From 864a2a2e499615495c99c874ad80f57620ac5e70 Mon Sep 17 00:00:00 2001 From: Arthur Hanson Rasmusson Date: Wed, 30 Sep 2026 10:14:09 -0400 Subject: guest-diag: mount tracefs before installing kprobes A fresh boot can leave /sys/kernel/tracing as an unmounted mount point; the probe adds then fail silently (probe count 0) and the whole sem/kptr pipeline goes blind. --- tools/guest-diag/guest_kprobes.sh | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'tools/guest-diag') diff --git a/tools/guest-diag/guest_kprobes.sh b/tools/guest-diag/guest_kprobes.sh index 3f28b29..75b2ba3 100644 --- a/tools/guest-diag/guest_kprobes.sh +++ b/tools/guest-diag/guest_kprobes.sh @@ -14,6 +14,13 @@ TR=/sys/kernel/tracing [ -d "$TR" ] || TR=/sys/kernel/debug/tracing +# A fresh boot may leave tracefs unmounted even though the mount point exists +# (observed: mkdir of events/kprobes/enable fails with "Directory +# nonexistent" and every probe add fails silently). Mount it if needed. +if [ ! -d "$TR/events" ]; then + mount -t tracefs tracefs "$TR" 2>/dev/null || \ + mount -t debugfs debugfs "$TR" 2>/dev/null || true +fi # An enabled kprobe event cannot be deleted (EBUSY); disable the group first. echo 0 > "$TR/events/kprobes/enable" 2>/dev/null || true -- cgit v1.2.3