rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 0-...!: (1 GPs behind) idle=ac3/1/0x4000000000000000 softirq=51825/51826 fqs=1 (t=10502 jiffies g=82893 q=42) rcu: rcu_preempt kthread starved for 10501 jiffies! g82893 f0x0 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:28712 pid: 14 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:4972 [inline] __schedule+0xa9a/0x4900 kernel/sched/core.c:6253 schedule+0xd2/0x260 kernel/sched/core.c:6326 schedule_timeout+0x14a/0x2a0 kernel/time/timer.c:1881 rcu_gp_fqs_loop+0x186/0x810 kernel/rcu/tree.c:1955 rcu_gp_kthread+0x1de/0x320 kernel/rcu/tree.c:2128 kthread+0x405/0x4f0 kernel/kthread.c:327 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 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: 18078 Comm: syz-executor.3 Not tainted 5.16.0-rc7-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:strlen+0x43/0x90 lib/string.c:487 Code: 08 0f b6 04 02 48 89 fa 83 e2 07 38 d0 7f 04 84 c0 75 48 80 7d 00 00 74 39 48 bb 00 00 00 00 00 fc ff df 48 89 e8 48 83 c0 01 <48> 89 c2 48 89 c1 48 c1 ea 03 83 e1 07 0f b6 14 1a 38 ca 7f 04 84 RSP: 0018:ffffc90000fd88e8 EFLAGS: 00000086 RAX: ffffffff89ad510a RBX: dffffc0000000000 RCX: 0000000000000001 RDX: 0000000000000006 RSI: ffffffff8bb812a0 RDI: ffffffff89ad5100 RBP: ffffffff89ad5100 R08: 0000000000000002 R09: 0000000000000000 R10: fffffbfff1b223b2 R11: 0000000000000000 R12: 0000000000000002 R13: ffffffff8ba7e660 R14: ffffffff8bb812a0 R15: ffffc90000fd89c8 FS: 00007fd5bfeaa700(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b2ec37000 CR3: 00000000790f5000 CR4: 00000000003526e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: strlen include/linux/fortify-string.h:102 [inline] trace_event_get_offsets_lock_acquire include/trace/events/lock.h:13 [inline] perf_trace_lock_acquire+0xbe/0x550 include/trace/events/lock.h:13 trace_lock_acquire include/trace/events/lock.h:13 [inline] lock_acquire+0x416/0x510 kernel/locking/lockdep.c:5608 rcu_lock_acquire include/linux/rcupdate.h:268 [inline] rcu_read_lock include/linux/rcupdate.h:688 [inline] __perf_event_output kernel/events/core.c:7485 [inline] perf_event_output_forward+0xa5/0x280 kernel/events/core.c:7507 __perf_event_overflow+0x13c/0x3d0 kernel/events/core.c:9207 perf_swevent_hrtimer+0x37c/0x3f0 kernel/events/core.c:10600 __run_hrtimer kernel/time/hrtimer.c:1685 [inline] __hrtimer_run_queues+0x1c0/0xe50 kernel/time/hrtimer.c:1749 hrtimer_interrupt+0x31c/0x790 kernel/time/hrtimer.c:1811 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1086 [inline] __sysvec_apic_timer_interrupt+0x146/0x530 arch/x86/kernel/apic/apic.c:1103 sysvec_apic_timer_interrupt+0x8e/0xc0 arch/x86/kernel/apic/apic.c:1097 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638 RIP: 0010:queued_write_lock_slowpath+0x13b/0x2c0 kernel/locking/qrwlock.c:78 Code: fc ff df 49 01 c7 41 83 c6 03 41 0f b6 07 41 38 c6 7c 08 84 c0 0f 85 3e 01 00 00 8b 03 3d 00 01 00 00 74 19 f3 90 41 0f b6 07 <41> 38 c6 7c ec 84 c0 74 e8 48 89 df e8 94 9f 60 00 eb de 48 89 df RSP: 0018:ffffc900031b71d0 EFLAGS: 00000206 RAX: 0000000000000000 RBX: ffff88814af720c0 RCX: ffffffff815c5e7f RDX: ffffed10295ee419 RSI: 