ring-buffer: Fix subbuf resize race with ring buffer readers

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-89771
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-09-11 20:20:08 UTC
Updated2026-09-11 20:20:08 UTC
DescriptionIn the Linux kernel, the following vulnerability has been resolved: ring-buffer: Fix subbuf resize race with ring buffer readers trace_buffer subbuf_size is read lockless in ring_buffer_read_page() and ring_buffer_read_start(), while it can simultaneously be resized with ring_buffer_subbuf_order_set(). Instead of trace_buffer::subbuf_size, use bpage::order in ring_buffer_read_start() and ring_buffer_read_page(). In ring_buffer_read_start(), even with resize_disabled, there is still a possibility of a race with a buffer modification. Hold the trace_buffer mutex to synchronise with any pending ring buffer order modification. trace_buffer::subbuf_size is now actually useless, remove it. Also, create accessors rb_subbuf_capacity() and rb_page_capacity() which return the actual size available for storing events, while rb_subbuf_size() returns the actual subbuf page-size.

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected f9b94daa542a8d2532f0930f01cd9aec2d19621b 6d666f0b8b36c0765cf19fbe6de5a7ba5a73aad9 git Not specified
CNA Linux Linux affected f9b94daa542a8d2532f0930f01cd9aec2d19621b 50f4a793c4ff24826efb0ac700989a5063cc53df git Not specified
CNA Linux Linux affected f9b94daa542a8d2532f0930f01cd9aec2d19621b 0c7c517827a453128a8f58bfd849546a29813b27 git Not specified
CNA Linux Linux affected f9b94daa542a8d2532f0930f01cd9aec2d19621b 8a5f63637890f03177146efddaba5ec7a1b4d61f git Not specified
CNA Linux Linux affected 6.8 Not specified
CNA Linux Linux unaffected 6.8 semver Not specified
CNA Linux Linux unaffected 6.12.109 6.12.* semver Not specified
CNA Linux Linux unaffected 6.18.50 6.18.* semver Not specified
CNA Linux Linux unaffected 7.2.4 7.2.* semver Not specified
CNA Linux Linux unaffected 7.3-rc1 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/6d666f0b8b36c0765cf19fbe6de5a7ba5a73aad9 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/50f4a793c4ff24826efb0ac700989a5063cc53df 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/8a5f63637890f03177146efddaba5ec7a1b4d61f 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/0c7c517827a453128a8f58bfd849546a29813b27 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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