Commit 06a130e4 authored by Veronika Molnarova's avatar Veronika Molnarova Committed by Arnaldo Carvalho de Melo
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perf test: Handle perftool-testsuite_probe failure due to broken DWARF 



Test case test_adding_blacklisted ends in failure if the blacklisted
probe is of an assembler function with no DWARF available. At the same
time, probing the blacklisted function with ASM DWARF doesn't test the
blacklist itself as the failure is a result of the broken DWARF.

When the broken DWARF output is encountered, check if the probed
function was compiled by the assembler. If so, the broken DWARF message
is expected and does not report a perf issue, else report a failure.  If
the ASM DWARF affected the probe, try the next probe on the blacklist.
If the first 5 probes are defective due to broken DWARF, skip the test
case.

Fixes: def5480d ("perf testsuite probe: Add test for blacklisted kprobes handling")
Signed-off-by: default avatarVeronika Molnarova <vmolnaro@redhat.com>
Tested-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Michael Petlan <mpetlan@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Veronika Molnarova <vmolnaro@redhat.com>
Link: https://lore.kernel.org/r/20241017161555.236769-1-vmolnaro@redhat.com


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent d822ca29

tools/perf/tests/shell/base_probe/test_adding_blacklisted.sh

+54 −15
Original line number Diff line number Diff line
@@ -19,35 +19,74 @@ 
TEST_RESULT=0



# skip if not supported

BLACKFUNC=`head -n 1 /sys/kernel/debug/kprobes/blacklist 2> /dev/null | cut -f2`

if [ -z "$BLACKFUNC" ]; then

BLACKFUNC_LIST=`head -n 5 /sys/kernel/debug/kprobes/blacklist 2> /dev/null | cut -f2`

if [ -z "$BLACKFUNC_LIST" ]; then

	print_overall_skipped

	exit 0

fi



# try to find vmlinux with DWARF debug info

VMLINUX_FILE=$(perf probe -v random_probe |& grep "Using.*for symbols" | sed -r 's/^Using (.*) for symbols$/\1/')



# remove all previously added probes

clear_all_probes





### adding blacklisted function



# functions from blacklist should be skipped by perf probe

! $CMD_PERF probe $BLACKFUNC > $LOGS_DIR/adding_blacklisted.log 2> $LOGS_DIR/adding_blacklisted.err

PERF_EXIT_CODE=$?



REGEX_SCOPE_FAIL="Failed to find scope of probe point"

REGEX_SKIP_MESSAGE=" is blacklisted function, skip it\."

REGEX_NOT_FOUND_MESSAGE="Probe point \'$BLACKFUNC\' not found."

REGEX_NOT_FOUND_MESSAGE="Probe point \'$RE_EVENT\' not found."

REGEX_ERROR_MESSAGE="Error: Failed to add events."

REGEX_INVALID_ARGUMENT="Failed to write event: Invalid argument"

REGEX_SYMBOL_FAIL="Failed to find symbol at $RE_ADDRESS"

REGEX_OUT_SECTION="$BLACKFUNC is out of \.\w+, skip it"

REGEX_OUT_SECTION="$RE_EVENT is out of \.\w+, skip it"

REGEX_MISSING_DECL_LINE="A function DIE doesn't have decl_line. Maybe broken DWARF?"



BLACKFUNC=""

SKIP_DWARF=0



for BLACKFUNC in $BLACKFUNC_LIST; do

	echo "Probing $BLACKFUNC"



	# functions from blacklist should be skipped by perf probe

	! $CMD_PERF probe $BLACKFUNC > $LOGS_DIR/adding_blacklisted.log 2> $LOGS_DIR/adding_blacklisted.err

	PERF_EXIT_CODE=$?



	# check for bad DWARF polluting the result

	../common/check_all_patterns_found.pl "$REGEX_MISSING_DECL_LINE" >/dev/null < $LOGS_DIR/adding_blacklisted.err



	if [ $? -eq 0 ]; then

		SKIP_DWARF=1

		echo "Result polluted by broken DWARF, trying another probe"



		# confirm that the broken DWARF comes from assembler

		if [ -n "$VMLINUX_FILE" ]; then

			readelf -wi "$VMLINUX_FILE" |

			awk -v probe="$BLACKFUNC" '/DW_AT_language/ { comp_lang = $0 }

						   $0 ~ probe { if (comp_lang) { print comp_lang }; exit }' |

			grep -q "MIPS assembler"



			CHECK_EXIT_CODE=$?

			if [ $CHECK_EXIT_CODE -ne 0 ]; then

				SKIP_DWARF=0 # broken DWARF while available

				break

			fi

		fi

	else

		../common/check_all_lines_matched.pl "$REGEX_SKIP_MESSAGE" "$REGEX_NOT_FOUND_MESSAGE" "$REGEX_ERROR_MESSAGE" "$REGEX_SCOPE_FAIL" "$REGEX_INVALID_ARGUMENT" "$REGEX_SYMBOL_FAIL" "$REGEX_OUT_SECTION" < $LOGS_DIR/adding_blacklisted.err

		CHECK_EXIT_CODE=$?



		SKIP_DWARF=0

		break

	fi

done



if [ $SKIP_DWARF -eq 1 ]; then

	print_testcase_skipped "adding blacklisted function $BLACKFUNC"

else

	print_results $PERF_EXIT_CODE $CHECK_EXIT_CODE "adding blacklisted function $BLACKFUNC"

	(( TEST_RESULT += $? ))



fi



### listing not-added probe