Linux vulnerability

What happened

In the Linux kernel, the following vulnerability has been resolved: md/md-bitmap: fix wrong bitmap_limit for clustermd when write sb In clustermd, separate write-intent-bitmaps are used for each cluster node: 0 4k 8k 12k ------------------------------------------------------------------- | idle | md super | bm super [0] + bits | | bm bits[0, contd] | bm super[1] + bits | bm bits[1, contd] | | bm super[2] + bits | bm bits [2, contd] | bm super[3] + bits | | bm bits [3, contd] | | | So in node 1, pg_index in __write_sb_page() could equal to bitmap->storage.file_pages. Then bitmap_limit will be calculated to 0. md_super_write() will be called with 0 size. That means the first 4k sb area of node 1 will never be updated through filemap_write_page(). This bug causes hang of mdadm/clustermd_tests/01r1_Grow_resize. Here use (pg_index % bitmap->storage.file_pages) to make calculation of bitmap_limit correct.

Affected versions

Linux: 655cc01889fa9b65441922565cddee64af49e6d6 through before 5eaf57fdfa37c869e61e9908e03edd707f9145b8 (git); ab99a87542f194f28e2364a42afbf9fb48b1c724 through before 60196f92bbc7901eb5cfa5d456651b87ea50a4a3 (git); ab99a87542f194f28e2364a42afbf9fb48b1c724 through before bc3a9788961631359527763d7e1fcf26554c7cb1 (git); ab99a87542f194f28e2364a42afbf9fb48b1c724 through before 6130825f34d41718c98a9b1504a79a23e379701e (git); 5600d6013c634c2b6b6c6c55c8ecb50c3a6211f2 (git); 6.6.44 through before 6.6.157 (semver); 6.10.3 through before 6.11 (semver); 6.11 Fixed: See vendor advisory.

Why it matters

Review the vendor advisory and exposure of the affected product to determine operational impact.

Detection & mitigation

• Apply vendor-provided updates or mitigations.
• Review affected product exposure and access logs.