3.2.94-rc1 review patch. If anyone has any objections, please let me know.
------------------ From: Mikulas Patocka <[email protected]> commit f9c79bc05a2a91f4fba8bfd653579e066714b1ec upstream. 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 <[email protected]> Acked-by: NeilBrown <[email protected]> Signed-off-by: Shaohua Li <[email protected]> [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings <[email protected]> --- --- a/drivers/md/raid1.c +++ b/drivers/md/raid1.c @@ -875,13 +875,16 @@ static void make_request(struct mddev *m */ DEFINE_WAIT(w); for (;;) { - flush_signals(current); + sigset_t full, old; prepare_to_wait(&conf->wait_barrier, &w, TASK_INTERRUPTIBLE); if (bio->bi_sector + bio->bi_size/512 <= mddev->suspend_lo || bio->bi_sector >= mddev->suspend_hi) break; + sigfillset(&full); + sigprocmask(SIG_BLOCK, &full, &old); schedule(); + sigprocmask(SIG_SETMASK, &old, NULL); } finish_wait(&conf->wait_barrier, &w); } --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -3823,12 +3823,16 @@ static void make_request(struct mddev *m * 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) + logical_sector < mddev->suspend_hi) { + sigset_t full, old; + sigfillset(&full); + sigprocmask(SIG_BLOCK, &full, &old); schedule(); + sigprocmask(SIG_SETMASK, &old, NULL); + } goto retry; }
