rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P8885/1:b..l rcu: (detected by 1, t=10502 jiffies, g=43897, q=377 ncpus=2) task:syz.0.837 state:R running task stack:26336 pid:8885 tgid:8883 ppid:5841 task_flags:0x40054c flags:0x08080000 Call Trace: context_switch kernel/sched/core.c:5298 [inline] __schedule+0x15dd/0x52d0 kernel/sched/core.c:6911 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7238 irqentry_exit+0x599/0x620 kernel/entry/common.c:239 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:__orc_find arch/x86/kernel/unwind_orc.c:103 [inline] RIP: 0010:orc_find arch/x86/kernel/unwind_orc.c:238 [inline] RIP: 0010:unwind_next_frame+0x528/0x23c0 arch/x86/kernel/unwind_orc.c:510 Code: 4c 89 f8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df 0f b6 04 08 84 c0 75 27 49 63 07 4c 01 f8 49 8d 4f 04 4c 39 e0 48 0f 46 e9 <49> 8d 47 fc 48 0f 47 d8 4d 0f 46 ef 48 39 dd 76 a2 e9 76 fd ff ff RSP: 0000:ffffc900034d7258 EFLAGS: 00000283 RAX: ffffffff8bafe48d RBX: ffffffff909a2e04 RCX: ffffffff909a2e08 RDX: ffffffff909a2e04 RSI: ffffffff914e564c RDI: ffffffff8c27d820 RBP: ffffffff909a2e08 R08: 0000000000000001 R09: ffffffff8e75e5e0 R10: ffffc900034d7378 R11: ffffffff81b0eba0 R12: ffffffff8bafe574 R13: ffffffff909a2e04 R14: ffffc900034d7328 R15: ffffffff909a2e04 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] __kmalloc_cache_noprof+0x31c/0x660 mm/slub.c:5380 kmalloc_noprof include/linux/slab.h:950 [inline] slab_free_hook mm/slub.c:2637 [inline] slab_free mm/slub.c:6165 [inline] kmem_cache_free+0x15b/0x630 mm/slub.c:6295 tear_down_vmas+0x312/0x520 mm/mmap.c:1264 exit_mmap+0x4b6/0xa10 mm/mmap.c:1322 __mmput+0x118/0x430 kernel/fork.c:1175 exit_mm+0x168/0x220 kernel/exit.c:581 do_exit+0x6a2/0x23c0 kernel/exit.c:964 do_group_exit+0x21b/0x2d0 kernel/exit.c:1118 get_signal+0x1284/0x1330 kernel/signal.c:3034 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:226 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:325 [inline] __do_fast_syscall_32+0x415/0x640 arch/x86/entry/syscall_32.c:310 do_fast_syscall_32+0x33/0x70 arch/x86/entry/syscall_32.c:332 entry_SYSENTER_compat_after_hwframe+0x84/0x8e RIP: 0023:0xf70bef6c RSP: 002b:00000000f54ad5bc EFLAGS: 00000206 ORIG_RAX: 00000000000000f0 RAX: fffffffffffffe00 RBX: 00000000f74b4f88 RCX: 0000000000000080 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00000000f74b4f8c RBP: 0000000000000081 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 rcu: rcu_preempt kthread timer wakeup didn't happen for 10499 jiffies! g43897 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=0 timer-softirq=18186 rcu: rcu_preempt kthread starved for 10500 jiffies! g43897 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:28120 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5298 [inline] __schedule+0x15dd/0x52d0 kernel/sched/core.c:6911 __schedule_loop kernel/sched/core.c:6993 [inline] schedule+0x164/0x360 kernel/sched/core.c:7008 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: Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 8878 Comm: syz.2.836 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 RIP: 0010:num_possible_cpus include/linux/cpumask.h:1222 [inline] RIP: 0010:mm_get_cid kernel/sched/sched.h:3853 [inline] RIP: 0010:sched_mm_cid_fork+0x5b0/0x1120 kernel/sched/core.c:10679 Code: 00 00 31 ed 31 db e9 7b 01 00 00 49 c7 c4 98 5e 1b 8e 49 c1 ec 03 41 bd 00 00 00 80 eb 0a 89 e8 f7 d8 0f 81 e3 fe ff ff f3 90 <48> b8 00 00 00 00 00 fc ff df 41 0f b6 04 04 84 c0 75 40 44 8b 35 RSP: 0000:ffffc9000cf5fc48 EFLAGS: 00000887 RAX: 0000000080000000 RBX: ffff88807dab97d0 RCX: 0000000080000001 RDX: dffffc0000000000 RSI: 0000000000000002 RDI: ffff88807dab97d0 RBP: 0000000080000000 R08: 1ffff1100fb571a9 R09: 0000000000000000 R10: ffff88807dab8e94 R11: fffff520019ebf78 R12: 1ffffffff1c36bd3 R13: 0000000080000000 R14: 0000000000000002 R15: ffff88807dab8c40 FS: 0000000000000000(0000) GS:ffff888125451000(0063) knlGS:00000000f54bdb40 CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033 CR2: 0000000033c0bff8 CR3: 0000000075f82000 CR4: 00000000003526f0 DR0: ffffffffffffffff DR1: 00000000000001f8 DR2: 0000000000000083 DR3: 0000000000000030 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Call Trace: bprm_execve+0xda1/0x1460 fs/exec.c:1771 do_execveat_common+0x50d/0x690 fs/exec.c:1846 __do_compat_sys_execveat fs/exec.c:1968 [inline] __se_compat_sys_execveat fs/exec.c:1961 [inline] __ia32_compat_sys_execveat+0xcd/0xf0 fs/exec.c:1961 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline] do_int80_emulation+0x173/0x4d0 arch/x86/entry/syscall_32.c:172 asm_int80_emulation+0x1a/0x20 arch/x86/include/asm/idtentry.h:621 RIP: 0023:0xf70cef6c Code: 90 85 d2 74 0a 89 ce 81 e6 ff 0f 00 00 89 32 85 c0 74 05 c1 e9 0c 89 08 31 c0 5e 5d c3 90 0f 1f 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 58 b8 RSP: 002b:00000000f54bd50c EFLAGS: 00000206 ORIG_RAX: 0000000000000166 RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 0000000080000000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000001000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000