rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P2974/1:b..l (detected by 0, t=10502 jiffies, g=69241, q=71) task:udevd state:R running task stack:25264 pid: 2974 ppid: 1 flags:0x00000000 Call Trace: context_switch kernel/sched/core.c:4986 [inline] __schedule+0xab2/0x4e90 kernel/sched/core.c:6296 preempt_schedule_common+0x45/0xc0 kernel/sched/core.c:6462 preempt_schedule_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:35 __raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline] _raw_spin_unlock+0x36/0x40 kernel/locking/spinlock.c:186 spin_unlock include/linux/spinlock.h:394 [inline] fast_dput fs/dcache.c:792 [inline] fast_dput fs/dcache.c:765 [inline] dput+0x4e5/0xbd0 fs/dcache.c:900 path_put fs/namei.c:557 [inline] terminate_walk+0x3f4/0x5c0 fs/namei.c:676 path_openat+0x1683/0x2940 fs/namei.c:3610 do_filp_open+0x1aa/0x400 fs/namei.c:3636 do_sys_openat2+0x16d/0x4d0 fs/open.c:1214 do_sys_open fs/open.c:1230 [inline] __do_sys_openat fs/open.c:1246 [inline] __se_sys_openat fs/open.c:1241 [inline] __x64_sys_openat+0x13f/0x1f0 fs/open.c:1241 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: 0033:0x7f19c9e18697 RSP: 002b:00007ffe25acd1d0 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007f19cc155000 RCX: 00007f19c9e18697 RDX: 0000000000080000 RSI: 00007ffe25acd308 RDI: 00000000ffffff9c RBP: 00007ffe25acd308 R08: 0000000000000008 R09: 0000000000000001 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000080000 R13: 00007f19cc155000 R14: 0000000000000001 R15: 0000000000000000 rcu: rcu_preempt kthread starved for 10475 jiffies! g69241 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:28720 pid: 14 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:4986 [inline] __schedule+0xab2/0x4e90 kernel/sched/core.c:6296 schedule+0xd2/0x260 kernel/sched/core.c:6369 schedule_timeout+0x14a/0x2a0 kernel/time/timer.c:1881 rcu_gp_fqs_loop+0x186/0x810 kernel/rcu/tree.c:1971 rcu_gp_kthread+0x1de/0x320 kernel/rcu/tree.c:2144 kthread+0x2e9/0x3a0 kernel/kthread.c:377 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: 17114 Comm: syz-executor.4 Not tainted 5.16.0-rc6-next-20211224-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:__lock_acquire+0x171/0x5470 kernel/locking/lockdep.c:4930 Code: 41 8b b5 60 0a 00 00 48 ba 00 00 00 00 00 fc ff df 48 c1 e9 03 0f b6 0c 11 48 c7 c2 00 39 50 90 83 e2 07 83 c2 03 89 74 24 10 <38> ca 7c 08 84 c9 0f 85 d2 13 00 00 83 7c 24 10 2f 8b 0d 68 b6 f3 RSP: 0018:ffffc90000dc0c50 EFLAGS: 00000006 RAX: ffffffff8ffb9060 RBX: 1ffff920001b81b5 RCX: 0000000000000004 RDX: 0000000000000003 RSI: 0000000000000002 RDI: ffffffff8bba2890 RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000001 R10: fffffbfff1b2663a R11: 0000000000000000 R12: 0000000000000000 R13: ffff8880286e8000 R14: ffffffff8bba2888 R15: 0000000000000002 FS: 00007fe257b97700(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b2eb35000 CR3: 0000000015efc000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600 Call Trace: lock_acquire kernel/locking/lockdep.c:5639 [inline] lock_acquire+0x1ab/0x510 kernel/locking/lockdep.c:5604 seqcount_lockdep_reader_access include/linux/seqlock.h:103 [inline] ktime_get+0x7c/0x470 kernel/time/timekeeping.c:827 clockevents_program_event+0x141/0x370 