Re: [PATCH v2] dmaengine: idxd: avoid deadlock in process_misc_interrupts()

From: Dave Jiang
Date: Tue Aug 23 2022 - 14:27:27 EST



On 8/23/2022 9:37 AM, Jerry Snitselaar wrote:
idxd_device_clear_state() now grabs the idxd->dev_lock
itself, so don't grab the lock prior to calling it.

This was seen in testing after dmar fault occurred on system,
resulting in lockup stack traces.

Cc: Fenghua Yu <fenghua.yu@xxxxxxxxx>
Cc: Dave Jiang <dave.jiang@xxxxxxxxx>
Cc: Vinod Koul <vkoul@xxxxxxxxxx>
Cc: dmaengine@xxxxxxxxxxxxxxx
Fixes: cf4ac3fef338 ("dmaengine: idxd: fix lockdep warning on device driver removal")
Signed-off-by: Jerry Snitselaar <jsnitsel@xxxxxxxxxx>

Thanks Jerry!

Reviewed-by: Dave Jiang <dave.jiang@xxxxxxxxx>

---
v2: add Fixes tag, and add subsystem to summary

drivers/dma/idxd/irq.c | 2 --
1 file changed, 2 deletions(-)

diff --git a/drivers/dma/idxd/irq.c b/drivers/dma/idxd/irq.c
index 743ead5ebc57..5b9921475be6 100644
--- a/drivers/dma/idxd/irq.c
+++ b/drivers/dma/idxd/irq.c
@@ -324,13 +324,11 @@ static int process_misc_interrupts(struct idxd_device *idxd, u32 cause)
idxd->state = IDXD_DEV_HALTED;
idxd_wqs_quiesce(idxd);
idxd_wqs_unmap_portal(idxd);
- spin_lock(&idxd->dev_lock);
idxd_device_clear_state(idxd);
dev_err(&idxd->pdev->dev,
"idxd halted, need %s.\n",
gensts.reset_type == IDXD_DEVICE_RESET_FLR ?
"FLR" : "system reset");
- spin_unlock(&idxd->dev_lock);
return -ENXIO;
}
}