[for-next][PATCH 0/3] tracing: Some small updates for 4.12

[for-next][PATCH 0/3] tracing: Some small updates for 4.12

[Steven Rostedt]

  git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace.git
for-next

Head SHA1: 77c0eddeeeee14bf0fb0c0bb97e782981bbcf084


Amey Telawane (1):
      tracing: Use strlcpy() instead of strcpy() in __trace_find_cmdline()

Dan Carpenter (1):
      ftrace: Remove an unneeded condition

Steven Rostedt (VMware) (1):
      ftrace: Simplify ftrace_match_record() even more

----
 kernel/trace/ftrace.c | 20 +++++++++-----------
 kernel/trace/trace.c  |  2 +-
 2 files changed, 10 insertions(+), 12 deletions(-)

[for-next][PATCH 1/3] tracing: Use strlcpy() instead of strcpy() in __trace_find_cmdline()

[Steven Rostedt]

[-- Attachment #1: 0001-tracing-Use-strlcpy-instead-of-strcpy-in-__trace_fin.patch --]
[-- Type: text/plain, Size: 1323 bytes --]

From: Amey Telawane <ameyt@codeaurora.org>

Strcpy is inherently not safe, and strlcpy() should be used instead.
__trace_find_cmdline() uses strcpy() because the comms saved must have a
terminating nul character, but it doesn't hurt to add the extra protection
of using strlcpy() instead of strcpy().

Link: http://lkml.kernel.org/r/1493806274-13936-1-git-send-email-amit.pundir@linaro.org

Signed-off-by: Amey Telawane <ameyt@codeaurora.org>
[AmitP: Cherry-picked this commit from CodeAurora kernel/msm-3.10
https://source.codeaurora.org/quic/la/kernel/msm-3.10/commit/?id=2161ae9a70b12cf18ac8e5952a20161ffbccb477]
Signed-off-by: Amit Pundir <amit.pundir@linaro.org>
[ Updated change log and removed the "- 1" from len parameter ]
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 kernel/trace/trace.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 80eda7d254ed..4ad4420b33d6 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -1976,7 +1976,7 @@ static void __trace_find_cmdline(int pid, char comm[])
 
 	map = savedcmd->map_pid_to_cmdline[pid];
 	if (map != NO_CMDLINE_MAP)
-		strcpy(comm, get_saved_cmdlines(map));
+		strlcpy(comm, get_saved_cmdlines(map), TASK_COMM_LEN);
 	else
 		strcpy(comm, "<...>");
 }
-- 
2.10.2

[for-next][PATCH 2/3] ftrace: Remove an unneeded condition

[Steven Rostedt]

[-- Attachment #1: 0002-ftrace-Remove-an-unneeded-condition.patch --]
[-- Type: text/plain, Size: 751 bytes --]

From: Dan Carpenter <dan.carpenter@oracle.com>

We know that "mod_matches" is true here so there is no need to check
again.

Link: http://lkml.kernel.org/r/20170331152130.GA4947@mwanda

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 kernel/trace/ftrace.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 00077a57b746..84286d347cd8 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -3644,7 +3644,7 @@ ftrace_match_record(struct dyn_ftrace *rec, struct ftrace_glob *func_g,
 				return 0;
 		}
 
-		if (mod_matches && exclude_mod)
+		if (exclude_mod)
 			return 0;
 
 func_match:
-- 
2.10.2

[for-next][PATCH 3/3] ftrace: Simplify ftrace_match_record() even more

[Steven Rostedt]

[-- Attachment #1: 0003-ftrace-Simplify-ftrace_match_record-even-more.patch --]
[-- Type: text/plain, Size: 2381 bytes --]

From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>

Dan Carpenter sent a patch to remove a check in ftrace_match_record()
because the logic of the code made the check redundant. I looked deeper into
the code, and made the following logic table, with the three variables and
the result of the original code.

modname        mod_matches     exclude_mod         result
-------        -----------     -----------         ------
  0                 0               0              return 0
  0                 0               1              func_match
  0                 1               *             < cannot exist >
  1                 0               0              return 0
  1                 0               1              func_match
  1                 1               0              func_match
  1                 1               1              return 0

Notice that when mod_matches == exclude mod, the result is always to
return 0, and when mod_matches != exclude_mod, then the result is to test
the function. This means we only need test if mod_matches is equal to
exclude_mod.

Cc: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 kernel/trace/ftrace.c | 20 +++++++++-----------
 1 file changed, 9 insertions(+), 11 deletions(-)

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 84286d347cd8..39dca4e86a94 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -3631,22 +3631,20 @@ ftrace_match_record(struct dyn_ftrace *rec, struct ftrace_glob *func_g,
 		/* blank module name to match all modules */
 		if (!mod_g->len) {
 			/* blank module globbing: modname xor exclude_mod */
-			if ((!exclude_mod) != (!modname))
+			if (!exclude_mod != !modname)
 				goto func_match;
 			return 0;
 		}
 
-		/* not matching the module */
-		if (!modname || !mod_matches) {
-			if (exclude_mod)
-				goto func_match;
-			else
-				return 0;
-		}
-
-		if (exclude_mod)
+		/*
+		 * exclude_mod is set to trace everything but the given
+		 * module. If it is set and the module matches, then
+		 * return 0. If it is not set, and the module doesn't match
+		 * also return 0. Otherwise, check the function to see if
+		 * that matches.
+		 */
+		if (!mod_matches == !exclude_mod)
 			return 0;
-
 func_match:
 		/* blank search means to match all funcs in the mod */
 		if (!func_g->len)
-- 
2.10.2