Joerg Roedel
b15bf74405
[ Upstream commit754265bcab] 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:256e4621c2('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>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.