From: "Steven Rostedt (Google)" <[email protected]> eventfs uses the tracefs_inode and assumes that it's already initialized to zero. That is, it doesn't set fields to zero (like ti->private) after getting its tracefs_inode. This causes bugs due to stale values.
Just initialize the entire structure to zero on allocation so there isn't any more surprises. This is a partial fix to access to ti->private. The assignment still needs to be made before the dentry is instantiated. Cc: [email protected] Fixes: 5790b1fb3d672 ("eventfs: Remove eventfs_file and just use eventfs_inode") Reported-by: kernel test robot <[email protected]> Closes: https://lore.kernel.org/oe-lkp/[email protected] Suggested-by: Linus Torvalds <[email protected]> Signed-off-by: Steven Rostedt (Google) <[email protected]> --- Changes since last version: https://lore.kernel.org/all/[email protected]/ - Moved vfs_inode to top of tracefs_inode structure so that the rest can be initialized with memset_after() as the vfs_inode portion is already cleared with a memset() itself in inode_init_once(). fs/tracefs/inode.c | 6 ++++-- fs/tracefs/internal.h | 3 ++- 2 files changed, 6 insertions(+), 3 deletions(-) diff --git a/fs/tracefs/inode.c b/fs/tracefs/inode.c index e1b172c0e091..888e42087847 100644 --- a/fs/tracefs/inode.c +++ b/fs/tracefs/inode.c @@ -38,8 +38,6 @@ static struct inode *tracefs_alloc_inode(struct super_block *sb) if (!ti) return NULL; - ti->flags = 0; - return &ti->vfs_inode; } @@ -779,7 +777,11 @@ static void init_once(void *foo) { struct tracefs_inode *ti = (struct tracefs_inode *) foo; + /* inode_init_once() calls memset() on the vfs_inode portion */ inode_init_once(&ti->vfs_inode); + + /* Zero out the rest */ + memset_after(ti, 0, vfs_inode); } static int __init tracefs_init(void) diff --git a/fs/tracefs/internal.h b/fs/tracefs/internal.h index 91c2bf0b91d9..7d84349ade87 100644 --- a/fs/tracefs/internal.h +++ b/fs/tracefs/internal.h @@ -11,9 +11,10 @@ enum { }; struct tracefs_inode { + struct inode vfs_inode; + /* The below gets initialized with memset_after(ti, 0, vfs_inode) */ unsigned long flags; void *private; - struct inode vfs_inode; }; /* -- 2.43.0
