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authorChristoph Hellwig <hch@lst.de>2022-06-14 09:48:24 +0200
committerJens Axboe <axboe@kernel.dk>2022-06-17 15:31:05 +0200
commit50e34d78815e474d410f342fbe783b18192ca518 (patch)
treec71b4e1bf63b621b1dba9a1e5b740b31f41d0552 /block
parentblock/bfq: Enable I/O statistics (diff)
downloadlinux-50e34d78815e474d410f342fbe783b18192ca518.tar.xz
linux-50e34d78815e474d410f342fbe783b18192ca518.zip
block: disable the elevator int del_gendisk
The elevator is only used for file system requests, which are stopped in del_gendisk. Move disabling the elevator and freeing the scheduler tags to the end of del_gendisk instead of doing that work in disk_release and blk_cleanup_queue to avoid a use after free on q->tag_set from disk_release as the tag_set might not be alive at that point. Move the blk_qos_exit call as well, as it just depends on the elevator exit and would be the only reason to keep the not exactly cheap queue freeze in disk_release. Fixes: e155b0c238b2 ("blk-mq: Use shared tags for shared sbitmap support") Reported-by: syzbot+3e3f419f4a7816471838@syzkaller.appspotmail.com Signed-off-by: Christoph Hellwig <hch@lst.de> Tested-by: syzbot+3e3f419f4a7816471838@syzkaller.appspotmail.com Link: https://lore.kernel.org/r/20220614074827.458955-2-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block')
-rw-r--r--block/blk-core.c13
-rw-r--r--block/genhd.c39
2 files changed, 11 insertions, 41 deletions
diff --git a/block/blk-core.c b/block/blk-core.c
index 06ff5bbfe8f6..27fb1357ad4b 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -322,19 +322,6 @@ void blk_cleanup_queue(struct request_queue *q)
blk_mq_exit_queue(q);
}
- /*
- * In theory, request pool of sched_tags belongs to request queue.
- * However, the current implementation requires tag_set for freeing
- * requests, so free the pool now.
- *
- * Queue has become frozen, there can't be any in-queue requests, so
- * it is safe to free requests now.
- */
- mutex_lock(&q->sysfs_lock);
- if (q->elevator)
- blk_mq_sched_free_rqs(q);
- mutex_unlock(&q->sysfs_lock);
-
/* @q is and will stay empty, shutdown and put */
blk_put_queue(q);
}
diff --git a/block/genhd.c b/block/genhd.c
index 27205ae47d59..e0675772178b 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -652,6 +652,17 @@ void del_gendisk(struct gendisk *disk)
blk_sync_queue(q);
blk_flush_integrity();
+ blk_mq_cancel_work_sync(q);
+
+ blk_mq_quiesce_queue(q);
+ if (q->elevator) {
+ mutex_lock(&q->sysfs_lock);
+ elevator_exit(q);
+ mutex_unlock(&q->sysfs_lock);
+ }
+ rq_qos_exit(q);
+ blk_mq_unquiesce_queue(q);
+
/*
* Allow using passthrough request again after the queue is torn down.
*/
@@ -1120,31 +1131,6 @@ static const struct attribute_group *disk_attr_groups[] = {
NULL
};
-static void disk_release_mq(struct request_queue *q)
-{
- blk_mq_cancel_work_sync(q);
-
- /*
- * There can't be any non non-passthrough bios in flight here, but
- * requests stay around longer, including passthrough ones so we
- * still need to freeze the queue here.
- */
- blk_mq_freeze_queue(q);
-
- /*
- * Since the I/O scheduler exit code may access cgroup information,
- * perform I/O scheduler exit before disassociating from the block
- * cgroup controller.
- */
- if (q->elevator) {
- mutex_lock(&q->sysfs_lock);
- elevator_exit(q);
- mutex_unlock(&q->sysfs_lock);
- }
- rq_qos_exit(q);
- __blk_mq_unfreeze_queue(q, true);
-}
-
/**
* disk_release - releases all allocated resources of the gendisk
* @dev: the device representing this disk
@@ -1166,9 +1152,6 @@ static void disk_release(struct device *dev)
might_sleep();
WARN_ON_ONCE(disk_live(disk));
- if (queue_is_mq(disk->queue))
- disk_release_mq(disk->queue);
-
blkcg_exit_queue(disk->queue);
disk_release_events(disk);