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| author | Jens Axboe <axboe@suse.de> | 2005-04-16 15:25:40 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:25:40 -0700 |
| commit | 4a534f93b371e8e6e87ae302757365f0f583e06b (patch) | |
| tree | f9ed5470c81bd63dba86f425a2c3731802000c79 /drivers/block/ll_rw_blk.c | |
| parent | 9c340d80f66faaea3522812d0d8c91d6a1b48a22 (diff) | |
| download | lwn-4a534f93b371e8e6e87ae302757365f0f583e06b.tar.gz lwn-4a534f93b371e8e6e87ae302757365f0f583e06b.zip | |
[PATCH] possible use-after-free of bio
There is a possibility that a bio will be accessed after it has been freed
on SCSI. It happens if you submit a bio with BIO_SYNC marked and the
auto-unplugging kicks the request_fn, SCSI re-enables interrupts in-between
so if the request completes between the add_request() in __make_request()
and the bio_sync() call, we could be looking at a dead bio. It's a slim
race, but it has been triggered in the Real World.
So assign bio_sync() to a local variable instead.
Signed-off-by: Jens Axboe <axboe@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'drivers/block/ll_rw_blk.c')
| -rw-r--r-- | drivers/block/ll_rw_blk.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/drivers/block/ll_rw_blk.c b/drivers/block/ll_rw_blk.c index 02242e8ba996..2d6934a02867 100644 --- a/drivers/block/ll_rw_blk.c +++ b/drivers/block/ll_rw_blk.c @@ -2559,7 +2559,7 @@ EXPORT_SYMBOL(__blk_attempt_remerge); static int __make_request(request_queue_t *q, struct bio *bio) { struct request *req, *freereq = NULL; - int el_ret, rw, nr_sectors, cur_nr_sectors, barrier, err; + int el_ret, rw, nr_sectors, cur_nr_sectors, barrier, err, sync; sector_t sector; sector = bio->bi_sector; @@ -2567,6 +2567,7 @@ static int __make_request(request_queue_t *q, struct bio *bio) cur_nr_sectors = bio_cur_sectors(bio); rw = bio_data_dir(bio); + sync = bio_sync(bio); /* * low level driver can indicate that it wants pages above a @@ -2698,7 +2699,7 @@ get_rq: out: if (freereq) __blk_put_request(q, freereq); - if (bio_sync(bio)) + if (sync) __generic_unplug_device(q); spin_unlock_irq(q->queue_lock); |