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authorBart Van Assche <bart.vanassche@sandisk.com>2017-05-31 14:43:45 -0700
committerJens Axboe <axboe@fb.com>2017-06-01 13:07:55 -0600
commitb425e50492583b10cceb388af36ef0bd3bdf842a (patch)
tree646b41ed42cda808590a654ec0c3b3883f915af8 /block
parent5be6b75610cefd1e21b98a218211922c2feb6e08 (diff)
downloadlinux-sh-b425e50492583b10cceb388af36ef0bd3bdf842a.tar.gz
block: Avoid that blk_exit_rl() triggers a use-after-free
Since the introduction of .init_rq_fn() and .exit_rq_fn() it is essential that the memory allocated for struct request_queue stays around until all blk_exit_rl() calls have finished. Hence make blk_init_rl() take a reference on struct request_queue. This patch fixes the following crash: general protection fault: 0000 [#2] SMP CPU: 3 PID: 28 Comm: ksoftirqd/3 Tainted: G D 4.12.0-rc2-dbg+ #2 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.0.0-prebuilt.qemu-project.org 04/01/2014 task: ffff88013a108040 task.stack: ffffc9000071c000 RIP: 0010:free_request_size+0x1a/0x30 RSP: 0018:ffffc9000071fd38 EFLAGS: 00010202 RAX: 6b6b6b6b6b6b6b6b RBX: ffff880067362a88 RCX: 0000000000000003 RDX: ffff880067464178 RSI: ffff880067362a88 RDI: ffff880135ea4418 RBP: ffffc9000071fd40 R08: 0000000000000000 R09: 0000000100180009 R10: ffffc9000071fd38 R11: ffffffff81110800 R12: ffff88006752d3d8 R13: ffff88006752d3d8 R14: ffff88013a108040 R15: 000000000000000a FS: 0000000000000000(0000) GS:ffff88013fd80000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fa8ec1edb00 CR3: 0000000138ee8000 CR4: 00000000001406e0 Call Trace: mempool_destroy.part.10+0x21/0x40 mempool_destroy+0xe/0x10 blk_exit_rl+0x12/0x20 blkg_free+0x4d/0xa0 __blkg_release_rcu+0x59/0x170 rcu_process_callbacks+0x260/0x4e0 __do_softirq+0x116/0x250 smpboot_thread_fn+0x123/0x1e0 kthread+0x109/0x140 ret_from_fork+0x31/0x40 Fixes: commit e9c787e65c0c ("scsi: allocate scsi_cmnd structures as part of struct request") Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com> Acked-by: Tejun Heo <tj@kernel.org> Reviewed-by: Hannes Reinecke <hare@suse.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Cc: Jan Kara <jack@suse.cz> Cc: <stable@vger.kernel.org> # v4.11+ Signed-off-by: Jens Axboe <axboe@fb.com>
Diffstat (limited to 'block')
-rw-r--r--block/blk-cgroup.c2
-rw-r--r--block/blk-core.c10
-rw-r--r--block/blk-sysfs.c2
-rw-r--r--block/blk.h2
4 files changed, 11 insertions, 5 deletions
diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index 7c2947128f58..0480892e97e5 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -74,7 +74,7 @@ static void blkg_free(struct blkcg_gq *blkg)
blkcg_policy[i]->pd_free_fn(blkg->pd[i]);
if (blkg->blkcg != &blkcg_root)
- blk_exit_rl(&blkg->rl);
+ blk_exit_rl(blkg->q, &blkg->rl);
blkg_rwstat_exit(&blkg->stat_ios);
blkg_rwstat_exit(&blkg->stat_bytes);
diff --git a/block/blk-core.c b/block/blk-core.c
index c7068520794b..a7421b772d0e 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -648,13 +648,19 @@ int blk_init_rl(struct request_list *rl, struct request_queue *q,
if (!rl->rq_pool)
return -ENOMEM;
+ if (rl != &q->root_rl)
+ WARN_ON_ONCE(!blk_get_queue(q));
+
return 0;
}
-void blk_exit_rl(struct request_list *rl)
+void blk_exit_rl(struct request_queue *q, struct request_list *rl)
{
- if (rl->rq_pool)
+ if (rl->rq_pool) {
mempool_destroy(rl->rq_pool);
+ if (rl != &q->root_rl)
+ blk_put_queue(q);
+ }
}
struct request_queue *blk_alloc_queue(gfp_t gfp_mask)
diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c
index 712b018e9f54..283da7fbe034 100644
--- a/block/blk-sysfs.c
+++ b/block/blk-sysfs.c
@@ -809,7 +809,7 @@ static void blk_release_queue(struct kobject *kobj)
blk_free_queue_stats(q->stats);
- blk_exit_rl(&q->root_rl);
+ blk_exit_rl(q, &q->root_rl);
if (q->queue_tags)
__blk_queue_free_tags(q);
diff --git a/block/blk.h b/block/blk.h
index 2ed70228e44f..83c8e1100525 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -59,7 +59,7 @@ void blk_free_flush_queue(struct blk_flush_queue *q);
int blk_init_rl(struct request_list *rl, struct request_queue *q,
gfp_t gfp_mask);
-void blk_exit_rl(struct request_list *rl);
+void blk_exit_rl(struct request_queue *q, struct request_list *rl);
void blk_rq_bio_prep(struct request_queue *q, struct request *rq,
struct bio *bio);
void blk_queue_bypass_start(struct request_queue *q);