PT-2026-44244 · Linux · Linux
Published
2026-05-28
·
Updated
2026-05-28
·
CVE-2026-46121
None
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In the Linux kernel, the following vulnerability has been resolved:
mm/damon/sysfs-schemes: protect memcg path kfree() with damon sysfs lock
Patch series "mm/damon/sysfs-schemes: fix use-after-free for [memcg ]path".
Reads of 'memcg path' and 'path' files in DAMON sysfs interface could race
with their writes, results in use-after-free. Fix those.
This patch (of 2):
damon sysfs scheme filter->mmecg path can be read and written by users,
via DAMON sysfs memcg path file. It can also be indirectly read, for the
parameters {on,off}line committing to DAMON. The reads for parameters
committing are protected by damon sysfs lock to avoid the sysfs files
being destroyed while any of the parameters are being read. But the
user-driven direct reads and writes are not protected by any lock, while
the write is deallocating the memcg path-pointing buffer. As a result,
the readers could read the already freed buffer (user-after-free). Note
that the user-reads don't race when the same open file is used by the
writer, due to kernfs's open file locking. Nonetheless, doing the reads
and writes with separate open files would be common. Fix it by protecting
both the user-direct reads and writes with damon sysfs lock.
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Related Identifiers
Affected Products
Linux