cbcvebase.
CVE-2022-50530
published 2025-10-07

CVE-2022-50530: In the Linux kernel, the following vulnerability has been resolved: blk-mq: fix null pointer dereference in blk_mq_clear_rq_mapping() Our syzkaller report a…

PriorityP418medium5.5CVSS 3.1
AVLACLPRLUINSUCNINAH
EPSS
0.13%
2.9th percentile
In the Linux kernel, the following vulnerability has been resolved:

blk-mq: fix null pointer dereference in blk_mq_clear_rq_mapping()

Our syzkaller report a null pointer dereference, root cause is
following:

__blk_mq_alloc_map_and_rqs
set->tags[hctx_idx] = blk_mq_alloc_map_and_rqs
blk_mq_alloc_map_and_rqs
blk_mq_alloc_rqs
// failed due to oom
alloc_pages_node
// set->tags[hctx_idx] is still NULL
blk_mq_free_rqs
drv_tags = set->tags[hctx_idx];
// null pointer dereference is triggered
blk_mq_clear_rq_mapping(drv_tags, ...)

This is because commit 63064be150e4 ("blk-mq:
Add blk_mq_alloc_map_and_rqs()") merged the two steps:

1) set->tags[hctx_idx] = blk_mq_alloc_rq_map()
2) blk_mq_alloc_rqs(..., set->tags[hctx_idx])

into one step:

set->tags[hctx_idx] = blk_mq_alloc_map_and_rqs()

Since tags is not initialized yet in this case, fix the problem by
checking if tags is NULL pointer in blk_mq_clear_rq_mapping().

Affected

9 ranges
VendorProductVersion rangeFixed in
debianlinux< linux 6.0.6-1 (bookworm)linux 6.0.6-1 (bookworm)
linuxlinux
linuxlinux>= 63064be150e4b1ba1e4af594ef5aa81adf21a52d < 6a440e6d04431e774dc084abe88c106e2a474c1a6a440e6d04431e774dc084abe88c106e2a474c1a
linuxlinux>= 63064be150e4b1ba1e4af594ef5aa81adf21a52d < 76dd298094f484c6250ebd076fa53287477b232876dd298094f484c6250ebd076fa53287477b2328
linuxlinux_kernel
linuxlinux_kernel>= 0 < 6.0.6-16.0.6-1
linuxlinux_kernel>= 0 < 6.0.6-16.0.6-1
linuxlinux_kernel>= 0 < 6.0.6-16.0.6-1
linuxlinux_kernel>= 5.16 < 6.0.66.0.6

CVSS provenance

nvdv3.15.5MEDIUMCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
osv5.5MEDIUM
vendor_debian5.5MEDIUM
vendor_redhat5.5MEDIUM
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