Commit 71cade82 authored by Steven Rostedt (Google)'s avatar Steven Rostedt (Google)
Browse files

eventfs: Do not invalidate dentry in create_file/dir_dentry() 

With the call to simple_recursive_removal() on the entire eventfs sub
system when the directory is removed, it performs the d_invalidate on all
the dentries when it is removed. There's no need to do clean ups when a
dentry is being created while the directory is being deleted.

As dentries are cleaned up by the simpler_recursive_removal(), trying to
do d_invalidate() in these functions will cause the dentry to be
invalidated twice, and crash the kernel.

Link: https://lore.kernel.org/all/20231116123016.140576-1-naresh.kamboju@linaro.org/
Link: https://lkml.kernel.org/r/20231120235154.422970988@goodmis.org



Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Fixes: 407c6726 ("eventfs: Use simple_recursive_removal() to clean up dentries")
Reported-by: default avatarMark Rutland <mark.rutland@arm.com>
Reported-by: default avatarNaresh Kamboju <naresh.kamboju@linaro.org>
Reported-by: default avatarLinux Kernel Functional Testing <lkft@linaro.org>
Signed-off-by: default avatarSteven Rostedt (Google) <rostedt@goodmis.org>
parent 88903dae

fs/tracefs/event_inode.c

+6 −13
Original line number Diff line number Diff line
@@ -326,7 +326,6 @@ create_file_dentry(struct eventfs_inode *ei, int idx, 
	struct eventfs_attr *attr = NULL;

	struct dentry **e_dentry = &ei->d_children[idx];

	struct dentry *dentry;

	bool invalidate = false;



	mutex_lock(&eventfs_mutex);

	if (ei->is_freed) {
@@ -389,17 +388,14 @@ create_file_dentry(struct eventfs_inode *ei, int idx, 
		 * Otherwise it means two dentries exist with the same name.

		 */

		WARN_ON_ONCE(!ei->is_freed);

		invalidate = true;

		dentry = NULL;

	}

	mutex_unlock(&eventfs_mutex);



	if (invalidate)

		d_invalidate(dentry);



	if (lookup || invalidate)

	if (lookup)

		dput(dentry);



	return invalidate ? NULL : dentry;

	return dentry;

}



/**
@@ -439,7 +435,6 @@ static struct dentry * 
create_dir_dentry(struct eventfs_inode *pei, struct eventfs_inode *ei,

		  struct dentry *parent, bool lookup)

{

	bool invalidate = false;

	struct dentry *dentry = NULL;



	mutex_lock(&eventfs_mutex);
@@ -495,16 +490,14 @@ create_dir_dentry(struct eventfs_inode *pei, struct eventfs_inode *ei, 
		 * Otherwise it means two dentries exist with the same name.

		 */

		WARN_ON_ONCE(!ei->is_freed);

		invalidate = true;

		dentry = NULL;

	}

	mutex_unlock(&eventfs_mutex);

	if (invalidate)

		d_invalidate(dentry);



	if (lookup || invalidate)

	if (lookup)

		dput(dentry);



	return invalidate ? NULL : dentry;

	return dentry;

}



/**