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tracefs: Zero out the tracefs_inode when allocating it

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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 <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Ajay Kaher <ajay.kaher@broadcom.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Fixes: 5790b1fb3d672 ("eventfs: Remove eventfs_file and just use eventfs_inode")
Reported-by: kernel test robot <oliver.sang@intel.com>
Closes: https://lore.kernel.org/oe-lkp/202401291043.e62e89dc-oliver.sang@intel.com
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
This commit is contained in:
Steven Rostedt (Google) 2024-01-31 13:49:19 -05:00
parent 66bbea9ed6
commit d81786f53a
2 changed files with 6 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
fs/tracefs/inode.c
View File

@ -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)

3
fs/tracefs/internal.h
View File

@ -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;
};
/*