[v6.1] INFO: rcu detected stall in ipv6_rcv

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 090666d3cc90 Linux 6.1.177
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=158b5546580000
kernel config: https://syzkaller.appspot.com/x/.config?x=f5aae664b2df43c2
dashboard link: https://syzkaller.appspot.com/bug?extid=3c03ad83fa737bf2eb5c
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/0a97b9de9f21/disk-090666d3.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/40f470f8fbd0/vmlinux-090666d3.xz
kernel image: https://storage.googleapis.com/syzbot-assets/baabfa2bfd44/bzImage-090666d3.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+3c03ad...@syzkaller.appspotmail.com

rcu: INFO: rcu_preempt detected expedited stalls on CPUs/tasks: { 0-.... } 2686 jiffies s: 6193 root: 0x1/.
rcu: blocking rcu_node structures (internal RCU debug):
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 4711 Comm: syz.9.42 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
RIP: 0010:__kasan_check_read+0x0/0x10 mm/kasan/shadow.c:31
Code: 41 5c 41 5d 41 5e 41 5f 5d c3 48 c7 c7 b2 ae 61 8c eb 0a 48 c7 c7 42 38 46 8c 48 89 de e8 d8 cc 51 08 31 ed eb d7 00 00 cc cc <89> f6 48 8b 0c 24 31 d2 e9 c3 ec ff ff 0f 1f 00 89 f6 48 8b 0c 24
RSP: 0018:ffffc90000007318 EFLAGS: 00000002
RAX: 0000000000000001 RBX: 000000000000004a RCX: ffffffff96c17103
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff90b10248
RBP: ffffc90000007550 R08: dffffc0000000000 R09: 1ffffffff2162049
R10: dffffc0000000000 R11: fffffbfff216204a R12: ffff888025c046d8
R13: ffff888025c03c00 R14: ffff888025c04820 R15: ffff888025c04840
FS: 00007f8aa4b9d6c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f69647ed2f8 CR3: 000000002442c000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
Call Trace:
<IRQ>
instrument_atomic_read include/linux/instrumented.h:72 [inline]
_test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline]
__lock_acquire+0xe4d/0x7c40 kernel/locking/lockdep.c:5033
lock_acquire+0x1bb/0x4a0 kernel/locking/lockdep.c:5676
seqcount_lockdep_reader_access+0xcd/0x1d0 include/linux/seqlock.h:102
timekeeping_get_delta kernel/time/timekeeping.c:254 [inline]
timekeeping_get_ns kernel/time/timekeeping.c:388 [inline]
ktime_get_update_offsets_now+0x95/0x3e0 kernel/time/timekeeping.c:2320
hrtimer_update_base kernel/time/hrtimer.c:652 [inline]
hrtimer_interrupt+0x11a/0x980 kernel/time/hrtimer.c:1859
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1107 [inline]
__sysvec_apic_timer_interrupt+0x153/0x5a0 arch/x86/kernel/apic/apic.c:1124
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline]
sysvec_apic_timer_interrupt+0x4d/0xc0 arch/x86/kernel/apic/apic.c:1118
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:get_current arch/x86/include/asm/current.h:15 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x4/0x60 kernel/kcov.c:215
Code: 00 00 00 00 00 90 53 48 89 fb e8 17 00 00 00 48 8b 3d 40 02 9f 0c 48 89 de 5b e9 a7 5b 50 00 00 00 cc cc 00 00 cc 48 8b 04 24 <65> 48 8b 0d 94 4d 80 7e 65 8b 15 95 4d 80 7e 81 e2 00 01 ff 00 74
RSP: 0018:ffffc900000079c8 EFLAGS: 00000246
RAX: ffffffff882cc77d RBX: ffff88807a9963c0 RCX: ffff888025c03c00
