rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 1-...!: (1 GPs behind) idle=393/1/0x4000000000000000 softirq=9355/9358 fqs=17 (t=10500 jiffies g=10593 q=412) rcu: rcu_preempt kthread timer wakeup didn't happen for 10459 jiffies! g10593 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=0 timer-softirq=5729 rcu: rcu_preempt kthread starved for 10460 jiffies! g10593 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:26136 pid: 14 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:4972 [inline] __schedule+0xb72/0x1460 kernel/sched/core.c:6253 schedule+0x12b/0x1f0 kernel/sched/core.c:6326 schedule_timeout+0x1b9/0x300 kernel/time/timer.c:1881 rcu_gp_fqs_loop+0x1fd/0x770 kernel/rcu/tree.c:1955 rcu_gp_kthread+0xa5/0x350 kernel/rcu/tree.c:2128 kthread+0x468/0x490 kernel/kthread.c:327 ret_from_fork+0x1f/0x30 rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 4863 Comm: syz-executor.0 Not tainted 5.16.0-rc8-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:lock_is_held include/linux/lockdep.h:283 [inline] RIP: 0010:rcu_read_lock_sched_held+0x84/0x130 kernel/rcu/update.c:125 Code: e8 61 62 9c 08 85 c0 74 2a 45 31 ff e8 b5 cb 00 00 84 c0 74 24 e8 0c cd 00 00 84 c0 74 1b 48 c7 c7 60 dd b1 8c be ff ff ff ff d7 5e 9c 08 85 c0 74 36 41 bf 01 00 00 00 48 c7 04 24 0e 36 e0 RSP: 0018:ffffc900000079c0 EFLAGS: 00000002 RAX: 1ffffffff1964401 RBX: 1ffff92000000f38 RCX: 0000000080010004 RDX: 0000000000000000 RSI: 00000000ffffffff RDI: ffffffff8cb1dd60 RBP: ffffc90000007a48 R08: dffffc0000000000 R09: fffffbfff1bfd59e R10: fffffbfff1bfd59e R11: 0000000000000000 R12: 0000000000000000 R13: 1ffff92000000f5c R14: dffffc0000000000 R15: 0000000000000000 FS: 00007f3fe3228700(0000) GS:ffff8880b9a00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b2e325000 CR3: 000000001daef000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: trace_lock_acquire+0x59/0x190 include/trace/events/lock.h:13 lock_acquire+0xa5/0x4d0 kernel/locking/lockdep.c:5608 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xd1/0x120 kernel/locking/spinlock.c:162 debug_object_activate+0x97/0x6a0 lib/debugobjects.c:661 debug_hrtimer_activate kernel/time/hrtimer.c:420 [inline] debug_activate kernel/time/hrtimer.c:475 [inline] enqueue_hrtimer kernel/time/hrtimer.c:1084 [inline] __run_hrtimer kernel/time/hrtimer.c:1702 [inline] __hrtimer_run_queues+0x594/0xa60 kernel/time/hrtimer.c:1749 hrtimer_interrupt+0x3b3/0x1040 kernel/time/hrtimer.c:1811 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1086 [inline] __sysvec_apic_timer_interrupt+0xf9/0x270 arch/x86/kernel/apic/apic.c:1103 sysvec_apic_timer_interrupt+0x8c/0xb0 arch/x86/kernel/apic/apic.c:1097 asm_sysvec_apic_timer_interrupt+0x12/0x20 RIP: 0010:__sanitizer_cov_trace_pc+0x0/0x60 kernel/kcov.c:196 Code: 84 00 00 00 00 00 0f 1f 40 00 be 0d 00 00 00 