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| author | Andrei Vagin <avagin@google.com> | 2026-09-25 16:24:50 +0000 |
|---|---|---|
| committer | Borislav Petkov (AMD) <bp@alien8.de> | 2026-09-25 12:21:14 -0700 |
| commit | 731300df4f7d7d7153a2aa23b6c4992df3d2a60b (patch) | |
| tree | 6a5bf3759032c8a035730f0d643f5903f968b162 /tools/perf/scripts/python/task-analyzer.py | |
| parent | 6916dec7a02fe0f50d6dc80e5f5c55f11cebd874 (diff) | |
x86/fpu: Document reasoning of FX-only fallback
Add a comment to check_xstate_in_sigframe() to explain the reasoning behind
falling back to the FX-only state when signal frame metadata is
inconsistent.
The fallback is intended to preserve backward compatibility with legacy
user-space processes that are not aware of XSAVE states and might only
fill or copy the legacy FP state.
However, this fallback should be avoided whenever possible. If a process
was actively using extended features, falling back to the FX-only state
silently resets those extended registers to their initial state, which
can lead to silent user-space state corruption.
Signed-off-by: Andrei Vagin <avagin@google.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Alexander Mikhalitsyn <alexander@mihalicyn.com>
Reviewed-by: Chang S. Bae <chang.seok.bae@intel.com>
Link: https://patch.msgid.link/20260925162454.1403405-5-avagin@google.com
Diffstat (limited to 'tools/perf/scripts/python/task-analyzer.py')
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