diff options
| author | Shaohua Li <shli@fb.com> | 2015-09-02 22:49:47 +0200 |
|---|---|---|
| committer | NeilBrown <neilb@suse.com> | 2015-11-01 03:48:26 +0100 |
| commit | 0fd22b45b2d2e1de162d6a47327d449e0ed45ad2 (patch) | |
| tree | 19405695d4fee2c0d07ede5af8d95e54952c459b /drivers | |
| parent | raid5-cache: switching to state machine for log disk cache flush (diff) | |
| download | linux-0fd22b45b2d2e1de162d6a47327d449e0ed45ad2.tar.xz linux-0fd22b45b2d2e1de162d6a47327d449e0ed45ad2.zip | |
raid5-cache: fix a user-after-free bug
r5l_compress_stripe_end_list() can free an io_unit. This breaks the
assumption only reclaimer can free io_unit. We can add a reference count
based io_unit free, but since only reclaim can wait io_unit becoming to
STRIPE_END state, we use a simple global wait queue here.
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: NeilBrown <neilb@suse.com>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/md/raid5-cache.c | 18 |
1 files changed, 7 insertions, 11 deletions
diff --git a/drivers/md/raid5-cache.c b/drivers/md/raid5-cache.c index 41542ebd813b..496f8e2578cc 100644 --- a/drivers/md/raid5-cache.c +++ b/drivers/md/raid5-cache.c @@ -79,6 +79,7 @@ struct r5l_log { * dones't wait for specific io_unit * switching to IO_UNIT_STRIPE_END * state) */ + wait_queue_head_t iounit_wait; struct list_head no_space_stripes; /* pending stripes, log has no space */ spinlock_t no_space_stripes_lock; @@ -109,7 +110,6 @@ struct r5l_io_unit { struct list_head stripe_list; /* stripes added to the io_unit */ int state; - wait_queue_head_t wait_state; }; /* r5l_io_unit state */ @@ -162,7 +162,6 @@ static struct r5l_io_unit *r5l_alloc_io_unit(struct r5l_log *log) INIT_LIST_HEAD(&io->log_sibling); INIT_LIST_HEAD(&io->stripe_list); io->state = IO_UNIT_RUNNING; - init_waitqueue_head(&io->wait_state); return io; } @@ -243,8 +242,8 @@ static void __r5l_set_io_unit_state(struct r5l_io_unit *io, r5l_wake_reclaim(log, 0); r5l_compress_stripe_end_list(log); + wake_up(&log->iounit_wait); } - wake_up(&io->wait_state); } static void r5l_set_io_unit_state(struct r5l_io_unit *io, @@ -622,10 +621,11 @@ void r5l_flush_stripe_to_raid(struct r5l_log *log) submit_bio(WRITE_FLUSH, &log->flush_bio); } -static void r5l_kick_io_unit(struct r5l_log *log, struct r5l_io_unit *io) +static void r5l_kick_io_unit(struct r5l_log *log) { md_wakeup_thread(log->rdev->mddev->thread); - wait_event(io->wait_state, io->state >= IO_UNIT_STRIPE_END); + wait_event_lock_irq(log->iounit_wait, !list_empty(&log->stripe_end_ios), + log->io_list_lock); } static void r5l_write_super(struct r5l_log *log, sector_t cp); @@ -670,12 +670,7 @@ static void r5l_do_reclaim(struct r5l_log *log) else if (!list_empty(&log->running_ios)) target_list = &log->running_ios; - io = list_first_entry(target_list, - struct r5l_io_unit, log_sibling); - spin_unlock_irq(&log->io_list_lock); - /* nobody else can delete the io, we are safe */ - r5l_kick_io_unit(log, io); - spin_lock_irq(&log->io_list_lock); + r5l_kick_io_unit(log); } spin_unlock_irq(&log->io_list_lock); @@ -1079,6 +1074,7 @@ int r5l_init_log(struct r5conf *conf, struct md_rdev *rdev) log->rdev->mddev, "reclaim"); if (!log->reclaim_thread) goto reclaim_thread; + init_waitqueue_head(&log->iounit_wait); INIT_LIST_HEAD(&log->no_space_stripes); spin_lock_init(&log->no_space_stripes_lock); |