From: Tomas Glozar Date: Mon, 13 Jul 2026 14:10:47 +0000 (+0200) Subject: rtla/timerlat_top: Fix on-threshold actions firing on signal X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=fafb66e5903c2bcfc7b7e259042a8282f18a6faa;p=thirdparty%2Flinux.git rtla/timerlat_top: Fix on-threshold actions firing on signal A bug was reported when rtla-timerlat-top tool performs on-threshold actions, even though no threshold was hit. This is reproduced even if no threshold is set at all: $ rtla timerlat top -q -c 0 --on-threshold shell,command='echo BAD' BAD Timer Latency ... The bug is due to incorrect logic in timerlat_top_bpf_main_loop(). The loop uses timerlat_bpf_wait(), the return values of which are: - > 0 (number of ringbuffer entries): at least 1 CPU hit threshold - = 0: time out - < 0: wait was interrupted by a signal Commit 3138df6f0cd0 ("rtla/timerlat: Exit top main loop on any non-zero wait_retval") changed the condition for "threshold hit" from "wait_reval == 1" (exactly 1 CPU hit threshold) to "wait_retval != 0", to fix a race where multiple CPUs hit the threshold at the same time. That also made it incorrectly include a signal (< 0), coming from either duration expired (SIGALRM) or user interrupt (SIGINT). Check for wait_retval greater than zero in the if condition to cover all return values correctly. Fixes: 3138df6f0cd0 ("rtla/timerlat: Exit top main loop on any non-zero wait_retval") Reported-by: Attila Fazekas Reviewed-by: Wander Lairson Costa Link: https://lore.kernel.org/r/20260713141047.687877-1-tglozar@redhat.com Signed-off-by: Tomas Glozar --- diff --git a/tools/tracing/rtla/src/timerlat_top.c b/tools/tracing/rtla/src/timerlat_top.c index 18e1071a2e24..6206a0a565ad 100644 --- a/tools/tracing/rtla/src/timerlat_top.c +++ b/tools/tracing/rtla/src/timerlat_top.c @@ -536,7 +536,7 @@ timerlat_top_bpf_main_loop(struct osnoise_tool *tool) if (!params->quiet) timerlat_print_stats(tool); - if (wait_retval != 0) { + if (wait_retval > 0) { /* Stopping requested by tracer */ retval = common_threshold_handler(tool); if (retval)