syzbot


INFO: rcu detected stall in rtnl_dellink

Status: upstream: reported on 2025/02/23 01:04
Reported-by: syzbot+8f0a130cfa0a24c612bb@syzkaller.appspotmail.com
First crash: 17d, last: 17d

Sample crash report:
IPVS: nq: UDP 224.0.0.2:0 - no destination available
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P10738/1:b..l
	(detected by 1, t=10502 jiffies, g=51181, q=550 ncpus=2)
task:syz.2.1700      state:R  running task     stack:23624 pid:10738 ppid:4250   flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5243 [inline]
 __schedule+0x143f/0x4570 kernel/sched/core.c:6560
 preempt_schedule_irq+0xf7/0x1c0 kernel/sched/core.c:6872
 irqentry_exit+0x53/0x80 kernel/entry/common.c:439
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:lock_acquire+0x26f/0x5a0 kernel/locking/lockdep.c:5666
Code: 2b 00 74 08 4c 89 f7 e8 9f 49 77 00 f6 44 24 61 02 0f 85 84 01 00 00 41 f7 c7 00 02 00 00 74 01 fb 48 c7 44 24 40 0e 36 e0 45 <4b> c7 44 25 00 00 00 00 00 43 c7 44 25 09 00 00 00 00 43 c7 44 25
RSP: 0018:ffffc90003596a00 EFLAGS: 00000206
RAX: 0000000000000001 RBX: 1ffff920006b2d4c RCX: 1ffff920006b2cec
RDX: dffffc0000000000 RSI: ffffffff8b0c2ec0 RDI: ffffffff8b5f6d80
RBP: ffffc90003596b48 R08: dffffc0000000000 R09: fffffbfff2256c4d
R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffff920006b2d48
R13: dffffc0000000000 R14: ffffc90003596a60 R15: 0000000000000246
 rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
 rcu_read_lock include/linux/rcupdate.h:791 [inline]
 page_ext_get+0x39/0x2a0 mm/page_ext.c:157
 __page_table_check_zero+0x139/0x4b0 mm/page_table_check.c:146
 page_table_check_free include/linux/page_table_check.h:46 [inline]
 free_pages_prepare mm/page_alloc.c:1460 [inline]
 free_pcp_prepare mm/page_alloc.c:1509 [inline]
 free_unref_page_prepare+0x12b6/0x15b0 mm/page_alloc.c:3384
 free_unref_page+0x33/0x3e0 mm/page_alloc.c:3479
 qlink_free mm/kasan/quarantine.c:168 [inline]
 qlist_free_all+0x76/0xe0 mm/kasan/quarantine.c:187
 kasan_quarantine_reduce+0x156/0x170 mm/kasan/quarantine.c:294
 __kasan_slab_alloc+0x1f/0x70 mm/kasan/common.c:305
 kasan_slab_alloc include/linux/kasan.h:201 [inline]
 slab_post_alloc_hook+0x52/0x3a0 mm/slab.h:737
 slab_alloc_node mm/slub.c:3398 [inline]
 kmem_cache_alloc_node+0x136/0x310 mm/slub.c:3443
 __alloc_skb+0xd3/0x2c0 net/core/skbuff.c:505
 alloc_skb include/linux/skbuff.h:1271 [inline]
 nlmsg_new include/net/netlink.h:991 [inline]
 mpls_netconf_notify_devconf+0x42/0xf0 net/mpls/af_mpls.c:1188
 mpls_dev_notify+0x57a/0x790 net/mpls/af_mpls.c:1657
 notifier_call_chain kernel/notifier.c:87 [inline]
 raw_notifier_call_chain+0xd0/0x170 kernel/notifier.c:455
 call_netdevice_notifiers_extack net/core/dev.c:2008 [inline]
 call_netdevice_notifiers net/core/dev.c:2022 [inline]
 unregister_netdevice_many+0xe48/0x1710 net/core/dev.c:10947
 rtnl_delete_link net/core/rtnetlink.c:3172 [inline]
 rtnl_dellink+0x4ef/0x890 net/core/rtnetlink.c:3223
 rtnetlink_rcv_msg+0x822/0x1000 net/core/rtnetlink.c:6150
 netlink_rcv_skb+0x1cd/0x410 net/netlink/af_netlink.c:2493
 netlink_unicast_kernel net/netlink/af_netlink.c:1311 [inline]
 netlink_unicast+0x7e2/0x970 net/netlink/af_netlink.c:1337
 netlink_sendmsg+0xa26/0xd60 net/netlink/af_netlink.c:1859
 sock_sendmsg_nosec net/socket.c:718 [inline]
 __sock_sendmsg net/socket.c:730 [inline]
 ____sys_sendmsg+0x5d3/0x9a0 net/socket.c:2519
 ___sys_sendmsg net/socket.c:2573 [inline]
 __sys_sendmsg+0x2a9/0x390 net/socket.c:2602
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fb98dd8d169
RSP: 002b:00007fb98eb5e038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007fb98dfa6080 RCX: 00007fb98dd8d169
RDX: 0000000000000840 RSI: 00004000000002c0 RDI: 0000000000000007
RBP: 00007fb98de0e2a0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007fb98dfa6080 R15: 00007ffd16941548
 </TASK>
rcu: rcu_preempt kthread starved for 9966 jiffies! g51181 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:26712 pid:16    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5243 [inline]
 __schedule+0x143f/0x4570 kernel/sched/core.c:6560
 schedule+0xbf/0x180 kernel/sched/core.c:6636
 schedule_timeout+0x1b9/0x300 kernel/time/timer.c:1965
 rcu_gp_fqs_loop+0x2d2/0x1150 kernel/rcu/tree.c:1706
 rcu_gp_kthread+0xa3/0x3b0 kernel/rcu/tree.c:1905
 kthread+0x28d/0x320 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:
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0 skipped: idling at native_safe_halt arch/x86/include/asm/irqflags.h:51 [inline]
NMI backtrace for cpu 0 skipped: idling at arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline]
NMI backtrace for cpu 0 skipped: idling at acpi_safe_halt drivers/acpi/processor_idle.c:111 [inline]
NMI backtrace for cpu 0 skipped: idling at acpi_idle_do_entry+0x10f/0x340 drivers/acpi/processor_idle.c:567

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/02/23 01:03 linux-6.1.y 3a8358583626 d34966d1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in rtnl_dellink
* Struck through repros no longer work on HEAD.