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Differential D59949

kmsan: avoid false reports while processing NMIs
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Authored by chs on Thu, Sep 24, 12:09 AM.
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Details

Reviewers
imp
kib
markj
jhb
Summary

The NMI asm path needs two KMSAN hooks to avoid false reports:

  • KMSAN_INIT_ARG clears the parameter shadow for calling an instrumented C function from asm code
  • KMSAN_MARK_TRAPFRAME marks a trapframe that was initialized in asm code as initialized.

Sponsored by: Netflix
Assisted-By: Claude Code - Opus 5 (1M context)

Diff Detail

Repository
rG FreeBSD src repository
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Lint Skipped
Unit
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Build Status
Buildable 77233
Build 74116: arc lint + arc unit

Event Timeline

chs requested review of this revision.Thu, Sep 24, 12:09 AM
chs created this revision.
Harbormaster completed remote builds in B77233: Diff 187546.Thu, Sep 24, 12:09 AM
chs added a parent revision: D59948: kmsan: skip memdescs of type MEMDESC_VMPAGES.Thu, Sep 24, 12:09 AM
chs added a child revision: D59950: tcp: avoid disclosing uninitialize data in tcp_log code.
imp added reviewers: kib, markj, jhb.Tue, Sep 29, 10:23 PM
markj added inline comments.Thu, Oct 1, 3:30 PM
sys/amd64/amd64/exception.S
879

Why are we doing this here? We're either about to return back to the interrupted context via iret, or we're going to call pmc_hook. In the latter case, the trapframe has already been marked by the trap() call above.

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PathSize
sys/
amd64/
amd64/
2 lines
include/
42 lines

Diff 187546

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sys/amd64/amd64/exception.S

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sys/amd64/include/asmacros.h

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