mei: me: do not reset when less than expected data is received (b1b94b5d) · Commits · 戴 / test

There is a race in ME hardware between data copy for host and interrupt delivery. An interrupt can be delivered prior to whole data copied for the host to read but rather then going trough the reset we just merely need to wait for the next interrupt. The bug is visible in read/write stress with multiple connections per client This is a regression caused as a side effect of the commit: commit mei: do not run reset flow from the interrupt thread Signed-off-by:

Tomas Winkler <tomas.winkler@intel.com> Cc: stable <stable@vger.kernel.org> # 3.14 Signed-off-by:

Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/misc/mei/hw-me.c

+9 −0

Original line number	Diff line number	Diff line
		@@ -507,7 +507,16 @@ irqreturn_t mei_me_irq_thread_handler(int irq, void *dev_id)
		while (slots > 0) {
		dev_dbg(&dev->pdev->dev, "slots to read = %08x\n", slots);
		rets = mei_irq_read_handler(dev, &complete_list, &slots);
		/* There is a race between ME write and interrupt delivery:
		* Not all data is always available immediately after the
		* interrupt, so try to read again on the next interrupt.
		*/
		if (rets == -ENODATA)
		break;

		if (rets && dev->dev_state != MEI_DEV_RESETTING) {
		dev_err(&dev->pdev->dev, "mei_irq_read_handler ret = %d.\n",
		rets);
		schedule_work(&dev->reset_work);
		goto end;
		}

drivers/misc/mei/interrupt.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -351,7 +351,7 @@ int mei_irq_read_handler(struct mei_device *dev,
		dev_err(&dev->pdev->dev, "less data available than length=%08x.\n",
		*slots);
		/* we can't read the message */
		ret = -EBADMSG;
		ret = -ENODATA;
		goto end;
		}

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