Don't allow FBT to recurse into FBT functions when DTrace is built as part of the kernel
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Authored by rwatson on Oct 4 2015, 11:43 AM.

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andrew
bz
br

Summary

Normally, DTrace avoids recursion into itself by recognising functions in its own kernel module. On ARMv[67], when building DTrace into the kernel itself, the normal further rule of not entering functions prefixed with dtrace_ is insufficient for FBT, which also contains functions prefixed with fbt_. This change blocks that recursion by disallowing FBT instrumentation of fbt_ functions.

Test Plan

Deployed in Cambridge L41 2014-2015.

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Repository

rS FreeBSD src repository - subversion

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rwatson updated this revision to Diff 9127.Oct 4 2015, 11:43 AM

rwatson retitled this revision from to Don't allow FBT to recurse into FBT functions when DTrace is built as part of the kernel.

rwatson updated this object.

rwatson edited the test plan for this revision. (Show Details)

rwatson added reviewers: andrew, br, bz.

rwatson set the repository for this revision to rS FreeBSD src repository - subversion.

rwatson added a project: ARM.

Herald added a subscriber: imp. · View Herald TranscriptOct 4 2015, 11:43 AM

Updated patch generated against Subversion, and contains more context. No functional change.

This should be replaced with fbt_excluded. Ruslan added it for arm64, but it doesn't seem to be used elsewhere. This will mean we can remove the dtrace_ and __ cased above.

Revision Contents
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Path

Size

sys/

cddl/

dev/

fbt/

arm/

fbt_isa.c

7 lines

Diff 9127

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sys/cddl/dev/fbt/arm/fbt_isa.c

Don't allow FBT to recurse into FBT functions when DTrace is built as part of the kernelNeeds ReviewPublicActions