WARNING in do_clear_cpu_cap

Status: premoderation: reported C repro on 2026/07/30 14:16
Bug presence: origin:upstream
[Documentation on labels]
Reported-by: syzbot+b31203073a433c8f4adf@syzkaller.appspotmail.com
First crash: 4d23h, last: 1d05h
▶ ▼ Bug presence (2)
Date Name Commit Repro Result
2026/08/02 lts (merge base) 8c9d5557c8e6 C [report] WARNING in do_clear_cpu_cap
2026/08/02 upstream (ToT) 2d2338c93da7 C [report] WARNING in do_clear_cpu_cap
▶ ▼ Similar bugs (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream WARNING in do_clear_cpu_cap kernel prio:low -1 syz, C done 42 2h26m 3d20h 0/29 upstream: reported C repro on 2026/07/31 17:13

Sample crash report:
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------------[ cut here ]------------
WARNING: CPU: 1 PID: 0 at arch/x86/kernel/cpu/cpuid-deps.c:117 do_clear_cpu_cap+0x401/0x440 arch/x86/kernel/cpu/cpuid-deps.c:117
Modules linked in:
CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Tainted: G S                 syzkaller #0 0b31bef96cff8e44f9e14c4f768eb06c85e3b290
Tainted: [S]=CPU_OUT_OF_SPEC
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:do_clear_cpu_cap+0x401/0x440 arch/x86/kernel/cpu/cpuid-deps.c:117
Code: 84 24 e0 00 00 00 75 29 48 8d 65 d8 5b 41 5c 41 5d 41 5e 41 5f 5d e9 ce ba 66 04 cc e8 a8 1d 48 00 0f 0b eb 92 e8 9f 1d 48 00 <0f> 0b e9 31 fd ff ff e8 83 59 64 04 48 c7 c1 10 a4 ec 87 80 e1 07
RSP: 0000:ffffc900001a7ac0 EFLAGS: 00010093
RAX: ffffffff813f5421 RBX: dffffc0000000001 RCX: ffff888103669300
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc900001a7bf8 R08: ffffc900001a7b7f R09: 0000000000000000
R10: ffffc900001a7b20 R11: fffff52000034f70 R12: 0000000000000001
R13: 0000000000000070 R14: f8f8f8f8f8f8f8f8 R15: 0000000000000070
FS:  0000000000000000(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 00000000074aa000 CR4: 00000000003506b0
Call Trace:
 <TASK>
 setup_clear_cpu_cap+0x19/0x30 arch/x86/kernel/cpu/cpuid-deps.c:147
 early_init_intel+0x9e8/0x1020 arch/x86/kernel/cpu/intel.c:336
 init_intel+0x2c/0x8a0 arch/x86/kernel/cpu/intel.c:557
 identify_cpu+0xd29/0x3660 arch/x86/kernel/cpu/common.c:1931
 identify_secondary_cpu+0x16/0x80 arch/x86/kernel/cpu/common.c:2046
 smp_store_cpu_info arch/x86/kernel/smpboot.c:333 [inline]
 ap_starting+0x107/0x1c0 arch/x86/kernel/smpboot.c:192
 start_secondary+0x7c/0x140 arch/x86/kernel/smpboot.c:282
 common_startup_64+0x13b/0x157
 </TASK>
---[ end trace 0000000000000000 ]---
------------[ cut here ]------------
WARNING: CPU: 1 PID: 0 at arch/x86/kernel/cpu/cpuid-deps.c:117 do_clear_cpu_cap+0x401/0x440 arch/x86/kernel/cpu/cpuid-deps.c:117
Modules linked in:
CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Tainted: G S      W          syzkaller #0 0b31bef96cff8e44f9e14c4f768eb06c85e3b290
Tainted: [S]=CPU_OUT_OF_SPEC, [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:do_clear_cpu_cap+0x401/0x440 arch/x86/kernel/cpu/cpuid-deps.c:117
Code: 84 24 e0 00 00 00 75 29 48 8d 65 d8 5b 41 5c 41 5d 41 5e 41 5f 5d e9 ce ba 66 04 cc e8 a8 1d 48 00 0f 0b eb 92 e8 9f 1d 48 00 <0f> 0b e9 31 fd ff ff e8 83 59 64 04 48 c7 c1 10 a4 ec 87 80 e1 07
RSP: 0000:ffffc900001a7980 EFLAGS: 00010093
RAX: ffffffff813f5421 RBX: dffffc0000000001 RCX: ffff888103669300
