Differential D49243

libdtrace: Fix an off-by-one in CPU ID handling
ClosedPublic
Actions

Authored by markj on Mar 5 2025, 10:59 AM.

Tags

None

Referenced Files

	Unknown Object (File)
	Sat, Oct 25, 12:56 AM

	Unknown Object (File)
	Thu, Oct 16, 7:09 AM

	Unknown Object (File)
	Wed, Oct 15, 10:35 PM

	Unknown Object (File)
	Mon, Oct 13, 9:56 AM

	Unknown Object (File)
	Mon, Oct 13, 8:17 AM

	Unknown Object (File)
	Mon, Oct 13, 8:17 AM

	Unknown Object (File)
	Mon, Oct 13, 5:01 AM

	Unknown Object (File)
	Mon, Oct 13, 4:25 AM

View All 61 Files

Subscribers

Details

Reviewers

Group Reviewers

Commits

rG0ae0226cd12a: libdtrace: Fix an off-by-one in CPU ID handling
rG9a30c8d347bf: libdtrace: Fix an off-by-one in CPU ID handling

Summary

The illumos-specific _SC_CPUID_MAX is the largest CPU ID in the system. This
was mapped to _SC_NPROCESSORS_CONF, which is the total number of CPUs recognized
by the kernel. If CPU IDs are contiguous, as is the case on amd64 and arm64,
this value is one greater than the maximum ID. As a result, when consuming
per-CPU dtrace buffers, libdtrace tries to fetch from a non-existent CPU. This
is mostly harmless in practice, but still wrong.

As we don't have a sysconf value for the maximum CPU ID, add a wrapper which
fetches it using the kern.smp.maxid sysctl.

Sponsored by: Innovate UK

Diff Detail

Repository

rG FreeBSD src repository

Lint

Lint Skipped

Unit

Tests Skipped

Build Status

Buildable 62769
Build 59653: arc lint + arc unit

Event Timeline

markj created this revision.Mar 5 2025, 10:59 AM

Herald added a reviewer: gnn. · View Herald TranscriptMar 5 2025, 10:59 AM

Herald added a subscriber: imp. · View Herald Transcript

markj requested review of this revision.Mar 5 2025, 10:59 AM

markj added a parent revision: D49242: libdtrace: Fix an off-by-one in the priority queue implementation.

Harbormaster completed remote builds in B62769: Diff 151911.Mar 5 2025, 11:00 AM

This revision was not accepted when it landed; it landed in state Needs Review.Mar 10 2025, 3:05 AM

Closed by commit rG9a30c8d347bf: libdtrace: Fix an off-by-one in CPU ID handling (authored by markj). · Explain Why

This revision was automatically updated to reflect the committed changes.

markj added a commit: rG9a30c8d347bf: libdtrace: Fix an off-by-one in CPU ID handling.

markj added a commit: rG0ae0226cd12a: libdtrace: Fix an off-by-one in CPU ID handling.Apr 2 2025, 3:15 PM

Revision Contents
Changeset List

Path

Size

cddl/

contrib/

opensolaris/

lib/

libdtrace/

common/

6 lines

8 lines

1 line

14 lines

5 lines

Diff 151911

cddl/contrib/opensolaris/lib/libdtrace/common/dt_aggregate.c

Loading...

cddl/contrib/opensolaris/lib/libdtrace/common/dt_consume.c

Loading...

cddl/contrib/opensolaris/lib/libdtrace/common/dt_impl.h

Loading...

cddl/contrib/opensolaris/lib/libdtrace/common/dt_subr.c

Loading...

cddl/contrib/opensolaris/lib/libdtrace/common/dtrace.h

Loading...