=============================
WARNING: suspicious RCU usage
syzkaller #0 Not tainted
-----------------------------
net/sched/sch_api.c:304 suspicious rcu_dereference_protected() usage!
other info that might help us debug this:
rcu_scheduler_active = 2, debug_locks = 1
8 locks held by udevd/6053:
#0: ffff88807e946460 (sb_writers#3){.+.+}-{0:0}, at: mnt_want_write+0x3d/0x90 fs/namespace.c:386
#1: ffffffff8c6ad298 (tomoyo_ss){....}-{0:0}, at: rcu_lock_acquire+0x5/0x30 include/linux/rcupdate.h:312
#2: ffffc90000dd0be0 ((&d->timer)){+.-.}-{0:0}, at: lockdep_copy_map include/linux/lockdep.h:45 [inline]
#2: ffffc90000dd0be0 ((&d->timer)){+.-.}-{0:0}, at: call_timer_fn+0xbb/0x530 kernel/time/timer.c:1441
#3: ffffffff8c11c760 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x5/0x30 include/linux/rcupdate.h:312
#4: ffffffff8c11c7c0 (rcu_read_lock_bh){....}-{1:2}, at: rcu_lock_acquire+0x9/0x30 include/linux/rcupdate.h:313
#5: ffff888020496108 (&sch->q.lock){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:364 [inline]
#5: ffff888020496108 (&sch->q.lock){+.-.}-{2:2}, at: __dev_xmit_skb net/core/dev.c:3911 [inline]
#5: ffff888020496108 (&sch->q.lock){+.-.}-{2:2}, at: __dev_queue_xmit+0xb8a/0x2ed0 net/core/dev.c:4253
#6: ffff888020496148 (dev->qdisc_running_key ?: &qdisc_running_key){+...}-{0:0}, at: tipc_l2_send_msg+0x30a/0x3c0 net/tipc/bearer.c:518
#7: ffffffff8c11c760 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x5/0x30 include/linux/rcupdate.h:312
stack backtrace:
CPU: 1 PID: 6053 Comm: udevd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
Call Trace:
dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106
qdisc_lookup+0xa6/0x650 net/sched/sch_api.c:304
qdisc_tree_reduce_backlog+0x190/0x430 net/sched/sch_api.c:793
sfq_enqueue+0x148e/0x2260 net/sched/sch_sfq.c:-1
qdisc_enqueue include/net/sch_generic.h:832 [inline]
netem_dequeue+0xd39/0x1400 net/sched/sch_netem.c:737
dequeue_skb net/sched/sch_generic.c:292 [inline]
qdisc_restart net/sched/sch_generic.c:397 [inline]
__qdisc_run+0x237/0x1480 net/sched/sch_generic.c:415
__dev_xmit_skb net/core/dev.c:3942 [inline]
__dev_queue_xmit+0xeb9/0x2ed0 net/core/dev.c:4253
tipc_l2_send_msg+0x30a/0x3c0 net/tipc/bearer.c:518
tipc_bearer_xmit_skb+0x292/0x3c0 net/tipc/bearer.c:577
tipc_disc_timeout+0x568/0x6b0 net/tipc/discover.c:338
call_timer_fn+0x16c/0x530 kernel/time/timer.c:1451
expire_timers kernel/time/timer.c:1496 [inline]
__run_timers+0x525/0x7c0 kernel/time/timer.c:1767
run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1780
handle_softirqs+0x328/0x820 kernel/softirq.c:576
__do_softirq kernel/softirq.c:610 [inline]
invoke_softirq kernel/softirq.c:450 [inline]
__irq_exit_rcu+0x12f/0x220 kernel/softirq.c:659
irq_exit_rcu+0x5/0x20 kernel/softirq.c:671
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1108
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:preempt_latency_start kernel/sched/core.c:5492 [inline]
RIP: 0010:preempt_count_add+0xa2/0x190 kernel/sched/core.c:5515
