[v6.6] INFO: rcu detected stall in futex
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syzbot
Aug 10, 2025, 5:30:30 AM8/10/25
to syzkaller...@googlegroups.com
Hello,
syzbot found the following issue on:
HEAD commit: 3a8ababb8b6a Linux 6.6.101
git tree: linux-6.6.y
console output: https://syzkaller.appspot.com/x/log.txt?x=1702f2f0580000
kernel config: https://syzkaller.appspot.com/x/.config?x=a2bd95b6de4839b7
dashboard link: https://syzkaller.appspot.com/bug?extid=795c184c6744be404955
compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/ae2055ece513/disk-3a8ababb.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/72f91e4de841/vmlinux-3a8ababb.xz
kernel image: https://storage.googleapis.com/syzbot-assets/3dae292c190e/bzImage-3a8ababb.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+795c18...@syzkaller.appspotmail.com
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 1-....: (3 ticks this GP) idle=1edc/1/0x4000000000000000 softirq=98218/98221 fqs=4827
rcu: hardirqs softirqs csw/system
rcu: number: 6490740 0 0
rcu: cputime: 4778 47739 0 ==> 52500(ms)
rcu: (detected by 0, t=10502 jiffies, g=75785, q=355 ncpus=2)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 12507 Comm: syz.6.2510 Not tainted 6.6.101-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:native_save_fl arch/x86/include/asm/irqflags.h:26 [inline]
RIP: 0010:arch_local_save_flags arch/x86/include/asm/irqflags.h:89 [inline]
RIP: 0010:arch_irqs_disabled arch/x86/include/asm/irqflags.h:131 [inline]
RIP: 0010:lock_is_held_type+0x11e/0x190 kernel/locking/lockdep.c:5827
Code: 01 00 00 00 48 c7 c7 c0 cb aa 8a e8 bc 12 00 00 b8 ff ff ff ff 65 0f c1 05 d7 6d 95 75 83 f8 01 75 40 48 c7 04 24 00 00 00 00 <9c> 8f 04 24 f7 04 24 00 02 00 00 75 46 41 f7 c5 00 02 00 00 74 01
RSP: 0018:ffffc900001f0798 EFLAGS: 00000046
RAX: 0000000000000001 RBX: ffff888069da5a00 RCX: e620dd694f3e2800
RDX: ffff888069da5a00 RSI: ffffffff8aaacbc0 RDI: ffffffff8afc6780
RBP: 0000000000000001 R08: dffffc0000000000 R09: 1ffffffff21b46a4
R10: dffffc0000000000 R11: fffffbfff21b46a5 R12: 0000000000000000
R13: 0000000000000046 R14: ffffffff8cd2fba0 R15: ffff888069da64e0
FS: 00007fb33af656c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c286b4a CR3: 0000000055e7d000 CR4: 00000000003506e0
DR0: 0000200000000300 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
<IRQ>
trace_call_bpf+0x1aa/0x690 kernel/trace/bpf_trace.c:143
perf_trace_run_bpf_submit+0x7a/0x1c0 kernel/events/core.c:10248
perf_trace_preemptirq_template+0x281/0x340 include/trace/events/preemptirq.h:14
trace_irq_disable+0xbf/0xe0 include/trace/events/preemptirq.h:36
irqentry_enter+0x3b/0x50 kernel/entry/common.c:381
sysvec_irq_work+0xe/0xc0 arch/x86/kernel/irq_work.c:17
asm_sysvec_irq_work+0x1a/0x20 arch/x86/include/asm/idtentry.h:723
RIP: 0010:rcu_read_unlock_special+0x88/0x4c0 kernel/rcu/tree_plugin.h:682
Code: f1 f1 f1 00 f2 f2 f2 4a 89 04 2b 66 42 c7 44 2b 09 f3 f3 42 c6 44 2b 0b f3 65 44 8b 35 a9 4e 93 7e 41 f7 c6 00 00 f0 00 74 45 <48> c7 44 24 40 0e 36 e0 45 4a c7 04 2b 00 00 00 00 66 42 c7 44 2b
RSP: 0018:ffffc900001f0b00 EFLAGS: 00000206
RAX: e620dd694f3e2800 RBX: 1ffff9200003e168 RCX: e620dd694f3e2800
RDX: dffffc0000000000 RSI: ffffffff8aaaba40 RDI: ffffffff8afc6780
RBP: ffffc900001f0c00 R08: ffffffff8e4a84ef R09: 1ffffffff1c9509d
R10: dffffc0000000000 R11: fffffbfff1c9509e R12: ffffffff8cd35400
R13: dffffc0000000000 R14: 0000000000000246 R15: 0000000000000002
__rcu_read_unlock+0x7c/0xd0 kernel/rcu/tree_plugin.h:426
rcu_read_unlock include/linux/rcupdate.h:818 [inline]
ieee80211_rx_napi+0x21d/0x3c0 net/mac80211/rx.c:5430
ieee80211_rx include/net/mac80211.h:4969 [inline]
ieee80211_handle_queued_frames+0x106/0x1a0 net/mac80211/main.c:319
tasklet_action_common+0x2eb/0x4c0 kernel/softirq.c:809
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:finish_task_switch+0x26a/0x920 kernel/sched/core.c:5255
Code: 0f 84 37 01 00 00 48 85 db 0f 85 56 01 00 00 0f 1f 44 00 00 4c 8b 75 d0 4c 89 e7 e8 40 6b 1a 09 e8 fb a3 2f 00 fb 4c 8b 65 c0 <49> 8d bc 24 f8 15 00 00 48 89 f8 48 c1 e8 03 42 0f b6 04 28 84 c0
RSP: 0018:ffffc9000b5df898 EFLAGS: 00000282
RAX: e620dd694f3e2800 RBX: 0000000000000000 RCX: e620dd694f3e2800
RDX: dffffc0000000000 RSI: ffffffff8aaaba40 RDI: ffffffff8afc6780
RBP: ffffc9000b5df8f0 R08: ffffffff8e4a84ef R09: 1ffffffff1c9509d
R10: dffffc0000000000 R11: fffffbfff1c9509e R12: ffff888069da5a00
R13: dffffc0000000000 R14: ffff888076f21e00 R15: ffff8880b8f3cf08
context_switch kernel/sched/core.c:5384 [inline]
__schedule+0x14da/0x44d0 kernel/sched/core.c:6700
schedule+0xbd/0x170 kernel/sched/core.c:6774
futex_wait_queue+0x138/0x1b0 kernel/futex/waitwake.c:355
futex_wait+0x19f/0x530 kernel/futex/waitwake.c:656
do_futex+0x2ff/0x3e0 kernel/futex/syscalls.c:106
__do_sys_futex kernel/futex/syscalls.c:183 [inline]
__se_sys_futex+0x36f/0x3f0 kernel/futex/syscalls.c:164
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fb33a18ebe9
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:00007fb33af650e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: ffffffffffffffda RBX: 00007fb33a3b5fa8 RCX: 00007fb33a18ebe9
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fb33a3b5fa8
RBP: 00007fb33a3b5fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fb33a3b6038 R14: 00007ffcc9327d80 R15: 00007ffcc9327e68
</TASK>
---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.
syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title
If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)
If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report
If you want to undo deduplication, reply with:
#syz undup
syzbot found the following issue on:
HEAD commit: 3a8ababb8b6a Linux 6.6.101
git tree: linux-6.6.y
console output: https://syzkaller.appspot.com/x/log.txt?x=1702f2f0580000
kernel config: https://syzkaller.appspot.com/x/.config?x=a2bd95b6de4839b7
dashboard link: https://syzkaller.appspot.com/bug?extid=795c184c6744be404955
compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/ae2055ece513/disk-3a8ababb.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/72f91e4de841/vmlinux-3a8ababb.xz
kernel image: https://storage.googleapis.com/syzbot-assets/3dae292c190e/bzImage-3a8ababb.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+795c18...@syzkaller.appspotmail.com
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 1-....: (3 ticks this GP) idle=1edc/1/0x4000000000000000 softirq=98218/98221 fqs=4827
rcu: hardirqs softirqs csw/system
rcu: number: 6490740 0 0
rcu: cputime: 4778 47739 0 ==> 52500(ms)
rcu: (detected by 0, t=10502 jiffies, g=75785, q=355 ncpus=2)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 12507 Comm: syz.6.2510 Not tainted 6.6.101-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:native_save_fl arch/x86/include/asm/irqflags.h:26 [inline]
RIP: 0010:arch_local_save_flags arch/x86/include/asm/irqflags.h:89 [inline]
RIP: 0010:arch_irqs_disabled arch/x86/include/asm/irqflags.h:131 [inline]
RIP: 0010:lock_is_held_type+0x11e/0x190 kernel/locking/lockdep.c:5827
Code: 01 00 00 00 48 c7 c7 c0 cb aa 8a e8 bc 12 00 00 b8 ff ff ff ff 65 0f c1 05 d7 6d 95 75 83 f8 01 75 40 48 c7 04 24 00 00 00 00 <9c> 8f 04 24 f7 04 24 00 02 00 00 75 46 41 f7 c5 00 02 00 00 74 01
RSP: 0018:ffffc900001f0798 EFLAGS: 00000046
RAX: 0000000000000001 RBX: ffff888069da5a00 RCX: e620dd694f3e2800
RDX: ffff888069da5a00 RSI: ffffffff8aaacbc0 RDI: ffffffff8afc6780
RBP: 0000000000000001 R08: dffffc0000000000 R09: 1ffffffff21b46a4
R10: dffffc0000000000 R11: fffffbfff21b46a5 R12: 0000000000000000
R13: 0000000000000046 R14: ffffffff8cd2fba0 R15: ffff888069da64e0
FS: 00007fb33af656c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c286b4a CR3: 0000000055e7d000 CR4: 00000000003506e0
DR0: 0000200000000300 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
<IRQ>
trace_call_bpf+0x1aa/0x690 kernel/trace/bpf_trace.c:143
perf_trace_run_bpf_submit+0x7a/0x1c0 kernel/events/core.c:10248
perf_trace_preemptirq_template+0x281/0x340 include/trace/events/preemptirq.h:14
trace_irq_disable+0xbf/0xe0 include/trace/events/preemptirq.h:36
irqentry_enter+0x3b/0x50 kernel/entry/common.c:381
sysvec_irq_work+0xe/0xc0 arch/x86/kernel/irq_work.c:17
asm_sysvec_irq_work+0x1a/0x20 arch/x86/include/asm/idtentry.h:723
RIP: 0010:rcu_read_unlock_special+0x88/0x4c0 kernel/rcu/tree_plugin.h:682
Code: f1 f1 f1 00 f2 f2 f2 4a 89 04 2b 66 42 c7 44 2b 09 f3 f3 42 c6 44 2b 0b f3 65 44 8b 35 a9 4e 93 7e 41 f7 c6 00 00 f0 00 74 45 <48> c7 44 24 40 0e 36 e0 45 4a c7 04 2b 00 00 00 00 66 42 c7 44 2b
RSP: 0018:ffffc900001f0b00 EFLAGS: 00000206
RAX: e620dd694f3e2800 RBX: 1ffff9200003e168 RCX: e620dd694f3e2800
RDX: dffffc0000000000 RSI: ffffffff8aaaba40 RDI: ffffffff8afc6780
RBP: ffffc900001f0c00 R08: ffffffff8e4a84ef R09: 1ffffffff1c9509d
R10: dffffc0000000000 R11: fffffbfff1c9509e R12: ffffffff8cd35400
R13: dffffc0000000000 R14: 0000000000000246 R15: 0000000000000002
__rcu_read_unlock+0x7c/0xd0 kernel/rcu/tree_plugin.h:426
rcu_read_unlock include/linux/rcupdate.h:818 [inline]
ieee80211_rx_napi+0x21d/0x3c0 net/mac80211/rx.c:5430
ieee80211_rx include/net/mac80211.h:4969 [inline]
ieee80211_handle_queued_frames+0x106/0x1a0 net/mac80211/main.c:319
tasklet_action_common+0x2eb/0x4c0 kernel/softirq.c:809
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:finish_task_switch+0x26a/0x920 kernel/sched/core.c:5255
Code: 0f 84 37 01 00 00 48 85 db 0f 85 56 01 00 00 0f 1f 44 00 00 4c 8b 75 d0 4c 89 e7 e8 40 6b 1a 09 e8 fb a3 2f 00 fb 4c 8b 65 c0 <49> 8d bc 24 f8 15 00 00 48 89 f8 48 c1 e8 03 42 0f b6 04 28 84 c0
RSP: 0018:ffffc9000b5df898 EFLAGS: 00000282
