Several block drivers call alloc_disk() followed by put_disk() if
something fails before device_add_disk() is called without calling
blk_cleanup_queue(). Make sure that also for this scenario a request
queue is dissociated from the cgroup controller. This patch avoids
that loading the parport_pc, paride and pf drivers triggers the
following kernel crash:
BUG: KASAN: null-ptr-deref in pi_init+0x42e/0x580 [paride]
Read of size 4 at addr 0000000000000008 by task modprobe/744
Call Trace:
dump_stack+0x9a/0xeb
kasan_report+0x139/0x350
pi_init+0x42e/0x580 [paride]
pf_init+0x2bb/0x1000 [pf]
do_one_initcall+0x8e/0x405
do_init_module+0xd9/0x2f2
load_module+0x3ab4/0x4700
SYSC_finit_module+0x176/0x1a0
do_syscall_64+0xee/0x2b0
entry_SYSCALL_64_after_hwframe+0x42/0xb7
Reported-by: Alexandru Moise <00moses.alexande...@gmail.com>
Fixes: a063057d7c73 ("block: Fix a race between request queue removal and the
block cgroup controller") # v4.17
Signed-off-by: Bart Van Assche <bart.vanass...@wdc.com>
Tested-by: Alexandru Moise <00moses.alexande...@gmail.com>
Cc: Tejun Heo <t...@kernel.org>
Cc: Christoph Hellwig <h...@lst.de>
Cc: Ming Lei <ming....@redhat.com>
Cc: Johannes Thumshirn <jthumsh...@suse.de>
Cc: Alexandru Moise <00moses.alexande...@gmail.com>
Cc: Joseph Qi <joseph...@linux.alibaba.com>
Cc: <sta...@vger.kernel.org>
---
block/blk-sysfs.c | 25 +++++++++++++++++++++++++
1 file changed, 25 insertions(+)
diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c
index ca1984ecbdeb..26275d9babcb 100644
--- a/block/blk-sysfs.c
+++ b/block/blk-sysfs.c
@@ -802,6 +802,31 @@ static void __blk_release_queue(struct work_struct *work)
blk_stat_remove_callback(q, q->poll_cb);
blk_stat_free_callback(q->poll_cb);
+ if (!blk_queue_dead(q)) {
+ /*
+ * Last reference was dropped without having called
+ * blk_cleanup_queue().
+ */
+ WARN_ONCE(blk_queue_init_done(q),
+ "request queue %p has been registered but
blk_cleanup_queue() has not been called for that queue\n",
+ q);
+ blk_exit_queue(q);
+ }
+
+#ifdef CONFIG_BLK_CGROUP
+ {
+ struct blkcg_gq *blkg;
+
+ rcu_read_lock();
+ blkg = blkg_lookup(&blkcg_root, q);
+ rcu_read_unlock();
+
+ WARN(blkg,
+ "request queue %p is being released but it has not yet
been removed from the blkcg controller\n",
+ q);
+ }
+#endif
+
blk_free_queue_stats(q->stats);
blk_exit_rl(q, &q->root_rl);
--
2.18.0
