Commit 553698f9 authored by Jens Axboe's avatar Jens Axboe Committed by Linus Torvalds

[PATCH] cfq-iosched: fix crash in do_div()

We don't clear the seek stat values in cfq_alloc_io_context(), and if
->seek_mean is unlucky enough to be set to -36 by chance, the first
invocation of cfq_update_io_seektime() will oops with a divide by zero
in do_div().

Just memset the entire cic instead of filling invididual values
independently.
Signed-off-by: default avatarJens Axboe <axboe@suse.de>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 9cedc194
......@@ -1323,17 +1323,12 @@ cfq_alloc_io_context(struct cfq_data *cfqd, gfp_t gfp_mask)
struct cfq_io_context *cic = kmem_cache_alloc(cfq_ioc_pool, gfp_mask);
if (cic) {
RB_CLEAR(&cic->rb_node);
cic->key = NULL;
cic->cfqq[ASYNC] = NULL;
cic->cfqq[SYNC] = NULL;
memset(cic, 0, sizeof(*cic));
RB_CLEAR_COLOR(&cic->rb_node);
cic->last_end_request = jiffies;
cic->ttime_total = 0;
cic->ttime_samples = 0;
cic->ttime_mean = 0;
INIT_LIST_HEAD(&cic->queue_list);
cic->dtor = cfq_free_io_context;
cic->exit = cfq_exit_io_context;
INIT_LIST_HEAD(&cic->queue_list);
atomic_inc(&ioc_count);
}
......
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