fix regression in "epoll: Keep a reference on files added to the check list"

epoll_loop_check_proc() can run into a file already committed to destruction;
we can't grab a reference on those and don't need to add them to the set for
reverse path check anyway.

Tested-by: Marc Zyngier <maz@kernel.org>
Fixes: a9ed4a6560 ("epoll: Keep a reference on files added to the check list")
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2020-09-02 11:30:48 -04:00
parent 52c479697c
commit 77f4689de1

View File

@ -1995,9 +1995,9 @@ static int ep_loop_check_proc(void *priv, void *cookie, int call_nests)
* during ep_insert().
*/
if (list_empty(&epi->ffd.file->f_tfile_llink)) {
get_file(epi->ffd.file);
list_add(&epi->ffd.file->f_tfile_llink,
&tfile_check_list);
if (get_file_rcu(epi->ffd.file))
list_add(&epi->ffd.file->f_tfile_llink,
&tfile_check_list);
}
}
}