Commit e5bc49ba authored Mar 12, 2009 by Oleg Nesterov Committed by Linus Torvalds Mar 12, 2009

pipe_rdwr_fasync: fix the error handling to prevent the leak/crash



If the second fasync_helper() fails, pipe_rdwr_fasync() returns the error
but leaves the file on ->fasync_readers.

This was always wrong, but since 233e70f4
"saner FASYNC handling on file close" we have the new problem.  Because in
this case setfl() doesn't set FASYNC bit, __fput() will not do
->fasync(0), and we leak fasync_struct with ->fa_file pointing to the
freed file.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 8d0df7a3

fs/pipe.c

+4 −4

Original line number	Diff line number	Diff line
		@@ -699,12 +699,12 @@ pipe_rdwr_fasync(int fd, struct file *filp, int on)
		int retval;

		mutex_lock(&inode->i_mutex);

		retval = fasync_helper(fd, filp, on, &pipe->fasync_readers);

		if (retval >= 0)
		if (retval >= 0) {
		retval = fasync_helper(fd, filp, on, &pipe->fasync_writers);

		if (retval < 0) /* this can happen only if on == T */
		fasync_helper(-1, filp, 0, &pipe->fasync_readers);
		}
		mutex_unlock(&inode->i_mutex);

		if (retval < 0)