rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P6579/1:b..l (detected by 0, t=10502 jiffies, g=7837, q=103) task:syz-executor634 state:R running task stack:29168 pid: 6579 ppid: 6530 flags:0x00000000 Call Trace: context_switch kernel/sched/core.c:4940 [inline] __schedule+0x940/0x26f0 kernel/sched/core.c:6287 preempt_schedule_common+0x45/0xc0 kernel/sched/core.c:6459 preempt_schedule_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:35 __raw_spin_unlock include/linux/spinlock_api_smp.h:152 [inline] _raw_spin_unlock+0x36/0x40 kernel/locking/spinlock.c:186 spin_unlock include/linux/spinlock.h:403 [inline] filemap_map_pages+0x1216/0x1880 mm/filemap.c:3338 do_fault_around mm/memory.c:4152 [inline] do_read_fault mm/memory.c:4167 [inline] do_fault mm/memory.c:4301 [inline] handle_pte_fault mm/memory.c:4559 [inline] __handle_mm_fault+0x28dd/0x5320 mm/memory.c:4694 handle_mm_fault+0x1c8/0x790 mm/memory.c:4792 do_user_addr_fault+0x48b/0x11c0 arch/x86/mm/fault.c:1397 handle_page_fault arch/x86/mm/fault.c:1485 [inline] exc_page_fault+0x9e/0x180 arch/x86/mm/fault.c:1541 asm_exc_page_fault+0x1e/0x30 arch/x86/include/asm/idtentry.h:568 RIP: 0033:0x7fd630840030 RSP: 002b:00007ffe42bd48b8 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00000000000f4240 R08: 0000000000000000 R09: 00007fd6308a0140 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffe42bd4930 R14: 00007ffe42bd4920 R15: 00007ffe42bd48e4 rcu: rcu_preempt kthread starved for 10502 jiffies! g7837 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:28696 pid: 14 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:4940 [inline] __schedule+0x940/0x26f0 kernel/sched/core.c:6287 schedule+0xd3/0x270 kernel/sched/core.c:6366 schedule_timeout+0x14a/0x2a0 kernel/time/timer.c:1881 rcu_gp_fqs_loop+0x186/0x800 kernel/rcu/tree.c:1957 rcu_gp_kthread+0x1de/0x320 kernel/rcu/tree.c:2130 kthread+0x3e5/0x4d0 kernel/kthread.c:319 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: 6581 Comm: syz-executor634 Not tainted 5.15.0-rc5-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:check_preemption_disabled+0x2/0x170 lib/smp_processor_id.c:13 Code: 1f 44 00 00 e8 7f 8d 64 f8 65 48 8b 3c 25 40 f0 01 00 e8 51 c9 1c f8 eb 99 0f 1f 44 00 00 0f 0b e9 23 ff ff ff cc 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 RSP: 0018:ffffc90000dc0d80 EFLAGS: 00000086 RAX: 0000000000000001 RBX: 0000000000000001 RCX: ffffffff8161b4b4 RDX: 0000000000000001 RSI: ffffffff89e42be0 RDI: ffffffff89e42c20 RBP: 1ffff920001b81b9 R08: 0000000000000000 R09: ffff8880b9d32a0b R10: ffffed10173a6541 R11: 0000000000000000 R12: 0000000000000001 R13: dffffc0000000000 R14: 0000000000000000 R15: ffff8880b9d223c0 FS: 00007fd6307cc700(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffe42bd4898 CR3: 00000000199e6000 CR4: 0000000000350ee0 Call Trace: rcu_lockdep_current_cpu_online kernel/rcu/tree.c:1169 [inline] rcu_lockdep_current_cpu_online+0x2d/0x150 kernel/rcu/tree.c:1160 rcu_read_lock_held_common kernel/rcu/update.c:112 [inline] rcu_read_lock_held_common kernel/rcu/update.c:102 [inline] rcu_read_lock_sched_held+0x25/0x70 kernel/rcu/update.c:123 trace_lock_release include/trace/events/lock.h:58 [inline] lock_release+0x522/0x720 kernel/locking/lockdep.c:5636 seqcount_lockdep_reader_access