On 2020-06-02 18:38, Robin Murphy wrote:
Unlike the other instances which represent a complete loss of consistency within the rcache mechanism itself, or a fundamental and obvious misconfiguration by an IOMMU driver, the BUG_ON() in iova_magazine_free_pfns() can be provoked at more or less any time in a "spooky action-at-a-distance" manner by any old device driver passing nonsense to dma_unmap_*() which then propagates through to queue_iova().
Not only is this well outside the IOVA layer's control, it's also nowhere near fatal enough to justify panicking anyway - all that really achieves is to make debugging the offending driver more difficult. Let's simply WARN and otherwise ignore bogus PFNs.
Reported-by: Prakash Gupta guptap@codeaurora.org Signed-off-by: Robin Murphy robin.murphy@arm.com
drivers/iommu/iova.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
Copying stable@vger.kernel.org
You can add Reviewed-by: Prakash Gupta guptap@codeaurora.org
diff --git a/drivers/iommu/iova.c b/drivers/iommu/iova.c index 0e6a9536eca6..612cbf668adf 100644 --- a/drivers/iommu/iova.c +++ b/drivers/iommu/iova.c @@ -811,7 +811,9 @@ iova_magazine_free_pfns(struct iova_magazine *mag, struct iova_domain *iovad) for (i = 0 ; i < mag->size; ++i) { struct iova *iova = private_find_iova(iovad, mag->pfns[i]);
BUG_ON(!iova);
if (WARN_ON(!iova))continue;- private_free_iova(iovad, iova); }