rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P27554/1:b..l rcu: (detected by 1, t=10502 jiffies, g=201361, q=185 ncpus=2) task:syz.3.6676 state:R running task stack:24104 pid:27554 tgid:27554 ppid:5820 task_flags:0x400640 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5387 [inline] __schedule+0x10e9/0x6820 kernel/sched/core.c:7188 preempt_schedule_irq+0x50/0x90 kernel/sched/core.c:7512 irqentry_exit_to_kernel_mode_preempt include/linux/irq-entry-common.h:476 [inline] irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:547 [inline] irqentry_exit+0x1fe/0x790 kernel/entry/common.c:164 asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:task_css include/linux/cgroup.h:521 [inline] RIP: 0010:mem_cgroup_from_task mm/memcontrol.c:1080 [inline] RIP: 0010:get_mem_cgroup_from_mm+0xa4/0x5c0 mm/memcontrol.c:1133 Code: 00 00 e8 ef 7a 1a 09 85 c0 0f 85 a0 00 00 00 48 85 db 0f 84 e6 00 00 00 48 8d bb f8 13 00 00 48 89 f8 48 c1 e8 03 80 3c 28 00 <0f> 85 34 04 00 00 4c 8b bb f8 13 00 00 e8 ba 7a 1a 09 85 c0 0f 85 RSP: 0018:ffffc9000e446b58 EFLAGS: 00000246 RAX: 1ffff1100dcd171f RBX: ffff88806e68a500 RCX: 0000000000000001 RDX: 0000000000000046 RSI: ffffffff8df341ae RDI: ffff88806e68b8f8 RBP: dffffc0000000000 R08: 00000000bdda7ede R09: 0000000000000007 R10: 0000000000000200 R11: 0000000000000000 R12: ffff8880365524c0 R13: ffffed1006caa5e6 R14: ffffffff827fb709 R15: 0000000000000000 __mem_cgroup_charge+0x1a/0x1c0 mm/memcontrol.c:5022 mem_cgroup_charge include/linux/memcontrol.h:644 [inline] shmem_alloc_and_add_folio+0x451/0xd40 mm/shmem.c:1985 shmem_get_folio_gfp+0x6ab/0x1900 mm/shmem.c:2564 shmem_get_folio mm/shmem.c:2670 [inline] shmem_write_begin+0x1a4/0x420 mm/shmem.c:3303 generic_perform_write+0x292/0xa40 mm/filemap.c:4325 shmem_file_write_iter+0x10e/0x140 mm/shmem.c:3478 __kernel_write_iter+0x2ac/0x920 fs/read_write.c:621 dump_emit_page fs/coredump.c:1304 [inline] dump_user_range+0x3f9/0xad0 fs/coredump.c:1378 elf_core_dump+0x2d5f/0x3d10 fs/binfmt_elf.c:2109 coredump_write fs/coredump.c:1053 [inline] do_coredump fs/coredump.c:1132 [inline] vfs_coredump+0x29a0/0x5770 fs/coredump.c:1206 get_signal+0x1f2a/0x21e0 kernel/signal.c:3022 arch_do_signal_or_restart+0x91/0x7a0 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:64 [inline] exit_to_user_mode_loop kernel/entry/common.c:98 [inline] __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline] irqentry_exit_to_user_mode_prepare include/linux/irq-entry-common.h:252 [inline] irqentry_exit_to_user_mode include/linux/irq-entry-common.h:323 [inline] irqentry_exit+0x403/0x790 kernel/entry/common.c:162 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618 RIP: 0033:0x7f3d5b4527f7 RSP: 002b:00007f3d5c48e1a0 EFLAGS: 00010206 RAX: 0000000000000000 RBX: 000000000000000b RCX: 00007f3d5b59c819 RDX: 00007f3d5c48e1c0 RSI: 00007f3d5c48e2f0 RDI: 000000000000000b RBP: 00007f3d5b632c91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000 R13: 00007f3d5b816038 R14: 00007f3d5b815fa0 R15: 00007ffea3ccccb8 rcu: rcu_preempt kthread timer wakeup didn't happen for 10501 jiffies! g201361 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=0 timer-softirq=106772 rcu: rcu_preempt kthread starved for 10502 jiffies! g201361 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:26472 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5387 [inline] __schedule+0x10e9/0x6820 kernel/sched/core.c:7188 __schedule_loop kernel/sched/core.c:7267 [inline] schedule+0xdd/0x390 kernel/sched/core.c:7282 schedule_timeout+0x127/0x280 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1a9/0x900 kernel/rcu/tree.c:2095 rcu_gp_kthread+0x179/0x230 kernel/rcu/tree.c:2297 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x72b/0xd50 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: 27556 Comm: syz.2.6678 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:__sanitizer_cov_trace_pc+0x0/0x70 kernel/kcov.c:210 Code: 