[syzbot] [sctp?] INFO: rcu detected stall in inet6_rtm_newaddr (3)

[syzbot <syzbot+3e17d9c9a137bb913b61@syzkaller.appspotmail.com>]

Hello,

syzbot found the following issue on:

HEAD commit:    e9565e23cd89 Merge tag 'sched_ext-for-6.15-rc6-fixes' of g..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=17bd4af4580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=bc44e21a0b824ef8
dashboard link: https://syzkaller.appspot.com/bug?extid=3e17d9c9a137bb913b61
compiler:       Debian clang version 20.1.2 (++20250402124445+58df0ef89dd6-1~exp1~20250402004600.97), Debian LLD 20.1.2
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=14a572f4580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/35d8c0778a31/disk-e9565e23.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/5f73f5f4ca4c/vmlinux-e9565e23.xz
kernel image: https://storage.googleapis.com/syzbot-assets/ad13ba9fecea/bzImage-e9565e23.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+3e17d9c9a137bb913b61@syzkaller.appspotmail.com

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	0-...!: (2 ticks this GP) idle=4c1c/1/0x4000000000000000 softirq=17820/17820 fqs=0
rcu: 	(detected by 1, t=10502 jiffies, g=13441, q=130 ncpus=2)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 5964 Comm: syz-executor Not tainted 6.15.0-rc6-syzkaller-00047-ge9565e23cd89 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:lock_release+0x2a2/0x3e0 kernel/locking/lockdep.c:5890
Code: b8 09 b8 ff ff ff ff 65 0f c1 05 49 79 d7 10 83 f8 01 75 51 48 c7 44 24 20 00 00 00 00 9c 8f 44 24 20 f7 44 24 20 00 02 00 00 <75> 56 f7 c3 00 02 00 00 74 01 fb 65 48 8b 05 fb 3c d7 10 48 3b 44
RSP: 0018:ffffc90000007bf8 EFLAGS: 00000046
RAX: 0000000000000001 RBX: 0000000000000006 RCX: 51a5468642bc5400
RDX: 0000000000000002 RSI: ffffffff8d936f16 RDI: ffffffff8bc1d820
RBP: ffff8880269f8b40 R08: ffff88802cf3bc83 R09: 1ffff110059e7790
R10: dffffc0000000000 R11: ffffed10059e7791 R12: 0000000000000002
R13: 0000000000000002 R14: ffff88805a967300 R15: ffff8880269f8000
FS:  0000555587b64500(0000) GS:ffff8881260c7000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000000600 CR3: 000000007d574000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 __raw_spin_unlock include/linux/spinlock_api_smp.h:141 [inline]
 _raw_spin_unlock+0x16/0x50 kernel/locking/spinlock.c:186
 spin_unlock include/linux/spinlock.h:391 [inline]
 advance_sched+0x99f/0xc90 net/sched/sch_taprio.c:981
 __run_hrtimer kernel/time/hrtimer.c:1761 [inline]
 __hrtimer_run_queues+0x52c/0xc60 kernel/time/hrtimer.c:1825
 hrtimer_interrupt+0x45b/0xaa0 kernel/time/hrtimer.c:1887
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1038 [inline]
 __sysvec_apic_timer_interrupt+0x108/0x410 arch/x86/kernel/apic/apic.c:1055
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline]
 sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1049
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:unwind_next_frame+0x180c/0x2390 arch/x86/kernel/unwind_orc.c:665
Code: 85 f4 08 00 00 b3 01 8b 84 24 84 00 00 00 41 39 06 4c 8b 7c 24 48 48 8b 7c 24 70 0f 85 54 01 00 00 48 8b 44 24 58 80 3c 28 00 <74> 05 e8 7d 05 b0 00 4d 8b 66 38 49 8d 7e 08 48 89 f8 48 c1 e8 03
RSP: 0018:ffffc90003fceeb8 EFLAGS: 00000246
RAX: 1ffff920007f9df8 RBX: ffffffff90b37101 RCX: 0000000000000001
RDX: ffffc90003fcefc8 RSI: dffffc0000000000 RDI: ffffc90003fcefc0
RBP: dffffc0000000000 R08: ffffc90003fcff48 R09: 0000000000000000
R10: ffffc90003fcefd8 R11: fffff520007f9dfd R12: ffffc90003fcff48
R13: ffffc90003fcefd8 R14: ffffc90003fcef88 R15: ffffffff8171ca05
 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:68
 poison_kmalloc_redzone mm/kasan/common.c:377 [inline]
 __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:394
 kasan_kmalloc include/linux/kasan.h:260 [inline]
 __do_kmalloc_node mm/slub.c:4327 [inline]
 __kmalloc_noprof+0x27a/0x4f0 mm/slub.c:4339
 kmalloc_noprof include/linux/slab.h:909 [inline]
 kzalloc_noprof include/linux/slab.h:1039 [inline]
 fib6_info_alloc+0x30/0xf0 net/ipv6/ip6_fib.c:155
 ip6_route_info_create+0x4b3/0x1360 net/ipv6/route.c:3802
 ip6_route_add+0x28/0x160 net/ipv6/route.c:3896
 addrconf_prefix_route net/ipv6/addrconf.c:2487 [inline]
 inet6_addr_add+0x6b2/0xc00 net/ipv6/addrconf.c:3052
 inet6_rtm_newaddr+0x93d/0xd20 net/ipv6/addrconf.c:5063
 rtnetlink_rcv_msg+0x7cc/0xb70 net/core/rtnetlink.c:6955
 netlink_rcv_skb+0x21c/0x490 net/netlink/af_netlink.c:2534
 netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline]
 netlink_unicast+0x758/0x8d0 net/netlink/af_netlink.c:1339
 netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1883
 sock_sendmsg_nosec net/socket.c:712 [inline]
 __sock_sendmsg+0x21c/0x270 net/socket.c:727
 __sys_sendto+0x3bd/0x520 net/socket.c:2180
 __do_sys_sendto net/socket.c:2187 [inline]
 __se_sys_sendto net/socket.c:2183 [inline]
 __x64_sys_sendto+0xde/0x100 net/socket.c:2183
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xf6/0x210 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f281bd907fc
Code: 2a 5f 02 00 44 8b 4c 24 2c 4c 8b 44 24 20 89 c5 44 8b 54 24 28 48 8b 54 24 18 b8 2c 00 00 00 48 8b 74 24 10 8b 7c 24 08 0f 05 <48> 3d 00 f0 ff ff 77 34 89 ef 48 89 44 24 08 e8 70 5f 02 00 48 8b
RSP: 002b:00007f281c0df670 EFLAGS: 00000293 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007f281cae4620 RCX: 00007f281bd907fc
RDX: 0000000000000040 RSI: 00007f281cae4670 RDI: 0000000000000003
RBP: 0000000000000000 R08: 00007f281c0df6c4 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000003
R13: 0000000000000000 R14: 00007f281cae4670 R15: 0000000000000000
 </TASK>
rcu: rcu_preempt kthread timer wakeup didn't happen for 10501 jiffies! g13441 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: 	Possible timer handling issue on cpu=0 timer-softirq=8937
rcu: rcu_preempt kthread starved for 10502 jiffies! g13441 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:27496 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x16e2/0x4cd0 kernel/sched/core.c:6767
 __schedule_loop kernel/sched/core.c:6845 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:6860
 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2046
 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2248
 kthread+0x711/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>


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