RAX: e620dd694f3e2800 RBX: 0000000000000000 RCX: e620dd694f3e2800
RDX: dffffc0000000000 RSI: ffffffff8aaaba40 RDI: ffffffff8afc6780
RBP: ffffc9000b5df8f0 R08: ffffffff8e4a84ef R09: 1ffffffff1c9509d
R10: dffffc0000000000 R11: fffffbfff1c9509e R12: ffff888069da5a00
R13: dffffc0000000000 R14: ffff888076f21e00 R15: ffff8880b8f3cf08
context_switch kernel/sched/core.c:5384 [inline]
__schedule+0x14da/0x44d0 kernel/sched/core.c:6700
schedule+0xbd/0x170 kernel/sched/core.c:6774
futex_wait_queue+0x138/0x1b0 kernel/futex/waitwake.c:355
futex_wait+0x19f/0x530 kernel/futex/waitwake.c:656
do_futex+0x2ff/0x3e0 kernel/futex/syscalls.c:106
__do_sys_futex kernel/futex/syscalls.c:183 [inline]
__se_sys_futex+0x36f/0x3f0 kernel/futex/syscalls.c:164
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fb33a18ebe9
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:00007fb33af650e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: ffffffffffffffda RBX: 00007fb33a3b5fa8 RCX: 00007fb33a18ebe9
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fb33a3b5fa8
RBP: 00007fb33a3b5fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fb33a3b6038 R14: 00007ffcc9327d80 R15: 00007ffcc9327e68
</TASK>
---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.
syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title
If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)
If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report
If you want to undo deduplication, reply with:
#syz undup
syzbot
Aug 15, 2025, 12:31:33 PM8/15/25
to syzkaller...@googlegroups.com
syzbot has found a reproducer for the following issue on:
HEAD commit: bb9c90ab9c5a Linux 6.6.102
git tree: linux-6.6.y
console output: https://syzkaller.appspot.com/x/log.txt?x=1543fc34580000
kernel config: https://syzkaller.appspot.com/x/.config?x=7b989b97a0687b0a
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/3741b512b75a/disk-bb9c90ab.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/dedce7f4c998/vmlinux-bb9c90ab.xz
kernel image: https://storage.googleapis.com/syzbot-assets/acd529da0064/bzImage-bb9c90ab.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+795c18...@syzkaller.appspotmail.com
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 0-....: (1 GPs behind) idle=7be4/1/0x4000000000000000 softirq=58901/58902 fqs=5248
rcu: hardirqs softirqs csw/system
rcu: number: 9810253 0 0
rcu: cputime: 5959 46558 0 ==> 52500(ms)
rcu: (detected by 1, t=10502 jiffies, g=57901, q=172636 ncpus=2)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 21667 Comm: syz.3.7377 Not tainted 6.6.102-syzkaller #0
RIP: 0010:lock_release+0x134/0x8b0 kernel/locking/lockdep.c:5770
Code: e8 03 42 0f b6 04 28 84 c0 0f 85 20 05 00 00 83 3b 00 0f 85 51 04 00 00 4c 89 74 24 10 48 c7 84 24 a0 00 00 00 00 00 00 00 9c <8f> 84 24 a0 00 00 00 48 8b 84 24 a0 00 00 00 48 89 44 24 50 fa 48
RSP: 0018:ffffc900000072f8 EFLAGS: 00000046
RAX: 0000000000000000 RBX: ffff88807aad64dc RCX: bf08485e18b92900
RDX: 0000000000000000 RSI: ffffffff8afc66a0 RDI: ffffffff8afc6660
RBP: ffffc90000007410 R08: ffffffff8e4a882f R09: 1ffffffff1c95105
R10: dffffc0000000000 R11: fffffbfff1c95106 R12: ffffffff81ac4d14
R13: dffffc0000000000 R14: ffff88807aad5a00 R15: 1ffff92000000e6c
FS: 00007f9fe08ae6c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
Call Trace:
<IRQ>
rcu_lock_release include/linux/rcupdate.h:344 [inline]
rcu_read_unlock include/linux/rcupdate.h:819 [inline]
__perf_event_output kernel/events/core.c:7983 [inline]
perf_event_output_forward+0x2f7/0x3a0 kernel/events/core.c:7992
__perf_event_overflow+0x447/0x630 kernel/events/core.c:9717
perf_swevent_overflow kernel/events/core.c:9793 [inline]
perf_swevent_event+0x2f5/0x5c0 kernel/events/core.c:-1
perf_tp_event+0x4f9/0x13a0 kernel/events/core.c:10343
perf_trace_run_bpf_submit+0xf4/0x1c0 kernel/events/core.c:10267
perf_trace_preemptirq_template+0x281/0x340 include/trace/events/preemptirq.h:14
trace_irq_enable+0xbf/0xe0 include/trace/events/preemptirq.h:40
trace_hardirqs_on+0x18/0x40 kernel/trace/trace_preemptirq.c:56
RSP: 0018:ffffc90000007b00 EFLAGS: 00000206
RAX: bf08485e18b92900 RBX: 1ffff92000000f68 RCX: bf08485e18b92900
RDX: dffffc0000000000 RSI: ffffffff8aaab9c0 RDI: ffffffff8afc66c0