RDX: 0000000000000100 RSI: ffffffff8a8c2920 RDI: ffff88807a9963c0
RBP: 000000000000003a R08: ffffffff8e2121af R09: 1ffffffff1c42435
R10: dffffc0000000000 R11: fffffbfff1c42436 R12: ffffffff882cc760
R13: dffffc0000000000 R14: ffff88807a9963c0 R15: 1ffff1100f532c84
sock_wfree+0x1d/0x600 net/core/sock.c:2435
skb_orphan include/linux/skbuff.h:3169 [inline]
ip6_rcv_core+0x108c/0x1700 net/ipv6/ip6_input.c:291
ipv6_rcv+0x6e/0xb0 net/ipv6/ip6_input.c:307
__netif_receive_skb_one_core net/core/dev.c:5619 [inline]
__netif_receive_skb+0xcc/0x290 net/core/dev.c:5733
process_backlog+0x37c/0x710 net/core/dev.c:6061
__napi_poll+0xbb/0x460 net/core/dev.c:6628
napi_poll net/core/dev.c:6695 [inline]
net_rx_action+0x622/0xbc0 net/core/dev.c:6809
handle_softirqs+0x291/0x910 kernel/softirq.c:596
__do_softirq kernel/softirq.c:630 [inline]
invoke_softirq kernel/softirq.c:470 [inline]
__irq_exit_rcu+0x13b/0x230 kernel/softirq.c:679
irq_exit_rcu+0x5/0x20 kernel/softirq.c:691
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline]
sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1118
</IRQ>
<TASK>
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:__sanitizer_cov_trace_pc+0x41/0x60 kernel/kcov.c:221
Code: ff 00 74 11 81 fa 00 01 00 00 75 35 83 b9 1c 16 00 00 00 74 2c 8b 91 f8 15 00 00 83 fa 02 75 21 48 8b 91 00 16 00 00 48 8b 32 <48> 8d 7e 01 8b 89 fc 15 00 00 48 39 cf 73 08 48 89 3a 48 89 44 f2
RSP: 0018:ffffc900036274d8 EFLAGS: 00000246
RAX: ffffffff81dda6af RBX: ffffffff81dda66d RCX: ffff888025c03c00
RDX: ffffc90024a15000 RSI: 000000000001cb5a RDI: ffffffff8adf4280
RBP: 0000000000000001 R08: dffffc0000000000 R09: 1ffffffff2162048
R10: dffffc0000000000 R11: fffffbfff2162049 R12: dffffc0000000000
R13: ffff88802f632030 R14: 0000000000048a19 R15: ffff88813fff9120
rcu_read_lock_sched include/linux/rcupdate.h:884 [inline]
pfn_valid+0x10f/0x420 include/linux/mmzone.h:1857
page_table_check_set+0x25/0x6d0 mm/page_table_check.c:108
page_table_check_pte_set include/linux/page_table_check.h:83 [inline]
set_pte_at arch/x86/include/asm/pgtable.h:1009 [inline]
copy_present_pte mm/memory.c:1000 [inline]
copy_pte_range mm/memory.c:1091 [inline]
copy_pmd_range mm/memory.c:1177 [inline]
copy_pud_range mm/memory.c:1214 [inline]
copy_p4d_range mm/memory.c:1238 [inline]
copy_page_range+0x2586/0x3a60 mm/memory.c:1332
dup_mmap kernel/fork.c:703 [inline]
dup_mm kernel/fork.c:1547 [inline]
copy_mm+0xeb0/0x1680 kernel/fork.c:1596
copy_process+0x19a6/0x40c0 kernel/fork.c:2357
kernel_clone+0x24b/0x900 kernel/fork.c:2764
__do_sys_clone kernel/fork.c:2905 [inline]
__se_sys_clone kernel/fork.c:2889 [inline]
__x64_sys_clone+0x1a7/0x220 kernel/fork.c:2889
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f8aa3d9de59
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:00007f8aa4b9cfd8 EFLAGS: 00000206 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 00007f8aa4025fa0 RCX: 00007f8aa3d9de59
RDX: 0000200000003140 RSI: 0000200000003110 RDI: 00000000000c0000
RBP: 00007f8aa3e33e6f R08: 00002000000031c0 R09: 00002000000031c0
R10: 0000200000003180 R11: 0000000000000206 R12: 0000000000000000
R13: 00007f8aa4026038 R14: 00007f8aa4025fa0 R15: 00007ffeec294628
</TASK>


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