rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 1-...!: (10499 ticks this GP) idle=2e3/1/0x4000000000000000 softirq=32889/32889 fqs=0 (t=10502 jiffies g=47321 q=11) rcu: rcu_preempt kthread starved for 10503 jiffies! g47321 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->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:R running task stack:28648 pid: 14 ppid: 2 flags:0x00004000 Call Trace: <TASK> context_switch kernel/sched/core.c:4986 [inline] __schedule+0xab2/0x4d90 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:381 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 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 10767 Comm: syz-executor.0 Not tainted 5.16.0-rc6-next-20211222-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:preempt_count arch/x86/include/asm/preempt.h:27 [inline] RIP: 0010:preempt_count_sub+0x42/0x150 kernel/sched/core.c:5474 Code: e0 07 48 c1 e9 03 83 c0 03 0f b6 14 11 38 d0 7c 08 84 d2 0f 85 e4 00 00 00 8b 0d 79 e0 ff 0e 85 c9 75 1b 65 8b 05 2e 57 b2 7e <89> c2 81 e2 ff ff ff 7f 39 da 7c 13 81 fb fe 00 00 00 76 63 f7 db RSP: 0018:ffffc9000539ee10 EFLAGS: 00000246 RAX: 0000000080000001 RBX: 0000000000000001 RCX: 0000000000000000 RDX: 0000000000000004 RSI: ffffc9000539f440 RDI: 0000000000000001 RBP: ffffc9000539f458 R08: ffffffff8e21089a R09: 0000000000000001 R10: fffff52000a73dea R11: 0000000000088077 R12: ffffc90005398000 R13: ffffc9000539ef2d R14: ffffc9000539eef8 R15: ffffc9000539ef2c FS: 00007f3e33b33700(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b2e438000 CR3: 0000000077c84000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> unwind_next_frame+0xee1/0x1ce0 arch/x86/kernel/unwind_orc.c:624 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+0x656/0xf10 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: 0033:0x7f3e351bde99 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:00007f3e33b33168 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 00007f3e352d0f60 RCX: 00007f3e351bde99 RDX: 0000000000000000 RSI: 000000000000000a RDI: 0000000000000005 RBP: 00007f3e35217ff1 R08: 0000000000000000 R09: 0000000000000000 R10: 00008400fffffffb R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffdece15d9f R14: 00007f3e33b33300 R15: 0000000000022000 </TASK> NMI backtrace for cpu 1 CPU: 1 PID: 10766 Comm: syz-executor.1 Not tainted 5.16.0-rc6-next-20211222-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+0x262/0x3f0 kernel/rcu/tree_stall.h:343 print_cpu_stall kernel/rcu/tree_stall.h:604 [inline] check_cpu_stall kernel/rcu/tree_stall.h:688 [inline] rcu_pending kernel/rcu/tree.c:3927 [inline] rcu_sched_clock_irq.cold+0x9d/0x746 kernel/rcu/tree.c:2625 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:unwind_next_frame+0x195/0x1ce0 arch/x86/kernel/unwind_orc.c:443 Code: 14 00 00 41 f6 85 88 00 00 00 03 0f 85 ce 02 00 00 4d 8d 6e 35 48 b8 00 00 00 00 00 fc ff df 4c 89 ea 48 c1 ea 03 0f b6 04 02 <4c> 89 ea 83 e2 07 38 d0 7f 08 84 c0 0f 85 e4 0a 00 00 4c 89 e1 41 RSP: 0018:ffffc9000562ef20 EFLAGS: 00000a07 RAX: 0000000000000000 RBX: 1ffff92000ac5dec RCX: 1ffffffff209ff20 RDX: 1ffff92000ac5e05 RSI: 0000000000000000 RDI: ffff88807a34ec20 RBP: 0000000000000001 R08: ffffffff8e20c8f8 R09: 0000000000000001 R10: fffff52000ac5e0a R11: 0000000000088077 R12: ffffc9000562f040 R13: ffffc9000562f02d R14: ffffc9000562eff8 R15: 0000000000000d40 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 mm/kasan/common.c:45 [inline] set_alloc_info mm/kasan/common.c:436 [inline] __kasan_slab_alloc+0x90/0xc0 mm/kasan/common.c:469 kasan_slab_alloc include/linux/kasan.h:260 [inline] slab_post_alloc_hook mm/slab.h:741 [inline] slab_alloc_node mm/slub.c:3230 [inline] slab_alloc mm/slub.c:3238 [inline] kmem_cache_alloc+0x202/0x3a0 mm/slub.c:3243 kmem_cache_zalloc include/linux/slab.h:705 [inline] jbd2_alloc_handle include/linux/jbd2.h:1603 [inline] new_handle fs/jbd2/transaction.c:481 [inline] jbd2__journal_start+0x191/0x930 fs/jbd2/transaction.c:508 __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:5923 __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: 0033:0x7f225cfc0e99 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:00007f225b936168 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 00007f225d0d3f60 RCX: 00007f225cfc0e99 RDX: 0000000000000000 RSI: 000000000000000a RDI: 0000000000000005 RBP: 00007f225d01aff1 R08: 0000000000000000 R09: 0000000000000000 R10: 00008400fffffffb R11: 0000000000000246 R12: 0000000000000000 R13: 00007fffb5bdabaf R14: 00007f225b936300 R15: 0000000000022000 </TASK> sched: RT throttling activated ---------------- Code disassembly (best guess): 0: e0 07 loopne 0x9 2: 48 c1 e9 03 shr $0x3,%rcx 6: 83 c0 03 add $0x3,%eax 9: 0f b6 14 11 movzbl (%rcx,%rdx,1),%edx d: 38 d0 cmp %dl,%al f: 7c 08 jl 0x19 11: 84 d2 test %dl,%dl 13: 0f 85 e4 00 00 00 jne 0xfd 19: 8b 0d 79 e0 ff 0e mov 0xeffe079(%rip),%ecx # 0xeffe098 1f: 85 c9 test %ecx,%ecx 21: 75 1b jne 0x3e 23: 65 8b 05 2e 57 b2 7e mov %gs:0x7eb2572e(%rip),%eax # 0x7eb25758 * 2a: 89 c2 mov %eax,%edx <-- trapping instruction 2c: 81 e2 ff ff ff 7f and $0x7fffffff,%edx 32: 39 da cmp %ebx,%edx 34: 7c 13 jl 0x49 36: 81 fb fe 00 00 00 cmp $0xfe,%ebx 3c: 76 63 jbe 0xa1 3e: f7 db neg %ebx