RBP: ffffc90000007bf0 R08: ffffffff8e4a882f R09: 1ffffffff1c95105
R10: dffffc0000000000 R11: fffffbfff1c95106 R12: ffffffff8cd35400
R13: dffffc0000000000 R14: 0000000000000246 R15: 0000000000000001
mac80211_hwsim_beacon+0xbb/0x1b0 drivers/net/wireless/virtual/mac80211_hwsim.c:2295
__run_hrtimer kernel/time/hrtimer.c:1755 [inline]
__hrtimer_run_queues+0x51e/0xc40 kernel/time/hrtimer.c:1819
hrtimer_run_softirq+0x187/0x2b0 kernel/time/hrtimer.c:1836
Code: 0f 84 37 01 00 00 48 85 db 0f 85 56 01 00 00 0f 1f 44 00 00 4c 8b 75 d0 4c 89 e7 e8 c0 a3 1a 09 e8 ab a2 2f 00 fb 4c 8b 65 c0 <49> 8d bc 24 f8 15 00 00 48 89 f8 48 c1 e8 03 42 0f b6 04 28 84 c0
RSP: 0018:ffffc9000d79f7f8 EFLAGS: 00000282
RAX: bf08485e18b92900 RBX: 0000000000000000 RCX: bf08485e18b92900
RDX: dffffc0000000000 RSI: ffffffff8aaab9c0 RDI: ffffffff8afc66c0
RBP: ffffc9000d79f850 R08: ffffffff8e4a882f R09: 1ffffffff1c95105
R10: dffffc0000000000 R11: fffffbfff1c95106 R12: ffff88807aad5a00
R13: dffffc0000000000 R14: ffff888030598000 R15: ffff8880b8e3cf08
context_switch kernel/sched/core.c:5383 [inline]
__schedule+0x14da/0x44d0 kernel/sched/core.c:6699
preempt_schedule_common+0x82/0xc0 kernel/sched/core.c:6866
preempt_schedule+0xab/0xc0 kernel/sched/core.c:6890
preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk_64.S:45
class_preempt_destructor include/linux/preempt.h:478 [inline]
try_to_wake_up+0x756/0x1140 kernel/sched/core.c:4355
wake_up_process kernel/sched/core.c:4480 [inline]
wake_up_q+0xb6/0x100 kernel/sched/core.c:1031
futex_wake+0x40d/0x4b0 kernel/futex/waitwake.c:184
do_futex+0x35d/0x3e0 kernel/futex/syscalls.c:111
RAX: ffffffffffffffda RBX: 00007f9fdfbb5fa8 RCX: 00007f9fdf98ebe9
RDX: 00000000000f4240 RSI: 0000000000000081 RDI: 00007f9fdfbb5fac
RBP: 00007f9fdfbb5fa0 R08: 0000000000745a69 R09: 0000000000000000
R10: 0000000000000004 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f9fdfbb6038 R14: 00007ffdd764b900 R15: 00007ffdd764b9e8
</TASK>
---
If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.
HEAD commit: bb9c90ab9c5a Linux 6.6.102
git tree: linux-6.6.y
console output: https://syzkaller.appspot.com/x/log.txt?x=1543fc34580000
kernel config: https://syzkaller.appspot.com/x/.config?x=7b989b97a0687b0a
dashboard link: https://syzkaller.appspot.com/bug?extid=795c184c6744be404955
compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1343fc34580000
compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/3741b512b75a/disk-bb9c90ab.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/dedce7f4c998/vmlinux-bb9c90ab.xz
kernel image: https://storage.googleapis.com/syzbot-assets/acd529da0064/bzImage-bb9c90ab.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+795c18...@syzkaller.appspotmail.com
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: hardirqs softirqs csw/system
rcu: number: 9810253 0 0
rcu: cputime: 5959 46558 0 ==> 52500(ms)
rcu: (detected by 1, t=10502 jiffies, g=57901, q=172636 ncpus=2)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 21667 Comm: syz.3.7377 Not tainted 6.6.102-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:native_save_fl arch/x86/include/asm/irqflags.h:26 [inline]
RIP: 0010:arch_local_save_flags arch/x86/include/asm/irqflags.h:89 [inline]
RIP: 0010:arch_local_irq_save arch/x86/include/asm/irqflags.h:107 [inline]
RIP: 0010:native_save_fl arch/x86/include/asm/irqflags.h:26 [inline]
RIP: 0010:arch_local_save_flags arch/x86/include/asm/irqflags.h:89 [inline]
RIP: 0010:lock_release+0x134/0x8b0 kernel/locking/lockdep.c:5770
Code: e8 03 42 0f b6 04 28 84 c0 0f 85 20 05 00 00 83 3b 00 0f 85 51 04 00 00 4c 89 74 24 10 48 c7 84 24 a0 00 00 00 00 00 00 00 9c <8f> 84 24 a0 00 00 00 48 8b 84 24 a0 00 00 00 48 89 44 24 50 fa 48
RSP: 0018:ffffc900000072f8 EFLAGS: 00000046
RAX: 0000000000000000 RBX: ffff88807aad64dc RCX: bf08485e18b92900
RDX: 0000000000000000 RSI: ffffffff8afc66a0 RDI: ffffffff8afc6660
RBP: ffffc90000007410 R08: ffffffff8e4a882f R09: 1ffffffff1c95105
R10: dffffc0000000000 R11: fffffbfff1c95106 R12: ffffffff81ac4d14
R13: dffffc0000000000 R14: ffff88807aad5a00 R15: 1ffff92000000e6c
FS: 00007f9fe08ae6c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2d063fff CR3: 000000007b6f3000 CR4: 00000000003506f0
