WARNING in do_clear_cpu_cap

Status: upstream: reported C repro on 2026/07/31 17:13
Subsystems: kernel
Labels: prio:low
[Documentation on labels]
Reported-by: syzbot+6cdbd5e494b199d820c3@syzkaller.appspotmail.com
First crash: 3d18h, last: 3h08m
Cause bisection: introduced by (bisect log) :
commit 684826f8271ad97580b138b9ffd462005e470b99
Author: Sergey Senozhatsky <senozhatsky@chromium.org>
Date: Wed Sep 11 02:54:56 2024 +0000

  zram: free secondary algorithms names

Crash: WARNING in do_clear_cpu_cap (log)
Repro: C syz .config
  
✨ AI Patch Versions (1)
Version Stage Reported Report Link Job
1 moderation 2026/07/31 15:26 Discussion c3c1fb43-1c46-43f9-9819-b9e6b7d3e0b4
✨ AI Jobs (2)
ID Workflow Result Correct Bug Created Started Finished Revision Error
c3c1fb43 patching WARNING in do_clear_cpu_cap 2026/07/31 14:13 2026/07/31 14:13 2026/07/31 15:26 7664cf44

			
		
f23f0d44 assessment-security DenialOfService: ❌ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ❌ VMGuestTrigger: ❌ VMHostTrigger: ❌ WARNING in do_clear_cpu_cap 2026/07/31 02:04 2026/07/31 02:04 2026/07/31 02:06 aaffb173

			
		
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [kernel?] WARNING in do_clear_cpu_cap 2 (3) 2026/07/31 18:22
Similar bugs (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
android-6-12 WARNING in do_clear_cpu_cap origin:upstream -1 syz, C 9 12h23m 3d14h 0/1 premoderation: reported C repro on 2026/07/30 14:16

Sample crash report:
Disabled fast string operations
------------[ cut here ]------------
alternatives_patched
WARNING: arch/x86/kernel/cpu/cpuid-deps.c:127 at do_clear_cpu_cap+0x416/0x450 arch/x86/kernel/cpu/cpuid-deps.c:127, CPU#1: swapper/1/0
Modules linked in:
CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Tainted: G S                  syzkaller #0 PREEMPT_{RT,(full)} 
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+0x416/0x450 arch/x86/kernel/cpu/cpuid-deps.c:127
Code: 00 00 00 75 2d 48 8d 65 d8 5b 41 5c 41 5d 41 5e 41 5f 5d e9 4c 42 d8 09 cc e8 d6 8c 56 00 90 0f 0b 90 eb 94 e8 cb 8c 56 00 90 <0f> 0b 90 e9 06 fd ff ff e8 dd 75 d4 09 48 c7 c1 58 83 af 8f 80 e1
RSP: 0000:ffffc900001d7ba0 EFLAGS: 00010093
RAX: ffffffff816f4e25 RBX: dffffc0000000001 RCX: ffff88801cec8000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc900001d7cd8 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffed10170e4903 R12: 0000000000000070
R13: dffffc0000000000 R14: 0000000000000001 R15: 0000000000000070
FS:  0000000000000000(0000) GS:ffff888125d41000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000000dfb0000 CR4: 00000000003506b0
Call Trace:
 <TASK>
 early_init_intel+0xb3d/0xea0 arch/x86/kernel/cpu/intel.c:309
 init_intel+0x28/0x780 arch/x86/kernel/cpu/intel.c:528
 identify_cpu+0xc7a/0x3660 arch/x86/kernel/cpu/common.c:2053
 identify_secondary_cpu+0xaa/0x160 arch/x86/kernel/cpu/common.c:2177
 ap_starting+0x9c/0x150 arch/x86/kernel/smpboot.c:190
 start_secondary+0x66/0x110 arch/x86/kernel/smpboot.c:280
 common_startup_64+0x13e/0x157
 </TASK>

