CVE-2026-80730
Received Received - Intake

Kernel panic in Linux kernel ring buffer cleanup

Publication date: 2026-09-03

Last updated on: 2026-09-03

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: ring-buffer: Fix crash passing ERR_PTR to kthread_stop() In test_ringbuffer()'s out_free cleanup loop, the check `!rb_threads[cpu]` only catches NULL entries and misses entries that hold an ERR_PTR. rb_threads[] is static, so unassigned slots are NULL. But when kthread_run_on_cpu() fails for a cpu, it stores ERR_PTR(-ENOMEM) (or -EINTR) in rb_threads[cpu] before the creation loop jumps to out_free. That entry is non-NULL, so the old `!ptr` check does not break, and the cleanup proceeds to call kthread_stop() on the ERR_PTR. kthread_stop() then dereferences the bogus pointer, crashing the kernel during the late_initcall self-test. crash logs: BUG: kernel NULL pointer dereference, address: 000000000000001c Oops: 0002 [#1] SMP NOPTI CPU: 1 PID: 1 Comm: swapper/0 Not tainted 7.2.0-rc6-dirty #7 PREEMPT(lazy) RIP: 0010:kthread_stop+0x2e/0x220 RBX: fffffffffffffff4 CR2: 000000000000001c Call Trace: <TASK> test_ringbuffer+0x1ec/0x650 do_one_initcall+0x6c/0x2c0 kernel_init_freeable+0x21d/0x420 kernel_init+0x15/0x1c0 ret_from_fork+0x21b/0x320 </TASK> Kernel panic - not syncing: Fatal exception

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Meta Information

Published
2026-09-03
Last Modified
2026-09-03
Generated
2026-09-03
AI Q&A
2026-09-03
EPSS Evaluated
N/A
NVD
CVE-2026-80730
EUVD
EUVD-2026-70334

Affected Vendors & Products

Showing 2 associated CPEs
Vendor Product Version / Range
linux_kernel linux_kernel *
linux_kernel linux_kernel 7.2.0-rc6

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-UNKNOWN

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Executive Summary

This is a Linux kernel vulnerability where a cleanup loop incorrectly handles error pointers. When kthread_run_on_cpu() fails, it stores an ERR_PTR in an array. The cleanup loop only checks for NULL entries, missing ERR_PTR values. Calling kthread_stop() on an ERR_PTR causes a kernel crash due to dereferencing an invalid pointer.

Detection Guidance

This vulnerability is specific to the Linux kernel and can be detected by checking kernel crash logs for a NULL pointer dereference in kthread_stop() during late_initcall. Look for crash logs with messages like 'BUG: kernel NULL pointer dereference' or 'kernel panic' related to kthread_stop().

Commands to check: dmesg | grep -i 'NULL pointer dereference' or journalctl -k | grep -i 'kthread_stop'.

Impact Analysis

This vulnerability can cause kernel crashes during system boot or initialization, leading to system instability or unavailability. It specifically affects systems running vulnerable Linux kernel versions during late_initcall self-tests.

Mitigation Strategies

Apply the Linux kernel patch that fixes this issue. Update to a kernel version where the bug is resolved. If using a vulnerable kernel, avoid triggering the test_ringbuffer() function which may cause kernel crashes.

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