Call Trace:
<IRQ>
rcu_lock_release include/linux/rcupdate.h:344 [inline]
rcu_read_unlock include/linux/rcupdate.h:819 [inline]
__perf_event_output kernel/events/core.c:7983 [inline]
perf_event_output_forward+0x2f7/0x3a0 kernel/events/core.c:7992
__perf_event_overflow+0x447/0x630 kernel/events/core.c:9717
perf_swevent_overflow kernel/events/core.c:9793 [inline]
perf_swevent_event+0x2f5/0x5c0 kernel/events/core.c:-1
perf_tp_event+0x4f9/0x13a0 kernel/events/core.c:10343
perf_trace_run_bpf_submit+0xf4/0x1c0 kernel/events/core.c:10267
perf_trace_preemptirq_template+0x281/0x340 include/trace/events/preemptirq.h:14
trace_irq_enable+0xbf/0xe0 include/trace/events/preemptirq.h:40
trace_hardirqs_on+0x18/0x40 kernel/trace/trace_preemptirq.c:56
asm_sysvec_irq_work+0x1a/0x20 arch/x86/include/asm/idtentry.h:723
RIP: 0010:rcu_read_unlock_special+0x88/0x4c0 kernel/rcu/tree_plugin.h:682
Code: f1 f1 f1 00 f2 f2 f2 4a 89 04 2b 66 42 c7 44 2b 09 f3 f3 42 c6 44 2b 0b f3 65 44 8b 35 39 58 93 7e 41 f7 c6 00 00 f0 00 74 45 <48> c7 44 24 40 0e 36 e0 45 4a c7 04 2b 00 00 00 00 66 42 c7 44 2b
RIP: 0010:rcu_read_unlock_special+0x88/0x4c0 kernel/rcu/tree_plugin.h:682
RSP: 0018:ffffc90000007b00 EFLAGS: 00000206
RAX: bf08485e18b92900 RBX: 1ffff92000000f68 RCX: bf08485e18b92900
RDX: dffffc0000000000 RSI: ffffffff8aaab9c0 RDI: ffffffff8afc66c0
RBP: ffffc90000007bf0 R08: ffffffff8e4a882f R09: 1ffffffff1c95105
R10: dffffc0000000000 R11: fffffbfff1c95106 R12: ffffffff8cd35400
R13: dffffc0000000000 R14: 0000000000000246 R15: 0000000000000001
__rcu_read_unlock+0x7c/0xd0 kernel/rcu/tree_plugin.h:426
rcu_read_unlock include/linux/rcupdate.h:818 [inline]
ieee80211_iterate_active_interfaces_atomic+0x15a/0x180 net/mac80211/util.c:804
rcu_read_unlock include/linux/rcupdate.h:818 [inline]
mac80211_hwsim_beacon+0xbb/0x1b0 drivers/net/wireless/virtual/mac80211_hwsim.c:2295
__run_hrtimer kernel/time/hrtimer.c:1755 [inline]
__hrtimer_run_queues+0x51e/0xc40 kernel/time/hrtimer.c:1819
hrtimer_run_softirq+0x187/0x2b0 kernel/time/hrtimer.c:1836
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:finish_task_switch+0x26a/0x920 kernel/sched/core.c:5254
__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
Code: 0f 84 37 01 00 00 48 85 db 0f 85 56 01 00 00 0f 1f 44 00 00 4c 8b 75 d0 4c 89 e7 e8 c0 a3 1a 09 e8 ab a2 2f 00 fb 4c 8b 65 c0 <49> 8d bc 24 f8 15 00 00 48 89 f8 48 c1 e8 03 42 0f b6 04 28 84 c0
RSP: 0018:ffffc9000d79f7f8 EFLAGS: 00000282
RAX: bf08485e18b92900 RBX: 0000000000000000 RCX: bf08485e18b92900
RDX: dffffc0000000000 RSI: ffffffff8aaab9c0 RDI: ffffffff8afc66c0
RBP: ffffc9000d79f850 R08: ffffffff8e4a882f R09: 1ffffffff1c95105
R10: dffffc0000000000 R11: fffffbfff1c95106 R12: ffff88807aad5a00
R13: dffffc0000000000 R14: ffff888030598000 R15: ffff8880b8e3cf08
context_switch kernel/sched/core.c:5383 [inline]
__schedule+0x14da/0x44d0 kernel/sched/core.c:6699
preempt_schedule_common+0x82/0xc0 kernel/sched/core.c:6866
preempt_schedule+0xab/0xc0 kernel/sched/core.c:6890
preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk_64.S:45
class_preempt_destructor include/linux/preempt.h:478 [inline]
try_to_wake_up+0x756/0x1140 kernel/sched/core.c:4355
wake_up_process kernel/sched/core.c:4480 [inline]
wake_up_q+0xb6/0x100 kernel/sched/core.c:1031
futex_wake+0x40d/0x4b0 kernel/futex/waitwake.c:184
do_futex+0x35d/0x3e0 kernel/futex/syscalls.c:111
__do_sys_futex kernel/futex/syscalls.c:183 [inline]
__se_sys_futex+0x36f/0x3f0 kernel/futex/syscalls.c:164
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f9fdf98ebe9
__se_sys_futex+0x36f/0x3f0 kernel/futex/syscalls.c:164
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
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:00007f9fe08ae0e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: ffffffffffffffda RBX: 00007f9fdfbb5fa8 RCX: 00007f9fdf98ebe9
RDX: 00000000000f4240 RSI: 0000000000000081 RDI: 00007f9fdfbb5fac
RBP: 00007f9fdfbb5fa0 R08: 0000000000745a69 R09: 0000000000000000
R10: 0000000000000004 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f9fdfbb6038 R14: 00007ffdd764b900 R15: 00007ffdd764b9e8
</TASK>
---
If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.
