rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 0-...!: (10500 ticks this GP) idle=0fd/1/0x4000000000000000 softirq=204617/204617 fqs=17 (t=10502 jiffies g=342597 q=102) rcu: rcu_preempt kthread starved for 10456 jiffies! g342597 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:28472 pid: 14 ppid: 2 flags:0x00004000 Call Trace: <TASK> context_switch kernel/sched/core.c:4972 [inline] __schedule+0xa9a/0x4940 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 </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: 18407 Comm: syz-executor.2 Not tainted 5.16.0-rc5-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:check_preemption_disabled+0x28/0x170 lib/smp_processor_id.c:16 Code: cc cc 41 56 41 55 49 89 f5 41 54 55 48 89 fd 53 0f 1f 44 00 00 65 44 8b 25 7d 95 bd 76 65 8b 1d ee ef bd 76 81 e3 ff ff ff 7f <31> ff 89 de 0f 1f 44 00 00 85 db 74 11 0f 1f 44 00 00 44 89 e0 5b RSP: 0018:ffffc90000fd8d68 EFLAGS: 00000002 RAX: 0000000000000000 RBX: 0000000000010002 RCX: 0000000000000001 RDX: 0000000000000000 RSI: ffffffff89abf940 RDI: ffffffff8a0491e0 RBP: ffffffff8a0491e0 R08: 0000000000000000 R09: ffffffff8d90fad7 R10: fffffbfff1b21f5a R11: 0000000000000000 R12: 0000000000000001 R13: ffffffff89abf940 R14: 00000000ffffffff R15: ffff8880b04acbd8 FS: 00007fe0a38bc700(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b2e437000 CR3: 000000014e36e000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <IRQ> lockdep_recursion_finish kernel/locking/lockdep.c:438 [inline] lock_is_held_type+0xd7/0x140 kernel/locking/lockdep.c:5681 lock_is_held include/linux/lockdep.h:283 [inline] rcu_read_lock_sched_held+0x3a/0x70 kernel/rcu/update.c:125 trace_lock_release include/trace/events/lock.h:58 [inline] lock_release+0x522/0x720 kernel/locking/lockdep.c:5648 seqcount_lockdep_reader_access include/linux/seqlock.h:104 [inline] ktime_get_update_offsets_now+0x93/0x5c0 kernel/time/timekeeping.c:2297 hrtimer_update_base kernel/time/hrtimer.c:631 [inline] hrtimer_interrupt+0x142/0x790 kernel/time/hrtimer.c:1793 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 </IRQ> <TASK> asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638 RIP: 0010:node_dirty_limit mm/page-writeback.c:476 [inline] RIP: 0010:node_dirty_ok+0x143/0x270 mm/page-writeback.c:497 Code: 89 e7 49 01 c5 e8 fd 2b 07 00 31 ff 49 01 c5 49 29 dd 48 8b 1d de 43 ae 0e 65 48 8b 2c 25 40 70 02 00 48 89 de e8 1d e6 d7 ff <48> 85 db 0f 85 b3 00 00 00 e8 7f e3 d7 ff 48 63 15 d8 0e 27 0a 4c RSP: 0018:ffffc90002967000 EFLAGS: 00000246 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffff8880b04ac100 RDI: 0000000000000003 RBP: ffff8880b04ac100 R08: 0000000000000000 R09: ffff88813fffef27 R10: ffffffff819f0413 R11: 0000000000000001 R12: ffff88813fffa000 R13: 000000000001475e R14: 0000000000000000 R15: ffff88813fffbc00 get_page_from_freelist+0x1d3/0x2f50 mm/page_alloc.c:4080 __alloc_pages+0x1b2/0x500 mm/page_alloc.c:5369 alloc_pages+0x1a7/0x300 mm/mempolicy.c:2191 folio_alloc+0x1c/0x70 mm/mempolicy.c:2201 filemap_alloc_folio mm/filemap.c:1036 [inline] __filemap_get_folio+0x5f2/0xd60 mm/filemap.c:1951 pagecache_get_page+0x2c/0x1a0 mm/folio-compat.c:125 