0000000000000004 RDI: ffff88814af720c0 RBP: 1ffff92000636e3b R08: 0000000000000001 R09: ffff88814af720c3 R10: ffffed10295ee418 R11: 0000000000000001 R12: ffff88814af720c4 R13: 00000000000000ff R14: 0000000000000003 R15: ffffed10295ee418 queued_write_lock include/asm-generic/qrwlock.h:97 [inline] do_raw_write_lock+0x1ce/0x280 kernel/locking/spinlock_debug.c:210 jbd2_log_start_commit+0x1f/0x40 fs/jbd2/journal.c:525 jbd2_journal_stop+0x502/0xf20 fs/jbd2/transaction.c:1913 __ext4_journal_stop+0xde/0x1f0 fs/ext4/ext4_jbd2.c:127 ext4_dirty_inode+0xe8/0x110 fs/ext4/inode.c:5920 __mark_inode_dirty+0x45b/0xfe0 fs/fs-writeback.c:2399 mark_inode_dirty include/linux/fs.h:2451 [inline] generic_write_end+0x31b/0x500 fs/buffer.c:2202 ext4_da_write_end+0x1c2/0x990 fs/ext4/inode.c:3059 generic_perform_write+0x2c6/0x510 mm/filemap.c:3765 ext4_buffered_write_iter+0x1ac/0x3b0 fs/ext4/file.c:269 ext4_file_write_iter+0x423/0x14e0 fs/ext4/file.c:681 call_write_iter include/linux/fs.h:2162 [inline] do_iter_readv_writev+0x472/0x750 fs/read_write.c:725 do_iter_write+0x188/0x710 fs/read_write.c:851 vfs_iter_write+0x70/0xa0 fs/read_write.c:892 iter_file_splice_write+0x6fa/0xc10 fs/splice.c:689 do_splice_from fs/splice.c:767 [inline] direct_splice_actor+0x110/0x180 fs/splice.c:936 splice_direct_to_actor+0x34b/0x8c0 fs/splice.c:891 do_splice_direct+0x1b3/0x280 fs/splice.c:979 do_sendfile+0xaf2/0x1250 fs/read_write.c:1245 __do_sys_sendfile64 fs/read_write.c:1310 [inline] __se_sys_sendfile64 fs/read_write.c:1296 [inline] __x64_sys_sendfile64+0x1cc/0x210 fs/read_write.c:1296 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7fd5c1534e99 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:00007fd5bfeaa168 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 00007fd5c1647f60 RCX: 00007fd5c1534e99 RDX: 0000000000000000 RSI: 000000000000000c RDI: 0000000000000005 RBP: 00007fd5c158eff1 R08: 0000000000000000 R09: 0000000000000000 R10: 00008400fffffffb R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffe3285dabf R14: 00007fd5bfeaa300 R15: 0000000000022000 NMI backtrace for cpu 0 CPU: 0 PID: 18075 Comm: syz-executor.0 Not tainted 5.16.0-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:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 nmi_cpu_backtrace.cold+0x47/0x144 lib/nmi_backtrace.c:111 nmi_trigger_cpumask_backtrace+0x1b3/0x230 lib/nmi_backtrace.c:62 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline] rcu_dump_cpu_stacks+0x25e/0x3f0 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.cold+0x5c/0x759 kernel/rcu/tree.c:2597 update_process_times+0x16d/0x200 kernel/time/timer.c:1785 tick_sched_handle+0x9b/0x180 kernel/time/tick-sched.c:226 tick_sched_timer+0x1b0/0x2d0 kernel/time/tick-sched.c:1428 __run_hrtimer kernel/time/hrtimer.c:1685 [inline] __hrtimer_run_queues+0x1c0/0xe50 kernel/time/hrtimer.c:1749 hrtimer_interrupt+0x31c/0x790 kernel/time/hrtimer.c:1811 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1086 [inline] __sysvec_apic_timer_interrupt+0x146/0x530 arch/x86/kernel/apic/apic.c:1103 sysvec_apic_timer_interrupt+0x8e/0xc0 arch/x86/kernel/apic/apic.c:1097 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638 