Commit dc4b1658 authored by Heiko Carstens's avatar Heiko Carstens Committed by Shuah Khan
Browse files

selftests/ftrace: Use readelf to find entry point in uprobe test 

The uprobe events test fails on s390, but also on x86 (Fedora 41). The
problem appears to be that there is an assumption that adding a uprobe to
the beginning of the executable mapping of /bin/sh is sufficient to trigger
a uprobe event when /bin/sh is executed.

This assumption is not necessarily true. Therefore use "readelf -h" to find
the entry point address of /bin/sh and use this address when adding the
uprobe event.

This adds a dependency to readelf which is not always installed. Therefore
add a check and exit with exit_unresolved if it is not installed.

Link: https://lore.kernel.org/r/20250220130102.2079179-1-hca@linux.ibm.com


Signed-off-by: default avatarHeiko Carstens <hca@linux.ibm.com>
Acked-by: default avatarSteven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: default avatarShuah Khan <skhan@linuxfoundation.org>
parent e402c708

tools/testing/selftests/ftrace/test.d/dynevent/add_remove_uprobe.tc

+7 −3
Original line number Diff line number Diff line
@@ -3,14 +3,18 @@ 
# description: Generic dynamic event - add/remove/test uprobe events

# requires: uprobe_events



if ! which readelf > /dev/null 2>&1 ; then

  echo "No readelf found. skipped."

  exit_unresolved

fi



echo 0 > events/enable

echo > dynamic_events



REALBIN=`readlink -f /bin/sh`

ENTRYPOINT=`readelf -h ${REALBIN} | grep Entry | sed -e 's/[^0]*//'`



echo 'cat /proc/$$/maps' | /bin/sh | \

	grep "r-xp .*${REALBIN}$" | \

	awk '{printf "p:myevent %s:0x%s\n", $6,$3 }' >> uprobe_events

echo "p:myevent ${REALBIN}:${ENTRYPOINT}" >> uprobe_events



grep -q myevent uprobe_events

test -d events/uprobes/myevent