syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P7603/1:b..l
rcu: 	(detected by 0, t=10502 jiffies, g=16237, q=404 ncpus=2)
task:syz.2.332       state:R  running task     stack:26488 pid:7603  tgid:7603  ppid:5814   task_flags:0x400040 flags:0x00004002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x116f/0x5de0 kernel/sched/core.c:6767
 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7090
 irqentry_exit+0x36/0x90 kernel/entry/common.c:354
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:__orc_find+0x3d/0xf0 arch/x86/kernel/unwind_orc.c:104
Code: 53 48 83 ec 08 85 d2 0f 84 99 00 00 00 49 89 fe 48 89 f0 49 39 fc 72 7b 48 b9 00 00 00 00 00 fc ff df 49 89 ff 48 89 fd eb 0c <48> 8d 6b 04 49 89 df 49 39 ec 72 4e 4c 89 e2 48 29 ea 48 89 d6 48
RSP: 0018:ffffc9001beb7768 EFLAGS: 00000202
RAX: ffffffff9128c424 RBX: ffffffff90a06120 RCX: dffffc0000000000
RDX: ffffffff82327f08 RSI: 0000000000000000 RDI: ffffffff90a06120
RBP: ffffffff90a06120 R08: ffffffff9128c42a R09: 0000000000000000
R10: 0000000000000002 R11: 0000000000013282 R12: ffffffff90a06120
R13: ffffffff823282ee R14: ffffffff90a06120 R15: ffffffff90a06120
 orc_find arch/x86/kernel/unwind_orc.c:227 [inline]
 unwind_next_frame+0x2ec/0x20a0 arch/x86/kernel/unwind_orc.c:494
 arch_stack_walk+0x94/0x100 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122
 save_stack+0x160/0x1f0 mm/page_owner.c:156
 __reset_page_owner+0x84/0x1a0 mm/page_owner.c:308
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1262 [inline]
 __free_frozen_pages+0x69d/0xff0 mm/page_alloc.c:2725
 __folio_put+0x329/0x450 mm/swap.c:112
 folio_put include/linux/mm.h:1580 [inline]
 put_page include/linux/mm.h:1649 [inline]
 skb_page_unref include/linux/skbuff_ref.h:43 [inline]
 __skb_frag_unref include/linux/skbuff_ref.h:56 [inline]
 skb_release_data+0x618/0x960 net/core/skbuff.c:1091
 skb_release_all net/core/skbuff.c:1162 [inline]
 __kfree_skb+0x4f/0x70 net/core/skbuff.c:1176
 __tcp_close+0x24a/0xff0 net/ipv4/tcp.c:3100
 tcp_close+0x28/0x120 net/ipv4/tcp.c:3247
 tls_sk_proto_close+0x35c/0xad0 net/tls/tls_main.c:398
 inet_release+0x13c/0x280 net/ipv4/af_inet.c:435
 inet6_release+0x4f/0x70 net/ipv6/af_inet6.c:487
 __sock_release+0xb0/0x270 net/socket.c:647
 sock_close+0x1c/0x30 net/socket.c:1391
 __fput+0x3ff/0xb70 fs/file_table.c:465
 task_work_run+0x14d/0x240 kernel/task_work.c:227
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:114 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0x27b/0x2a0 kernel/entry/common.c:218
 do_syscall_64+0xda/0x260 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f6cb558e969
RSP: 002b:00007ffde902b9b8 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007f6cb57b7ba0 RCX: 00007f6cb558e969
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00007f6cb57b7ba0 R08: 0000000000040f78 R09: 0000001ce902bcaf
R10: 00007f6cb57b7ac0 R11: 0000000000000246 R12: 00000000000417f7
R13: 00007f6cb57b6160 R14: ffffffffffffffff R15: 00007ffde902bad0
 </TASK>
rcu: rcu_preempt kthread starved for 10495 jiffies! g16237 f0x0 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:27304 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x116f/0x5de0 kernel/sched/core.c:6767
 __schedule_loop kernel/sched/core.c:6845 [inline]
 schedule+0xe7/0x3a0 kernel/sched/core.c:6860
 schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x1ea/0xb00 kernel/rcu/tree.c:2046
