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[108.212.132.20]) by smtp.gmail.com with ESMTPSA id 00721157ae682-79cb4521761sm39104447b3.0.2026.03.30.11.11.15 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 30 Mar 2026 11:11:15 -0700 (PDT) From: Wesley Atwell To: rostedt@goodmis.org, mhiramat@kernel.org Cc: mark.rutland@arm.com, mathieu.desnoyers@efficios.com, linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, Wesley Atwell Subject: [PATCH v7 2/2] tracing: Preserve repeated trace_trigger boot parameters Date: Mon, 30 Mar 2026 12:11:03 -0600 Message-ID: <20260330181103.1851230-2-atwellwea@gmail.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260330181103.1851230-1-atwellwea@gmail.com> References: <20260330181103.1851230-1-atwellwea@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit trace_trigger= tokenizes bootup_trigger_buf in place and stores pointers into that buffer for later trigger registration. Repeated trace_trigger= parameters overwrite the buffer contents from earlier calls, leaving only the last set of parsed event and trigger strings. Keep each new trace_trigger= string at the end of bootup_trigger_buf and parse only the appended range. That preserves the earlier event and trigger strings while still letting repeated parameters queue additional boot-time triggers. This also lets Bootconfig array values work naturally when they expand to repeated trace_trigger= entries. Before this change, only the last trace_trigger= instance survived boot. Signed-off-by: Wesley Atwell --- Changes since v6: https://lore.kernel.org/all/20260329184254.1813273-1-atwellwea@gmail.com/ - split trace_trigger= handling into its own patch - follow Steven Rostedt's suggested bootup_trigger_buf offset approach - account for the terminating NUL when advancing boot_trigger_buf_len --- kernel/trace/trace_events.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c index 249d1cba72c0..dd26e838d4de 100644 --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -3679,20 +3679,27 @@ static struct boot_triggers { } bootup_triggers[MAX_BOOT_TRIGGERS]; static char bootup_trigger_buf[COMMAND_LINE_SIZE]; +static int boot_trigger_buf_len; static int nr_boot_triggers; static __init int setup_trace_triggers(char *str) { char *trigger; char *buf; + int len = boot_trigger_buf_len; int i; - strscpy(bootup_trigger_buf, str, COMMAND_LINE_SIZE); + if (len >= COMMAND_LINE_SIZE) + return 1; + + strscpy(bootup_trigger_buf + len, str, COMMAND_LINE_SIZE - len); trace_set_ring_buffer_expanded(NULL); disable_tracing_selftest("running event triggers"); - buf = bootup_trigger_buf; - for (i = 0; i < MAX_BOOT_TRIGGERS; i++) { + buf = bootup_trigger_buf + len; + boot_trigger_buf_len += strlen(buf) + 1; + + for (i = nr_boot_triggers; i < MAX_BOOT_TRIGGERS; i++) { trigger = strsep(&buf, ","); if (!trigger) break; -- 2.43.0