diff options
| author | Mikulas Patocka <mpatocka@redhat.com> | 2017-06-08 01:05:31 +0200 |
|---|---|---|
| committer | Shaohua Li <shli@fb.com> | 2017-06-13 19:18:02 +0200 |
| commit | f9c79bc05a2a91f4fba8bfd653579e066714b1ec (patch) | |
| tree | b5a229ab75dc24ca0387588e4ea38a9da23b1ce1 | |
| parent | md: fix deadlock between mddev_suspend() and md_write_start() (diff) | |
| download | linux-f9c79bc05a2a91f4fba8bfd653579e066714b1ec.tar.xz linux-f9c79bc05a2a91f4fba8bfd653579e066714b1ec.zip | |
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.c | 5 | ||||
| -rw-r--r-- | drivers/md/raid5.c | 5 |
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; |