Linux Kernel MD Freeze Array Race in Raid1 Update
CVE-2025-71225 Published on February 18, 2026
md: suspend array while updating raid_disks via sysfs
In the Linux kernel, the following vulnerability has been resolved:
md: suspend array while updating raid_disks via sysfs
In raid1_reshape(), freeze_array() is called before modifying the r1bio
memory pool (conf->r1bio_pool) and conf->raid_disks, and
unfreeze_array() is called after the update is completed.
However, freeze_array() only waits until nr_sync_pending and
(nr_pending - nr_queued) of all buckets reaches zero. When an I/O error
occurs, nr_queued is increased and the corresponding r1bio is queued to
either retry_list or bio_end_io_list. As a result, freeze_array() may
unblock before these r1bios are released.
This can lead to a situation where conf->raid_disks and the mempool have
already been updated while queued r1bios, allocated with the old
raid_disks value, are later released. Consequently, free_r1bio() may
access memory out of bounds in put_all_bios() and release r1bios of the
wrong size to the new mempool, potentially causing issues with the
mempool as well.
Since only normal I/O might increase nr_queued while an I/O error occurs,
suspending the array avoids this issue.
Note: Updating raid_disks via ioctl SET_ARRAY_INFO already suspends
the array. Therefore, we suspend the array when updating raid_disks
via sysfs to avoid this issue too.
Products Associated with CVE-2025-71225
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Affected Versions
Linux:- Version e2d59925221cd562e07fee38ec8839f7209ae603 and below 165d1359f945b72c5f90088f60d48ff46115269e is affected.
- Version e2d59925221cd562e07fee38ec8839f7209ae603 and below 0107b18cd8ac17eb3e54786adc05a85cdbb6ef22 is affected.
- Version e2d59925221cd562e07fee38ec8839f7209ae603 and below 2cc583653bbe050bacd1cadcc9776d39bf449740 is affected.
- Version 1b9203bb4c658c0242afa6fdb025c71d2fc3ad76 is affected.
- Version 8ccf6cfb157419847f3cb2bfdfbcdbd39860e8e9 is affected.
- Version 3.10 is affected.
- Before 3.10 is unaffected.
- Version 6.12.70, <= 6.12.* is unaffected.
- Version 6.18.10, <= 6.18.* is unaffected.
- Version 6.19, <= * is unaffected.
Exploit Probability
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