VYPR
← All advisories
Unrated severityNVD Advisory· Published Jul 5, 2024· Updated May 4, 2025

md/raid5: fix deadlock that raid5d() wait for itself to clear MD_SB_CHANGE_PENDING

CVE-2024-39476

Description

In the Linux kernel, the following vulnerability has been resolved:

md/raid5: fix deadlock that raid5d() wait for itself to clear MD_SB_CHANGE_PENDING

Xiao reported that lvm2 test lvconvert-raid-takeover.sh can hang with small possibility, the root cause is exactly the same as commit bed9e27baf52 ("Revert "md/raid5: Wait for MD_SB_CHANGE_PENDING in raid5d"")

However, Dan reported another hang after that, and junxiao investigated the problem and found out that this is caused by plugged bio can't issue from raid5d().

Current implementation in raid5d() has a weird dependence:

1) md_check_recovery() from raid5d() must hold 'reconfig_mutex' to clear MD_SB_CHANGE_PENDING; 2) raid5d() handles IO in a deadloop, until all IO are issued; 3) IO from raid5d() must wait for MD_SB_CHANGE_PENDING to be cleared;

This behaviour is introduce before v2.6, and for consequence, if other context hold 'reconfig_mutex', and md_check_recovery() can't update super_block, then raid5d() will waste one cpu 100% by the deadloop, until 'reconfig_mutex' is released.

Refer to the implementation from raid1 and raid10, fix this problem by skipping issue IO if MD_SB_CHANGE_PENDING is still set after md_check_recovery(), daemon thread will be woken up when 'reconfig_mutex' is released. Meanwhile, the hang problem will be fixed as well.

Affected products

153

Patches

8
b32aa95843ca
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.gitvia osv
commit
634ba3c97ec4
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.gitvia osv
commit
aa64464c8f4d
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.gitvia osv
commit
098d54934814
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.gitvia osv
commit
3f8d5e802d4c
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.gitvia osv
commit
cd2538e5af49
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.gitvia osv
commit
e332a12f65d8
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.gitvia osv
commit
151f66bb618d
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.gitvia osv
commit

Vulnerability mechanics

Generated on May 9, 2026. Inputs: CWE entries + fix-commit diffs from this CVE's patches. Citations validated against bundle.

References

8

News mentions

0

No linked articles in our index yet.