Commit a9de4eb1 authored by Steven Rostedt (Google)'s avatar Steven Rostedt (Google)
Browse files

eventfs: Fix WARN_ON() in create_file_dentry() 

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: 5790b1fb ("eventfs: Remove eventfs_file and just use eventfs_inode")
Signed-off-by: default avatarSteven Rostedt (Google) <rostedt@goodmis.org>
parent 0f7f544a

fs/tracefs/event_inode.c

+2 −1
Original line number Diff line number Diff line
@@ -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);