48 c7 c7 e0 af b5 8c e8 8f 66 4a 00 c3 cc cc cc cc cc cc cc cc cc cc cc cc cc cc <48> 8b 04 24 65 48 8b 0c 25 c0 6f 02 00 65 8b 15 a4 f1 7d 7e f7 c2 RSP: 0018:ffffc9000a33ee48 EFLAGS: 00000202 RAX: 0000000000000002 RBX: ffff88814b1ea000 RCX: 0000000000040000 RDX: ffff8880228d3a00 RSI: 0000000000000001 RDI: 0000000000000000 RBP: 0000000000000001 R08: ffffffff821f7389 R09: ffffed102963d414 R10: ffffed102963d414 R11: 0000000000000000 R12: ffff88803364d32a R13: 1ffff110066c9a65 R14: 0000000000000001 R15: 1ffff1102963d40a ext4_claim_free_clusters+0x32/0xa0 fs/ext4/balloc.c:621 ext4_da_reserve_space+0x13f/0x340 fs/ext4/inode.c:1473 ext4_insert_delayed_block fs/ext4/inode.c:1645 [inline] ext4_da_map_blocks fs/ext4/inode.c:1763 [inline] ext4_da_get_block_prep+0x92c/0x1410 fs/ext4/inode.c:1827 ext4_block_write_begin+0x6ca/0x1840 fs/ext4/inode.c:1078 ext4_da_write_begin+0x57b/0x7d0 fs/ext4/inode.c:2966 generic_perform_write+0x2dd/0x600 mm/filemap.c:3754 ext4_buffered_write_iter+0x391/0x520 fs/ext4/file.c:269 ext4_file_write_iter+0x8f7/0x1bd0 do_iter_readv_writev+0x54f/0x740 do_iter_write+0x21e/0x7b0 fs/read_write.c:851 iter_file_splice_write+0x7eb/0xfa0 fs/splice.c:689 do_splice_from fs/splice.c:767 [inline] direct_splice_actor+0xe6/0x1c0 fs/splice.c:936 splice_direct_to_actor+0x529/0xd00 fs/splice.c:891 do_splice_direct+0x291/0x3e0 fs/splice.c:979 do_sendfile+0x6fe/0x1040 fs/read_write.c:1245 __do_sys_sendfile64 fs/read_write.c:1310 [inline] __se_sys_sendfile64+0x171/0x1d0 fs/read_write.c:1296 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f3fe48b2e99 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f3fe3228168 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 00007f3fe49c5f60 RCX: 00007f3fe48b2e99 RDX: 0000000000000000 RSI: 000000000000000d RDI: 0000000000000006 RBP: 00007f3fe490cff1 R08: 0000000000000000 R09: 0000000000000000 R10: 00008400fffffffb R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffc38d9a11f R14: 00007f3fe3228300 R15: 0000000000022000 NMI backtrace for cpu 1 CPU: 1 PID: 4848 Comm: syz-executor.1 Not tainted 5.16.0-rc8-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1dc/0x2d8 lib/dump_stack.c:106 nmi_cpu_backtrace+0x45f/0x490 lib/nmi_backtrace.c:111 nmi_trigger_cpumask_backtrace+0x16a/0x280 lib/nmi_backtrace.c:62 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline] rcu_dump_cpu_stacks+0x22d/0x390 kernel/rcu/tree_stall.h:343 print_cpu_stall kernel/rcu/tree_stall.h:627 [inline] check_cpu_stall kernel/rcu/tree_stall.h:711 [inline] rcu_pending kernel/rcu/tree.c:3878 [inline] rcu_sched_clock_irq+0x1e33/0x2bc0 kernel/rcu/tree.c:2597 update_process_times+0x197/0x200 kernel/time/timer.c:1785 tick_sched_handle kernel/time/tick-sched.c:226 [inline] tick_sched_timer+0x27d/0x420 kernel/time/tick-sched.c:1428 __run_hrtimer kernel/time/hrtimer.c:1685 [inline] __hrtimer_run_queues+0x4cb/0xa60 kernel/time/hrtimer.c:1749 hrtimer_interrupt+0x3b3/0x1040 kernel/time/hrtimer.c:1811 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1086 [inline] __sysvec_apic_timer_interrupt+0xf9/0x270 arch/x86/kernel/apic/apic.c:1103 sysvec_apic_timer_interrupt+0x8c/0xb0 arch/x86/kernel/apic/apic.c:1097 asm_sysvec_apic_timer_interrupt+0x12/0x20 RIP: 0010:ext4_block_write_begin+0xa8b/0x1840 Code: 31 ff e8 c8 39 5b ff 48 83 e3 04 75 66 44 8b 74 24 2c 44 89 f7 8b 74 24 0c e8 a1 36 5b ff 48 8b 5c 24 20 89 df 4c 8b 64 24 68 <44> 89 e6 e8 8d 36 5b ff 8b 44 24 0c 44 39 e3 48 8b 5c 24 18 0f 87 RSP: 0018:ffffc9000a117060 EFLAGS: 00000297 RAX: 0000000000000002 RBX: 0000000000000000 RCX: ffffffff822948d1 RDX: ffff888034059d00 RSI: 0000000000001000 RDI: 0000000000000000 RBP: ffffc9000a1171b0 R08: ffffffff8229490f R09: fffff940001f04f9 R10: fffff940001f04f9 R11: 0000000000000000 R12: 0000000000000000 R13: dffffc0000000000 R14: 0000000000001000 R15: ffff88803d112bc8 ext4_da_write_begin+0x57b/0x7d0 fs/ext4/inode.c:2966 generic_perform_write+0x2dd/0x600 mm/filemap.c:3754 ext4_buffered_write_iter+0x391/0x520 fs/ext4/file.c:269 ext4_file_write_iter+0x8f7/0x1bd0 do_iter_readv_writev+0x54f/0x740 do_iter_write+0x21e/0x7b0 fs/read_write.c:851 iter_file_splice_write+0x7eb/0xfa0 fs/splice.c:689 do_splice_from fs/splice.c:767 [inline] direct_splice_actor+0xe6/0x1c0 fs/splice.c:936 splice_direct_to_actor+0x529/0xd00 fs/splice.c:891 do_splice_direct+0x291/0x3e0 fs/splice.c:979 do_sendfile+0x6fe/0x1040 fs/read_write.c:1245 __do_sys_sendfile64 fs/read_write.c:1310 [inline] __se_sys_sendfile64+0x171/0x1d0 fs/read_write.c:1296 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f2587ebbe99 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f2586831168 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 00007f2587fcef60 RCX: 00007f2587ebbe99 RDX: 0000000000000000 RSI: 000000000000000d RDI: 0000000000000006 RBP: 00007f2587f15ff1 R08: 0000000000000000 R09: 0000000000000000 R10: 00008400fffffffb R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffffc1e6c2f R14: 00007f2586831300 R15: 0000000000022000 sched: RT throttling activated ---------------- Code disassembly (best guess): 0: e8 61 62 9c 08 callq 0x89c6266 5: 85 c0 test %eax,%eax 7: 74 2a je 0x33 9: 45 31 ff xor %r15d,%r15d c: e8 b5 cb 00 00 callq 0xcbc6 11: 84 c0 test %al,%al 13: 74 24 je 0x39 15: e8 0c cd 00 00 callq 0xcd26 1a: 84 c0 test %al,%al 1c: 74 1b je 0x39 1e: 48 c7 c7 60 dd b1 8c mov $0xffffffff8cb1dd60,%rdi 25: be ff ff ff ff mov $0xffffffff,%esi * 2a: e8 d7 5e 9c 08 callq 0x89c5f06 <-- trapping instruction 2f: 85 c0 test %eax,%eax 31: 74 36 je 0x69 33: 41 bf 01 00 00 00 mov $0x1,%r15d 39: 48 rex.W 3a: c7 .byte 0xc7 3b: 04 24 add $0x24,%al 3d: 0e (bad) 3e: 36 ss 3f: e0 .byte 0xe0