syzbot
Aug 21, 2025, 7:49:35 AM8/21/25
to syzkaller...@googlegroups.com
syzbot has found a reproducer for the following issue on:
HEAD commit: bb9c90ab9c5a Linux 6.6.102
git tree: linux-6.6.y
console output: https://syzkaller.appspot.com/x/log.txt?x=13adb7a2580000
kernel config: https://syzkaller.appspot.com/x/.config?x=7b989b97a0687b0a
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=113196f0580000
Downloadable assets:
rcu: hardirqs softirqs csw/system
rcu: number: 17351194 0 0
rcu: cputime: 6424 46093 0 ==> 52500(ms)
rcu: (detected by 1, t=10502 jiffies, g=9269, q=548 ncpus=2)
RIP: 0010:memory_is_nonzero mm/kasan/generic.c:102 [inline]
RIP: 0010:memory_is_poisoned_n mm/kasan/generic.c:127 [inline]
RIP: 0010:memory_is_poisoned mm/kasan/generic.c:159 [inline]
RIP: 0010:check_region_inline mm/kasan/generic.c:178 [inline]
RIP: 0010:kasan_check_range+0x89/0x290 mm/kasan/generic.c:187
Code: 00 fc ff df 4d 8d 34 19 4d 89 f4 4d 29 dc 49 83 fc 10 7f 29 4d 85 e4 0f 84 41 01 00 00 4c 89 cb 48 f7 d3 4c 01 fb 41 80 3b 00 <0f> 85 cc 01 00 00 49 ff c3 48 ff c3 75 ee e9 21 01 00 00 44 89 dd
RSP: 0018:ffffc900000071a8 EFLAGS: 00000046
RAX: 0000000000000001 RBX: ffffffffffffffff RCX: ffffffff81706455
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8e4a8828
RBP: ffffc900000072e0 R08: ffffffff8e4a882f R09: 1ffffffff1c95105
R10: dffffc0000000000 R11: fffffbfff1c95105 R12: 0000000000000001
R13: 0000000000000000 R14: fffffbfff1c95106 R15: 1ffffffff1c95105
FS: 00007fa6599a26c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
Call Trace:
<IRQ>
instrument_atomic_read include/linux/instrumented.h:68 [inline]
_test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline]
cpumask_test_cpu include/linux/cpumask.h:504 [inline]
cpu_online include/linux/cpumask.h:1082 [inline]
rcu_read_unlock_special+0x305/0x4c0 kernel/rcu/tree_plugin.h:664
perf_event_output_forward+0x2e6/0x3a0 kernel/events/core.c:7992
RSP: 0018:ffffc90000007a00 EFLAGS: 00000206
RAX: 2caa672456fd4f00 RBX: 1ffff92000000f48 RCX: 2caa672456fd4f00
R10: dffffc0000000000 R11: fffffbfff1c95106 R12: ffffffff8cd35400
R13: dffffc0000000000 R14: 0000000000000246 R15: 0000000000000001
__napi_poll+0xc0/0x460 net/core/dev.c:6600
napi_poll net/core/dev.c:6667 [inline]
net_rx_action+0x5ea/0xbf0 net/core/dev.c:6803
Code: 44 24 20 f6 44 24 21 02 74 0b 0f 0b 48 f7 03 08 00 00 00 74 63 bf 01 00 00 00 e8 4b da e5 f6 e8 46 5f 16 f7 fb bf 01 00 00 00 <e8> db b5 ff ff 48 c7 44 24 40 00 00 00 00 9c 8f 44 24 40 8b 44 24
RSP: 0018:ffffc900034b7a00 EFLAGS: 00000286
RAX: 2caa672456fd4f00 RBX: 0000000000000000 RCX: 2caa672456fd4f00
RDX: dffffc0000000000 RSI: ffffffff8aaab9c0 RDI: 0000000000000001
RBP: ffffc900034b7ab0 R08: ffffffff8e4a882f R09: 1ffffffff1c95105
R10: dffffc0000000000 R11: fffffbfff1c95106 R12: 0000000000000000
R13: 0000000000000000 R14: dffffc0000000000 R15: 1ffff92000696f40
irqentry_exit+0x67/0x70 kernel/entry/common.c:438
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:try_to_wake_up+0x73f/0x1140 kernel/sched/core.c:4355
Code: 0f 1f 44 00 00 bf 01 00 00 00 e8 ec 5a ff ff 65 8b 05 0d aa a7 7e 85 c0 74 22 65 48 8b 04 25 28 00 00 00 48 3b 44 24 40 75 59 <44> 89 f0 48 83 c4 48 5b 41 5c 41 5d 41 5e 41 5f 5d c3 e8 ca 8b a4
RSP: 0018:ffffc900034b7b70 EFLAGS: 00000246
RAX: 2caa672456fd4f00 RBX: ffff8880b8e3d198 RCX: 0000000000000000
RDX: dffffc0000000000 RSI: ffffffff8aaab9c0 RDI: 00000000ffffffff
RBP: ffff88802d6e5a00 R08: ffffffff8e4a882f R09: 1ffffffff1c95105
R10: dffffc0000000000 R11: fffffbfff1c95106 R12: 0000000000000000
R13: dffffc0000000000 R14: 0000000000000001 R15: dffffc0000000000
RAX: ffffffffffffffda RBX: 00007fa658db5fa8 RCX: 00007fa658b8ebe9
RDX: 00000000000f4240 RSI: 0000000000000081 RDI: 00007fa658db5fac
RBP: 00007fa658db5fa0 R08: 0000000000745d1e R09: 0000000000000000
R10: ffffffffffffffff R11: 0000000000000246 R12: 0000000000000000
R13: 00007fa658db6038 R14: 00007fff1c7f3bc0 R15: 00007fff1c7f3ca8
HEAD commit: bb9c90ab9c5a Linux 6.6.102
git tree: linux-6.6.y
console output: https://syzkaller.appspot.com/x/log.txt?x=13adb7a2580000
kernel config: https://syzkaller.appspot.com/x/.config?x=7b989b97a0687b0a
dashboard link: https://syzkaller.appspot.com/bug?extid=795c184c6744be404955
compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=16e2d7a2580000
compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=113196f0580000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/3741b512b75a/disk-bb9c90ab.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/dedce7f4c998/vmlinux-bb9c90ab.xz
