In the Linux kernel, the following vulnerability has been resolved:
x86/kexec: Disable KCOV instrumentation after load_segments()
The load_segments() function changes segment registers, invalidating GS base
(which KCOV relies on for per-cpu data). When CONFIG_KCOV is enabled, any
subsequent instrumented C code call (e.g. native_gdt_invalidate()) begins
crashing the kernel in an endless loop.
To reproduce the problem, it's sufficient to do kexec on a KCOV-instrumented
kernel:
$ kexec -l /boot/otherKernel
$ kexec -e
The real-world context for this problem is enabling crash dump collection in
syzkaller. For this, the tool loads a panic kernel before fuzzing and then
calls makedumpfile after the panic. This workflow requires both CONFIG_KEXEC
and CONFIG_KCOV to be enabled simultaneously.
Adding safeguards directly to the KCOV fast-path (__sanitizer_cov_trace_pc())
is also undesirable as it would introduce an extra performance overhead.
Disabling instrumentation for the individual functions would be too fragile,
so disable KCOV instrumentation for the entire machine_kexec_64.c and
physaddr.c. If coverage-guided fuzzing ever needs these components in the
future, other approaches should be considered.
The problem is not relevant for 32 bit kernels as CONFIG_KCOV is not supported
there.
[ bp: Space out comment for better readability. ]
References
Configurations
Configuration 1 (hide)
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History
18 May 2026, 12:39
| Type | Values Removed | Values Added |
|---|---|---|
| CWE | NVD-CWE-noinfo | |
| References | () https://git.kernel.org/stable/c/1e3e98596c2769721ade0418434852fb3af4849a - Patch | |
| References | () https://git.kernel.org/stable/c/917e3ad3321e75ca0223d5ccf26ceda116aa51e1 - Patch | |
| References | () https://git.kernel.org/stable/c/de05c66fab8847237a9ca216934e56d3ee837f08 - Patch | |
| CVSS |
v2 : v3 : |
v2 : unknown
v3 : 5.5 |
| First Time |
Linux linux Kernel
Linux |
|
| CPE | cpe:2.3:o:linux:linux_kernel:7.0:rc6:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:7.0:rc4:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:7.0:rc3:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:7.0:rc5:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:7.0:rc2:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:7.0:rc1:*:*:*:*:*:* |
08 May 2026, 14:16
| Type | Values Removed | Values Added |
|---|---|---|
| New CVE |
Information
Published : 2026-05-08 14:16
Updated : 2026-05-18 12:39
NVD link : CVE-2026-43331
Mitre link : CVE-2026-43331
CVE.ORG link : CVE-2026-43331
JSON object : View
Products Affected
linux
- linux_kernel
CWE