce/0x6b0 kernel/sched/core.c:8304
 process_huge_page mm/memory.c:5100 [inline]
 clear_huge_page+0x208/0x8a0 mm/memory.c:5161
 __do_huge_pmd_anonymous_page+0x2df/0xe80 mm/huge_memory.c:608
 do_huge_pmd_anonymous_page+0x654/0xce0 mm/huge_memory.c:771
 create_huge_pmd mm/memory.c:4238 [inline]
 __handle_mm_fault mm/memory.c:4473 [inline]
 handle_mm_fault+0x207e/0x2620 mm/memory.c:4600
 do_user_addr_fault+0x8ce/0x1120 arch/x86/mm/fault.c:1390
 handle_page_fault arch/x86/mm/fault.c:1475 [inline]
 exc_page_fault+0xa1/0x1e0 arch/x86/mm/fault.c:1531
 asm_exc_page_fault+0x1e/0x30 arch/x86/include/asm/idtentry.h:577
RIP: 0033:0x407bea
Code: 30 48 8b 34 24 48 85 f6 74 17 8b 44 24 18 0f c8 89 c0 48 89 44 24 18 48 83 fe 01 0f 85 a1 01 00 00 48 8b 44 24 10 8b 74 24 18 <89> 30 e9 d2 fc ff ff 48 8b 44 24 10 8b 10 48 8b 04 24 48 85 c0 0f
RSP: 002b:00007ffcc12f0e00 EFLAGS: 00010246
RAX: 0000000020000540 RBX: 0000000000970000 RCX: 0000000000000000
RDX: 844f2f5a1932628c RSI: 0000000000000001 RDI: 0000000002a932f0
RBP: 00007ffcc12f0ef8 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000004 R11: 000000000000befe R12: 0000000000000001
R13: 0000000000000000 R14: 000000000056bf80 R15: 000000000003df97