[v6.6] INFO: rcu detected stall in syscall_enter_from_user_mode

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 0a805b6ea8cd Linux 6.6.116
git tree: linux-6.6.y
console output: https://syzkaller.appspot.com/x/log.txt?x=17076c12580000
kernel config: https://syzkaller.appspot.com/x/.config?x=12606d4b8832c7e4
dashboard link: https://syzkaller.appspot.com/bug?extid=4be3f0fbbfd7ebd3390c
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/743e52c6a2c2/disk-0a805b6e.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/b7385817c222/vmlinux-0a805b6e.xz
kernel image: https://storage.googleapis.com/syzbot-assets/587fbfb2961d/bzImage-0a805b6e.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+4be3f0...@syzkaller.appspotmail.com

rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 1-....: (10500 ticks this GP) idle=68cc/1/0x4000000000000000 softirq=21284/21284 fqs=4180
rcu: hardirqs softirqs csw/system
rcu: number: 1412721 0 0
rcu: cputime: 19596 32882 36 ==> 52480(ms)
rcu: (t=10500 jiffies g=20189 q=962 ncpus=2)
CPU: 1 PID: 6422 Comm: syz.2.95 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
RIP: 0010:__kernel_text_address+0x2e/0x30 kernel/extable.c:92
Code: 53 48 89 fb e8 23 00 00 00 85 c0 0f 95 c0 48 81 fb 00 80 9c 8f 0f 93 c1 48 81 fb cb 63 b2 8f 0f 92 c2 20 ca 08 c2 0f b6 c2 5b <c3> 90 66 0f 1f 00 55 41 56 53 48 81 ff 00 00 00 81 0f 93 c0 48 81
RSP: 0018:ffffc900001f03b8 EFLAGS: 00000202
RAX: 0000000000000001 RBX: ffffc900001f0430 RCX: 0000000000000100
RDX: ffff88802333bc01 RSI: 0000000000000002 RDI: ffffffff81746c6c
RBP: 0000000000000002 R08: ffff88802333bc00 R09: 0000000000000003
R10: 0000000000000004 R11: 0000000000000100 R12: ffff88802333bc00
R13: 00000000000000e8 R14: dffffc0000000000 R15: 1ffff9200003e086
FS: 00007fabb1acd6c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000100000000 CR3: 000000005daa0000 CR4: 00000000003506e0
DR0: 0000200000000300 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
<IRQ>
unwind_get_return_address+0x5d/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_slab_alloc+0x6c/0x80 mm/kasan/common.c:328
kasan_slab_alloc include/linux/kasan.h:188 [inline]
slab_post_alloc_hook+0x6e/0x4d0 mm/slab.h:767
slab_alloc_node mm/slub.c:3495 [inline]
slab_alloc mm/slub.c:3503 [inline]
__kmem_cache_alloc_lru mm/slub.c:3510 [inline]
kmem_cache_alloc+0x11e/0x2e0 mm/slub.c:3519
dst_alloc+0x105/0x170 net/core/dst.c:89
ip6_dst_alloc net/ipv6/route.c:344 [inline]
icmp6_dst_alloc+0x7b/0x400 net/ipv6/route.c:3306
ndisc_send_skb+0x419/0x14b0 net/ipv6/ndisc.c:493
addrconf_rs_timer+0x2bc/0x600 net/ipv6/addrconf.c:4006
call_timer_fn+0x16e/0x530 kernel/time/timer.c:1700
expire_timers kernel/time/timer.c:1751 [inline]
__run_timers+0x52d/0x7d0 kernel/time/timer.c:2022
run_timer_softirq+0x67/0xf0 kernel/time/timer.c:2035
handle_softirqs+0x280/0x820 kernel/softirq.c:578
__do_softirq kernel/softirq.c:612 [inline]
invoke_softirq kernel/softirq.c:452 [inline]
__irq_exit_rcu+0xc7/0x190 kernel/softirq.c:661
irq_exit_rcu+0x9/0x20 kernel/softirq.c:673
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline]
sysvec_apic_timer_interrupt+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1088
</IRQ>
<TASK>
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:__syscall_enter_from_user_work kernel/entry/common.c:97 [inline]
RIP: 0010:syscall_enter_from_user_mode+0x2e/0x80 kernel/entry/common.c:118
Code: 41 56 53 48 89 f3 49 89 fe 48 8b 7c 24 10 e8 e9 fa ff ff 66 90 66 90 e8 90 1e 1d f7 e8 4b 1e 1d f7 fb 65 48 8b 05 62 e3 94 75 <48> 8b 70 08 40 f6 c6 3f 74 0b 4c 89 f7 5b 41 5e e9 8d b0 03 f7 48
RSP: 0018:ffffc900037b7f08 EFLAGS: 00000286
RAX: ffff88802333bc00 RBX: 00000000000000ca RCX: 37f7a9724ad7aa00
RDX: dffffc0000000000 RSI: ffffffff8aaabce0 RDI: ffffffff8afc6b00
RBP: ffffc900037b7f48 R08: ffffffff8e4a8d6f R09: 1ffffffff1c951ad
R10: dffffc0000000000 R11: fffffbfff1c951ae R12: 0000000000000000
R13: 0000000000000000 R14: ffffc900037b7f58 R15: 0000000000000000
do_syscall_64+0x28/0xb0 arch/x86/entry/common.c:77
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fabb0b8f6c9
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:00007fabb1acd0e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: ffffffffffffffda RBX: 00007fabb0de5fa8 RCX: 00007fabb0b8f6c9
RDX: 00000000000f4240 RSI: 0000000000000081 RDI: 00007fabb0de5fac
RBP: 00007fabb0de5fa0 R08: 0000000000745d1e R09: 0000000000000000
R10: 0000000000000004 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fabb0de6038 R14: 00007fffce6593e0 R15: 00007fffce6594c8
</TASK>


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