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc900001a7ab0 R08: ffffc900001a7a3f R09: 0000000000000000
R10: ffffc900001a79e0 R11: fffff52000034f48 R12: 0000000000000001
R13: 0000000000000070 R14: f8f8f8f8f8f8f8f8 R15: 0000000000000070
FS:  0000000000000000(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 00000000074aa000 CR4: 00000000003506b0
Call Trace:
 <TASK>
 clear_cpu_cap arch/x86/kernel/cpu/cpuid-deps.c:142 [inline]
 clear_feature arch/x86/kernel/cpu/cpuid-deps.c:97 [inline]
 do_clear_cpu_cap+0x17a/0x440 arch/x86/kernel/cpu/cpuid-deps.c:119
 setup_clear_cpu_cap+0x19/0x30 arch/x86/kernel/cpu/cpuid-deps.c:147
 early_init_intel+0x9e8/0x1020 arch/x86/kernel/cpu/intel.c:336
 init_intel+0x2c/0x8a0 arch/x86/kernel/cpu/intel.c:557
 identify_cpu+0xd29/0x3660 arch/x86/kernel/cpu/common.c:1931
 identify_secondary_cpu+0x16/0x80 arch/x86/kernel/cpu/common.c:2046
 smp_store_cpu_info arch/x86/kernel/smpboot.c:333 [inline]
 ap_starting+0x107/0x1c0 arch/x86/kernel/smpboot.c:192
 start_secondary+0x7c/0x140 arch/x86/kernel/smpboot.c:282
 common_startup_64+0x13b/0x157
 </TASK>
---[ end trace 0000000000000000 ]---
------------[ cut here ]------------
WARNING: CPU: 1 PID: 0 at arch/x86/kernel/cpu/cpuid-deps.c:117 do_clear_cpu_cap+0x401/0x440 arch/x86/kernel/cpu/cpuid-deps.c:117
Modules linked in:
CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Tainted: G S      W          syzkaller #0 0b31bef96cff8e44f9e14c4f768eb06c85e3b290
Tainted: [S]=CPU_OUT_OF_SPEC, [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:do_clear_cpu_cap+0x401/0x440 arch/x86/kernel/cpu/cpuid-deps.c:117
Code: 84 24 e0 00 00 00 75 29 48 8d 65 d8 5b 41 5c 41 5d 41 5e 41 5f 5d e9 ce ba 66 04 cc e8 a8 1d 48 00 0f 0b eb 92 e8 9f 1d 48 00 <0f> 0b e9 31 fd ff ff e8 83 59 64 04 48 c7 c1 10 a4 ec 87 80 e1 07
RSP: 0000:ffffc900001a7ac0 EFLAGS: 00010093
RAX: ffffffff813f5421 RBX: dffffc0000000001 RCX: ffff888103669300
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc900001a7bf8 R08: ffffc900001a7b7f R09: 0000000000000000
R10: ffffc900001a7b20 R11: fffff52000034f70 R12: 0000000000000001
R13: 0000000000000129 R14: f8f8f8f8f8f8f8f8 R15: 0000000000000129
FS:  0000000000000000(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 00000000074aa000 CR4: 00000000003506b0
Call Trace:
 <TASK>
 setup_clear_cpu_cap+0x19/0x30 arch/x86/kernel/cpu/cpuid-deps.c:147
 early_init_intel+0x9f2/0x1020 arch/x86/kernel/cpu/intel.c:337
 init_intel+0x2c/0x8a0 arch/x86/kernel/cpu/intel.c:557
 identify_cpu+0xd29/0x3660 arch/x86/kernel/cpu/common.c:1931
 identify_secondary_cpu+0x16/0x80 arch/x86/kernel/cpu/common.c:2046
 smp_store_cpu_info arch/x86/kernel/smpboot.c:333 [inline]
 ap_starting+0x107/0x1c0 arch/x86/kernel/smpboot.c:192
 start_secondary+0x7c/0x140 arch/x86/kernel/smpboot.c:282
 common_startup_64+0x13b/0x157
 </TASK>
---[ end trace 0000000000000000 ]---
------------[ cut here ]------------
WARNING: CPU: 1 PID: 0 at arch/x86/kernel/cpu/cpuid-deps.c:117 do_clear_cpu_cap+0x401/0x440 arch/x86/kernel/cpu/cpuid-deps.c:117
Modules linked in:
CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Tainted: G S      W          syzkaller #0 0b31bef96cff8e44f9e14c4f768eb06c85e3b290
Tainted: [S]=CPU_OUT_OF_SPEC, [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:do_clear_cpu_cap+0x401/0x440 arch/x86/kernel/cpu/cpuid-deps.c:117
