syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
	(detected by 0, t=10502 jiffies, g=8017, q=54 ncpus=2)
rcu: All QSes seen, last rcu_preempt kthread activity 10503 (4294955930-4294945427), jiffies_till_next_fqs=1, root ->qsmask 0x0
rcu: rcu_preempt kthread starved for 10504 jiffies! g8017 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0
rcu: 	Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
rcu: RCU grace-period kthread stack dump:
task:rcu_preempt     state:R  running task     stack:27840 pid:16    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5244 [inline]
 __schedule+0x10ec/0x40b0 kernel/sched/core.c:6561
 schedule+0xb9/0x180 kernel/sched/core.c:6637
 schedule_timeout+0x15c/0x280 kernel/time/timer.c:2168
 rcu_gp_fqs_loop+0x2f2/0x1310 kernel/rcu/tree.c:1706
 rcu_gp_kthread+0x95/0x380 kernel/rcu/tree.c:1905
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 0 PID: 4293 Comm: syz-executor714 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:check_region_inline mm/kasan/generic.c:169 [inline]
RIP: 0010:kasan_check_range+0xf/0x290 mm/kasan/generic.c:189
Code: 0b b8 ea ff ff ff c3 0f 0b b8 ea ff ff ff c3 00 00 cc cc 00 00 cc cc 00 00 cc cc b0 01 48 85 f6 0f 84 a4 01 00 00 41 57 41 56 <53> 49 89 f8 49 01 f0 0f 82 57 02 00 00 49 89 f8 49 c1 e8 2f 41 81
RSP: 0018:ffffc90003e77a88 EFLAGS: 00000202
RAX: 961ce2d7f0de7201 RBX: ffff88801af59dc0 RCX: ffffffff812f4361
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffff88801af59dc0
RBP: ffffc90003e77c90 R08: dffffc0000000000 R09: fffffbfff1bfe1c6
R10: fffffbfff1bfe1c6 R11: 1ffffffff1bfe1c5 R12: dffffc0000000000
R13: ffff88801af5b6d0 R14: 0000000000000000 R15: 00007ffe4e46ae40
FS:  000055558954e3c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000020000006b000 CR3: 0000000076702000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 instrument_atomic_read include/linux/instrumented.h:72 [inline]
 _test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline]
 test_ti_thread_flag include/linux/thread_info.h:118 [inline]
 copy_fpstate_to_sigframe+0x291/0xcb0 arch/x86/kernel/fpu/signal.c:227
 get_sigframe arch/x86/kernel/signal.c:297 [inline]
 __setup_rt_frame arch/x86/kernel/signal.c:472 [inline]
 setup_rt_frame arch/x86/kernel/signal.c:784 [inline]
 handle_signal arch/x86/kernel/signal.c:828 [inline]
 arch_do_signal_or_restart+0x622/0x1240 arch/x86/kernel/signal.c:873
 exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174
 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210
 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline]
 syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:303
 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:87
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f20428774fd
Code: f6 48 89 78 10 bf df 00 00 00 48 c7 40 08 08 00 00 00 48 c7 40 18 09 00 00 00 31 c0 e8 cc 4b 03 00 0f 1f 40 00 89 df 83 c3 01 <e8> 1e 3c 03 00 83 fb 1e 75 f1 31 ff e8 b2 74 00 00 66 90 53 b8 04
RSP: 002b:00007ffe4e46b220 EFLAGS: 00000202
RAX: 0000000000000000 RBX: 0000000000000004 RCX: 00007f20428ac0d9
RDX: 000020000006b000 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f2042903036
R13: 00007ffe4e46b250 R14: 0000200000000148 R15: 0000000000000000
 </TASK>