syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P5126/1:b..l
	(detected by 0, t=10502 jiffies, g=12369, q=28 ncpus=2)
task:syz.0.163       state:R  running task     stack:25232 pid:5126  ppid:4279   flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5245 [inline]
 __schedule+0x11d1/0x40e0 kernel/sched/core.c:6562
 preempt_schedule_irq+0xbb/0x160 kernel/sched/core.c:6874
 irqentry_exit+0x63/0x70 kernel/entry/common.c:439
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:native_irq_disable arch/x86/include/asm/irqflags.h:40 [inline]
RIP: 0010:arch_local_irq_disable arch/x86/include/asm/irqflags.h:75 [inline]
RIP: 0010:arch_local_irq_save arch/x86/include/asm/irqflags.h:107 [inline]
RIP: 0010:lock_is_held_type+0x68/0x190 kernel/locking/lockdep.c:5701
Code: 48 8b 1d 1b d7 d5 75 83 bb dc 0a 00 00 00 0f 85 df 00 00 00 41 89 f7 49 89 fe 48 c7 04 24 00 00 00 00 9c 8f 04 24 4c 8b 2c 24 <fa> 48 c7 c7 00 1f 8c 8a e8 eb 12 00 00 65 ff 05 64 e1 d5 75 83 bb
RSP: 0018:ffffc9000d1b7458 EFLAGS: 00000246
RAX: 0000000000000000 RBX: ffff888074b03b80 RCX: ec8cffcd2ddddc00
RDX: 0000000000000000 RSI: 00000000ffffffff RDI: ffffffff8cb2d6e0
RBP: 00000000ffffffff R08: dffffc0000000000 R09: 1ffffffff215e848
R10: dffffc0000000000 R11: fffffbfff215e849 R12: ffffea00011378c8
R13: 0000000000000246 R14: ffffffff8cb2d6e0 R15: 00000000ffffffff
 lock_is_held include/linux/lockdep.h:283 [inline]
 rcu_read_lock_sched_held+0x86/0x110 kernel/rcu/update.c:125
 task_css include/linux/cgroup.h:509 [inline]
 mem_cgroup_from_task+0x49/0x110 mm/memcontrol.c:985
 get_mem_cgroup_from_mm+0xd2/0x290 mm/memcontrol.c:1038
 __mem_cgroup_charge+0x11/0x80 mm/memcontrol.c:6943
 mem_cgroup_charge include/linux/memcontrol.h:672 [inline]
 shmem_add_to_page_cache+0x90d/0x1c50 mm/shmem.c:708
 shmem_get_folio_gfp+0x158e/0x3400 mm/shmem.c:1971
 shmem_fault+0x1b6/0x780 mm/shmem.c:2156
 __do_fault+0x13b/0x4e0 mm/memory.c:4278
 do_read_fault mm/memory.c:4629 [inline]
 do_fault mm/memory.c:4758 [inline]
 handle_pte_fault mm/memory.c:5029 [inline]
 __handle_mm_fault mm/memory.c:5171 [inline]
 handle_mm_fault+0x2407/0x3ee0 mm/memory.c:5292
 faultin_page mm/gup.c:1026 [inline]
 __get_user_pages+0x40d/0xec0 mm/gup.c:1250
 populate_vma_page_range+0x214/0x2b0 mm/gup.c:1607
 __mm_populate+0x25c/0x380 mm/gup.c:1721
 mm_populate include/linux/mm.h:2891 [inline]
 vm_mmap_pgoff+0x212/0x2d0 mm/util.c:525
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fdb95b9aeb9
RSP: 002b:00007fdb96993028 EFLAGS: 00000246 ORIG_RAX: 0000000000000009
RAX: ffffffffffffffda RBX: 00007fdb95e15fa0 RCX: 00007fdb95b9aeb9
RDX: b635773f06ebbeee RSI: 0000000000b36000 RDI: 0000200000000000
RBP: 00007fdb95c08c1f R08: ffffffffffffffff R09: 0000000000000000
R10: 0000000000008031 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fdb95e16038 R14: 00007fdb95e15fa0 R15: 00007fff752482c8
 </TASK>
rcu: rcu_preempt kthread timer wakeup didn't happen for 10536 jiffies! g12369 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: 	Possible timer handling issue on cpu=0 timer-softirq=5811
rcu: rcu_preempt kthread starved for 10542 jiffies! g12369 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:27184 pid:16    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5245 [inline]
 __schedule+0x11d1/0x40e0 kernel/sched/core.c:6562
 schedule+0xb9/0x180 kernel/sched/core.c:6638
 schedule_timeout+0x184/0x2d0 kernel/time/timer.c:2168
 rcu_gp_fqs_loop+0x303/0x1340 kernel/rcu/tree.c:1706
 rcu_gp_kthread+0x99/0x3b0 kernel/rcu/tree.c:1905
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 0 PID: 5135 Comm: syz.2.164 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
RIP: 0010:lock_acquire+0x225/0x4a0 kernel/locking/lockdep.c:5666
Code: f7 84 24 80 00 00 00 00 02 00 00 43 c6 44 3d 04 f8 0f 85 f0 00 00 00 41 f7 c6 00 02 00 00 74 01 fb 48 c7 44 24 60 0e 36 e0 45 <4b> c7 44 3d 00 00 00 00 00 43 c7 44 3d 08 00 00 00 00 65 48 8b 04
RSP: 0018:ffffc9000d6afb60 EFLAGS: 00000206
RAX: 0000000000000001 RBX: 0000000000000000 RCX: 5787c87a0d859500
RDX: 0000000000000000 RSI: ffffffff8a8c23a0 RDI: ffffffff8adf0d20
RBP: ffffc9000d6afc80 R08: dffffc0000000000 R09: 1ffffffff215e84e
R10: dffffc0000000000 R11: fffffbfff215e84f R12: 0000000000000000
R13: 1ffff92001ad5f78 R14: 0000000000000246 R15: dffffc0000000000
FS:  00007fd84a12d6c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000000058 CR3: 0000000027e04000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 __might_fault+0xc2/0x120 mm/memory.c:5850
 _copy_from_user+0x27/0x170 lib/usercopy.c:14
 copy_from_user include/linux/uaccess.h:161 [inline]
 restore_sigcontext arch/x86/kernel/signal.c:92 [inline]
 __ia32_sys_rt_sigreturn+0x21d/0x760 arch/x86/kernel/signal.c:675
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fd84913c2d9
Code: 11 06 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 90 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 c7 c0 0f 00 00 00 0f 05 <0f> 1f 80 00 00 00 00 48 81 ec 48 01 00 00 49 89 d0 64 48 8b 0c 25
RSP: 002b:00007fd84a12ca80 EFLAGS: 00000202 ORIG_RAX: 000000000000000f
RAX: ffffffffffffffda RBX: 00007fd849415fa0 RCX: 00007fd84913c2d9
RDX: 00007fd84a12ca80 RSI: 00007fd84a12cbb0 RDI: 0000000000000021
RBP: 00007fd849208c1f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000
R13: 00007fd849416038 R14: 00007fd849415fa0 R15: 00007ffce8743668
 </TASK>