kernel image: https://storage.googleapis.com/syzbot-assets/acd529da0064/bzImage-bb9c90ab.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/dedce7f4c998/vmlinux-bb9c90ab.xz
kernel image: https://storage.googleapis.com/syzbot-assets/acd529da0064/bzImage-bb9c90ab.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+795c18...@syzkaller.appspotmail.com
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 0-....: (1 GPs behind) idle=2c64/1/0x4000000000000000 softirq=12169/12170 fqs=5249
Reported-by: syzbot+795c18...@syzkaller.appspotmail.com
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: hardirqs softirqs csw/system
rcu: number: 17351194 0 0
rcu: cputime: 6424 46093 0 ==> 52500(ms)
rcu: (detected by 1, t=10502 jiffies, g=9269, q=548 ncpus=2)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 5989 Comm: syz.0.30 Not tainted 6.6.102-syzkaller #0
NMI backtrace for cpu 0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:bytes_is_nonzero mm/kasan/generic.c:85 [inline]
RIP: 0010:memory_is_nonzero mm/kasan/generic.c:102 [inline]
RIP: 0010:memory_is_poisoned_n mm/kasan/generic.c:127 [inline]
RIP: 0010:memory_is_poisoned mm/kasan/generic.c:159 [inline]
RIP: 0010:check_region_inline mm/kasan/generic.c:178 [inline]
RIP: 0010:kasan_check_range+0x89/0x290 mm/kasan/generic.c:187
Code: 00 fc ff df 4d 8d 34 19 4d 89 f4 4d 29 dc 49 83 fc 10 7f 29 4d 85 e4 0f 84 41 01 00 00 4c 89 cb 48 f7 d3 4c 01 fb 41 80 3b 00 <0f> 85 cc 01 00 00 49 ff c3 48 ff c3 75 ee e9 21 01 00 00 44 89 dd
RSP: 0018:ffffc900000071a8 EFLAGS: 00000046
RAX: 0000000000000001 RBX: ffffffffffffffff RCX: ffffffff81706455
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8e4a8828
RBP: ffffc900000072e0 R08: ffffffff8e4a882f R09: 1ffffffff1c95105
R10: dffffc0000000000 R11: fffffbfff1c95105 R12: 0000000000000001
R13: 0000000000000000 R14: fffffbfff1c95106 R15: 1ffffffff1c95105
FS: 00007fa6599a26c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000007df83000 CR4: 00000000003506f0
Call Trace:
<IRQ>
instrument_atomic_read include/linux/instrumented.h:68 [inline]
_test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline]
cpumask_test_cpu include/linux/cpumask.h:504 [inline]
cpu_online include/linux/cpumask.h:1082 [inline]
rcu_read_unlock_special+0x305/0x4c0 kernel/rcu/tree_plugin.h:664
__rcu_read_unlock+0x7c/0xd0 kernel/rcu/tree_plugin.h:426
rcu_read_unlock include/linux/rcupdate.h:818 [inline]
__perf_event_output kernel/events/core.c:7983 [inline]
rcu_read_unlock include/linux/rcupdate.h:818 [inline]
perf_event_output_forward+0x2e6/0x3a0 kernel/events/core.c:7992
__perf_event_overflow+0x447/0x630 kernel/events/core.c:9717
perf_swevent_overflow kernel/events/core.c:9793 [inline]
perf_swevent_event+0x2f5/0x5c0 kernel/events/core.c:-1
perf_tp_event+0x4f9/0x13a0 kernel/events/core.c:10343
perf_trace_run_bpf_submit+0xf4/0x1c0 kernel/events/core.c:10267
perf_trace_preemptirq_template+0x281/0x340 include/trace/events/preemptirq.h:14
trace_irq_enable+0xbf/0xe0 include/trace/events/preemptirq.h:40
trace_hardirqs_on+0x18/0x40 kernel/trace/trace_preemptirq.c:56
perf_swevent_overflow kernel/events/core.c:9793 [inline]
perf_swevent_event+0x2f5/0x5c0 kernel/events/core.c:-1
perf_tp_event+0x4f9/0x13a0 kernel/events/core.c:10343
perf_trace_run_bpf_submit+0xf4/0x1c0 kernel/events/core.c:10267
perf_trace_preemptirq_template+0x281/0x340 include/trace/events/preemptirq.h:14
trace_irq_enable+0xbf/0xe0 include/trace/events/preemptirq.h:40
trace_hardirqs_on+0x18/0x40 kernel/trace/trace_preemptirq.c:56
asm_sysvec_irq_work+0x1a/0x20 arch/x86/include/asm/idtentry.h:723
RIP: 0010:rcu_read_unlock_special+0x88/0x4c0 kernel/rcu/tree_plugin.h:682
Code: f1 f1 f1 00 f2 f2 f2 4a 89 04 2b 66 42 c7 44 2b 09 f3 f3 42 c6 44 2b 0b f3 65 44 8b 35 39 58 93 7e 41 f7 c6 00 00 f0 00 74 45 <48> c7 44 24 40 0e 36 e0 45 4a c7 04 2b 00 00 00 00 66 42 c7 44 2b
RIP: 0010:rcu_read_unlock_special+0x88/0x4c0 kernel/rcu/tree_plugin.h:682
RSP: 0018:ffffc90000007a00 EFLAGS: 00000206
RAX: 2caa672456fd4f00 RBX: 1ffff92000000f48 RCX: 2caa672456fd4f00
RDX: dffffc0000000000 RSI: ffffffff8aaab9c0 RDI: ffffffff8afc66c0
RBP: ffffc90000007b00 R08: ffffffff8e4a882f R09: 1ffffffff1c95105
R10: dffffc0000000000 R11: fffffbfff1c95106 R12: ffffffff8cd35400
R13: dffffc0000000000 R14: 0000000000000246 R15: 0000000000000001
