From bippy-851b3ed3d212 Mon Sep 17 00:00:00 2001 From: Greg Kroah-Hartman To: Reply-to: , Subject: CVE-2024-26755: md: Don't suspend the array for interrupted reshape Description =========== In the Linux kernel, the following vulnerability has been resolved: md: Don't suspend the array for interrupted reshape md_start_sync() will suspend the array if there are spares that can be added or removed from conf, however, if reshape is still in progress, this won't happen at all or data will be corrupted(remove_and_add_spares won't be called from md_choose_sync_action for reshape), hence there is no need to suspend the array if reshape is not done yet. Meanwhile, there is a potential deadlock for raid456: 1) reshape is interrupted; 2) set one of the disk WantReplacement, and add a new disk to the array, however, recovery won't start until the reshape is finished; 3) then issue an IO across reshpae position, this IO will wait for reshape to make progress; 4) continue to reshape, then md_start_sync() found there is a spare disk that can be added to conf, mddev_suspend() is called; Step 4 and step 3 is waiting for each other, deadlock triggered. Noted this problem is found by code review, and it's not reporduced yet. Fix this porblem by don't suspend the array for interrupted reshape, this is safe because conf won't be changed until reshape is done. The Linux kernel CVE team has assigned CVE-2024-26755 to this issue. Affected and fixed versions =========================== Issue introduced in 6.7 with commit bc08041b32ab and fixed in 6.7.7 with commit 60d6130d0ac1 Issue introduced in 6.7 with commit bc08041b32ab and fixed in 6.8 with commit 9e46c70e829b Please see https://www.kernel.org for a full list of currently supported kernel versions by the kernel community. Unaffected versions might change over time as fixes are backported to older supported kernel versions. The official CVE entry at https://cve.org/CVERecord/?id=CVE-2024-26755 will be updated if fixes are backported, please check that for the most up to date information about this issue. Affected files ============== The file(s) affected by this issue are: drivers/md/md.c Mitigation ========== The Linux kernel CVE team recommends that you update to the latest stable kernel version for this, and many other bugfixes. Individual changes are never tested alone, but rather are part of a larger kernel release. Cherry-picking individual commits is not recommended or supported by the Linux kernel community at all. If however, updating to the latest release is impossible, the individual changes to resolve this issue can be found at these commits: https://git.kernel.org/stable/c/60d6130d0ac1d883ed93c2a1e10aadb60967fd48 https://git.kernel.org/stable/c/9e46c70e829bddc24e04f963471e9983a11598b7