syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
	(detected by 0, t=10502 jiffies, g=29881, q=388 ncpus=2)
rcu: All QSes seen, last rcu_preempt kthread activity 10496 (4294966527-4294956031), jiffies_till_next_fqs=1, root ->qsmask 0x0
rcu: rcu_preempt kthread starved for 10497 jiffies! g29881 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x0 ->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:R  running task     stack:27840 pid:16    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5244 [inline]
 __schedule+0x10e9/0x40d0 kernel/sched/core.c:6561
 schedule+0xb9/0x180 kernel/sched/core.c:6637
 schedule_timeout+0x15c/0x280 kernel/time/timer.c:1965
 rcu_gp_fqs_loop+0x2f2/0x1310 kernel/rcu/tree.c:1706
 rcu_gp_kthread+0x95/0x380 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: 6956 Comm: syz.2.1011 Not tainted 6.1.137-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025
RIP: 0010:unwind_next_frame+0x6d8/0x20b0 arch/x86/kernel/unwind_orc.c:-1
Code: c0 0f 84 83 02 00 00 44 89 f9 80 e1 07 38 c1 0f 8c 75 02 00 00 be 02 00 00 00 49 89 d6 4c 89 ff e8 2d ec 99 00 e9 3b 18 00 00 <48> 8b 44 24 50 42 80 3c 28 00 4c 8b 74 24 58 74 08 4c 89 f7 e8 4f
RSP: 0018:ffffc90000007510 EFLAGS: 00000297
RAX: 0000000000000015 RBX: ffffc900000075e8 RCX: ffffffff8e168030
RDX: ffffffff8e8a00fc RSI: ffffffff8e167fe8 RDI: 0000000000000001
RBP: ffffffff8e8a0166 R08: 0000000000000012 R09: 0000000000000016
R10: fffff52000000ec9 R11: 1ffff92000000ec7 R12: ffffffff8e8a0162
R13: dffffc0000000000 R14: ffffffff8e16802c R15: 0000000000000005
FS:  00007f0d9b04a6c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f0d9b028f98 CR3: 000000007df1d000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 arch_stack_walk+0x10c/0x140 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x98/0xe0 kernel/stacktrace.c:122
 kasan_save_stack mm/kasan/common.c:45 [inline]
 kasan_set_track+0x4b/0x70 mm/kasan/common.c:52
 kasan_save_free_info+0x2d/0x50 mm/kasan/generic.c:516
 ____kasan_slab_free+0x126/0x1e0 mm/kasan/common.c:236
 kasan_slab_free include/linux/kasan.h:177 [inline]
 slab_free_hook mm/slub.c:1724 [inline]
 slab_free_freelist_hook+0x131/0x1a0 mm/slub.c:1750
 slab_free mm/slub.c:3661 [inline]
 kmem_cache_free+0xf7/0x290 mm/slub.c:3683
 tcp_write_queue_purge+0x13f/0x2f0 net/ipv4/tcp.c:3118
 tcp_done_with_error+0x3f/0xc0 net/ipv4/tcp_input.c:4393
 tcp_write_err net/ipv4/tcp_timer.c:70 [inline]
 tcp_write_timeout net/ipv4/tcp_timer.c:273 [inline]
 tcp_retransmit_timer+0x1257/0x2700 net/ipv4/tcp_timer.c:547
 tcp_write_timer+0x126/0x280 net/ipv4/tcp_timer.c:676
 call_timer_fn+0x1a0/0x670 kernel/time/timer.c:1504
 expire_timers kernel/time/timer.c:1549 [inline]
 __run_timers+0x525/0x7c0 kernel/time/timer.c:1820
 run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1833
 handle_softirqs+0x2a1/0x920 kernel/softirq.c:578
 __do_softirq kernel/softirq.c:612 [inline]
 invoke_softirq kernel/softirq.c:452 [inline]
 __irq_exit_rcu+0x12f/0x220 kernel/softirq.c:661
 irq_exit_rcu+0x5/0x20 kernel/softirq.c:673
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline]
 sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1118
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:lock_acquire+0x20f/0x490 kernel/locking/lockdep.c:5666
Code: 00 9c 8f 84 24 80 00 00 00 f6 84 24 81 00 00 00 02 0f 85 f5 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 66 43 c7 44 3d 09 00 00 43 c6 44 3d 0b
RSP: 0018:ffffc90004507a20 EFLAGS: 00000206
RAX: 0000000000000001 RBX: 0000000000000000 RCX: fd02c2ac1f5e7100
RDX: 0000000000000000 RSI: ffffffff8a6c0f80 RDI: ffffffff8abf0da0
RBP: ffffc90004507b30 R08: dffffc0000000000 R09: fffffbfff2117049
R10: fffffbfff2117049 R11: 1ffffffff2117048 R12: 0000000000000000
R13: 1ffff920008a0f50 R14: 0000000000000246 R15: dffffc0000000000
 rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
 rcu_read_lock include/linux/rcupdate.h:791 [inline]
 get_mem_cgroup_from_objcg+0x35/0x150 include/linux/memcontrol.h:520
 obj_cgroup_charge_pages mm/memcontrol.c:3099 [inline]
 obj_cgroup_charge+0x342/0x610 mm/memcontrol.c:3392
 memcg_slab_pre_alloc_hook mm/slab.h:501 [inline]
 slab_pre_alloc_hook+0x2e7/0x310 mm/slab.h:715
 slab_alloc_node mm/slub.c:3318 [inline]
 slab_alloc mm/slub.c:3406 [inline]
 __kmem_cache_alloc_lru mm/slub.c:3413 [inline]
 kmem_cache_alloc_lru+0x49/0x2e0 mm/slub.c:3429
 __d_alloc+0x31/0x700 fs/dcache.c:1774
 d_alloc+0x47/0x1a0 fs/dcache.c:1854
 lookup_one_qstr_excl+0xc6/0x240 fs/namei.c:1601
 do_unlinkat+0x188/0x560 fs/namei.c:4374
 __do_sys_unlink fs/namei.c:4438 [inline]
 __se_sys_unlink fs/namei.c:4436 [inline]
 __x64_sys_unlink+0x45/0x50 fs/namei.c:4436
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f0d9a18e969
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f0d9b04a038 EFLAGS: 00000246 ORIG_RAX: 0000000000000057
RAX: ffffffffffffffda RBX: 00007f0d9a3b5fa0 RCX: 00007f0d9a18e969
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000200000000280
RBP: 00007f0d9a210ab1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f0d9a3b5fa0 R15: 00007ffd7c986478
 </TASK>