syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P13196/1:b..l
rcu: 	(detected by 1, t=10502 jiffies, g=381641, q=147 ncpus=2)
task:syz.3.13472     state:R  running task     stack:24200 pid:13196 tgid:13195 ppid:11121  task_flags:0x40054c flags:0x00080001
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5387 [inline]
 __schedule+0x17b4/0x5680 kernel/sched/core.c:7188
 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7512
 irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:547 [inline]
 irqentry_exit+0x14f/0x730 kernel/entry/common.c:164
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:lock_release+0x2d7/0x3c0 kernel/locking/lockdep.c:5893
Code: 76 9e 11 00 00 00 00 eb b5 e8 05 56 15 0a f7 c3 00 02 00 00 74 b9 65 48 8b 05 f5 30 9e 11 48 3b 44 24 28 75 44 fb 48 83 c4 30 <5b> 41 5c 41 5d 41 5e 41 5f 5d e9 1a 46 18 0a cc 48 8d 3d 32 bf 94
RSP: 0018:ffffc90004436e40 EFLAGS: 00000282
RAX: b31383d7bebc8e00 RBX: 0000000000000202 RCX: 0000000000000046
RDX: 0000000000000001 RSI: ffffffff8e24a525 RDI: ffffffff8c289460
RBP: ffff88802e01e7f8 R08: ffffc90004437908 R09: 0000000000000000
R10: ffffc90004436f98 R11: fffff52000886df5 R12: 0000000000000001
R13: 0000000000000001 R14: ffffffff8e95cce0 R15: ffff88802e01dc40
 rcu_lock_release include/linux/rcupdate.h:310 [inline]
 rcu_read_unlock include/linux/rcupdate.h:869 [inline]
 class_rcu_destructor include/linux/rcupdate.h:1181 [inline]
 unwind_next_frame+0x1bba/0x2550 arch/x86/kernel/unwind_orc.c:709
 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
 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584
 poison_slab_object mm/kasan/common.c:253 [inline]
 __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285
 kasan_slab_free include/linux/kasan.h:235 [inline]
 slab_free_hook mm/slub.c:2689 [inline]
 slab_free mm/slub.c:6246 [inline]
 kmem_cache_free+0x182/0x650 mm/slub.c:6373
 free_buffer_head+0x55/0x220 fs/buffer.c:2950
 try_to_free_buffers+0x25b/0x300 fs/buffer.c:2891
 block_invalidate_folio+0x5f8/0x730 fs/buffer.c:1564
 folio_invalidate mm/truncate.c:140 [inline]
 truncate_cleanup_folio+0xcb/0x190 mm/truncate.c:160
 truncate_inode_pages_range+0x2ce/0xe30 mm/truncate.c:404
 kill_bdev block/bdev.c:91 [inline]
 blkdev_flush_mapping+0x109/0x2f0 block/bdev.c:720
 blkdev_put_whole block/bdev.c:727 [inline]
 bdev_release+0x417/0x650 block/bdev.c:1152
 blkdev_release+0x15/0x20 block/fops.c:705
 __fput+0x44f/0xa60 fs/file_table.c:510
 task_work_run+0x1d9/0x270 kernel/task_work.c:233
 exit_task_work include/linux/task_work.h:40 [inline]
 do_exit+0x70f/0x22c0 kernel/exit.c:975
 do_group_exit+0x21b/0x2d0 kernel/exit.c:1117
 get_signal+0x1284/0x1330 kernel/signal.c:3037
 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:207 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:238 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:328 [inline]
 do_syscall_64+0x33e/0xf80 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fe3e139c819
RSP: 002b:00007fe3e218c0e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 00007fe3e1615fa8 RCX: 00007fe3e139c819
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fe3e1615fa8
RBP: 00007fe3e1615fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fe3e1616038 R14: 00007fe3e173f960 R15: 00007fe3e173fa48
 </TASK>
rcu: rcu_preempt kthread timer wakeup didn't happen for 10498 jiffies! g381641 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: 	Possible timer handling issue on cpu=0 timer-softirq=148910
rcu: rcu_preempt kthread starved for 10499 jiffies! g381641 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:27536 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5387 [inline]
 __schedule+0x17b4/0x5680 kernel/sched/core.c:7188
 __schedule_loop kernel/sched/core.c:7267 [inline]
 schedule+0x164/0x360 kernel/sched/core.c:7282
 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+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: 13215 Comm: syz.9.13476 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:3880 [inline]
RIP: 0010:sched_mm_cid_fork+0x657/0x10e0 kernel/sched/core.c:10953
Code: c7 03 00 00 00 40 e9 19 01 00 00 49 c7 c4 b8 6e 29 8e 49 c1 ec 03 41 bd 00 00 00 80 eb 0a 89 e8 f7 d8 0f 81 09 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: 0018:ffffc90004497c48 EFLAGS: 00000887
RAX: 0000000080000000 RBX: ffff88807e8f6d90 RCX: 0000000080000001
RDX: dffffc0000000000 RSI: 0000000000000002 RDI: ffff88807e8f6d90
RBP: 0000000080000000 R08: 1ffff1100fd1ec61 R09: 0000000000000000
R10: ffff88807e8f644c R11: fffff52000892f78 R12: 1ffffffff1c52dd7
R13: 0000000080000000 R14: 0000000000000002 R15: ffff88807e8f6200
FS:  00007fe310dd26c0(0000) GS:ffff88812521e000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b3030aff8 CR3: 000000003da28000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 bprm_execve+0xdb7/0x1440 fs/exec.c:1771
 do_execveat_common+0x50d/0x690 fs/exec.c:1846
 __do_sys_execveat fs/exec.c:1941 [inline]
 __se_sys_execveat fs/exec.c:1934 [inline]
 __x64_sys_execveat+0xc7/0xf0 fs/exec.c:1934
 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: 0033:0x7fe30ff9c819
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:00007fe310dd2028 EFLAGS: 00000246 ORIG_RAX: 0000000000000142
RAX: ffffffffffffffda RBX: 00007fe310215fa0 RCX: 00007fe30ff9c819
RDX: 0000000000000000 RSI: 0000200000000000 RDI: 0000000000000004
RBP: 00007fe310032c91 R08: 0000000000001000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fe310216038 R14: 00007fe310215fa0 R15: 00007fe31033fa48
 </TASK>