[PATCH v2] eventfs: Initialize the tracefs inode properly

From: Steven Rostedt
Date: Tue Jan 30 2024 - 15:26:07 EST


From: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>

The tracefs-specific fields in the inode were not initialized before the
inode was exposed to others through the dentry with 'd_instantiate()'.

Move the field initializations up to before the d_instantiate.

Cc: stable@xxxxxxxxxxxxxxx
Fixes: 5790b1fb3d672 ("eventfs: Remove eventfs_file and just use eventfs_inode")
Reported-by: kernel test robot <oliver.sang@xxxxxxxxx>
Closes: https://lore.kernel.org/oe-lkp/202401291043.e62e89dc-oliver.sang@xxxxxxxxx
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx>
---
Changes since v1: https://lore.kernel.org/linux-trace-kernel/20240130190355.11486-2-torvalds@xxxxxxxxxxxxxxxxxxxx

- Since another patch zeroed out the entire tracefs_inode, there's no need
to initialize any of its fields to NULL.
(see https://lore.kernel.org/linux-trace-kernel/20240130151737.6e97ae00@xxxxxxxxxxxxxxxxxx/)

fs/tracefs/event_inode.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c
index 1c3dd0ad4660..824b1811e342 100644
--- a/fs/tracefs/event_inode.c
+++ b/fs/tracefs/event_inode.c
@@ -370,6 +370,8 @@ static struct dentry *create_dir(struct eventfs_inode *ei, struct dentry *parent

ti = get_tracefs(inode);
ti->flags |= TRACEFS_EVENT_INODE;
+ /* Only directories have ti->private set to an ei, not files */
+ ti->private = ei;

inc_nlink(inode);
d_instantiate(dentry, inode);
@@ -515,7 +517,6 @@ create_file_dentry(struct eventfs_inode *ei, int idx,
static void eventfs_post_create_dir(struct eventfs_inode *ei)
{
struct eventfs_inode *ei_child;
- struct tracefs_inode *ti;

lockdep_assert_held(&eventfs_mutex);

@@ -525,9 +526,6 @@ static void eventfs_post_create_dir(struct eventfs_inode *ei)
srcu_read_lock_held(&eventfs_srcu)) {
ei_child->d_parent = ei->dentry;
}
-
- ti = get_tracefs(ei->dentry->d_inode);
- ti->private = ei;
}

/**
--
2.43.0