__rcu_read_unlock+0x7c/0xd0 kernel/rcu/tree_plugin.h:426
rcu_read_unlock include/linux/rcupdate.h:818 [inline]
process_backlog+0x403/0x6e0 net/core/dev.c:6039
rcu_read_unlock include/linux/rcupdate.h:818 [inline]
__napi_poll+0xc0/0x460 net/core/dev.c:6600
napi_poll net/core/dev.c:6667 [inline]
net_rx_action+0x5ea/0xbf0 net/core/dev.c:6803
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:preempt_schedule_irq+0xb0/0x140 kernel/sched/core.c:7009
__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
Code: 44 24 20 f6 44 24 21 02 74 0b 0f 0b 48 f7 03 08 00 00 00 74 63 bf 01 00 00 00 e8 4b da e5 f6 e8 46 5f 16 f7 fb bf 01 00 00 00 <e8> db b5 ff ff 48 c7 44 24 40 00 00 00 00 9c 8f 44 24 40 8b 44 24
RSP: 0018:ffffc900034b7a00 EFLAGS: 00000286
RAX: 2caa672456fd4f00 RBX: 0000000000000000 RCX: 2caa672456fd4f00
RDX: dffffc0000000000 RSI: ffffffff8aaab9c0 RDI: 0000000000000001
RBP: ffffc900034b7ab0 R08: ffffffff8e4a882f R09: 1ffffffff1c95105
R10: dffffc0000000000 R11: fffffbfff1c95106 R12: 0000000000000000
R13: 0000000000000000 R14: dffffc0000000000 R15: 1ffff92000696f40
irqentry_exit+0x67/0x70 kernel/entry/common.c:438
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:try_to_wake_up+0x73f/0x1140 kernel/sched/core.c:4355
Code: 0f 1f 44 00 00 bf 01 00 00 00 e8 ec 5a ff ff 65 8b 05 0d aa a7 7e 85 c0 74 22 65 48 8b 04 25 28 00 00 00 48 3b 44 24 40 75 59 <44> 89 f0 48 83 c4 48 5b 41 5c 41 5d 41 5e 41 5f 5d c3 e8 ca 8b a4
RSP: 0018:ffffc900034b7b70 EFLAGS: 00000246
RAX: 2caa672456fd4f00 RBX: ffff8880b8e3d198 RCX: 0000000000000000
RDX: dffffc0000000000 RSI: ffffffff8aaab9c0 RDI: 00000000ffffffff
RBP: ffff88802d6e5a00 R08: ffffffff8e4a882f R09: 1ffffffff1c95105
R10: dffffc0000000000 R11: fffffbfff1c95106 R12: 0000000000000000
R13: dffffc0000000000 R14: 0000000000000001 R15: dffffc0000000000
wake_up_process kernel/sched/core.c:4480 [inline]
wake_up_q+0xb6/0x100 kernel/sched/core.c:1031
futex_wake+0x40d/0x4b0 kernel/futex/waitwake.c:184
do_futex+0x35d/0x3e0 kernel/futex/syscalls.c:111
wake_up_q+0xb6/0x100 kernel/sched/core.c:1031
futex_wake+0x40d/0x4b0 kernel/futex/waitwake.c:184
do_futex+0x35d/0x3e0 kernel/futex/syscalls.c:111
__do_sys_futex kernel/futex/syscalls.c:183 [inline]
__se_sys_futex+0x36f/0x3f0 kernel/futex/syscalls.c:164
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fa658b8ebe9
__se_sys_futex+0x36f/0x3f0 kernel/futex/syscalls.c:164
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
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:00007fa6599a20e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: ffffffffffffffda RBX: 00007fa658db5fa8 RCX: 00007fa658b8ebe9
RDX: 00000000000f4240 RSI: 0000000000000081 RDI: 00007fa658db5fac
RBP: 00007fa658db5fa0 R08: 0000000000745d1e R09: 0000000000000000
R10: ffffffffffffffff R11: 0000000000000246 R12: 0000000000000000
R13: 00007fa658db6038 R14: 00007fff1c7f3bc0 R15: 00007fff1c7f3ca8
syzbot
Oct 3, 2025, 2:02:04 PM10/3/25
to syzkaller...@googlegroups.com
syzbot suspects this issue was fixed by commit:
commit e7a375453cca2b8a0d2fa1b82b913f3fed7c0507
Author: Joel Fernandes <joela...@nvidia.com>
Date: Tue Jul 8 14:22:19 2025 +0000
rcu: Fix rcu_read_unlock() deadloop due to IRQ work
bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=10886a7c580000
start commit: bb9c90ab9c5a Linux 6.6.102
git tree: linux-6.6.y
#syz fix: rcu: Fix rcu_read_unlock() deadloop due to IRQ work
For information about bisection process see: https://goo.gl/tpsmEJ#bisection
commit e7a375453cca2b8a0d2fa1b82b913f3fed7c0507
Author: Joel Fernandes <joela...@nvidia.com>
Date: Tue Jul 8 14:22:19 2025 +0000
rcu: Fix rcu_read_unlock() deadloop due to IRQ work
bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=10886a7c580000
start commit: bb9c90ab9c5a Linux 6.6.102
git tree: linux-6.6.y
kernel config: https://syzkaller.appspot.com/x/.config?x=7b989b97a0687b0a
dashboard link: https://syzkaller.appspot.com/bug?extid=795c184c6744be404955
dashboard link: https://syzkaller.appspot.com/bug?extid=795c184c6744be404955
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=16e2d7a2580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=113196f0580000
If the result looks correct, please mark the issue as fixed by replying with:
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=113196f0580000
#syz fix: rcu: Fix rcu_read_unlock() deadloop due to IRQ work
For information about bisection process see: https://goo.gl/tpsmEJ#bisection
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