56 5b 5c 00 48 89 df 5b e9 7d e6 61 00 be 03 00 00 00 5b e9 62 4b f0 02 66 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1e fa 65 8b 05 45 a5 0a 12 48 8b 34 24 65 48 8b 15 21 a5 0a RSP: 0018:ffffc90000007e38 EFLAGS: 00000046 RAX: 0000000000010001 RBX: ffff88807a0ed300 RCX: 0000000000000001 RDX: ffff88806a72ca00 RSI: ffffffff81f5489e RDI: ffff8880b8428504 RBP: ffff8880b8428600 R08: 0000000000000005 R09: 000000000000001f R10: 0000000000000001 R11: 0000000000000001 R12: 0000000000000000 R13: ffff8880b84284c0 R14: 0000000000000000 R15: 00000000fffffffd FS: 00007f11fcae76c0(0000) GS:ffff8881242de000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00002000000ca030 CR3: 000000004f0d7000 CR4: 00000000003526f0 Call Trace: timerqueue_linked_first include/linux/timerqueue.h:48 [inline] base_update_next_timer kernel/time/hrtimer.c:1126 [inline] __remove_hrtimer+0x1cc/0x440 kernel/time/hrtimer.c:1162 __run_hrtimer kernel/time/hrtimer.c:1910 [inline] __hrtimer_run_queues+0x359/0xa00 kernel/time/hrtimer.c:1994 hrtimer_interrupt+0x3e5/0x940 kernel/time/hrtimer.c:2113 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline] __sysvec_apic_timer_interrupt+0x10b/0x460 arch/x86/kernel/apic/apic.c:1067 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1061 [inline] sysvec_apic_timer_interrupt+0x9e/0xc0 arch/x86/kernel/apic/apic.c:1061 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:lock_acquire+0x5e/0x370 kernel/locking/lockdep.c:5872 Code: 05 3b c2 2e 12 83 f8 07 0f 87 d9 02 00 00 48 0f a3 05 46 b8 f6 0e 0f 82 a4 02 00 00 8b 35 ce eb f6 0e 85 f6 0f 85 bf 00 00 00 <48> 8b 44 24 30 65 48 2b 05 dd c1 2e 12 0f 85 ed 02 00 00 48 83 c4 RSP: 0018:ffffc9000e437638 EFLAGS: 00000206 RAX: 0000000000000046 RBX: 0000000000000000 RCX: 0000000000000001 RDX: 0000000000000000 RSI: ffffffff8df341ae RDI: ffffffff8c1c1f80 RBP: ffffffff8e7e5460 R08: 00000000dacd92cc R09: 0000000000000007 R10: 0000000000000200 R11: 0000000000000000 R12: 0000000000000002 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 rcu_lock_acquire include/linux/rcupdate.h:300 [inline] rcu_read_lock include/linux/rcupdate.h:838 [inline] mt_find+0x14a/0x8e0 lib/maple_tree.c:6269 find_vma+0xbf/0x140 mm/mmap.c:908 lock_mm_and_find_vma+0x62/0x6f0 mm/mmap_lock.c:504 do_user_addr_fault+0x29a/0x12f0 arch/x86/mm/fault.c:1357 handle_page_fault arch/x86/mm/fault.c:1474 [inline] exc_page_fault+0x6f/0xd0 arch/x86/mm/fault.c:1527 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618 RIP: 0010:__put_user_nocheck_4+0x3/0x10 arch/x86/lib/putuser.S:104 Code: d9 0f 01 cb 89 01 31 c9 0f 01 ca e9 87 d7 03 00 0f 1f 80 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 01 cb <89> 01 31 c9 0f 01 ca c3 cc cc cc cc 90 90 90 90 90 90 90 90 90 90 RSP: 0018:ffffc9000e4379d8 EFLAGS: 00050246 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00002000000ca030 RDX: 0000000000080000 RSI: ffffffff895cb2a1 RDI: ffff88806a72ca00 RBP: ffffc9000e437d78 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000002 R11: 0000000000000000 R12: 0000000000000000 R13: 00002000000ca000 R14: ffffc9000e437dbc R15: 0000000000000002 ____sys_recvmsg+0x2ec/0x640 net/socket.c:2931 ___sys_recvmsg+0x16a/0x1a0 net/socket.c:2960 do_recvmmsg+0x301/0x760 net/socket.c:3055 __sys_recvmmsg net/socket.c:3129 [inline] __do_sys_recvmmsg net/socket.c:3152 [inline] __se_sys_recvmmsg net/socket.c:3145 [inline] __x64_sys_recvmmsg+0x22a/0x280 net/socket.c:3145 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x10b/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f11fbb9c819 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f11fcae7028 EFLAGS: 00000246 ORIG_RAX: 000000000000012b RAX: ffffffffffffffda RBX: 00007f11fbe15fa0 RCX: 00007f11fbb9c819 RDX: 0000000000010106 RSI: 00002000000000c0 RDI: 0000000000000003 RBP: 00007f11fbc32c91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f11fbe16038 R14: 00007f11fbe15fa0 R15: 00007ffcf3691368