rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P12051/1:b..l rcu: (detected by 0, t=10502 jiffies, g=48781, q=287 ncpus=2) task:syz.0.1688 state:R running task stack:25776 pid:12051 tgid:12048 ppid:5827 task_flags:0x400140 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5257 [inline] __schedule+0x14bc/0x5000 kernel/sched/core.c:6864 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7191 irqentry_exit+0x5d8/0x660 kernel/entry/common.c:216 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:lock_acquire+0x16c/0x340 kernel/locking/lockdep.c:5872 Code: 00 00 00 00 9c 8f 44 24 30 f7 44 24 30 00 02 00 00 0f 85 cd 00 00 00 f7 44 24 08 00 02 00 00 74 01 fb 65 48 8b 05 74 97 de 10 <48> 3b 44 24 58 0f 85 e5 00 00 00 48 83 c4 60 5b 41 5c 41 5d 41 5e RSP: 0018:ffffc90004eb7788 EFLAGS: 00000206 RAX: a083bef0acad8000 RBX: 0000000000000000 RCX: a083bef0acad8000 RDX: 000000005e4dde8b RSI: ffffffff8d969d83 RDI: ffffffff8bc018e0 RBP: ffffffff82301158 R08: ffffffff82301158 R09: ffffffff8df419e0 R10: dffffc0000000000 R11: fffff94000261a61 R12: 0000000000000002 R13: ffffffff8df419e0 R14: 0000000000000000 R15: 0000000000000246 rcu_lock_acquire include/linux/rcupdate.h:331 [inline] rcu_read_lock include/linux/rcupdate.h:867 [inline] get_mem_cgroup_from_mm+0x54/0x2a0 mm/memcontrol.c:936 __mem_cgroup_charge+0x15/0x80 mm/memcontrol.c:4744 mem_cgroup_charge include/linux/memcontrol.h:663 [inline] shmem_alloc_and_add_folio+0x790/0xf40 mm/shmem.c:1942 shmem_get_folio_gfp+0x59d/0x1660 mm/shmem.c:2556 shmem_get_folio mm/shmem.c:2662 [inline] shmem_write_begin+0x16c/0x330 mm/shmem.c:3315 generic_perform_write+0x2c5/0x900 mm/filemap.c:4314 shmem_file_write_iter+0xf8/0x120 mm/shmem.c:3490 new_sync_write fs/read_write.c:593 [inline] vfs_write+0x5c9/0xb30 fs/read_write.c:686 ksys_write+0x145/0x250 fs/read_write.c:738 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fa6c738f749 RSP: 002b:00007fa6c82ce038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007fa6c75e6180 RCX: 00007fa6c738f749 RDX: 00000000fffffecc RSI: 0000200000000180 RDI: 0000000000000005 RBP: 00007fa6c7413f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fa6c75e6218 R14: 00007fa6c75e6180 R15: 00007ffeee562a28 rcu: rcu_preempt kthread starved for 10323 jiffies! g48781 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:26928 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5257 [inline] __schedule+0x14bc/0x5000 kernel/sched/core.c:6864 __schedule_loop kernel/sched/core.c:6946 [inline] schedule+0x165/0x360 kernel/sched/core.c:6961 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2083 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2285 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 12072 Comm: syz.3.1691 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:__sanitizer_cov_trace_switch+0x82/0x130 kernel/kcov.c:350 Code: 00 00 b9 01 00 00 00 48 85 c0 0f 84 b4 00 00 00 41 57 41 56 41 54 53 48 8b 54 24 20 65 4c 8b 04 25 08 10 7d 92 45 31 c9 eb 08 <49> ff c1 4c 39 c8 74 77 4e 8b 54 ce 10 65 44 8b 1d e9 56 bb 10 41 RSP: 0018:ffffc9000430eca8 EFLAGS: 00000297 