From f0686a194549ca91f4fc6fedb9d39e8f7fd6b226 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Google)" Date: Tue, 6 Feb 2024 07:09:52 -0500 Subject: [PATCH] tracefs: Zero out the tracefs_inode when allocating it commit d81786f53aec14fd4d56263145a0635afbc64617 upstream. 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. Link: https://lore.kernel.org/linux-trace-kernel/20240131185512.315825944@goodmis.org Cc: stable@vger.kernel.org Cc: Masami Hiramatsu Cc: Mark Rutland Cc: Mathieu Desnoyers Cc: Christian Brauner Cc: Al Viro Cc: Ajay Kaher Cc: Greg Kroah-Hartman Fixes: 5790b1fb3d672 ("eventfs: Remove eventfs_file and just use eventfs_inode") Reported-by: kernel test robot Closes: https://lore.kernel.org/oe-lkp/202401291043.e62e89dc-oliver.sang@intel.com Suggested-by: Linus Torvalds Signed-off-by: Steven Rostedt (Google) Signed-off-by: Greg Kroah-Hartman --- 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 fc0f133eefdba..ad4c137b7be95 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 91c2bf0b91d9c..7d84349ade872 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; }; /*