a7y18lte-ubports/android_kernel_samsung_universal7885
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vfs: fix deadlock in file_remove_privs() on overlayfs

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commit c1892c37769cf89c7e7ba57528ae2ccb5d153c9b upstream.

file_remove_privs() is called with inode lock on file_inode(), which
proceeds to calling notify_change() on file->f_path.dentry.  Which triggers
the WARN_ON_ONCE(!inode_is_locked(inode)) in addition to deadlocking later
when ovl_setattr tries to lock the underlying inode again.

Fix this mess by not mixing the layers, but doing everything on underlying
dentry/inode.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Fixes: 07a2daab49c5 ("ovl: Copy up underlying inode's ->i_mode to overlay inode")
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Miklos Szeredi 2016-08-03 13:44:27 +02:00 committed by Greg Kroah-Hartman
parent 33f9cff6ec
commit 8e510cd921
1 changed files with 3 additions and 3 deletions
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6
fs/inode.c
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@ -1733,8 +1733,8 @@ static int __remove_privs(struct dentry *dentry, int kill)
*/
int file_remove_privs(struct file *file)
{
struct dentry *dentry = file->f_path.dentry;
struct inode *inode = d_inode(dentry);
struct dentry *dentry = file_dentry(file);
struct inode *inode = file_inode(file);
int kill;
int error = 0;
@ -1742,7 +1742,7 @@ int file_remove_privs(struct file *file)
if (IS_NOSEC(inode))
return 0;
kill = file_needs_remove_privs(file);
kill = dentry_needs_remove_privs(dentry);
if (kill < 0)
return kill;
if (kill)