[for-next][PATCH 0/4] tracing: Updates for 6.7

[for-next][PATCH 0/4] tracing: Updates for 6.7

[Steven Rostedt]

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

Head SHA1: 29e06c10702e81a7d0b75020ca514d2f2962704a


Christophe JAILLET (1):
      tracing/histograms: Simplify last_cmd_set()

Matthew Wilcox (Oracle) (1):
      powerpc: Remove initialisation of readpos

Steven Rostedt (Google) (2):
      eventfs: Fix WARN_ON() in create_file_dentry()
      eventfs: Fix typo in eventfs_inode union comment

----
 arch/powerpc/kernel/setup-common.c |  1 -
 fs/tracefs/event_inode.c           |  3 ++-
 fs/tracefs/internal.h              |  2 +-
 kernel/trace/trace_events_hist.c   | 11 ++---------
 4 files changed, 5 insertions(+), 12 deletions(-)

[for-next][PATCH 1/4] tracing/histograms: Simplify last_cmd_set()

[Steven Rostedt]

From: Christophe JAILLET <christophe.jaillet@wanadoo.fr>

Turn a kzalloc()+strcpy()+strncat() into an equivalent and less verbose
kasprintf().

Link: https://lore.kernel.org/linux-trace-kernel/30b6fb04dadc10a03cc1ad08f5d8a93ef623a167.1697899346.git.christophe.jaillet@wanadoo.fr

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Reviewed-by: Mukesh ojha <quic_mojha@quicinc.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
 kernel/trace/trace_events_hist.c | 11 ++---------
 1 file changed, 2 insertions(+), 9 deletions(-)

diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
index d06938ae0717..1abc07fba1b9 100644
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -774,23 +774,16 @@ static void last_cmd_set(struct trace_event_file *file, char *str)
 {
 	const char *system = NULL, *name = NULL;
 	struct trace_event_call *call;
-	int len;
 
 	if (!str)
 		return;
 
-	/* sizeof() contains the nul byte */
-	len = sizeof(HIST_PREFIX) + strlen(str);
 	kfree(last_cmd);
-	last_cmd = kzalloc(len, GFP_KERNEL);
+
+	last_cmd = kasprintf(GFP_KERNEL, HIST_PREFIX "%s", str);
 	if (!last_cmd)
 		return;
 
-	strcpy(last_cmd, HIST_PREFIX);
-	/* Again, sizeof() contains the nul byte */
-	len -= sizeof(HIST_PREFIX);
-	strncat(last_cmd, str, len);
-
 	if (file) {
 		call = file->event_call;
 		system = call->class->system;
-- 
2.42.0

[for-next][PATCH 2/4] powerpc: Remove initialisation of readpos

[Steven Rostedt]

From: "Matthew Wilcox (Oracle)" <willy@infradead.org>

While powerpc doesn't use the seq_buf readpos, it did explicitly
initialise it for no good reason.

Link: https://lore.kernel.org/linux-trace-kernel/20231024145600.739451-1-willy@infradead.org

Cc: Christoph Hellwig <hch@lst.de>
Cc: Justin Stitt <justinstitt@google.com>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Kees Cook <keescook@chromium.org>
Fixes: d0ed46b60396 ("tracing: Move readpos from seq_buf to trace_seq")
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
 arch/powerpc/kernel/setup-common.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/arch/powerpc/kernel/setup-common.c b/arch/powerpc/kernel/setup-common.c
index 2f1026fba00d..34975532e44c 100644
--- a/arch/powerpc/kernel/setup-common.c
+++ b/arch/powerpc/kernel/setup-common.c
@@ -601,7 +601,6 @@ struct seq_buf ppc_hw_desc __initdata = {
 	.buffer = ppc_hw_desc_buf,
 	.size = sizeof(ppc_hw_desc_buf),
 	.len = 0,
-	.readpos = 0,
 };
 
 static __init void probe_machine(void)
-- 
2.42.0

[for-next][PATCH 3/4] eventfs: Fix WARN_ON() in create_file_dentry()

[Steven Rostedt]

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

As the comment right above a WARN_ON() in create_file_dentry() states:

  * Note, with the mutex held, the e_dentry cannot have content
  * and the ei->is_freed be true at the same time.

But the WARN_ON() only has:

  WARN_ON_ONCE(ei->is_free);

Where to match the comment (and what it should actually do) is:

  dentry = *e_dentry;
  WARN_ON_ONCE(dentry && ei->is_free)

Also in that case, set dentry to NULL (although it should never happen).

Link: https://lore.kernel.org/linux-trace-kernel/20231024123628.62b88755@gandalf.local.home

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Fixes: 5790b1fb3d672 ("eventfs: Remove eventfs_file and just use eventfs_inode")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
 fs/tracefs/event_inode.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c
index 09ab93357957..4d2da7480e5f 100644
--- a/fs/tracefs/event_inode.c
+++ b/fs/tracefs/event_inode.c
@@ -264,8 +264,9 @@ create_file_dentry(struct eventfs_inode *ei, struct dentry **e_dentry,
 		 * Note, with the mutex held, the e_dentry cannot have content
 		 * and the ei->is_freed be true at the same time.
 		 */
-		WARN_ON_ONCE(ei->is_freed);
 		dentry = *e_dentry;
+		if (WARN_ON_ONCE(dentry && ei->is_freed))
+			dentry = NULL;
 		/* The lookup does not need to up the dentry refcount */
 		if (dentry && !lookup)
 			dget(dentry);
-- 
2.42.0

[for-next][PATCH 4/4] eventfs: Fix typo in eventfs_inode union comment

[Steven Rostedt]

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

It's eventfs_inode not eventfs_indoe. There's no deer involved!

Link: https://lore.kernel.org/linux-trace-kernel/20231024131024.5634c743@gandalf.local.home

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Fixes: 5790b1fb3d672 ("eventfs: Remove eventfs_file and just use eventfs_inode")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
 fs/tracefs/internal.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/tracefs/internal.h b/fs/tracefs/internal.h
index 298d3ecaf621..64fde9490f52 100644
--- a/fs/tracefs/internal.h
+++ b/fs/tracefs/internal.h
@@ -37,7 +37,7 @@ struct eventfs_inode {
 	/*
 	 * Union - used for deletion
 	 * @del_list:	list of eventfs_inode to delete
-	 * @rcu:	eventfs_indoe to delete in RCU
+	 * @rcu:	eventfs_inode to delete in RCU
 	 * @is_freed:	node is freed if one of the above is set
 	 */
 	union {
-- 
2.42.0