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WARNING in __static_key_slow_dec_cpuslocked (3)

Status: upstream: reported on 2026/03/04 20:35
Subsystems: kernel
[Documentation on labels]
Reported-by: syzbot+feb9ce36a95341bb47a4@syzkaller.appspotmail.com
Fix commit: wifi: mac80211: Fix static_branch_dec() underflow for aql_disable.
Patched on: [ci-upstream-linux-next-kasan-gce-root ci-upstream-rust-kasan-gce], missing on: [ci-qemu-gce-upstream-auto ci-qemu-native-arm64-kvm ci-qemu-upstream ci-qemu-upstream-386 ci-qemu2-arm32 ci-qemu2-arm64 ci-qemu2-arm64-compat ci-qemu2-arm64-mte ci-qemu2-riscv64 ci-snapshot-upstream-root ci-upstream-bpf-kasan-gce ci-upstream-bpf-next-kasan-gce ci-upstream-gce-arm64 ci-upstream-gce-leak ci-upstream-kasan-badwrites-root ci-upstream-kasan-gce ci-upstream-kasan-gce-386 ci-upstream-kasan-gce-root ci-upstream-kasan-gce-selinux-root ci-upstream-kasan-gce-smack-root ci-upstream-kmsan-gce-386-root ci-upstream-kmsan-gce-root ci-upstream-net-kasan-gce ci-upstream-net-this-kasan-gce ci2-upstream-fs ci2-upstream-kcsan-gce ci2-upstream-usb]
First crash: 35d, last: 35d
▶ ▼ Discussions (4)
Title Replies (including bot) Last reply
[PATCH] wifi: mac80211: fix static key race condition in aql_enable_write() 3 (3) 2026/03/06 20:45
[syzbot] [kernel?] WARNING in __static_key_slow_dec_cpuslocked (3) 1 (2) 2026/03/06 20:05
[PATCH v2] wifi: mac80211: Fix static_branch_dec() underflow for aql_disable. 1 (1) 2026/03/06 07:24
[PATCH] wifi: mac80211: Fix static_branch_dec() underflow for aql_disable. 3 (3) 2026/03/05 19:40
▶ ▼ Similar bugs (2)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream WARNING in __static_key_slow_dec_cpuslocked (2) kernel -1 C 1 1281d 1277d 0/29 closed as dup on 2022/09/12 12:42
upstream WARNING in __static_key_slow_dec_cpuslocked kernel -1 7 2498d 2495d 0/29 auto-closed as invalid on 2019/10/25 08:43

Sample crash report:
------------[ cut here ]------------
val == 0
WARNING: kernel/jump_label.c:311 at __static_key_slow_dec_cpuslocked.part.0+0x107/0x120 kernel/jump_label.c:311, CPU#0: syz.1.3155/20288
Modules linked in:
CPU: 0 UID: 0 PID: 20288 Comm: syz.1.3155 Tainted: G     U       L      syzkaller #0 PREEMPT(full) 
Tainted: [U]=USER, [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
RIP: 0010:__static_key_slow_dec_cpuslocked.part.0+0x107/0x120 kernel/jump_label.c:311
Code: f2 c9 ff 5b 5d c3 cc cc cc cc e8 54 f2 c9 ff 48 89 df e8 ac f9 ff ff eb ad e8 45 f2 c9 ff 90 0f 0b 90 eb a2 e8 3a f2 c9 ff 90 <0f> 0b 90 eb 97 48 89 df e8 5c 4b 33 00 e9 36 ff ff ff 0f 1f 80 00
RSP: 0018:ffffc9000b9f7c10 EFLAGS: 00010293
RAX: 0000000000000000 RBX: ffffffff9b3e5d40 RCX: ffffffff823c57b4
RDX: ffff8880285a0000 RSI: ffffffff823c5846 RDI: ffff8880285a0000
RBP: 0000000000000000 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 000000000000000a
R13: 1ffff9200173ef88 R14: 0000000000000001 R15: ffffc9000b9f7e98
FS:  00007f530dd726c0(0000) GS:ffff8881245e3000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000001140 CR3: 000000007cc4a000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 __static_key_slow_dec_cpuslocked kernel/jump_label.c:297 [inline]
 __static_key_slow_dec kernel/jump_label.c:321 [inline]
 static_key_slow_dec+0x7c/0xc0 kernel/jump_label.c:336
 aql_enable_write+0x2b2/0x310 net/mac80211/debugfs.c:343
 short_proxy_write+0x133/0x1a0 fs/debugfs/file.c:383
 vfs_write+0x2aa/0x1070 fs/read_write.c:684
 ksys_pwrite64 fs/read_write.c:793 [inline]
 __do_sys_pwrite64 fs/read_write.c:801 [inline]
 __se_sys_pwrite64 fs/read_write.c:798 [inline]
 __x64_sys_pwrite64+0x1eb/0x250 fs/read_write.c:798
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xc9/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f530cf9aeb9
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:00007f530dd72028 EFLAGS: 00000246 ORIG_RAX: 0000000000000012
RAX: ffffffffffffffda RBX: 00007f530d215fa0 RCX: 00007f530cf9aeb9
RDX: 0000000000000003 RSI: 0000000000000000 RDI: 0000000000000010
RBP: 00007f530d008c1f R08: 0000000000000000 R09: 0000000000000000
R10: 4200000000000005 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f530d216038 R14: 00007f530d215fa0 R15: 00007ffde89fb978
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/01/30 18:06 upstream 4d310797262f ea6dba22 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto WARNING in __static_key_slow_dec_cpuslocked
* Struck through repros no longer work on HEAD.