The expected logic of proc_map_files_get_link() is either to return 0
and initialize 'path' or return an error and leave 'path' uninitialized.
By the time dname_to_vma_addr() returns 0 the corresponding vma may have
already be gone. In this case the path is not initialized but the
return value is still 0. This results in 'general protection fault'
inside d_path().
Steps to reproduce:
CONFIG_CHECKPOINT_RESTORE=y
fd = open(...);
while (1) {
mmap(fd, ...);
munmap(fd, ...);
}
ls -la /proc/$PID/map_files
Addresses https://bugzilla.kernel.org/show_bug.cgi?id=68991
Signed-off-by: Artem Fetishev <artem_fetishev@epam.com>
Signed-off-by: Aleksandr Terekhov <aleksandr_terekhov@epam.com>
Reported-by: <wiebittewas@gmail.com>
Acked-by: Pavel Emelyanov <xemul@parallels.com>
Acked-by: Cyrill Gorcunov <gorcunov@openvz.org>
Reviewed-by: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
70335abb26