Crashes (33):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/07/30 17:30 upstream 11028ab62899 2377cd3d .config strace log report syz / log C [disk image] [vmlinux] [kernel image] ci2-upstream-fs WARNING in do_clear_cpu_cap
2026/07/30 13:26 upstream 11028ab62899 2377cd3d .config strace log report syz / log C [disk image] [vmlinux] [kernel image] ci2-upstream-fs WARNING in do_clear_cpu_cap
2026/08/01 19:44 upstream 0131b508c0e2 e611ffe1 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root WARNING in do_clear_cpu_cap
2026/08/01 19:43 upstream 0131b508c0e2 e611ffe1 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root WARNING in do_clear_cpu_cap
2026/07/31 00:47 upstream 3708dd948844 aaffb173 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs WARNING in do_clear_cpu_cap
2026/07/31 00:46 upstream 3708dd948844 aaffb173 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs WARNING in do_clear_cpu_cap
2026/07/30 10:26 upstream 11028ab62899 2377cd3d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs WARNING in do_clear_cpu_cap
2026/07/30 10:24 upstream 11028ab62899 2377cd3d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs WARNING in do_clear_cpu_cap
2026/07/30 10:23 upstream 11028ab62899 2377cd3d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs WARNING in do_clear_cpu_cap
2026/08/03 01:26 upstream bd1dde877520 e611ffe1 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in do_clear_cpu_cap
2026/08/03 00:01 upstream bd1dde877520 e611ffe1 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in do_clear_cpu_cap
2026/08/02 23:42 upstream bd1dde877520 e611ffe1 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in do_clear_cpu_cap
2026/08/02 20:20 upstream bd1dde877520 e611ffe1 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in do_clear_cpu_cap
2026/08/02 15:28 upstream 2d2338c93da7 e611ffe1 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in do_clear_cpu_cap
2026/08/02 13:25 upstream 2d2338c93da7 e611ffe1 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in do_clear_cpu_cap
2026/08/01 23:36 upstream 02dc699f83d0 e611ffe1 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in do_clear_cpu_cap
2026/07/30 22:15 upstream 3708dd948844 aaffb173 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in do_clear_cpu_cap
2026/07/30 22:10 upstream 3708dd948844 aaffb173 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in do_clear_cpu_cap
2026/07/30 20:24 upstream 11028ab62899 abc81b93 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in do_clear_cpu_cap
2026/08/02 08:56 upstream 2d2338c93da7 e611ffe1 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 WARNING in do_clear_cpu_cap
2026/08/01 19:42 upstream 02dc699f83d0 e611ffe1 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 WARNING in do_clear_cpu_cap
2026/08/01 19:42 upstream 02dc699f83d0 e611ffe1 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 WARNING in do_clear_cpu_cap
2026/08/01 19:39 upstream 02dc699f83d0 e611ffe1 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 WARNING in do_clear_cpu_cap
2026/07/31 05:10 upstream 3708dd948844 aaffb173 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 WARNING in do_clear_cpu_cap
2026/07/31 03:05 upstream 3708dd948844 aaffb173 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 WARNING in do_clear_cpu_cap
2026/07/31 02:47 upstream 3708dd948844 aaffb173 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 WARNING in do_clear_cpu_cap
2026/07/30 20:01 upstream 11028ab62899 abc81b93 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 WARNING in do_clear_cpu_cap
2026/07/30 17:31 upstream 11028ab62899 abc81b93 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 WARNING in do_clear_cpu_cap
2026/07/30 12:45 upstream 11028ab62899 abc81b93 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 WARNING in do_clear_cpu_cap
2026/08/01 19:35 linux-next cc2b5f627e8c e611ffe1 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce WARNING in do_clear_cpu_cap
2026/08/01 19:35 linux-next cc2b5f627e8c e611ffe1 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce WARNING in do_clear_cpu_cap
2026/07/30 15:48 linux-next cc2b5f627e8c 2377cd3d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce WARNING in do_clear_cpu_cap
2026/07/30 15:45 linux-next cc2b5f627e8c 2377cd3d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce WARNING in do_clear_cpu_cap
* Struck through repros no longer work on HEAD.