From 43ed384339ae67a74a8ba4851268b23216ef7a44 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Red Hat)" Date: Tue, 3 Nov 2015 22:15:14 -0500 Subject: [PATCH] tracing: Put back comma for empty fields in boot string parsing Both early_enable_events() and apply_trace_boot_options() parse a boot string that may get parsed later on. They both use strsep() which converts a comma into a nul character. To still allow the boot string to be parsed again the same way, the nul character gets converted back to a comma after the token is processed. The problem is that these two functions check for an empty parameter (two commas in a row ",,"), and continue the loop if the parameter is empty, but fails to place the comma back. In this case, the second parsing will end at this blank field, and not process fields afterward. In most cases, users should not have an empty field, but if its going to be checked, the code might as well be correct. Signed-off-by: Steven Rostedt --- kernel/trace/trace.c | 5 ++--- kernel/trace/trace_events.c | 16 ++++++++-------- 2 files changed, 10 insertions(+), 11 deletions(-) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 7fe7cc987dab..2198a630ef58 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -3636,10 +3636,9 @@ static void __init apply_trace_boot_options(void) if (!option) break; - if (!*option) - continue; - trace_set_options(&global_trace, option); + if (*option) + trace_set_options(&global_trace, option); /* Put back the comma to allow this to be called again */ if (buf) diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c index 292bccf3e011..bee1e1530052 100644 --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -3042,16 +3042,16 @@ early_enable_events(struct trace_array *tr, bool disable_first) if (!token) break; - if (!*token) - continue; - /* Restarting syscalls requires that we stop them first */ - if (disable_first) - ftrace_set_clr_event(tr, token, 0); + if (*token) { + /* Restarting syscalls requires that we stop them first */ + if (disable_first) + ftrace_set_clr_event(tr, token, 0); - ret = ftrace_set_clr_event(tr, token, 1); - if (ret) - pr_warn("Failed to enable trace event: %s\n", token); + ret = ftrace_set_clr_event(tr, token, 1); + if (ret) + pr_warn("Failed to enable trace event: %s\n", token); + } /* Put back the comma to allow this to be called again */ if (buf)