Code: ff ff ff 7f 39 f8 75 42 48 8b 5c 24 18 48 89 df e8 f3 b6 0b 00 85 c0 74 09 31 db 31 ff e8 e6 b6 0b 00 65 4c 8b 35 7e fe b0 7e <49> 81 c6 e8 14 00 00 4c 89 f0 48 c1 e8 03 42 80 3c 38 00 74 08 4c
RSP: 0018:ffffc9000350f208 EFLAGS: 00000246
RAX: 0000000000000000 RBX: ffffffff816d0cb7 RCX: ffffffff960c4f00
RDX: ffffc9000350ff00 RSI: ffffffff8a59e560 RDI: ffffffff816d0cb7
RBP: 000000000000a401 R08: 0000000000000004 R09: 000000000000000a
R10: fffff520006a1e61 R11: 1ffff920006a1e5f R12: ffff88801eab1dc0
R13: 0000000000000032 R14: ffff88801eab1dc0 R15: dffffc0000000000
is_module_text_address+0x17/0x140 kernel/module.c:4772
kernel_text_address kernel/extable.c:145 [inline]
__kernel_text_address+0x84/0x100 kernel/extable.c:105
unwind_get_return_address+0x49/0x80 arch/x86/kernel/unwind_orc.c:323
arch_stack_walk+0xf2/0x140 arch/x86/kernel/stacktrace.c:26
stack_trace_save+0x98/0xe0 kernel/stacktrace.c:122
kasan_save_stack mm/kasan/common.c:38 [inline]
kasan_set_track mm/kasan/common.c:46 [inline]
set_alloc_info mm/kasan/common.c:434 [inline]
____kasan_kmalloc mm/kasan/common.c:513 [inline]
__kasan_kmalloc+0xb5/0xf0 mm/kasan/common.c:522
kmalloc include/linux/slab.h:612 [inline]
kzalloc include/linux/slab.h:738 [inline]
tomoyo_encode2 security/tomoyo/realpath.c:45 [inline]
tomoyo_encode+0x27e/0x540 security/tomoyo/realpath.c:80
tomoyo_realpath_from_path+0x5cd/0x610 security/tomoyo/realpath.c:288
tomoyo_get_realpath security/tomoyo/file.c:151 [inline]
tomoyo_path_perm+0x1cd/0x510 security/tomoyo/file.c:822
security_path_truncate+0xcf/0x120 security/security.c:1214
handle_truncate fs/namei.c:3271 [inline]
do_open fs/namei.c:3620 [inline]
path_openat+0x282b/0x2f30 fs/namei.c:3750
do_filp_open+0x1b3/0x3e0 fs/namei.c:3777
do_sys_openat2+0x142/0x4a0 fs/open.c:1253
do_sys_open fs/open.c:1269 [inline]
__do_sys_openat fs/open.c:1285 [inline]
__se_sys_openat fs/open.c:1280 [inline]
__x64_sys_openat+0x135/0x160 fs/open.c:1280
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fde48ebd407
Code: 48 89 fa 4c 89 df e8 38 aa 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 fa 08 75 de e8 23 ff ff ff
RSP: 002b:00007ffcff12de70 EFLAGS: 00000202 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007fde48dcf880 RCX: 00007fde48ebd407
RDX: 00000000000a0241 RSI: 00007ffcff12eb30 RDI: ffffffffffffff9c
RBP: 0000557932751ba0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000124 R11: 0000000000000202 R12: 0000557932736010
R13: 00007ffcff12eb30 R14: 00007ffcff12e730 R15: 00007ffcff12e330
----------------
Code disassembly (best guess), 3 bytes skipped:
0: 7f 39 jg 0x3b
2: f8 clc
3: 75 42 jne 0x47
5: 48 8b 5c 24 18 mov 0x18(%rsp),%rbx
a: 48 89 df mov %rbx,%rdi
d: e8 f3 b6 0b 00 call 0xbb705
12: 85 c0 test %eax,%eax
14: 74 09 je 0x1f
16: 31 db xor %ebx,%ebx
18: 31 ff xor %edi,%edi
1a: e8 e6 b6 0b 00 call 0xbb705
1f: 65 4c 8b 35 7e fe b0 mov %gs:0x7eb0fe7e(%rip),%r14 # 0x7eb0fea5
26: 7e
* 27: 49 81 c6 e8 14 00 00 add $0x14e8,%r14 <-- trapping instruction
2e: 4c 89 f0 mov %r14,%rax
31: 48 c1 e8 03 shr $0x3,%rax
35: 42 80 3c 38 00 cmpb $0x0,(%rax,%r15,1)
3a: 74 08 je 0x44
3c: 4c rex.WR