RAX: 0000000000000020 RBX: ffff88801caa677c RCX: 0000000000000005 RDX: ffffffff81c59ad0 RSI: ffffffff8df9a930 RDI: 0000000000000004 RBP: 00000087b8de1f73 R08: ffff88807bba8000 R09: 0000000000000003 R10: 0000000000000003 R11: 0000000000000002 R12: ffff88801caa6010 R13: 0000000000000004 R14: 00000000000aeb84 R15: 000000000000076c FS: 00007f28ca7f76c0(0000) GS:ffff888125f4f000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 0000000057b10000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000009 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Call Trace: rb_read_data_buffer+0x110/0x580 kernel/trace/ring_buffer.c:1827 check_buffer+0x28a/0x750 kernel/trace/ring_buffer.c:4394 __rb_reserve_next+0x592/0xdb0 kernel/trace/ring_buffer.c:4493 rb_reserve_next_event kernel/trace/ring_buffer.c:4630 [inline] ring_buffer_lock_reserve+0xbb5/0x1010 kernel/trace/ring_buffer.c:4689 __trace_buffer_lock_reserve kernel/trace/trace.c:1079 [inline] trace_event_buffer_lock_reserve+0x1d0/0x6f0 kernel/trace/trace.c:2808 trace_event_buffer_reserve+0x248/0x340 kernel/trace/trace_events.c:672 do_trace_event_raw_event_bpf_trace_printk kernel/trace/bpf_trace.h:11 [inline] trace_event_raw_event_bpf_trace_printk+0x100/0x260 kernel/trace/bpf_trace.h:11 __do_trace_bpf_trace_printk kernel/trace/bpf_trace.h:11 [inline] trace_bpf_trace_printk+0x153/0x1b0 kernel/trace/bpf_trace.h:11 ____bpf_trace_printk kernel/trace/bpf_trace.c:379 [inline] bpf_trace_printk+0x11e/0x190 kernel/trace/bpf_trace.c:362 bpf_prog_b1367f0be6c54012+0x39/0x3f bpf_dispatcher_nop_func include/linux/bpf.h:1376 [inline] __bpf_prog_run include/linux/filter.h:723 [inline] bpf_prog_run include/linux/filter.h:730 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2075 [inline] bpf_trace_run2+0x284/0x4c0 kernel/trace/bpf_trace.c:2116 __bpf_trace_contention_begin+0xdc/0x130 include/trace/events/lock.h:95 __traceiter_contention_begin+0x7a/0xb0 include/trace/events/lock.h:95 __do_trace_contention_begin include/trace/events/lock.h:95 [inline] trace_contention_begin+0xde/0x100 include/trace/events/lock.h:95 __mutex_lock_common kernel/locking/mutex.c:610 [inline] __mutex_lock+0x198/0x1350 kernel/locking/mutex.c:770 __unix_dgram_recvmsg+0x1e1/0xd60 net/unix/af_unix.c:2573 sock_recvmsg_nosec+0x186/0x1c0 net/socket.c:1084 ____sys_recvmsg+0x21e/0x4c0 net/socket.c:-1 ___sys_recvmsg+0x1b5/0x510 net/socket.c:2863 do_recvmmsg+0x307/0x770 net/socket.c:2958 __sys_recvmmsg net/socket.c:3032 [inline] __do_sys_recvmmsg net/socket.c:3055 [inline] __se_sys_recvmmsg net/socket.c:3048 [inline] __x64_sys_recvmmsg+0x190/0x240 net/socket.c:3048 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f28c998f749 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 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f28ca7f7038 EFLAGS: 00000246 ORIG_RAX: 000000000000012b RAX: ffffffffffffffda RBX: 00007f28c9be6180 RCX: 00007f28c998f749 RDX: 0000000000010106 RSI: 00002000000000c0 RDI: 0000000000000006 RBP: 00007f28c9a13f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f28c9be6218 R14: 00007f28c9be6180 R15: 00007ffd433b8868