RIP: 0010:check_kcov_mode+0x7/0x40 kernel/kcov.c:166 Code: 00 e9 59 fe ff ff 48 8b 7c 24 08 e8 43 3b 46 00 e9 61 fd ff ff cc cc cc cc cc cc cc cc cc cc cc cc cc cc 65 8b 05 a9 ac 8b 7e <89> c2 81 e2 00 01 00 00 a9 00 01 ff 00 74 10 31 c0 85 d2 74 15 8b RSP: 0018:ffffc90003247250 EFLAGS: 00000246 RAX: 0000000080000001 RBX: ffff88814af72000 RCX: ffff88801a0d60c0 RDX: 0000000000000004 RSI: ffff88801a0d60c0 RDI: 0000000000000003 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: ffffffff8223dcf7 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: ffff88808a67ecdc R15: dffffc0000000000 write_comp_data kernel/kcov.c:221 [inline] __sanitizer_cov_trace_const_cmp1+0x22/0x80 kernel/kcov.c:273 start_this_handle+0x327/0x1380 fs/jbd2/transaction.c:402 jbd2__journal_start+0x399/0x930 fs/jbd2/transaction.c:525 __ext4_journal_start_sb+0x227/0x4a0 fs/ext4/ext4_jbd2.c:105 __ext4_journal_start fs/ext4/ext4_jbd2.h:326 [inline] ext4_dirty_inode+0x9d/0x110 fs/ext4/inode.c:5916 __mark_inode_dirty+0x45b/0xfe0 fs/fs-writeback.c:2399 mark_inode_dirty include/linux/fs.h:2451 [inline] generic_write_end+0x31b/0x500 fs/buffer.c:2202 ext4_da_write_end+0x1c2/0x990 fs/ext4/inode.c:3059 generic_perform_write+0x2c6/0x510 mm/filemap.c:3765 ext4_buffered_write_iter+0x1ac/0x3b0 fs/ext4/file.c:269 ext4_file_write_iter+0x423/0x14e0 fs/ext4/file.c:681 call_write_iter include/linux/fs.h:2162 [inline] do_iter_readv_writev+0x472/0x750 fs/read_write.c:725 do_iter_write+0x188/0x710 fs/read_write.c:851 vfs_iter_write+0x70/0xa0 fs/read_write.c:892 iter_file_splice_write+0x6fa/0xc10 fs/splice.c:689 do_splice_from fs/splice.c:767 [inline] direct_splice_actor+0x110/0x180 fs/splice.c:936 splice_direct_to_actor+0x34b/0x8c0 fs/splice.c:891 do_splice_direct+0x1b3/0x280 fs/splice.c:979 do_sendfile+0xaf2/0x1250 fs/read_write.c:1245 __do_sys_sendfile64 fs/read_write.c:1310 [inline] __se_sys_sendfile64 fs/read_write.c:1296 [inline] __x64_sys_sendfile64+0x1cc/0x210 fs/read_write.c:1296 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f01053f4e99 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:00007f0103d6a168 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 00007f0105507f60 RCX: 00007f01053f4e99 RDX: 0000000000000000 RSI: 000000000000000c RDI: 0000000000000005 RBP: 00007f010544eff1 R08: 0000000000000000 R09: 0000000000000000 R10: 00008400fffffffb R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffe2db6710f R14: 00007f0103d6a300 R15: 0000000000022000 sched: RT throttling activated ---------------- Code disassembly (best guess): 0: 08 0f or %cl,(%rdi) 2: b6 04 mov $0x4,%dh 4: 02 48 89 add -0x77(%rax),%cl 7: fa cli 8: 83 e2 07 and $0x7,%edx b: 38 d0 cmp %dl,%al d: 7f 04 jg 0x13 f: 84 c0 test %al,%al 11: 75 48 jne 0x5b 13: 80 7d 00 00 cmpb $0x0,0x0(%rbp) 17: 74 39 je 0x52 19: 48 bb 00 00 00 00 00 movabs $0xdffffc0000000000,%rbx 20: fc ff df 23: 48 89 e8 mov %rbp,%rax 26: 48 83 c0 01 add $0x1,%rax * 2a: 48 89 c2 mov %rax,%rdx <-- trapping instruction 2d: 48 89 c1 mov %rax,%rcx 30: 48 c1 ea 03 shr $0x3,%rdx 34: 83 e1 07 and $0x7,%ecx 37: 0f b6 14 1a movzbl (%rdx,%rbx,1),%edx 3b: 38 ca cmp %cl,%dl 3d: 7f 04 jg 0x43 3f: 84 .byte 0x84