mm: use down_read_killable for locking mmap_sem in access_remote_vm
This function is used by ptrace and proc files like /proc/pid/cmdline and /proc/pid/environ. Access_remote_vm never returns error codes, all errors are ignored and only size of successfully read data is returned. So, if current task was killed we'll simply return 0 (bytes read). Mmap_sem could be locked for a long time or forever if something goes wrong. Using a killable lock permits cleanup of stuck tasks and simplifies investigation. Link: http://lkml.kernel.org/r/156007494202.3335.16782303099589302087.stgit@buzz Signed-off-by:Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Reviewed-by:
Michal Koutný <mkoutny@suse.com> Acked-by:
Oleg Nesterov <oleg@redhat.com> Acked-by:
Michal Hocko <mhocko@suse.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Cyrill Gorcunov <gorcunov@gmail.com> Cc: Kirill Tkhai <ktkhai@virtuozzo.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Roman Gushchin <guro@fb.com> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
parent
cd9e2bb8