rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	0-...!: (3 ticks this GP) idle=41ac/1/0x4000000000000000 softirq=63632/63632 fqs=2
rcu: 	(detected by 1, t=10504 jiffies, g=64057, q=642 ncpus=2)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 19997 Comm: syz.0.3650 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
RIP: 0010:iterate_chain_key kernel/locking/lockdep.c:453 [inline]
RIP: 0010:__lock_acquire+0x56f/0x2630 kernel/locking/lockdep.c:5225
Code: fe 89 f7 29 f2 01 c6 c1 c7 08 31 d7 89 fa 29 f8 01 f7 c1 c2 10 41 89 f8 31 c2 89 d0 29 d6 01 fa c1 c8 0d 31 c6 89 f0 41 29 f0 <01> f2 c1 c0 04 89 d2 44 31 c0 48 c1 e0 20 48 09 d0 49 89 c7 4d 85
RSP: 0000:ffffc90000007c90 EFLAGS: 00000092
RAX: 0000000068c1bacb RBX: ffff888029ddb090 RCX: 0000000000000000
RDX: 0000000095481a34 RSI: 0000000068c1bacb RDI: 00000000ef9d33e4
RBP: ffff888029dda500 R08: 0000000086db7919 R09: 0000000000000007
R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000000
R13: 0000000000000007 R14: 0000000000020000 R15: 0000000000000003
FS:  00007f58efbf66c0(0000) GS:ffff8881242db000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c3686ee CR3: 0000000020f53000 CR4: 00000000003526f0
Call Trace:
 <IRQ>
 lock_acquire kernel/locking/lockdep.c:5868 [inline]
 lock_acquire+0x1b1/0x370 kernel/locking/lockdep.c:5825
 rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
 rcu_read_lock include/linux/rcupdate.h:838 [inline]
 advance_sched+0x699/0xc80 net/sched/sch_taprio.c:991
 __run_hrtimer kernel/time/hrtimer.c:1930 [inline]
 __hrtimer_run_queues+0x470/0xa00 kernel/time/hrtimer.c:1994
 hrtimer_interrupt+0x3e5/0x940 kernel/time/hrtimer.c:2113
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline]
 __sysvec_apic_timer_interrupt+0x10b/0x460 arch/x86/kernel/apic/apic.c:1067
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1061 [inline]
 sysvec_apic_timer_interrupt+0x9e/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:__sanitizer_cov_trace_const_cmp8+0x0/0x20 kernel/kcov.c:320
Code: 0c 24 89 f2 89 fe bf 05 00 00 00 e9 2a fe ff ff 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 <f3> 0f 1e fa 48 8b 0c 24 48 89 f2 48 89 fe bf 07 00 00 00 e9 f8 fd
RSP: 0000:ffffc900061ff998 EFLAGS: 00000246
RAX: 0000000000080000 RBX: ffffc900061ffb70 RCX: ffffc9001d21b000
RDX: 0000000000080000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000007 R09: fffffffffffff000
R10: ffffc900061ffbb0 R11: 0000000000000000 R12: 0000000000000008
R13: 0000000000000000 R14: ffffc900061ffbb0 R15: ffffc900061ffbb8
 __import_iovec+0xb8/0x640 lib/iov_iter.c:1389
 import_iovec+0x101/0x130 lib/iov_iter.c:1440
 copy_msghdr_from_user+0x2ed/0x4f0 net/socket.c:2635
 recvmsg_copy_msghdr net/socket.c:2884 [inline]
 ___sys_recvmsg+0xdd/0x1a0 net/socket.c:2956
 do_recvmmsg+0x301/0x760 net/socket.c:3055
 __sys_recvmmsg net/socket.c:3129 [inline]
 __do_sys_recvmmsg net/socket.c:3152 [inline]
 __se_sys_recvmmsg net/socket.c:3145 [inline]
 __x64_sys_recvmmsg+0x22a/0x280 net/socket.c:3145
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x10b/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f58f199cdd9
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:00007f58efbf6028 EFLAGS: 00000246 ORIG_RAX: 000000000000012b
RAX: ffffffffffffffda RBX: 00007f58f1c16090 RCX: 00007f58f199cdd9
RDX: 0000000000010106 RSI: 00002000000000c0 RDI: 0000000000000003
RBP: 00007f58f1a32d69 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f58f1c16128 R14: 00007f58f1c16090 R15: 00007ffcecc79ef8
 </TASK>
rcu: rcu_preempt kthread starved for 10500 jiffies! g64057 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1
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:28216 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5387 [inline]
 __schedule+0x10e9/0x6820 kernel/sched/core.c:7188
 __schedule_loop kernel/sched/core.c:7267 [inline]
 schedule+0xdd/0x390 kernel/sched/core.c:7282
 schedule_timeout+0x127/0x280 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x1a9/0x900 kernel/rcu/tree.c:2095
 rcu_gp_kthread+0x179/0x230 kernel/rcu/tree.c:2297
 kthread+0x370/0x450 kernel/kthread.c:436
 ret_from_fork+0x72b/0xd50 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:
CPU: 1 UID: 0 PID: 18139 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline]
RIP: 0010:smp_call_function_many_cond+0x589/0x1700 kernel/smp.c:892
Code: b8 00 00 00 00 00 fc ff df 48 8b 54 24 08 49 89 d5 49 89 d4 49 c1 ed 03 41 83 e4 07 49 01 c5 41 83 c4 03 e8 09 80 0c 00 f3 90 <41> 0f b6 45 00 41 38 c4 7c 08 84 c0 0f 85 63 0f 00 00 8b 45 08 31
RSP: 0018:ffffc90002e07620 EFLAGS: 00000293
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff81fcfafd
RDX: ffff888031b70000 RSI: ffffffff81fcfad7 RDI: ffff888031b70000
RBP: ffff8880b8443320 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000003
R13: ffffed1017088665 R14: 0000000000000001 R15: ffff8880b853c5c0
FS:  000055556b9c3500(0000) GS:ffff8881243db000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b31523ffc CR3: 000000002cb69000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 on_each_cpu_cond_mask+0x40/0x90 kernel/smp.c:1057
 __flush_tlb_multi arch/x86/include/asm/paravirt.h:46 [inline]
 flush_tlb_multi arch/x86/mm/tlb.c:1361 [inline]
 flush_tlb_mm_range+0x45f/0x16f0 arch/x86/mm/tlb.c:1451
 dup_mmap+0x12e8/0x2180 mm/mmap.c:1905
 dup_mm kernel/fork.c:1534 [inline]
 copy_mm kernel/fork.c:1586 [inline]
 copy_process+0x7b37/0x7fa0 kernel/fork.c:2262
 kernel_clone+0x12e/0x9c0 kernel/fork.c:2723
 __do_sys_clone+0xd9/0x120 kernel/fork.c:2864
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x10b/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ff8345c5852
Code: 89 e7 e8 71 8b f7 ff 45 31 c0 31 d2 31 f6 64 48 8b 04 25 10 00 00 00 bf 11 00 20 01 4c 8d 90 d0 02 00 00 b8 38 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 66 89 c5 85 c0 75 3b 64 48 8b 04 25 10 00 00
RSP: 002b:00007ffd0d964f20 EFLAGS: 00000246 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 00007ffd0d964f20 RCX: 00007ff8345c5852
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011
RBP: 00007ffd0d9650ac R08: 0000000000000000 R09: 0000000000000001
R10: 000055556b9c37d0 R11: 0000000000000246 R12: 0000000000000001
R13: 00000000000927c0 R14: 0000000000053ecb R15: 00007ffd0d965100
 </TASK>