mirrors/linux-stable
1
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git synced 2024-09-21 10:01:00 +00:00
Code Issues Releases Wiki Activity

usb: musb: Fix runtime PM race in musb_queue_resume_work

Browse source 
commit 0eaa1a3714 upstream.

musb_queue_resume_work() would call the provided callback if the runtime
PM status was 'active'. Otherwise, it would enqueue the request if the
hardware was still suspended (musb->is_runtime_suspended is true).

This causes a race with the runtime PM handlers, as it is possible to be
in the case where the runtime PM status is not yet 'active', but the
hardware has been awaken (PM resume function has been called).

When hitting the race, the resume work was not enqueued, which probably
triggered other bugs further down the stack. For instance, a telnet
connection on Ingenic SoCs would result in a 50/50 chance of a
segmentation fault somewhere in the musb code.

Rework the code so that either we call the callback directly if
(musb->is_runtime_suspended == 0), or enqueue the query otherwise.

Fixes: ea2f35c01d ("usb: musb: Fix sleeping function called from invalid context for hdrc glue")
Cc: stable@vger.kernel.org # v4.9+
Tested-by: Tony Lindgren <tony@atomide.com>
Reviewed-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Link: https://lore.kernel.org/r/20210123142502.16980-1-paul@crapouillou.net
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Paul Cercueil 2021-01-23 14:24:59 +00:00 committed by Greg Kroah-Hartman
parent a82ba907a8
commit 1cf76e4ca6
1 changed files with 18 additions and 15 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

33
drivers/usb/musb/musb_core.c
View file

@ -2240,32 +2240,35 @@ int musb_queue_resume_work(struct musb *musb,
{
struct musb_pending_work *w;
unsigned long flags;
bool is_suspended;
int error;
if (WARN_ON(!callback))
return -EINVAL;
if (pm_runtime_active(musb->controller))
return callback(musb, data);
w = devm_kzalloc(musb->controller, sizeof(*w), GFP_ATOMIC);
if (!w)
return -ENOMEM;
w->callback = callback;
w->data = data;
spin_lock_irqsave(&musb->list_lock, flags);
if (musb->is_runtime_suspended) {
is_suspended = musb->is_runtime_suspended;
if (is_suspended) {
w = devm_kzalloc(musb->controller, sizeof(*w), GFP_ATOMIC);
if (!w) {
error = -ENOMEM;
goto out_unlock;
}
w->callback = callback;
w->data = data;
list_add_tail(&w->node, &musb->pending_list);
error = 0;
} else {
dev_err(musb->controller, "could not add resume work %p\n",
callback);
devm_kfree(musb->controller, w);
error = -EINPROGRESS;
}
out_unlock:
spin_unlock_irqrestore(&musb->list_lock, flags);
if (!is_suspended)
error = callback(musb, data);
return error;
}
EXPORT_SYMBOL_GPL(musb_queue_resume_work);