On 6/7/18 8:46 AM, Jens Axboe wrote: > On 6/7/18 12:33 AM, Chunyu Hu wrote: >> kasan reported a user-after-free. I'm using a kvm machine, it panic >> during boot. I'm using the latest linux tree. which contains below. >> >> commit d377535405686f735b90a8ad4ba269484cd7c96e >> Author: Kent Overstreet <kent.overstreet@xxxxxxxxx> >> Date: Tue Jun 5 05:26:33 2018 -0400 >> >> dm: Use kzalloc for all structs with embedded biosets/mempools > > Can you try with the below? Li Wang, would be great if you could too. Please try this one instead. diff --git a/block/bio.c b/block/bio.c index 595663e0281a..0616d86b15c6 100644 --- a/block/bio.c +++ b/block/bio.c @@ -1967,6 +1967,21 @@ int bioset_init(struct bio_set *bs, } EXPORT_SYMBOL(bioset_init); +int bioset_init_from_src(struct bio_set *new, struct bio_set *src) +{ + unsigned int pool_size = src->bio_pool.min_nr; + int flags; + + flags = 0; + if (src->bvec_pool.min_nr) + flags |= BIOSET_NEED_BVECS; + if (src->rescue_workqueue) + flags |= BIOSET_NEED_RESCUER; + + return bioset_init(new, pool_size, src->front_pad, flags); +} +EXPORT_SYMBOL(bioset_init_from_src); + #ifdef CONFIG_BLK_CGROUP /** diff --git a/drivers/md/dm.c b/drivers/md/dm.c index 98dff36b89a3..20a8d63754bf 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -1953,9 +1953,10 @@ static void free_dev(struct mapped_device *md) kvfree(md); } -static void __bind_mempools(struct mapped_device *md, struct dm_table *t) +static int __bind_mempools(struct mapped_device *md, struct dm_table *t) { struct dm_md_mempools *p = dm_table_get_md_mempools(t); + int ret = 0; if (dm_table_bio_based(t)) { /* @@ -1982,13 +1983,16 @@ static void __bind_mempools(struct mapped_device *md, struct dm_table *t) bioset_initialized(&md->bs) || bioset_initialized(&md->io_bs)); - md->bs = p->bs; - memset(&p->bs, 0, sizeof(p->bs)); - md->io_bs = p->io_bs; - memset(&p->io_bs, 0, sizeof(p->io_bs)); + ret = bioset_init_from_src(&md->bs, &p->bs); + if (ret) + goto out; + ret = bioset_init_from_src(&md->io_bs, &p->io_bs); + if (ret) + bioset_exit(&md->bs); out: /* mempool bind completed, no longer need any mempools in the table */ dm_table_free_md_mempools(t); + return ret; } /* @@ -2033,6 +2037,7 @@ static struct dm_table *__bind(struct mapped_device *md, struct dm_table *t, struct request_queue *q = md->queue; bool request_based = dm_table_request_based(t); sector_t size; + int ret; lockdep_assert_held(&md->suspend_lock); @@ -2068,7 +2073,11 @@ static struct dm_table *__bind(struct mapped_device *md, struct dm_table *t, md->immutable_target = dm_table_get_immutable_target(t); } - __bind_mempools(md, t); + ret = __bind_mempools(md, t); + if (ret) { + old_map = ERR_PTR(ret); + goto out; + } old_map = rcu_dereference_protected(md->map, lockdep_is_held(&md->suspend_lock)); rcu_assign_pointer(md->map, (void *)t); @@ -2078,6 +2087,7 @@ static struct dm_table *__bind(struct mapped_device *md, struct dm_table *t, if (old_map) dm_sync_table(md); +out: return old_map; } diff --git a/include/linux/bio.h b/include/linux/bio.h index 810a8bee8f85..307682ac2f31 100644 --- a/include/linux/bio.h +++ b/include/linux/bio.h @@ -417,6 +417,7 @@ enum { extern int bioset_init(struct bio_set *, unsigned int, unsigned int, int flags); extern void bioset_exit(struct bio_set *); extern int biovec_init_pool(mempool_t *pool, int pool_entries); +extern int bioset_init_from_src(struct bio_set *new, struct bio_set *src); extern struct bio *bio_alloc_bioset(gfp_t, unsigned int, struct bio_set *); extern void bio_put(struct bio *); -- Jens Axboe