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authorMikulas Patocka <mpatocka@redhat.com>2017-06-07 19:05:31 -0400
committerShaohua Li <shli@fb.com>2017-06-13 10:18:02 -0700
commitf9c79bc05a2a91f4fba8bfd653579e066714b1ec (patch)
treeb5a229ab75dc24ca0387588e4ea38a9da23b1ce1
parentcc27b0c78c79680d128dbac79de0d40556d041bb (diff)
downloadlinux-f9c79bc05a2a91f4fba8bfd653579e066714b1ec.tar.bz2
md: don't use flush_signals in userspace processes
The function flush_signals clears all pending signals for the process. It may be used by kernel threads when we need to prepare a kernel thread for responding to signals. However using this function for an userspaces processes is incorrect - clearing signals without the program expecting it can cause misbehavior. The raid1 and raid5 code uses flush_signals in its request routine because it wants to prepare for an interruptible wait. This patch drops flush_signals and uses sigprocmask instead to block all signals (including SIGKILL) around the schedule() call. The signals are not lost, but the schedule() call won't respond to them. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Cc: stable@vger.kernel.org Acked-by: NeilBrown <neilb@suse.com> Signed-off-by: Shaohua Li <shli@fb.com>
-rw-r--r--drivers/md/raid1.c5
-rw-r--r--drivers/md/raid5.c5
2 files changed, 8 insertions, 2 deletions
diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index c71739b87ab7..7866563338fa 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -1334,7 +1334,7 @@ static void raid1_write_request(struct mddev *mddev, struct bio *bio,
*/
DEFINE_WAIT(w);
for (;;) {
- flush_signals(current);
+ sigset_t full, old;
prepare_to_wait(&conf->wait_barrier,
&w, TASK_INTERRUPTIBLE);
if (bio_end_sector(bio) <= mddev->suspend_lo ||
@@ -1344,7 +1344,10 @@ static void raid1_write_request(struct mddev *mddev, struct bio *bio,
bio->bi_iter.bi_sector,
bio_end_sector(bio))))
break;
+ sigfillset(&full);
+ sigprocmask(SIG_BLOCK, &full, &old);
schedule();
+ sigprocmask(SIG_SETMASK, &old, NULL);
}
finish_wait(&conf->wait_barrier, &w);
}
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index b218a42fd702..547d5fa45a42 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -5693,12 +5693,15 @@ static bool raid5_make_request(struct mddev *mddev, struct bio * bi)
* userspace, we want an interruptible
* wait.
*/
- flush_signals(current);
prepare_to_wait(&conf->wait_for_overlap,
&w, TASK_INTERRUPTIBLE);
if (logical_sector >= mddev->suspend_lo &&
logical_sector < mddev->suspend_hi) {
+ sigset_t full, old;
+ sigfillset(&full);
+ sigprocmask(SIG_BLOCK, &full, &old);
schedule();
+ sigprocmask(SIG_SETMASK, &old, NULL);
do_prepare = true;
}
goto retry;