Re: [syzbot] [net?] BUG: soft lockup in perf_event_open (2)

Re: [syzbot] [net?] BUG: soft lockup in perf_event_open (2)

[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit:    4edcdefd4083 Merge tag 'bpf-fixes' of git://git.kernel.org..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=16da941e580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=3c3d59be33cf7e9a
dashboard link: https://syzkaller.appspot.com/bug?extid=e04801269a8f6321dd79
compiler:       Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=164054ea580000

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-4edcdefd.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/01cc5d298db0/vmlinux-4edcdefd.xz
kernel image: https://storage.googleapis.com/syzbot-assets/59e4cf862ca3/bzImage-4edcdefd.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+e04801269a8f6321dd79@syzkaller.appspotmail.com

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	(detected by 0, t=10502 jiffies, g=61569, q=162 ncpus=1)
rcu: All QSes seen, last rcu_preempt kthread activity 10502 (4294967357-4294956855), jiffies_till_next_fqs=1, root ->qsmask 0x0
rcu: rcu_preempt kthread starved for 10502 jiffies! g61569 f0x2 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:27464 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5510 [inline]
 __schedule+0x17d9/0x56c0 kernel/sched/core.c:7234
 __schedule_loop kernel/sched/core.c:7311 [inline]
 schedule+0x164/0x2b0 kernel/sched/core.c:7326
 schedule_timeout+0x152/0x2c0 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x30c/0x11f0 kernel/rcu/tree.c:2123
 rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2325
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 0 UID: 0 PID: 5714 Comm: syz.3.20 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
RIP: 0010:unwind_next_frame+0x19ae/0x2550 arch/x86/kernel/unwind_orc.c:677
Code: e8 03 42 0f b6 04 20 84 c0 0f 85 b6 0a 00 00 4c 89 e8 48 c1 e8 03 42 0f b6 04 20 84 c0 0f 85 c5 0a 00 00 48 0f bf 03 49 01 c0 <49> 8d 56 40 4c 89 f7 4c 89 c6 e8 33 0e 00 00 84 c0 0f 84 4e 01 00
RSP: 0018:ffffc900000074e0 EFLAGS: 00000283
RAX: fffffffffffffff0 RBX: ffffffff91709a28 RCX: 0000000000000000
RDX: ffffffff91709a2a RSI: 0000000000000008 RDI: ffffc900000075e8
RBP: 1ffffffff22e1345 R08: ffffc900034df7c8 R09: 0000000000000000
R10: ffffc900000075d8 R11: fffff52000000ebd R12: dffffc0000000000
R13: ffffffff91709a29 R14: ffffc90000007588 R15: ffffc900000075d0
FS:  0000555594cee500(0000) GS:ffff88808c81b000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f5209872780 CR3: 0000000035426000 CR4: 0000000000352ef0
Call Trace:
 <IRQ>
 arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:584
 poison_slab_object mm/kasan/common.c:253 [inline]
 __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285
 kasan_slab_free include/linux/kasan.h:235 [inline]
 slab_free_hook mm/slub.c:2705 [inline]
 slab_free mm/slub.c:6405 [inline]
 kmem_cache_free+0x182/0x650 mm/slub.c:6532
 kfree_skb_reason include/linux/skbuff.h:1323 [inline]
 kfree_skb include/linux/skbuff.h:1332 [inline]
 hsr_forward_skb+0x1a27/0x28c0 net/hsr/hsr_forward.c:753
 send_hsr_supervision_frame+0x733/0xcf0 net/hsr/hsr_device.c:364
 hsr_announce+0x1db/0x370 net/hsr/hsr_device.c:421
 call_timer_fn+0x192/0x5e0 kernel/time/timer.c:1748
 expire_timers kernel/time/timer.c:1799 [inline]
 __run_timers kernel/time/timer.c:2374 [inline]
 __run_timer_base+0x652/0x8b0 kernel/time/timer.c:2386
 run_timer_base kernel/time/timer.c:2395 [inline]
 run_timer_softirq+0xb7/0x170 kernel/time/timer.c:2405
 handle_softirqs+0x225/0x840 kernel/softirq.c:622
 __do_softirq kernel/softirq.c:656 [inline]
 invoke_softirq kernel/softirq.c:496 [inline]
 __irq_exit_rcu+0xca/0x220 kernel/softirq.c:735
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:752
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline]
 sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1062
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0010:finish_task_switch+0x417/0xc60 kernel/sched/core.c:5361
Code: 04 00 00 41 c7 84 24 20 0e 00 00 00 00 00 00 0f 1f 44 00 00 49 83 c4 48 4c 89 e7 e8 a3 5a 23 0a e8 6e bc 39 00 fb 4c 8b 65 c8 <49> 8d bc 24 f8 16 00 00 48 89 f8 48 c1 e8 03 42 0f b6 04 30 84 c0
RSP: 0018:ffffc900034df880 EFLAGS: 00000206
RAX: 00000000000009c3 RBX: ffff88801fc3bf20 RCX: 0000000080000001
RDX: 0000000000000006 RSI: ffffffff8dfe613c RDI: ffffffff8c2aaf80
RBP: ffffc900034df8d0 R08: ffffffff9032f8f7 R09: 1ffffffff2065f1e
R10: dffffc0000000000 R11: fffffbfff2065f1f R12: ffff88803292a540
R13: ffff88801fc3bee8 R14: dffffc0000000000 R15: 1ffff11003f877e4
 context_switch kernel/sched/core.c:5513 [inline]
 __schedule+0x17e1/0x56c0 kernel/sched/core.c:7234
 preempt_schedule_common+0x82/0xd0 kernel/sched/core.c:7413
 preempt_schedule_thunk+0x16/0x40 arch/x86/entry/thunk.S:12
 __mutex_lock_common kernel/locking/mutex.c:656 [inline]
 __mutex_lock+0x321/0x1550 kernel/locking/mutex.c:821
 __do_sys_perf_event_open kernel/events/core.c:14249 [inline]
 __se_sys_perf_event_open+0x1984/0x1d40 kernel/events/core.c:13881
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f520999ce59
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:00007ffd9f0e1458 EFLAGS: 00000246 ORIG_RAX: 000000000000012a
RAX: ffffffffffffffda RBX: 00007f5209c15fa0 RCX: 00007f520999ce59
RDX: bfffffffffffffff RSI: 0000000000000000 RDI: 0000200000000180
RBP: 00007f5209a32e6f R08: 0000000000000000 R09: 0000000000000000
R10: ffffffffffffffff R11: 0000000000000246 R12: 0000000000000000
R13: 00007f5209c15fac R14: 00007f5209c15fa0 R15: 00007f5209c15fa0
 </TASK>


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