[PATCH] mmc: vub300: fix sleeping function call from invalid context in vub300_inactivity_timer_expired

[Jakov Novak <jakovnovak30@gmail.com>]

 Currently, the function vub300_inactivity_timer_expired, which gets
 called in a softirq context, calls a sleeping function in the following
 call chain:

 vub300_inactivity_timer_expired -> kref_put -> vub300_delete ->
 mmc_free_host -> cancel_delayed_work_sync -> __cancel_work_sync ->
 might_sleep -> BUG

 Fix this by replacing kref_put(&vub300->kref, vub300_delete) with
 vub300_queue_dead_work(vub300), which does the same thing, but in a
 workqueue context.

Fixes: 88095e7b473a ("mmc: Add new VUB300 USB-to-SD/SDIO/MMC driver")
Reported-and-tested-by: syzbot+1ee4f3b9228e35f14677@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=1ee4f3b9228e35f14677
Signed-off-by: Jakov Novak <jakovnovak30@gmail.com>
---
 drivers/mmc/host/vub300.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/mmc/host/vub300.c b/drivers/mmc/host/vub300.c
index 2dae474dcd06..df0096bc53db 100644
--- a/drivers/mmc/host/vub300.c
+++ b/drivers/mmc/host/vub300.c
@@ -744,7 +744,7 @@ static void vub300_inactivity_timer_expired(struct timer_list *t)
 	struct vub300_mmc_host *vub300 = timer_container_of(vub300, t,
 							    inactivity_timer);
 	if (!vub300->interface) {
-		kref_put(&vub300->kref, vub300_delete);
+		vub300_queue_dead_work(vub300);
 	} else if (vub300->cmd) {
 		mod_timer(&vub300->inactivity_timer, jiffies + HZ);
 	} else {
-- 
2.55.0