kernel/time/clockevents.c:326 tick_program_event+0xac/0x140 kernel/time/tick-oneshot.c:44 hrtimer_interrupt+0x36e/0x790 kernel/time/hrtimer.c:1824 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:unwind_next_frame+0xba/0x1ce0 arch/x86/kernel/unwind_orc.c:634 Code: 48 c7 04 13 00 00 00 00 48 8b 8c 24 98 00 00 00 65 48 2b 0c 25 28 00 00 00 0f 85 53 15 00 00 48 81 c4 a0 00 00 00 5b 5d 41 5c <41> 5d 41 5e 41 5f c3 4d 8d 66 48 48 b8 00 00 00 00 00 fc ff df 4c RSP: 0018:ffffc90004db6ed8 EFLAGS: 00000286 RAX: 0000000000000001 RBX: ffffffff816612c0 RCX: 0000000000000000 RDX: dffffc0000000000 RSI: ffffc90004db7e70 RDI: 0000000000000001 RBP: ffffc90004db6f80 R08: ffffffff8e1b92b8 R09: 0000000000000001 R10: fffff520009b6dea R11: 0000000000088077 R12: ffffc90004db6fb0 R13: ffffc90004db6f2d R14: ffffc90004db6ef8 R15: ffffc90004db6f2c arch_stack_walk+0x7d/0xe0 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x8c/0xc0 kernel/stacktrace.c:122 kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38 kasan_set_track+0x21/0x30 mm/kasan/common.c:45 kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:370 ____kasan_slab_free mm/kasan/common.c:366 [inline] ____kasan_slab_free+0x166/0x1a0 mm/kasan/common.c:328 kasan_slab_free include/linux/kasan.h:236 [inline] slab_free_hook mm/slub.c:1728 [inline] slab_free_freelist_hook+0x8b/0x1c0 mm/slub.c:1754 slab_free mm/slub.c:3509 [inline] kmem_cache_free+0xdb/0x3b0 mm/slub.c:3526 jbd2_free_handle include/linux/jbd2.h:1608 [inline] jbd2_journal_stop+0x656/0xf20 fs/jbd2/transaction.c:1937 __ext4_journal_stop+0xde/0x1f0 fs/ext4/ext4_jbd2.c:127 ext4_dirty_inode+0xe8/0x110 fs/ext4/inode.c:5927 __mark_inode_dirty+0x45b/0xfe0 fs/fs-writeback.c:2409 mark_inode_dirty include/linux/fs.h:2372 [inline] generic_write_end+0x3ea/0x6e0 fs/buffer.c:2240 ext4_da_write_end+0x1c2/0x990 fs/ext4/inode.c:3060 generic_perform_write+0x2c6/0x510 mm/filemap.c:3820 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:2079 [inline] do_iter_readv_writev+0x47a/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+0x723/0xc70 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: 0033:0x7fe259221e99 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:00007fe257b97168 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 00007fe259334f60 RCX: 00007fe259221e99 RDX: 0000000000000000 RSI: 0000000000000006 RDI: 0000000000000004 RBP: 00007fe25927bff1 R08: 0000000000000000 R09: 0000000000000000 R10: 00008400fffffffb R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffe2aa5036f R14: 00007fe257b97300 R15: 0000000000022000 sched: RT throttling activated ---------------- Code disassembly (best guess): 0: 41 8b b5 60 0a 00 00 mov 0xa60(%r13),%esi 7: 48 ba 00 00 00 00 00 movabs $0xdffffc0000000000,%rdx e: fc ff df 11: 48 c1 e9 03 shr $0x3,%rcx 15: 0f b6 0c 11 movzbl (%rcx,%rdx,1),%ecx 19: 48 c7 c2 00 39 50 90 mov $0xffffffff90503900,%rdx 20: 83 e2 07 and $0x7,%edx 23: 83 c2 03 add $0x3,%edx 26: 89 74 24 10 mov %esi,0x10(%rsp) * 2a: 38 ca cmp %cl,%dl <-- trapping instruction 2c: 7c 08 jl 0x36 2e: 84 c9 test %cl,%cl 30: 0f 85 d2 13 00 00 jne 0x1408 36: 83 7c 24 10 2f cmpl $0x2f,0x10(%rsp) 3b: 8b .byte 0x8b 3c: 0d .byte 0xd 3d: 68 .byte 0x68 3e: b6 f3 mov $0xf3,%dh