kernel.git/arch/arc/mm, branch linux-4.11.y

mm: larger stack guard gap, between vmas

2017-06-24T05:06:22Z

commit 1be7107fbe18eed3e319a6c3e83c78254b693acb upstream. Stack guard page is a useful feature to reduce a risk of stack smashing into a different mapping. We have been using a single page gap which is sufficient to prevent having stack adjacent to a different mapping. But this seems to be insufficient in the light of the stack usage in userspace. E.g. glibc uses as large as 64kB alloca() in many commonly used functions. Others use constructs liks gid_t buffer[NGROUPS_MAX] which is 256kB or stack strings with MAX_ARG_STRLEN. This will become especially dangerous for suid binaries and the default no limit for the stack size limit because those applications can be tricked to consume a large portion of the stack and a single glibc call could jump over the guard page. These attacks are not theoretical, unfortunatelly. Make those attacks less probable by increasing the stack guard gap to 1MB (on systems with 4k pages; but make it depend on the page size because systems with larger base pages might cap stack allocations in the PAGE_SIZE units) which should cover larger alloca() and VLA stack allocations. It is obviously not a full fix because the problem is somehow inherent, but it should reduce attack space a lot. One could argue that the gap size should be configurable from userspace, but that can be done later when somebody finds that the new 1MB is wrong for some special case applications. For now, add a kernel command line option (stack_guard_gap) to specify the stack gap size (in page units). Implementation wise, first delete all the old code for stack guard page: because although we could get away with accounting one extra page in a stack vma, accounting a larger gap can break userspace - case in point, a program run with "ulimit -S -v 20000" failed when the 1MB gap was counted for RLIMIT_AS; similar problems could come with RLIMIT_MLOCK and strict non-overcommit mode. Instead of keeping gap inside the stack vma, maintain the stack guard gap as a gap between vmas: using vm_start_gap() in place of vm_start (or vm_end_gap() in place of vm_end if VM_GROWSUP) in just those few places which need to respect the gap - mainly arch_get_unmapped_area(), and and the vma tree's subtree_gap support for that. Original-patch-by: Oleg Nesterov Original-patch-by: Michal Hocko Signed-off-by: Hugh Dickins Acked-by: Michal Hocko Tested-by: Helge Deller # parisc Signed-off-by: Linus Torvalds [wt: backport to 4.11: adjust context] Signed-off-by: Willy Tarreau Signed-off-by: Greg Kroah-Hartman

ARCv2: SLC: Make sure busy bit is set properly on SLC flushing

2017-03-31T00:32:33Z

As reported in STAR 9001165532, an SLC control reg read (for checking busy state) right after SLC invalidate command may incorrectly return NOT busy causing software to NOT spin-wait while operation is underway. (and for some reason this only happens if L1 cache is also disabled - as required by IOC programming model) Suggested workaround is to do an additional Control Reg read, which ensures the 2nd read gets the right status. Cc: stable@vger.kernel.org #4.10 Signed-off-by: Alexey Brodkin [vgupta: reworte changelog a bit] Signed-off-by: Vineet Gupta

sched/headers: Prepare to remove the dependency from

2017-03-02T07:42:37Z

Update code that relied on sched.h including various MM types for them. This will allow us to remove the include from . Acked-by: Linus Torvalds Cc: Mike Galbraith Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar

sched/headers: Prepare for new header dependencies before moving more code to

2017-03-02T07:42:30Z

We are going to split more MM APIs out of , which will have to be picked up from a couple of .c files. The APIs that we are going to move are: arch_pick_mmap_layout() arch_get_unmapped_area() arch_get_unmapped_area_topdown() mm_update_next_owner() Include the header in the files that are going to need it. Acked-by: Linus Torvalds Cc: Mike Galbraith Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar

sched/headers: Prepare for new header dependencies before moving code to

2017-03-02T07:42:29Z

We are going to split out of , which will have to be picked up from other headers and a couple of .c files. Create a trivial placeholder file that just maps to to make this patch obviously correct and bisectable. Include the new header in the files that are going to need it. Acked-by: Linus Torvalds Cc: Mike Galbraith Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar

Merge tag 'for-next-dma_ops' of git://git.kernel.org/pub/scm/linux/kernel/git/dledford/rdma

