syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
	(detected by 0, t=10502 jiffies, g=5541, q=32)
rcu: All QSes seen, last rcu_preempt kthread activity 10502 (4294963027-4294952525), jiffies_till_next_fqs=1, root ->qsmask 0x0
rcu: rcu_preempt kthread starved for 10502 jiffies! g5541 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1
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:27000 pid:   15 ppid:     2 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5029 [inline]
 __schedule+0x12c4/0x45b0 kernel/sched/core.c:6375
 schedule+0x11b/0x1f0 kernel/sched/core.c:6458
 schedule_timeout+0x1b9/0x300 kernel/time/timer.c:1914
 rcu_gp_fqs_loop+0x2bf/0x1080 kernel/rcu/tree.c:1972
 rcu_gp_kthread+0xa4/0x360 kernel/rcu/tree.c:2145
 kthread+0x3f6/0x4f0 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 4206 Comm: syz-executor325 Not tainted 5.15.179-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
RIP: 0010:kasan_mem_to_shadow include/linux/kasan.h:56 [inline]
RIP: 0010:memory_is_poisoned_n mm/kasan/generic.c:128 [inline]
RIP: 0010:memory_is_poisoned mm/kasan/generic.c:159 [inline]
RIP: 0010:check_region_inline mm/kasan/generic.c:180 [inline]
RIP: 0010:kasan_check_range+0x41/0x290 mm/kasan/generic.c:189
Code: 0f 82 59 02 00 00 48 89 fd 48 c1 ed 2f 81 fd ff ff 01 00 0f 82 46 02 00 00 48 89 fb 48 c1 eb 03 49 b8 00 00 00 00 00 fc ff df <4e> 8d 0c 03 4c 8d 54 37 ff 49 c1 ea 03 49 bb 01 00 00 00 00 fc ff
RSP: 0018:ffffc9000300f9b8 EFLAGS: 00000806
RAX: 0000000000000001 RBX: 1ffffffff2131e1e RCX: ffffffff8162f3ef
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff9098f0f0
RBP: 000000000001ffff R08: dffffc0000000000 R09: fffffbfff2131e1f
R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000000000000
R13: ffff888074e60ae8 R14: 1ffff1100e9cc162 R15: ffff888074e60b10
FS:  0000555591b9b3c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000020000006b000 CR3: 000000001ff15000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <TASK>
 instrument_atomic_read include/linux/instrumented.h:71 [inline]
 test_bit include/asm-generic/bitops/instrumented-non-atomic.h:134 [inline]
 __lock_acquire+0xcef/0x1ff0 kernel/locking/lockdep.c:4982
 lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
 __might_fault+0xb4/0x110 mm/memory.c:5357
 __clear_user arch/x86/lib/usercopy_64.c:20 [inline]
 clear_user+0xc2/0x150 arch/x86/lib/usercopy_64.c:54
 copy_siginfo_to_user+0x57/0x80 kernel/signal.c:3369
 __setup_rt_frame arch/x86/kernel/signal.c:490 [inline]
 setup_rt_frame arch/x86/kernel/signal.c:780 [inline]
 handle_signal arch/x86/kernel/signal.c:824 [inline]
 arch_do_signal_or_restart+0xb0a/0x1890 arch/x86/kernel/signal.c:869
 handle_signal_work kernel/entry/common.c:154 [inline]
 exit_to_user_mode_loop+0x97/0x130 kernel/entry/common.c:178
 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:214
 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline]
 syscall_exit_to_user_mode+0x5d/0x240 kernel/entry/common.c:307
 do_syscall_64+0x47/0xb0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fe860c24a29
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 1d 00 00 90 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 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffff9550578 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 0000000000000003 RCX: 00007fe860c24a29
RDX: 000020000006b000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: ffffffffffffffff R09: ffffffffffffffff
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fe860c75036
R13: 00007ffff95505b0 R14: 00007ffff95505f0 R15: 0000000000000000
 </TASK>