 rcu_gp_kthread+0x270/0x380 kernel/rcu/tree.c:2248
 kthread+0x3c2/0x780 kernel/kthread.c:464
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 0 UID: 0 PID: 7610 Comm: syz.1.331 Not tainted 6.15.0-rc6-syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:__sanitizer_cov_trace_pc+0x56/0x70 kernel/kcov.c:222
Code: 00 f0 00 75 35 8b 82 3c 16 00 00 85 c0 74 2b 8b 82 18 16 00 00 83 f8 02 75 20 48 8b 8a 20 16 00 00 8b 92 1c 16 00 00 48 8b 01 <48> 83 c0 01 48 39 d0 73 07 48 89 01 48 89 34 c1 c3 cc cc cc cc 0f
RSP: 0018:ffffc9001bf07350 EFLAGS: 00000246
RAX: 000000000007ffff RBX: ffff8880b853f740 RCX: ffffc9000d69f000
RDX: 0000000000080000 RSI: ffffffff81af1973 RDI: 0000000000000005
RBP: 0000000000000003 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: ffffed10170a7ee9
R13: 0000000000000001 R14: dffffc0000000000 R15: ffff8880b843b040
FS:  00007fb3b91256c0(0000) GS:ffff8881249e1000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000038030 CR3: 00000000359cc000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 rep_nop arch/x86/include/asm/vdso/processor.h:13 [inline]
 cpu_relax arch/x86/include/asm/vdso/processor.h:18 [inline]
 csd_lock_wait kernel/smp.c:340 [inline]
 smp_call_function_many_cond+0x4a3/0x1290 kernel/smp.c:885
 on_each_cpu_cond_mask+0x40/0x90 kernel/smp.c:1052
 __flush_tlb_multi arch/x86/include/asm/paravirt.h:91 [inline]
 flush_tlb_multi arch/x86/mm/tlb.c:1291 [inline]
 flush_tlb_mm_range+0x322/0x1780 arch/x86/mm/tlb.c:1381
 flush_tlb_page arch/x86/include/asm/tlbflush.h:324 [inline]
 ptep_clear_flush+0x136/0x180 mm/pgtable-generic.c:101
 wp_page_copy mm/memory.c:3544 [inline]
 do_wp_page+0x17c6/0x58e0 mm/memory.c:3939
 handle_pte_fault mm/memory.c:6013 [inline]
 __handle_mm_fault+0x1ada/0x2a40 mm/memory.c:6140
 handle_mm_fault+0x3fe/0xad0 mm/memory.c:6309
 do_user_addr_fault+0x7a6/0x1370 arch/x86/mm/fault.c:1388
 handle_page_fault arch/x86/mm/fault.c:1480 [inline]
 exc_page_fault+0x5c/0xc0 arch/x86/mm/fault.c:1538
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623
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 c3 cc cc cc cc 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:ffffc9001bf079f8 EFLAGS: 00050246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000200000038030
RDX: 0000000000080000 RSI: ffffffff893dfd83 RDI: 0000000000000005
RBP: ffffc9001bf07d98 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000002 R11: 0000000000000000 R12: 0000000000000000
R13: 0000200000038000 R14: ffffc9001bf07ddc R15: 0000000000000002
 ____sys_recvmsg+0x2ee/0x6b0 net/socket.c:2799
 ___sys_recvmsg+0x114/0x1a0 net/socket.c:2828
 do_recvmmsg+0x2fe/0x740 net/socket.c:2923
 __sys_recvmmsg net/socket.c:2997 [inline]
 __do_sys_recvmmsg net/socket.c:3020 [inline]
 __se_sys_recvmmsg net/socket.c:3013 [inline]
 __x64_sys_recvmmsg+0x22a/0x280 net/socket.c:3013
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x260 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fb3b838e969
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:00007fb3b9125038 EFLAGS: 00000246 ORIG_RAX: 000000000000012b
RAX: ffffffffffffffda RBX: 00007fb3b85b6080 RCX: 00007fb3b838e969
RDX: 0000000000010106 RSI: 00002000000000c0 RDI: 0000000000000003
RBP: 00007fb3b8410ab1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000001 R14: 00007fb3b85b6080 R15: 00007fff06b40b78
 </TASK>