In the Linux kernel, the following vulnerability has been resolved:
firmware: qcom: scm: Fix missing read barrier in qcom_scm_get_tzmem_pool()
Commit 2e4955167ec5 ("firmware: qcom: scm: Fix __scm and waitq
completion variable initialization") introduced a write barrier in probe
function to store global '__scm' variable. We all known barriers are
paired (see memory-barriers.txt: "Note that write barriers should
normally be paired with read or address-dependency barriers"), therefore
accessing it from concurrent contexts requires read barrier. Previous
commit added such barrier in qcom_scm_is_available(), so let's use that
directly.
Lack of this read barrier can result in fetching stale '__scm' variable
value, NULL, and dereferencing it.
Note that barrier in qcom_scm_is_available() satisfies here the control
dependency.
Published: 2025-03-06Modified: 2025-10-01
CVSS 3.xMEDIUM 5.5
CVSS:3.x/CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H