syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P1602/1:b..l
rcu: 	(detected by 1, t=10502 jiffies, g=219081, q=433 ncpus=2)
task:syz.5.8677      state:R  running task     stack:23328 pid:1602  tgid:1599  ppid:27880  task_flags:0x400140 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5388 [inline]
 __schedule+0x1821/0x5740 kernel/sched/core.c:7189
 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7513
 irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:547 [inline]
 irqentry_exit+0x14f/0x760 kernel/entry/common.c:164
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:filter_irq_stacks+0x4/0xa0 kernel/stacktrace.c:393
Code: ff ff ff 4c 89 f7 e8 1b 06 80 00 e9 57 ff ff ff e8 31 d8 f7 09 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa <41> 57 41 56 41 55 41 54 53 85 f6 74 70 49 89 fe 41 89 f4 31 db 49
RSP: 0018:ffffc90003887080 EFLAGS: 00000293
RAX: 000000000000000e RBX: 0000000000000801 RCX: 0000000000000001
RDX: 0000000000000820 RSI: 000000000000000e RDI: ffffc900038870e0
RBP: ffffc90003887310 R08: ffffffff81d5b796 R09: ffffffff8e95cde0
R10: dffffc0000000000 R11: ffffffff81b0efc0 R12: ffffffff8981cf65
R13: 0000000000000820 R14: ffffc900038870e0 R15: ffffc900038870e0
 stack_depot_save_flags+0x33/0x810 lib/stackdepot.c:667
 kasan_save_stack mm/kasan/common.c:58 [inline]
 kasan_save_track+0x4f/0x80 mm/kasan/common.c:78
 unpoison_slab_object mm/kasan/common.c:340 [inline]
 __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:366
 kasan_slab_alloc include/linux/kasan.h:253 [inline]
 slab_post_alloc_hook mm/slub.c:4569 [inline]
 slab_alloc_node mm/slub.c:4898 [inline]
 kmem_cache_alloc_noprof+0x2bc/0x650 mm/slub.c:4905
 dst_alloc+0x105/0x170 net/core/dst.c:90
 rt_dst_alloc net/ipv4/route.c:1651 [inline]
 __mkroute_output net/ipv4/route.c:2655 [inline]
 ip_route_output_key_hash_rcu+0x14d0/0x25d0 net/ipv4/route.c:2875
 ip_route_output_key_hash+0x18d/0x2a0 net/ipv4/route.c:2705
 __ip_route_output_key include/net/route.h:169 [inline]
 ip_route_output_flow+0x2a/0x150 net/ipv4/route.c:2932
 udp_sendmsg+0x141a/0x21a0 net/ipv4/udp.c:1409
 sock_sendmsg_nosec net/socket.c:787 [inline]
 __sock_sendmsg net/socket.c:802 [inline]
 ____sys_sendmsg+0x80a/0x9f0 net/socket.c:2698
 ___sys_sendmsg+0x2a5/0x360 net/socket.c:2752
 __sys_sendmmsg+0x27c/0x4e0 net/socket.c:2841
 __do_sys_sendmmsg net/socket.c:2868 [inline]
 __se_sys_sendmmsg net/socket.c:2865 [inline]
 __x64_sys_sendmmsg+0xa0/0xc0 net/socket.c:2865
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f0db359ce59
RSP: 002b:00007f0db44e7028 EFLAGS: 00000246 ORIG_RAX: 0000000000000133
RAX: ffffffffffffffda RBX: 00007f0db3816180 RCX: 00007f0db359ce59
RDX: 000000000800001d RSI: 0000200000007fc0 RDI: 0000000000000006
RBP: 00007f0db3632d6f R08: 0000000000000000 R09: 0000000000000000
R10: 000000000000001c R11: 0000000000000246 R12: 0000000000000000
R13: 00007f0db3816218 R14: 00007f0db3816180 R15: 00007ffdc07dc708
 </TASK>
rcu: rcu_preempt kthread timer wakeup didn't happen for 10498 jiffies! g219081 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: 	Possible timer handling issue on cpu=0 timer-softirq=123888
rcu: rcu_preempt kthread starved for 10499 jiffies! g219081 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:27544 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5388 [inline]
 __schedule+0x1821/0x5740 kernel/sched/core.c:7189
 __schedule_loop kernel/sched/core.c:7268 [inline]
 schedule+0x164/0x360 kernel/sched/core.c:7283
 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+0x389/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
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: 1609 Comm: syz.2.8679 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
RIP: 0010:__kasan_check_byte+0x14/0x40 mm/kasan/common.c:573
Code: fa ff ff 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1f 40 d6 41 56 53 48 89 f3 49 89 fe e8 3e 15 00 00 84 c0 <75> 16 be 01 00 00 00 4c 89 f7 31 d2 48 89 d9 89 c3 e8 f6 04 00 00
