Messages in this thread Patch in this message |  | | From | Soeren Moch <> | Subject | [PATCH] Revert "usb: core: remove local_irq_save() around ->complete() handler" | Date | Fri, 31 May 2019 23:53:40 +0200 |
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This reverts commit ed194d1367698a0872a2b75bbe06b3932ce9df3a.
In contrast to the original patch description, apparently not all handlers were audited properly. E.g. my RT5370 based USB WIFI adapter (driver in drivers/net/wireless/ralink/rt2x00) hangs after a while under heavy load. This revert fixes this.
Also revert the follow-up patch d6142b91e9cc249b3aa22c90fade67e2e2d52cdb ("usb: core: remove flags variable in __usb_hcd_giveback_urb()"), since now we need the flags variable again.
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Alan Stern <stern@rowland.harvard.edu> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: linux-usb@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: stable@vger.kernel.org # 4.20+ Signed-off-by: Soeren Moch <smoch@web.de> --- drivers/usb/core/hcd.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+)
diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c index 94d22551fc1b..08d25fcf8b8e 100644 --- a/drivers/usb/core/hcd.c +++ b/drivers/usb/core/hcd.c @@ -1739,6 +1739,7 @@ static void __usb_hcd_giveback_urb(struct urb *urb) struct usb_hcd *hcd = bus_to_hcd(urb->dev->bus); struct usb_anchor *anchor = urb->anchor; int status = urb->unlinked; + unsigned long flags;
urb->hcpriv = NULL; if (unlikely((urb->transfer_flags & URB_SHORT_NOT_OK) && @@ -1755,7 +1756,20 @@ static void __usb_hcd_giveback_urb(struct urb *urb)
/* pass ownership to the completion handler */ urb->status = status; + + /* + * We disable local IRQs here avoid possible deadlock because + * drivers may call spin_lock() to hold lock which might be + * acquired in one hard interrupt handler. + * + * The local_irq_save()/local_irq_restore() around complete() + * will be removed if current USB drivers have been cleaned up + * and no one may trigger the above deadlock situation when + * running complete() in tasklet. + */ + local_irq_save(flags); urb->complete(urb); + local_irq_restore(flags);
usb_anchor_resume_wakeups(anchor); atomic_dec(&urb->use_count); -- 2.17.1
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