Merge tag 'fs.v6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/idmapping

Pull vfs hardening update from Christian Brauner:
 "Jan pointed out that during shutdown both filp_close() and super block
  destruction will use basic printk logging when bugs are detected. This
  causes issues in a few scenarios:

   - Tools like syzkaller cannot figure out that the logged message
     indicates a bug.

   - Users that explicitly opt in to have the kernel bug on data
     corruption by selecting CONFIG_BUG_ON_DATA_CORRUPTION should see
     the kernel crash when they did actually select that option.

   - When there are busy inodes after the superblock is shut down later
     access to such a busy inodes walks through freed memory. It would
     be better to cleanly crash instead.

  All of this can be addressed by using the already existing
  CHECK_DATA_CORRUPTION() macro in these places when kernel bugs are
  detected. Its logging improvement is useful for all users.

  Otherwise this only has a meaningful behavioral effect when users do
  select CONFIG_BUG_ON_DATA_CORRUPTION which means this is backward
  compatible for regular users"

* tag 'fs.v6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/idmapping:
  fs: Use CHECK_DATA_CORRUPTION() when kernel bugs are detected

1 files changed, 3 insertions, 2 deletions

diff --git a/fs/open.c b/fs/open.c
index 68051c1c0579..8038cf652583 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -1413,8 +1413,9 @@ int filp_close(struct file *filp, fl_owner_t id)
 {
 	int retval = 0;
 
-	if (!file_count(filp)) {
-		printk(KERN_ERR "VFS: Close: file count is 0\n");
+	if (CHECK_DATA_CORRUPTION(file_count(filp) == 0,
+			"VFS: Close: file count is 0 (f_op=%ps)",
+			filp->f_op)) {
 		return 0;
 	}