2017-02-25T21:45:43Z

Pull rdma DMA mapping updates from Doug Ledford: "Drop IB DMA mapping code and use core DMA code instead. Bart Van Assche noted that the ib DMA mapping code was significantly similar enough to the core DMA mapping code that with a few changes it was possible to remove the IB DMA mapping code entirely and switch the RDMA stack to use the core DMA mapping code. This resulted in a nice set of cleanups, but touched the entire tree and has been kept separate for that reason." * tag 'for-next-dma_ops' of git://git.kernel.org/pub/scm/linux/kernel/git/dledford/rdma: (37 commits) IB/rxe, IB/rdmavt: Use dma_virt_ops instead of duplicating it IB/core: Remove ib_device.dma_device nvme-rdma: Switch from dma_device to dev.parent RDS: net: Switch from dma_device to dev.parent IB/srpt: Modify a debug statement IB/srp: Switch from dma_device to dev.parent IB/iser: Switch from dma_device to dev.parent IB/IPoIB: Switch from dma_device to dev.parent IB/rxe: Switch from dma_device to dev.parent IB/vmw_pvrdma: Switch from dma_device to dev.parent IB/usnic: Switch from dma_device to dev.parent IB/qib: Switch from dma_device to dev.parent IB/qedr: Switch from dma_device to dev.parent IB/ocrdma: Switch from dma_device to dev.parent IB/nes: Remove a superfluous assignment statement IB/mthca: Switch from dma_device to dev.parent IB/mlx5: Switch from dma_device to dev.parent IB/mlx4: Switch from dma_device to dev.parent IB/i40iw: Remove a superfluous assignment statement IB/hns: Switch from dma_device to dev.parent ...

arc: migrate exception table users off module.h and onto extable.h

2017-01-26T15:58:15Z

This file was only including module.h for exception table related functions. We've now separated that content out into its own file "extable.h" so now move over to that and avoid all the extra header content in module.h that we don't really need to compile this file. Since the file does have some EXPORT_SYMBOL, we add export.h include. Cc: Vineet Gupta Acked-by: Vineet Gupta Cc: linux-snps-arc@lists.infradead.org Signed-off-by: Paul Gortmaker

treewide: Constify most dma_map_ops structures

2017-01-24T17:23:35Z

Most dma_map_ops structures are never modified. Constify these structures such that these can be write-protected. This patch has been generated as follows: git grep -l 'struct dma_map_ops' | xargs -d\\n sed -i \ -e 's/struct dma_map_ops/const struct dma_map_ops/g' \ -e 's/const struct dma_map_ops {/struct dma_map_ops {/g' \ -e 's/^const struct dma_map_ops;$/struct dma_map_ops;/' \ -e 's/const const struct dma_map_ops /const struct dma_map_ops /g'; sed -i -e 's/const $struct dma_map_ops intel_dma_ops$/\1/' \ $(git grep -l 'struct dma_map_ops intel_dma_ops'); sed -i -e 's/const $struct dma_map_ops dma_iommu_ops$/\1/' \ $(git grep -l 'struct dma_map_ops' | grep ^arch/powerpc); sed -i -e '/^struct vmd_dev {$/,/^};$/ s/const $struct dma_map_ops[[:blank:]]dma_ops;$/\1/' \ -e '/^static void vmd_setup_dma_ops/,/^}$/ s/const $struct dma_map_ops \*dest$/\1/' \ -e 's/const $struct dma_map_ops \*dest = \&vmd->dma_ops$/\1/' \ drivers/pci/host/*.c sed -i -e '/^void __init pci_iommu_alloc(void)$/,/^}$/ s/dma_ops->/intel_dma_ops./' arch/ia64/kernel/pci-dma.c sed -i -e 's/static const struct dma_map_ops sn_dma_ops/static struct dma_map_ops sn_dma_ops/' arch/ia64/sn/pci/pci_dma.c sed -i -e 's/(const struct dma_map_ops \*)//' drivers/misc/mic/bus/vop_bus.c Signed-off-by: Bart Van Assche Reviewed-by: Christoph Hellwig Cc: Benjamin Herrenschmidt Cc: Boris Ostrovsky Cc: David Woodhouse Cc: Juergen Gross Cc: H. Peter Anvin Cc: Ingo Molnar Cc: linux-arch@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: Russell King Cc: x86@kernel.org Signed-off-by: Doug Ledford

ARC: Revert "ARC: mm: IOC: Don't enable IOC by default"

2017-01-19T03:21:06Z

The programming model has been fixed with prev patches so re-enable it by default This reverts commit 23cb1f644019bac49d87b4dd7c1eac0569cc4f53. Signed-off-by: Vineet Gupta

ARC: mm: split arc_cache_init to allow __init reaping of bulk

2017-01-19T03:21:02Z

arc_cache_init() is called for each core so can't be tagged __init. However bulk of it is only executed by master core and thus is candidate for __init reaping. So split it up to allow that. Signed-off-by: Vineet Gupta