RSP: 0018:ffffc90000007cb0 EFLAGS: 00000002
RAX: 0000000000000001 RBX: ffffffff8bab7e80 RCX: 0000000080010003
RDX: 0000000000000000 RSI: ffffffff8bab7e80 RDI: 1ffffffff34d7f5d
RBP: ffffffff84bca6dc R08: 0000000000000001 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffed1006e7d863 R12: 0000000000000000
R13: ffffffff9a6bfae8 R14: ffffffff9a6bfae8 R15: 0000000000000001
FS:  00007f22e8de76c0(0000) GS:ffff88812528a000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00002000000002c0 CR3: 0000000057034000 CR4: 0000000000350ef0
Call Trace:
 <IRQ>
 kasan_check_byte include/linux/kasan.h:402 [inline]
 lock_acquire+0x84/0x350 kernel/locking/lockdep.c:5842
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:132 [inline]
 _raw_spin_lock_irqsave+0x40/0x60 kernel/locking/spinlock.c:166
 debug_object_deactivate+0x6c/0x3a0 lib/debugobjects.c:890
 debug_hrtimer_deactivate kernel/time/hrtimer.c:490 [inline]
 __run_hrtimer kernel/time/hrtimer.c:1898 [inline]
 __hrtimer_run_queues+0x23a/0xa20 kernel/time/hrtimer.c:1994
 hrtimer_interrupt+0x44b/0x950 kernel/time/hrtimer.c:2113
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline]
 __sysvec_apic_timer_interrupt+0x102/0x430 arch/x86/kernel/apic/apic.c:1067
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1061 [inline]
 sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1061
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:unwind_get_return_address+0x4f/0x90 arch/x86/kernel/unwind_orc.c:385
Code: 4c 83 3b 00 74 3a 48 83 c3 48 49 89 df 49 c1 ef 03 43 80 3c 37 00 74 08 48 89 df e8 5b 11 ba 00 48 8b 3b e8 43 dc 18 00 85 c0 <74> 14 43 80 3c 37 00 74 08 48 89 df e8 40 11 ba 00 48 8b 03 eb 02
RSP: 0018:ffffc900037e5fe8 EFLAGS: 00000202
RAX: 0000000000000001 RBX: ffffc900037e6050 RCX: 0000000000000000
RDX: 0000000000000001 RSI: ffffffff8e21de79 RDI: ffffffff8203f302
RBP: ffffc900037e6090 R08: ffffc900037e6970 R09: ffffc900037e6058
R10: dffffc0000000000 R11: fffff520006fcc0d R12: ffff8880296a3d80
R13: 1ffff110052d486e R14: dffffc0000000000 R15: 1ffff920006fcc0a
 arch_stack_walk+0xfb/0x150 arch/x86/kernel/stacktrace.c:26
 stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122
 save_stack+0x122/0x230 mm/page_owner.c:165
 __set_page_owner+0x8d/0x4c0 mm/page_owner.c:341
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x231/0x280 mm/page_alloc.c:1858
 prep_new_page mm/page_alloc.c:1866 [inline]
 get_page_from_freelist+0x24ba/0x2540 mm/page_alloc.c:3946
 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5226
 alloc_pages_mpol+0x235/0x490 mm/mempolicy.c:2490
 folio_alloc_mpol_noprof+0x39/0x160 mm/mempolicy.c:2509
 shmem_alloc_folio mm/shmem.c:1933 [inline]
 shmem_alloc_and_add_folio+0x442/0xf80 mm/shmem.c:1975
 shmem_get_folio_gfp+0x5a9/0x1670 mm/shmem.c:2564
 shmem_get_folio mm/shmem.c:2670 [inline]
 shmem_write_begin+0x16c/0x330 mm/shmem.c:3303
 generic_perform_write+0x2e2/0x8f0 mm/filemap.c:4325
 shmem_file_write_iter+0xf8/0x120 mm/shmem.c:3478
 __kernel_write_iter+0x41e/0x880 fs/read_write.c:621
 dump_emit_page fs/coredump.c:1304 [inline]
 dump_user_range+0xc19/0x12c0 fs/coredump.c:1378
 elf_core_dump+0x34c2/0x3ad0 fs/binfmt_elf.c:2109
 coredump_write+0x1216/0x1910 fs/coredump.c:1053
 do_coredump fs/coredump.c:1132 [inline]
 vfs_coredump+0x3807/0x4530 fs/coredump.c:1206
 get_signal+0x1107/0x1330 kernel/signal.c:3022
 arch_do_signal_or_restart+0xbc/0x840 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+0x289/0x760 kernel/entry/common.c:162
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618
RIP: 0033:0x7f22e7f9ce61
Code: 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 83 c8 ff c3 66 2e 0f 1f
RSP: 002b:fffffffffffffe70 EFLAGS: 00010217
RAX: 0000000000000000 RBX: 00007f22e8215fa0 RCX: 00007f22e7f9ce59
RDX: 0000000000000000 RSI: fffffffffffffe70 RDI: 0000000000008000
RBP: 00007f22e8032d6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
R13: 00007f22e8216038 R14: 00007f22e8215fa0 R15: 00007ffd3211e9b8
 </TASK>