Description

In the Linux kernel, the following vulnerability has been resolved: md: Don't ignore read-only array in md_check_recovery() Usually if the array is not read-write, md_check_recovery() won't register new sync_thread in the first place. And if the array is read-write and sync_thread is registered, md_set_readonly() will unregister sync_thread before setting the array read-only. md/raid follow this behavior hence there is no problem. After commit f52f5c71f3d4 ("md: fix stopping sync thread"), following hang can be triggered by test shell/integrity-caching.sh: 1) array is read-only. dm-raid update super block: rs_update_sbs ro = mddev->ro mddev->ro = 0 -> set array read-write md_update_sb 2) register new sync thread concurrently. 3) dm-raid set array back to read-only: rs_update_sbs mddev->ro = ro 4) stop the array: raid_dtr md_stop stop_sync_thread set_bit(MD_RECOVERY_INTR, &mddev->recovery); md_wakeup_thread_directly(mddev->sync_thread); wait_event(..., !test_bit(MD_RECOVERY_RUNNING, &mddev->recovery)) 5) sync thread done: md_do_sync set_bit(MD_RECOVERY_DONE, &mddev->recovery); md_wakeup_thread(mddev->thread); 6) daemon thread can't unregister sync thread: md_check_recovery if (!md_is_rdwr(mddev) && !test_bit(MD_RECOVERY_NEEDED, &mddev->recovery)) return; -> -> MD_RECOVERY_RUNNING can't be cleared, hence step 4 hang; The root cause is that dm-raid manipulate 'mddev->ro' by itself, however, dm-raid really should stop sync thread before setting the array read-only. Unfortunately, I need to read more code before I can refacter the handler of 'mddev->ro' in dm-raid, hence let's fix the problem the easy way for now to prevent dm-raid regression.

Severity

 

CVSS Version 4.0 CVSS Version 3.x CVSS Version 2.0

CVSS 4.0 Severity and Metrics:

NIST: NVD

N/A

NVD assessment not yet provided.

NVD Analysts use publicly available information to associate vector strings and CVSS scores. We also display any CVSS information provided within the CVE List from the CNA.

Note: NVD Analysts have not published a CVSS score for this CVE at this time. NVD Analysts use publicly available information at the time of analysis to associate CVSS vector strings.

CVSS 3.x Severity and Metrics:

NIST: NVD

Base Score:  N/A

NVD assessment not yet provided.

NVD Analysts use publicly available information to associate vector strings and CVSS scores. We also display any CVSS information provided within the CVE List from the CNA.

Note: NVD Analysts have not published a CVSS score for this CVE at this time. NVD Analysts use publicly available information at the time of analysis to associate CVSS vector strings.

CVSS 2.0 Severity and Metrics:

NIST: NVD

Base Score: N/A

NVD assessment not yet provided.

NVD Analysts use publicly available information to associate vector strings and CVSS scores. We also display any CVSS information provided within the CVE List from the CNA.

Note: NVD Analysts have not published a CVSS score for this CVE at this time. NVD Analysts use publicly available information at the time of analysis to associate CVSS vector strings.

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

md: Don't ignore read-only array in md_check_recovery()

Usually if the array is not read-write, md_check_recovery() won't
register new sync_thread in the first place. And if the array is
read-write and sync_thread is registered, md_set_readonly() will
unregister sync_thread before setting the array read-only. md/raid
follow this behavior hence there is no problem.

After commit f52f5c71f3d4 ("md: fix stopping sync thread"), fo

kernel.org https://git.kernel.org/stable/c/2ea169c5a0b1134d573d07fc27a16f327ad0e7d3 [No types assigned]

kernel.org https://git.kernel.org/stable/c/55a48ad2db64737f7ffc0407634218cc6e4c513b [No types assigned]