From 3a150df945b7408c27cad2c01a1638e8b14ac562 Mon Sep 17 00:00:00 2001 From: Chunyu Hu Date: Wed, 22 Feb 2017 08:29:26 +0800 Subject: tracing: Fix code comment for ftrace_ops_get_func() There is no function 'ftrace_ops_recurs_func' existing in the current code, it was renamed to ftrace_ops_assist_func() in commit c68c0fa29341 ("ftrace: Have ftrace_ops_get_func() handle RCU and PER_CPU flags too"). Update the comment to the correct function name. Link: http://lkml.kernel.org/r/1487723366-14463-1-git-send-email-chuhu@redhat.com Signed-off-by: Chunyu Hu Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/ftrace.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel/trace/ftrace.c') diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 0c0609326391..fd84f2e30b6d 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -5487,7 +5487,7 @@ static void ftrace_ops_assist_func(unsigned long ip, unsigned long parent_ip, * Normally the mcount trampoline will call the ops->func, but there * are times that it should not. For example, if the ops does not * have its own recursion protection, then it should call the - * ftrace_ops_recurs_func() instead. + * ftrace_ops_assist_func() instead. * * Returns the function that the trampoline should call for @ops. */ -- cgit v1.2.3-59-g8ed1b From 92ad18ec26611e8a47639e600bd9dc42fbe2edcf Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (VMware)" Date: Thu, 2 Mar 2017 12:53:26 -0500 Subject: ftrace/graph: Do not modify the EMPTY_HASH for the function_graph filter On boot up, if the kernel command line sets a graph funtion with the kernel command line options "ftrace_graph_filter" or "ftrace_graph_notrace" then it updates the corresponding function graph hash, ftrace_graph_hash or ftrace_graph_notrace_hash respectively. Unfortunately, at boot up, these variables are pointers to the "EMPTY_HASH" which is a constant used as a placeholder when a hash has no entities. The problem was that the comand line version to set the hashes updated the actual EMPTY_HASH instead of creating a new hash for the function graph. This broke the EMPTY_HASH because not only did it modify a constant (not sure how that was allowed to happen, except maybe because it was done at early boot, const variables were still mutable), but it made the filters have functions listed in them when they were actually empty. The kernel command line function needs to allocate a new hash for the function graph filters and assign the necessary variables to that new hash instead. Link: http://lkml.kernel.org/r/1488420091.7212.17.camel@linux.intel.com Cc: Namhyung Kim Fixes: b9b0c831bed2 ("ftrace: Convert graph filter to use hash tables") Reported-by: Todd Brandt Tested-by: Todd Brandt Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/ftrace.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) (limited to 'kernel/trace/ftrace.c') diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index fd84f2e30b6d..44122e7a6418 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -4421,10 +4421,9 @@ static void __init set_ftrace_early_graph(char *buf, int enable) char *func; struct ftrace_hash *hash; - if (enable) - hash = ftrace_graph_hash; - else - hash = ftrace_graph_notrace_hash; + hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS); + if (WARN_ON(!hash)) + return; while (buf) { func = strsep(&buf, ","); @@ -4434,6 +4433,11 @@ static void __init set_ftrace_early_graph(char *buf, int enable) printk(KERN_DEBUG "ftrace: function %s not " "traceable\n", func); } + + if (enable) + ftrace_graph_hash = hash; + else + ftrace_graph_notrace_hash = hash; } #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ -- cgit v1.2.3-59-g8ed1b From 65a50c656276b0846bea09dd011c0a3d35b77f3e Mon Sep 17 00:00:00 2001 From: Todd Brandt Date: Thu, 2 Mar 2017 16:12:15 -0800 Subject: ftrace/graph: Add ftrace_graph_max_depth kernel parameter Early trace callgraphs can be extremely large on systems with several seconds of boot time. The max_depth parameter limits how deep the graph trace goes and reduces the output size. This parameter is the same as the max_graph_depth file in tracefs. Link: http://lkml.kernel.org/r/1488499935-23216-1-git-send-email-todd.e.brandt@linux.intel.com Signed-off-by: Todd Brandt [ changed comments about debugfs to tracefs ] Signed-off-by: Steven Rostedt (VMware) --- Documentation/admin-guide/kernel-parameters.txt | 6 ++++++ kernel/trace/ftrace.c | 9 +++++++++ 2 files changed, 15 insertions(+) (limited to 'kernel/trace/ftrace.c') diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 21e2d8863705..1c9016b27ee9 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -1173,6 +1173,12 @@ functions that can be changed at run time by the set_graph_notrace file in the debugfs tracing directory. + ftrace_graph_max_depth= + [FTRACE] Used with the function graph tracer. This is + the max depth it will trace into a function. This value + can be changed at run time by the max_graph_depth file + in the tracefs tracing directory. default: 0 (no limit) + gamecon.map[2|3]= [HW,JOY] Multisystem joystick and NES/SNES/PSX pad support via parallel port (up to 5 devices per port) diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 44122e7a6418..d129ae51329a 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -4415,6 +4415,15 @@ static int __init set_graph_notrace_function(char *str) } __setup("ftrace_graph_notrace=", set_graph_notrace_function); +static int __init set_graph_max_depth_function(char *str) +{ + if (!str) + return 0; + fgraph_max_depth = simple_strtoul(str, NULL, 0); + return 1; +} +__setup("ftrace_graph_max_depth=", set_graph_max_depth_function); + static void __init set_ftrace_early_graph(char *buf, int enable) { int ret; -- cgit v1.2.3-59-g8ed1b