CVE-2026-98344

NameCVE-2026-98344
DescriptionIn the Linux kernel, the following vulnerability has been resolved: dmaengine: Fix device kref underflow in dma_chan_put() dma_chan_get() takes chan->device->ref only on the slow path: /* no kref on fast path */ if (chan->client_count) { __module_get(owner); chan->client_count++; return 0; } if (!try_module_get(owner)) return -ENODEV; if (!dma_device_get(chan->device)) { // calls kref_get_unless_zero() dma_chan_put() drops the ref unconditionally, so every fast-path get/put pair drops one extra device reference. The bug fires when two conditions hold together: a non-private provider has a persistent client holding chan->client_count > 0 and another client cycles dmaengine_get()/dmaengine_put(). When the kref hits zero, the subsequent dma_find_channel() returns NULL even though the provider module is still loaded. Fix this by dropping device->ref only on the last put, matching the single slow-path get.
SourceCVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
ReferencesDLA-4841-1, DLA-4850-1, DSA-6568-1

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
linux (PTS)bookworm6.1.176-1vulnerable
bookworm (security)6.1.190-1fixed
trixie6.12.107-1vulnerable
trixie (security)6.12.113-1fixed
forky, sid7.2.12-1fixed
linux-6.12 (PTS)bookworm (security)6.12.113-1~deb12u1fixed

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
linuxsourcebookworm6.1.190-1DLA-4841-1
linuxsourcetrixie6.12.113-1DSA-6568-1
linuxsource(unstable)7.2.8-1
linux-6.12sourcebookworm6.12.113-1~deb12u1DLA-4850-1

Notes

https://git.kernel.org/linus/44dab659064eb5c10adb0306510eebe848ed592d (7.3-rc4)

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