kernel.git/arch/mips/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

MIPS: c-r4k: Fix Loongson-3's vcache/scache waysize calculation

2017-03-21T22:22:43Z

If scache.waysize is 0, r4k___flush_cache_all() will do nothing and then cause bugs. BTW, though vcache.waysize isn't being used by now, we also fix its calculation. Signed-off-by: Huacai Chen Cc: John Crispin Cc: Steven J . Hill Cc: Fuxin Zhang Cc: Zhangjin Wu Cc: linux-mips@linux-mips.org Cc: stable@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/15756/ Signed-off-by: Ralf Baechle

MIPS: Flush wrong invalid FTLB entry for huge page

2017-03-21T20:58:50Z

On VTLB+FTLB platforms (such as Loongson-3A R2), FTLB's pagesize is usually configured the same as PAGE_SIZE. In such a case, Huge page entry is not suitable to write in FTLB. Unfortunately, when a huge page is created, its page table entries haven't created immediately. Then the TLB refill handler will fetch an invalid page table entry which has no "HUGE" bit, and this entry may be written to FTLB. Since it is invalid, TLB load/store handler will then use tlbwi to write the valid entry at the same place. However, the valid entry is a huge page entry which isn't suitable for FTLB. Our solution is to modify build_huge_handler_tail. Flush the invalid old entry (whether it is in FTLB or VTLB, this is in order to reduce branches) and use tlbwr to write the valid new entry. Signed-off-by: Rui Wang Signed-off-by: Huacai Chen Cc: John Crispin Cc: Steven J . Hill Cc: Fuxin Zhang Cc: Zhangjin Wu Cc: Huacai Chen Cc: linux-mips@linux-mips.org Cc: stable@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/15754/ Signed-off-by: Ralf Baechle

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 ...

mm: wire up GFP flag passing in dma_alloc_from_contiguous

2017-02-25T01:46:55Z

The callers of the DMA alloc functions already provide the proper context GFP flags. Make sure to pass them through to the CMA allocator, to make the CMA compaction context aware. Link: http://lkml.kernel.org/r/20170127172328.18574-3-l.stach@pengutronix.de Signed-off-by: Lucas Stach Acked-by: Vlastimil Babka Acked-by: Michal Hocko Cc: Radim Krcmar Cc: Catalin Marinas Cc: Will Deacon Cc: Chris Zankel Cc: Ralf Baechle Cc: Paolo Bonzini Cc: Alexander Graf Cc: Joonsoo Kim Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

Merge tag 'mips_kvm_4.11_1' into mips-for-linux-next

2017-02-13T18:57:31Z

MIPS dependencies for KVM Miscellaneous MIPS architecture changes depended on by the MIPS KVM changes in the KVM tree. - Move pgd_alloc() out of header. - Exports so KVM can access page table management and TLBEX functions. - Add return errors to protected cache ops.

MIPS: Export some tlbex internals for KVM to use

2017-02-03T15:19:01Z

Export to TLB exception code generating functions so that KVM can construct a fast TLB refill handler for guest context without reinventing the wheel quite so much. Signed-off-by: James Hogan Acked-by: Ralf Baechle Cc: Ralf Baechle Cc: Paolo Bonzini Cc: "Radim Krčmář" Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org