From 0c98247932705214d189ddcf2f0fb5292612b4bc Mon Sep 17 00:00:00 2001 From: Robin Murphy Date: Tue, 2 Jun 2020 14:08:18 +0100 Subject: [PATCH] iommu/iova: Don't BUG on invalid PFNs [ Upstream commit d3e3d2be688b4b5864538de61e750721a311e4fc ] 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 Signed-off-by: Robin Murphy Reviewed-by: Prakash Gupta Link: https://lore.kernel.org/r/acbd2d092b42738a03a21b417ce64e27f8c91c86.1591103298.git.robin.murphy@arm.com Signed-off-by: Joerg Roedel Signed-off-by: Sasha Levin --- drivers/iommu/iova.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/iommu/iova.c b/drivers/iommu/iova.c index 4edf65dbbcab..2c97d2552c5b 100644 --- a/drivers/iommu/iova.c +++ b/drivers/iommu/iova.c @@ -845,7 +845,9 @@ 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); } -- 2.20.1