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authorJoerg Roedel <jroedel@suse.de>2019-09-06 11:39:54 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2019-09-21 08:17:14 +0300
commit0d50f7b1e8c80a8c20db5049e269468c059b0378 (patch)
tree9001e920f9d7ba9dd2b3f54a141dd8bd20264ee7 /block/blk-merge.c
parent52f32e4aec5051991ccc9aa19cf940e46a7c66f1 (diff)
downloadlinux-0d50f7b1e8c80a8c20db5049e269468c059b0378.tar.xz
iommu/amd: Fix race in increase_address_space()
[ Upstream commit 754265bcab78a9014f0f99cd35e0d610fcd7dfa7 ] After the conversion to lock-less dma-api call the increase_address_space() function can be called without any locking. Multiple CPUs could potentially race for increasing the address space, leading to invalid domain->mode settings and invalid page-tables. This has been happening in the wild under high IO load and memory pressure. Fix the race by locking this operation. The function is called infrequently so that this does not introduce a performance regression in the dma-api path again. Reported-by: Qian Cai <cai@lca.pw> Fixes: 256e4621c21a ('iommu/amd: Make use of the generic IOVA allocator') Signed-off-by: Joerg Roedel <jroedel@suse.de> Signed-off-by: Sasha Levin <sashal@kernel.org>
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