include/linux/seqlock.h:104 [inline] timekeeping_get_delta kernel/time/timekeeping.c:252 [inline] timekeeping_get_ns kernel/time/timekeeping.c:386 [inline] ktime_get+0x158/0x470 kernel/time/timekeeping.c:829 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:__orc_find+0x4a/0xf0 arch/x86/kernel/unwind_orc.c:50 Code: 49 89 fd 0f 87 9a 00 00 00 49 bf 00 00 00 00 00 fc ff df 49 89 fe 48 89 fd eb 0c 48 8d 6b 04 49 89 de 49 39 ec 72 4d 4c 89 e0 <48> 29 e8 48 89 c2 48 c1 e8 3f 48 c1 fa 02 48 01 d0 48 d1 f8 48 8d RSP: 0018:ffffc90002dff440 EFLAGS: 00000206 RAX: ffffffff8d83620c RBX: ffffffff8d8361fc RCX: ffffffff81c7c0bc RDX: 0000000000000000 RSI: ffffffff8df505e0 RDI: ffffffff8d8361ec RBP: ffffffff8d836200 R08: 0000000000000000 R09: ffffffff8df505e0 R10: fffff520005bfeb7 R11: 0000000000086089 R12: ffffffff8d83620c R13: ffffffff8d8361ec R14: ffffffff8d8361fc R15: dffffc0000000000 orc_find arch/x86/kernel/unwind_orc.c:173 [inline] unwind_next_frame+0x32a/0x1ce0 arch/x86/kernel/unwind_orc.c:443 arch_stack_walk+0x7d/0xe0 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x8c/0xc0 kernel/stacktrace.c:121 kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38 kasan_set_track mm/kasan/common.c:46 [inline] set_alloc_info mm/kasan/common.c:434 [inline] ____kasan_kmalloc mm/kasan/common.c:513 [inline] ____kasan_kmalloc mm/kasan/common.c:472 [inline] __kasan_kmalloc+0xa4/0xd0 mm/kasan/common.c:522 kmalloc include/linux/slab.h:591 [inline] tty_alloc_file drivers/tty/tty_io.c:187 [inline] tty_open+0x140/0x1000 drivers/tty/tty_io.c:2140 chrdev_open+0x266/0x770 fs/char_dev.c:414 do_dentry_open+0x4c8/0x11d0 fs/open.c:822 do_open fs/namei.c:3428 [inline] path_openat+0x1c9a/0x2740 fs/namei.c:3561 do_filp_open+0x1aa/0x400 fs/namei.c:3588 do_sys_openat2+0x16d/0x4d0 fs/open.c:1200 do_sys_open fs/open.c:1216 [inline] __do_sys_openat fs/open.c:1232 [inline] __se_sys_openat fs/open.c:1227 [inline] __x64_sys_openat+0x13f/0x1f0 fs/open.c:1227 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: 0033:0x7fd63081aaf9 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 11 15 00 00 90 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 b8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fd6307cc318 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007fd6308a23e8 RCX: 00007fd63081aaf9 RDX: 0000000000000802 RSI: 0000000020000840 RDI: ffffffffffffff9c RBP: 00007fd6308a23e0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 7974742f7665642f R13: 00007ffe42bd483f R14: 00007fd6307cc400 R15: 0000000000022000 INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 1.536 msecs ---------------- Code disassembly (best guess), 1 bytes skipped: 0: 44 00 00 add %r8b,(%rax) 3: e8 7f 8d 64 f8 callq 0xf8648d87 8: 65 48 8b 3c 25 40 f0 mov %gs:0x1f040,%rdi f: 01 00 11: e8 51 c9 1c f8 callq 0xf81cc967 16: eb 99 jmp 0xffffffb1 18: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1) 1d: 0f 0b ud2 1f: e9 23 ff ff ff jmpq 0xffffff47 24: cc int3 25: cc int3 26: cc int3 27: 41 56 push %r14 * 29: 41 55 push %r13 <-- trapping instruction 2b: 49 89 f5 mov %rsi,%r13 2e: 41 54 push %r12 30: 55 push %rbp 31: 48 89 fd mov %rdi,%rbp 34: 53 push %rbx 35: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1) 3a: 65 gs 3b: 44 rex.R 3c: 8b .byte 0x8b 3d: 25 .byte 0x25 3e: 7d .byte 0x7d