@@ -804,6 +804,31 @@ 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);
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.alexander00@gmail.com> Fixes: a063057d7c73 ("block: Fix a race between request queue removal and the block cgroup controller") Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com> Tested-by: Alexandru Moise <00moses.alexander00@gmail.com> Cc: Tejun Heo <tj@kernel.org> Cc: Alexandru Moise <00moses.alexander00@gmail.com> Cc: Joseph Qi <joseph.qi@linux.alibaba.com> --- block/blk-sysfs.c | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+)