From: Robin Murphy robin.murphy@arm.com
stable inclusion from linux-4.19.143 commit 9c9723816024195e6d68255e29db0dd4658f76ff
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[ 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 guptap@codeaurora.org Signed-off-by: Robin Murphy robin.murphy@arm.com Reviewed-by: Prakash Gupta guptap@codeaurora.org Link: https://lore.kernel.org/r/acbd2d092b42738a03a21b417ce64e27f8c91c86.159110329... Signed-off-by: Joerg Roedel jroedel@suse.de Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- 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 fd9ab92e9d1f..7f18dbeb7b7c 100644 --- a/drivers/iommu/iova.c +++ b/drivers/iommu/iova.c @@ -833,7 +833,9 @@ 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); }