Code: 84 24 e0 00 00 00 75 29 48 8d 65 d8 5b 41 5c 41 5d 41 5e 41 5f 5d e9 ce ba 66 04 cc e8 a8 1d 48 00 0f 0b eb 92 e8 9f 1d 48 00 <0f> 0b e9 31 fd ff ff e8 83 59 64 04 48 c7 c1 10 a4 ec 87 80 e1 07
RSP: 0000:ffffc900001a7980 EFLAGS: 00010093
RAX: ffffffff813f5421 RBX: dffffc0000000001 RCX: ffff888103669300
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc900001a7ab0 R08: ffffc900001a7a3f R09: 0000000000000000
R10: ffffc900001a79e0 R11: fffff52000034f48 R12: 0000000000000001
R13: 0000000000000129 R14: f8f8f8f8f8f8f8f8 R15: 0000000000000129
FS:  0000000000000000(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 00000000074aa000 CR4: 00000000003506b0
Call Trace:
 <TASK>
 clear_cpu_cap arch/x86/kernel/cpu/cpuid-deps.c:142 [inline]
 clear_feature arch/x86/kernel/cpu/cpuid-deps.c:97 [inline]
 do_clear_cpu_cap+0x17a/0x440 arch/x86/kernel/cpu/cpuid-deps.c:119
 setup_clear_cpu_cap+0x19/0x30 arch/x86/kernel/cpu/cpuid-deps.c:147
 early_init_intel+0x9f2/0x1020 arch/x86/kernel/cpu/intel.c:337
 init_intel+0x2c/0x8a0 arch/x86/kernel/cpu/intel.c:557
 identify_cpu+0xd29/0x3660 arch/x86/kernel/cpu/common.c:1931
 identify_secondary_cpu+0x16/0x80 arch/x86/kernel/cpu/common.c:2046
 smp_store_cpu_info arch/x86/kernel/smpboot.c:333 [inline]
 ap_starting+0x107/0x1c0 arch/x86/kernel/smpboot.c:192
 start_secondary+0x7c/0x140 arch/x86/kernel/smpboot.c:282
 common_startup_64+0x13b/0x157
 </TASK>
---[ end trace 0000000000000000 ]---
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Crashes (11):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/07/30 16:53 android16-6.12 f1c9c21d1c2f 2377cd3d .config strace log report syz / log C [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust WARNING in do_clear_cpu_cap
2026/07/30 15:58 android16-6.12 f1c9c21d1c2f 2377cd3d .config strace log report syz / log C [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust WARNING in do_clear_cpu_cap
2026/07/30 15:10 android16-6.12 f1c9c21d1c2f 2377cd3d .config strace log report syz / log C [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust WARNING in do_clear_cpu_cap
2026/08/03 08:32 android16-6.12 1a138e24e292 e611ffe1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust WARNING in do_clear_cpu_cap
2026/08/03 06:23 android16-6.12 1a138e24e292 e611ffe1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust WARNING in do_clear_cpu_cap
2026/08/02 16:11 android16-6.12 1a138e24e292 e611ffe1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust WARNING in do_clear_cpu_cap
2026/08/02 07:58 android16-6.12 1a138e24e292 e611ffe1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust WARNING in do_clear_cpu_cap
2026/08/01 21:55 android16-6.12 1a138e24e292 e611ffe1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust WARNING in do_clear_cpu_cap
2026/08/01 21:12 android16-6.12 1a138e24e292 e611ffe1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust WARNING in do_clear_cpu_cap
2026/07/31 03:25 android16-6.12 7d66c8550304 aaffb173 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust WARNING in do_clear_cpu_cap
2026/07/30 14:15 android16-6.12 f1c9c21d1c2f 2377cd3d .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust WARNING in do_clear_cpu_cap
* Struck through repros no longer work on HEAD.