syzbot

ip6_tunnel: ip6tnl1 xmit: Local address not yet configured!
ip6_tunnel: ip6tnl1 xmit: Local address not yet configured!
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P20390/1:b..l
rcu: 	(detected by 0, t=10503 jiffies, g=107805, q=233 ncpus=2)
task:syz.0.3896      state:R  running task     stack:25928 pid:20390 ppid:5792   flags:0x00004002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5380 [inline]
 __schedule+0x14d2/0x44d0 kernel/sched/core.c:6699
 preempt_schedule_irq+0xb5/0x140 kernel/sched/core.c:7009
 irqentry_exit+0x67/0x70 kernel/entry/common.c:438
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:lock_acquire+0x1f2/0x410 kernel/locking/lockdep.c:5758
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 04 3c 00 00 00 00 66 43 c7 44 3c 09 00 00 43 c6 44 3c 0b 00
RSP: 0018:ffffc9000c7476c0 EFLAGS: 00000206
RAX: 0000000000000001 RBX: 0000000000000000 RCX: 0111fb8d7a269b00
RDX: 0000000000000000 RSI: ffffffff8aaace60 RDI: ffffffff8afc63c0
RBP: ffffc9000c7477d0 R08: dffffc0000000000 R09: 1ffffffff21b4ea0
R10: dffffc0000000000 R11: fffffbfff21b4ea1 R12: 1ffff920018e8ee4
R13: ffffffff8cd2ff20 R14: 0000000000000246 R15: dffffc0000000000
 rcu_lock_acquire include/linux/rcupdate.h:334 [inline]
 rcu_read_lock include/linux/rcupdate.h:786 [inline]
 percpu_ref_put_many include/linux/percpu-refcount.h:330 [inline]
 percpu_ref_put+0x35/0x180 include/linux/percpu-refcount.h:351
 css_put include/linux/cgroup_refcnt.h:79 [inline]
 __mem_cgroup_charge+0x56/0x80 mm/memcontrol.c:7070
 mem_cgroup_charge include/linux/memcontrol.h:686 [inline]
 shmem_add_to_page_cache+0x8e7/0x1b40 mm/shmem.c:785
 shmem_get_folio_gfp+0xf05/0x2ac0 mm/shmem.c:2072
 shmem_get_folio mm/shmem.c:2165 [inline]
 shmem_write_begin+0xf2/0x420 mm/shmem.c:2707
 generic_perform_write+0x2fb/0x5b0 mm/filemap.c:4016
 shmem_file_write_iter+0xfb/0x120 mm/shmem.c:2884
 call_write_iter include/linux/fs.h:2018 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x43b/0x940 fs/read_write.c:584
 ksys_write+0x147/0x250 fs/read_write.c:637
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7feb1c98d97f
RSP: 002b:00007feb1d84edf0 EFLAGS: 00000293 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000001000000 RCX: 00007feb1c98d97f
RDX: 0000000001000000 RSI: 00007feb127f7000 RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000009832
R10: 0000000000000002 R11: 0000000000000293 R12: 0000000000000003
R13: 00007feb1d84eef0 R14: 00007feb1d84eeb0 R15: 00007feb127f7000
 </TASK>
rcu: rcu_preempt kthread starved for 10534 jiffies! g107805 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:27088 pid:17    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5380 [inline]
 __schedule+0x14d2/0x44d0 kernel/sched/core.c:6699
 schedule+0xbd/0x170 kernel/sched/core.c:6773
 schedule_timeout+0x160/0x280 kernel/time/timer.c:2167
 rcu_gp_fqs_loop+0x302/0x1560 kernel/rcu/tree.c:1667
 rcu_gp_kthread+0x99/0x380 kernel/rcu/tree.c:1866
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 20403 Comm: syz.8.3900 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
RIP: 0010:check_kcov_mode kernel/kcov.c:193 [inline]
RIP: 0010:write_comp_data kernel/kcov.c:245 [inline]
RIP: 0010:__sanitizer_cov_trace_const_cmp4+0x36/0x90 kernel/kcov.c:313
Code: 30 29 7e 7e 65 8b 0d 31 29 7e 7e 81 e1 00 01 ff 00 74 11 81 f9 00 01 00 00 75 5b 83 ba 1c 16 00 00 00 74 52 8b 8a f8 15 00 00 <83> f9 03 75 47 48 8b 8a 00 16 00 00 44 8b 8a fc 15 00 00 49 c1 e1
RSP: 0018:ffffc9000c3e7778 EFLAGS: 00000046
RAX: ffffffff813aa188 RBX: ffffc9000c3e77f0 RCX: 0000000000000002
RDX: ffff888023303c00 RSI: 0000000000000001 RDI: 0000000000000000
RBP: 0000000000000001 R08: ffff888023303c00 R09: 0000000000000003
R10: 0000000000000004 R11: 0000000000000002 R12: ffffffff8153665b
R13: ffffc9000c3e7bb8 R14: dffffc0000000000 R15: 1ffff9200187cefe
FS:  00007f24cd7526c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2d322ff8 CR3: 000000004aab3000 CR4: 00000000003506e0
Call Trace:
 <TASK>
 unwind_get_return_address+0x68/0xc0 arch/x86/kernel/unwind_orc.c:369
 arch_stack_walk+0x11d/0x190 arch/x86/kernel/stacktrace.c:26
 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
 kasan_save_stack mm/kasan/common.c:45 [inline]
 kasan_set_track+0x4e/0x70 mm/kasan/common.c:52
 kasan_save_free_info+0x2e/0x50 mm/kasan/generic.c:522
 ____kasan_slab_free+0x126/0x1e0 mm/kasan/common.c:236
 kasan_slab_free include/linux/kasan.h:164 [inline]
 slab_free_hook mm/slub.c:1811 [inline]
 slab_free_freelist_hook+0x130/0x1b0 mm/slub.c:1837
 slab_free mm/slub.c:3830 [inline]
 kmem_cache_free+0xf8/0x280 mm/slub.c:3852
 __sigqueue_free kernel/signal.c:461 [inline]
 collect_signal kernel/signal.c:604 [inline]
 __dequeue_signal+0x52b/0x680 kernel/signal.c:626
 dequeue_signal+0xe9/0x4b0 kernel/signal.c:649
 get_signal+0x551/0x1400 kernel/signal.c:2782
 arch_do_signal_or_restart+0x96/0x780 arch/x86/kernel/signal.c:310
 exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174
 exit_to_user_mode_prepare+0xf6/0x180 kernel/entry/common.c:210
 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
 syscall_exit_to_user_mode+0x1a/0x50 kernel/entry/common.c:302
 do_syscall_64+0x61/0xb0 arch/x86/entry/common.c:87
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f24cc98eec9
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:00007f24cd7520e8 EFLAGS: 00000246
RAX: fffffffffffffffc RBX: 00007f24ccbe5fa8 RCX: 00007f24cc98eec9
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f24ccbe5fa8
RBP: 00007f24ccbe5fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f24ccbe6038 R14: 00007fffcd93cd60 R15: 00007fffcd93ce48
 </TASK>