Prior to the change the function would blindly deference mm, exe_file and exe_file->f_inode, each of which could have been NULL or freed.
Use get_task_exe_file to safely obtain stable exe_file. Signed-off-by: Mateusz Guzik <mgu...@redhat.com> Acked-by: Konstantin Khlebnikov <khlebni...@yandex-team.ru> --- kernel/audit_watch.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/kernel/audit_watch.c b/kernel/audit_watch.c index d6709eb..0d302a8 100644 --- a/kernel/audit_watch.c +++ b/kernel/audit_watch.c @@ -19,6 +19,7 @@ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ +#include <linux/file.h> #include <linux/kernel.h> #include <linux/audit.h> #include <linux/kthread.h> @@ -544,10 +545,11 @@ int audit_exe_compare(struct task_struct *tsk, struct audit_fsnotify_mark *mark) unsigned long ino; dev_t dev; - rcu_read_lock(); - exe_file = rcu_dereference(tsk->mm->exe_file); + exe_file = get_task_exe_file(tsk); + if (!exe_file) + return 0; ino = exe_file->f_inode->i_ino; dev = exe_file->f_inode->i_sb->s_dev; - rcu_read_unlock(); + fput(exe_file); return audit_mark_compare(mark, ino, dev); } -- 1.8.3.1