rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P29841/1:b..l P29257/1:b..l P29892/1:b..l rcu: (detected by 0, t=10502 jiffies, g=301781, q=320 ncpus=2) task:modprobe state:R running task stack:23248 pid:29892 tgid:29892 ppid:3557 task_flags:0x400000 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5354 [inline] __schedule+0x1664/0x5590 kernel/sched/core.c:6966 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7294 irqentry_exit+0x5e4/0x700 kernel/entry/common.c:240 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:get_current arch/x86/include/asm/current.h:25 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0x8/0x70 kernel/kcov.c:216 Code: 8b 3d 04 02 56 0c 48 89 de 5b e9 83 90 5e 00 cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 48 8b 04 24 <65> 48 8b 0d 28 92 57 11 65 8b 15 49 92 57 11 81 e2 00 01 ff 00 74 RSP: 0018:ffffc900043b7878 EFLAGS: 00000212 RAX: ffffffff82471f53 RBX: ffffc900043b7c58 RCX: 0000000000000000 RDX: ffff88802f46bd00 RSI: 000000000000006c RDI: 000000000000002f RBP: 000000000000006c R08: ffffffff90121db7 R09: 1ffffffff20243b6 R10: dffffc0000000000 R11: fffffbfff20243b7 R12: dffffc0000000000 R13: ffffc900043b7c20 R14: ffffc900043b7c28 R15: ffff888035647320 link_path_walk+0xf3/0x18d0 fs/namei.c:2578 path_openat+0x2c3/0x3860 fs/namei.c:4826 do_file_open+0x23e/0x4a0 fs/namei.c:4859 do_sys_openat2+0x113/0x200 fs/open.c:1366 do_sys_open fs/open.c:1372 [inline] __do_sys_openat fs/open.c:1388 [inline] __se_sys_openat fs/open.c:1383 [inline] __x64_sys_openat+0x138/0x170 fs/open.c:1383 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fabcf6990ba RSP: 002b:00007ffd23e4b6a8 EFLAGS: 00000206 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007ffd23e4b720 RCX: 00007fabcf6990ba RDX: 0000000000080000 RSI: 00007ffd23e4b720 RDI: 00000000ffffff9c RBP: 00007ffd23e4b710 R08: 00007ffd23e4b917 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000018 R13: 00007fabcf66d000 R14: 00007ffd23e4b930 R15: 0000000000000000 task:udevd state:R running task stack:25456 pid:29257 tgid:29257 ppid:5192 task_flags:0x400140 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5354 [inline] __schedule+0x1664/0x5590 kernel/sched/core.c:6966 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7294 irqentry_exit+0x5e4/0x700 kernel/entry/common.c:240 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:lock_acquire+0x20b/0x2e0 kernel/locking/lockdep.c:5872 Code: e9 30 ff ff ff e8 e5 5a 0e 0a f7 c3 00 02 00 00 0f 84 38 ff ff ff 65 48 8b 05 81 87 7b 11 48 3b 44 24 30 75 33 fb 48 83 c4 38 <5b> 41 5c 41 5d 41 5e 41 5f 5d c3 cc cc cc cc cc 48 8d 3d 0e b9 73 RSP: 0018:ffffc900034d7338 EFLAGS: 00000282 RAX: 8af6a4e291e0a700 RBX: 0000000000000246 RCX: 0000000000000046 RDX: 000000000613a49c RSI: ffffffff8e1729a9 RDI: ffffffff8c27eb60 RBP: 0000000000000000 R08: ffffffff81769a45 R09: ffffffff8e760520 R10: ffffc900034d7498 R11: ffffffff81b0eed0 R12: 0000000000000002 R13: ffffffff8e760520 R14: 0000000000000000 R15: 0000000000000000 rcu_lock_acquire include/linux/rcupdate.h:312 [inline] rcu_read_lock include/linux/rcupdate.h:850 [inline] class_rcu_constructor include/linux/rcupdate.h:1193 [inline] unwind_next_frame+0xc2/0x23c0 arch/x86/kernel/unwind_orc.c:495 arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 poison_kmalloc_redzone mm/kasan/common.c:398 [inline] __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415 kasan_kmalloc include/linux/kasan.h:263 [inline] __do_kmalloc_node mm/slub.c:5262 [inline] __kmalloc_noprof+0x35c/0x760 mm/slub.c:5274 kmalloc_noprof include/linux/slab.h:954 [inline] kzalloc_noprof include/linux/slab.h:1188 [inline] tomoyo_encode2 security/tomoyo/realpath.c:45 [inline] tomoyo_encode+0x28b/0x550 security/tomoyo/realpath.c:80 tomoyo_realpath_from_path+0x58d/0x5d0 security/tomoyo/realpath.c:283 tomoyo_get_realpath security/tomoyo/file.c:151 [inline] tomoyo_path_perm+0x283/0x560 security/tomoyo/file.c:827 security_inode_getattr+0x12b/0x310 security/security.c:1869 vfs_getattr+0x23/0x70 fs/stat.c:259 vfs_statx_path+0x2b/0x230 fs/stat.c:299 vfs_statx+0x12e/0x200 fs/stat.c:356 vfs_fstatat+0x11b/0x170 fs/stat.c:373 __do_sys_newfstatat fs/stat.c:538 [inline] __se_sys_newfstatat fs/stat.c:532 [inline] __x64_sys_newfstatat+0x151/0x200 fs/stat.c:532 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f4405511b0a RSP: 002b:00007ffd6f6ff8d8 EFLAGS: 00000246 ORIG_RAX: 0000000000000106 RAX: ffffffffffffffda RBX: 000000000000002e RCX: 00007f4405511b0a RDX: 00007ffd6f6ff8e0 RSI: 00007ffd6f6ff9b0 RDI: 00000000ffffff9c RBP: 00007ffd6f7009f0 R08: 00007ffd6f701620 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffd6f701620 R13: 0000000000000000 R14: 00007ffd6f701220 R15: 00007ffd6f700e20 task:syz.0.5221 state:R running task stack:25360 pid:29841 tgid:29839 ppid:22765 task_flags:0x40044c flags:0x00080001 Call Trace: context_switch kernel/sched/core.c:5354 [inline] __schedule+0x1664/0x5590 kernel/sched/core.c:6966 preempt_schedule_common+0x82/0xd0 kernel/sched/core.c:7151 preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12 __raw_spin_unlock include/linux/spinlock_api_smp.h:169 [inline] _raw_spin_unlock+0x3f/0x50 kernel/locking/spinlock.c:186 spin_unlock include/linux/spinlock.h:390 [inline] zap_pte_range mm/memory.c:1946 [inline] zap_pmd_range mm/memory.c:2002 [inline] zap_pud_range mm/memory.c:2030 [inline] zap_p4d_range mm/memory.c:2051 [inline] unmap_page_range+0x3c17/0x4930 mm/memory.c:2072 unmap_single_vma mm/memory.c:2114 [inline] unmap_vmas+0x48f/0x6a0 mm/memory.c:2152 exit_mmap+0x280/0xa10 mm/mmap.c:1302 __mmput+0x118/0x430 kernel/fork.c:1179 exit_mm+0x168/0x220 kernel/exit.c:581 do_exit+0x8b9/0x2580 kernel/exit.c:962 do_group_exit+0x21b/0x2d0 kernel/exit.c:1116 get_signal+0x1284/0x1330 kernel/signal.c:3032 arch_do_signal_or_restart+0xbc/0x830 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:64 [inline] exit_to_user_mode_loop+0x86/0x480 kernel/entry/common.c:98 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:238 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:269 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:325 [inline] do_syscall_64+0x32d/0xf80 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f9bb7b9c799 RSP: 002b:00007f9bb5dd5028 EFLAGS: 00000246 ORIG_RAX: 000000000000012b RAX: 0000000000010106 RBX: 00007f9bb7e16090 RCX: 00007f9bb7b9c799 RDX: 0000000000010106 RSI: 00002000000000c0 RDI: 0000000000000003 RBP: 00007f9bb7c32bd9 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f9bb7e16128 R14: 00007f9bb7e16090 R15: 00007ffde956e5d8 rcu: rcu_preempt kthread starved for 10351 jiffies! g301781 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:28008 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5354 [inline] __schedule+0x1664/0x5590 kernel/sched/core.c:6966 __schedule_loop kernel/sched/core.c:7049 [inline] schedule+0x164/0x360 kernel/sched/core.c:7064 schedule_timeout+0x158/0x2c0 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x312/0x11d0 kernel/rcu/tree.c:2095 rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2297 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 rcu: Stack dump where RCU GP kthread last ran: CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:63 Code: 9d 6b 02 e9 83 ec 02 00 cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d e3 4f 19 00 fb f4 cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90 RSP: 0018:ffffffff8e407dc0 EFLAGS: 00000242 RAX: 000000000446b9cb RBX: ffffffff819ababd RCX: 0000000080000001 RDX: 0000000000000001 RSI: ffffffff8df00ec2 RDI: ffffffff8c27eb60 RBP: ffffffff8e407eb0 R08: ffff8880b863399b R09: 1ffff110170c6733 R10: dffffc0000000000 R11: ffffed10170c6734 R12: ffffffff90121db0 R13: 1ffffffff1c929d8 R14: 0000000000000000 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff88812544c000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007feb9e6a4cd9 CR3: 000000007ba4e000 CR4: 00000000003526f0 Call Trace: arch_safe_halt arch/x86/kernel/process.c:766 [inline] default_idle+0x9/0x20 arch/x86/kernel/process.c:767 default_idle_call+0x72/0xb0 kernel/sched/idle.c:122 cpuidle_idle_call kernel/sched/idle.c:191 [inline] do_idle+0x1bd/0x500 kernel/sched/idle.c:332 cpu_startup_entry+0x43/0x60 kernel/sched/idle.c:430 rest_init+0x2de/0x300 init/main.c:761 start_kernel+0x38a/0x3e0 init/main.c:1212 x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:310 x86_64_start_kernel+0x143/0x1c0 arch/x86/kernel/head64.c:291 common_startup_64+0x13e/0x147