[SRU][P/N/J][PATCH v2 0/1] CVE-2025-38584

[Alice C. Munduruca]

v2 -> Reworked structure to match flat hierarchy standard.

[ Impact ]

Despite previous attempts to fix this bug, a UAF still occurs in certain
situations within padata. In order to fix it for good, the previous queueing
system is completely removed and logic is rewritten to be safe.

[ Fix ]

plucky: backported from upstream, writing over a minor change with `cpumask_next_wrap`.
noble: redid backport from same provenance due to context changes.
jammy: cleanly applied plucky fix.

[ Tests ]

Compile, boot, and stress-ng (cpu) tested.

[ Where problems could occur ]

Given that padata has had this UAF for a while, there is not really a risk of
regression, so much as not having fixed the problem. The fact that changes to the
original patch are minor minimizes this risk.

Herbert Xu (1):
  padata: Fix pd UAF once and for all

 include/linux/padata.h |   3 -
 kernel/padata.c        | 132 ++++++++++++-----------------------------
 2 files changed, 37 insertions(+), 98 deletions(-)

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2.51.0