ext4_da_write_begin+0x3bc/0xad0 fs/ext4/inode.c:2958 generic_perform_write+0x205/0x510 mm/filemap.c:3754 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: 0033:0x7fe0a4f46e99 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:00007fe0a38bc168 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 00007fe0a5059f60 RCX: 00007fe0a4f46e99 RDX: 0000000000000000 RSI: 000000000000000b RDI: 0000000000000005 RBP: 00007fe0a4fa0ff1 R08: 0000000000000000 R09: 0000000000000000 R10: 00008400fffffffb R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffebde7d1af R14: 00007fe0a38bc300 R15: 0000000000022000 </TASK> NMI backtrace for cpu 0 CPU: 0 PID: 18395 Comm: syz-executor.3 Not tainted 5.16.0-rc5-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: <IRQ> __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+0x9d/0x746 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 </IRQ> <TASK> asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638 RIP: 0010:ext4_inode_table+0xca/0x110 fs/ext4/super.c:315 Code: 28 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 0f b6 14 02 48 89 f8 83 e0 07 83 c0 03 38 d0 7c 04 84 d2 75 21 8b 43 28 <48> c1 e0 20 49 09 c4 e8 3a fd 57 ff 4c 89 e0 5b 5d 41 5c c3 e8 0d RSP: 0018:ffffc90000edf0c0 EFLAGS: 00000246 RAX: 0000000000000000 RBX: ffff88807f357000 RCX: ffffc90005a8a000 RDX: 0000000000000000 RSI: ffffffff821eea2d RDI: ffff88807f357028 RBP: 0000000000000040 R08: 000000000000003f R09: 0000000000000000 R10: ffffffff821eea22 R11: 0000000000000000 R12: 0000000000000091 R13: 0000000000000010 R14: 00000000000004be R15: ffff88814ae76000 __ext4_get_inode_loc+0x26c/0x13f0 fs/ext4/inode.c:4413 ext4_get_inode_loc fs/ext4/inode.c:4544 [inline] ext4_reserve_inode_write+0x159/0x3c0 fs/ext4/inode.c:5713 __ext4_mark_inode_dirty+0x17b/0x8d0 fs/ext4/inode.c:5882 ext4_dirty_inode+0xd4/0x110 fs/ext4/inode.c:5919 __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: 0033:0x7f22842a9e99 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:00007f2282c1f168 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 00007f22843bcf60 RCX: 00007f22842a9e99 RDX: 0000000000000000 RSI: 000000000000000b RDI: 0000000000000005 RBP: 00007f2284303ff1 R08: 0000000000000000 R09: 0000000000000000 R10: 00008400fffffffb R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffff2a196ff R14: 00007f2282c1f300 R15: 0000000000022000 </TASK> sched: RT throttling activated ---------------- Code disassembly (best guess): 0: cc int3 1: cc int3 2: 41 56 push %r14 4: 41 55 push %r13 6: 49 89 f5 mov %rsi,%r13 9: 41 54 push %r12 b: 55 push %rbp c: 48 89 fd mov %rdi,%rbp f: 53 push %rbx 10: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1) 15: 65 44 8b 25 7d 95 bd mov %gs:0x76bd957d(%rip),%r12d # 0x76bd959a 1c: 76 1d: 65 8b 1d ee ef bd 76 mov %gs:0x76bdefee(%rip),%ebx # 0x76bdf012 24: 81 e3 ff ff ff 7f and $0x7fffffff,%ebx * 2a: 31 ff xor %edi,%edi <-- trapping instruction 2c: 89 de mov %ebx,%esi 2e: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1) 33: 85 db test %ebx,%ebx 35: 74 11 je 0x48 37: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1) 3c: 44 89 e0 mov %r12d,%eax 3f: 5b pop %rbx