talos-op-linux/Documentation/admin-guide, branch v4.12.5

mm: larger stack guard gap, between vmas

2017-06-19T13:50:20+00:00

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

Merge tag 'powerpc-4.12-5' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux

2017-06-09T16:44:46+00:00

Pull powerpc fixes from Michael Ellerman: "Mostly fairly minor, of note are: - Fix percpu allocations to be NUMA aware - Limit 4k page size config to 64TB virtual address space - Avoid needlessly restoring FP and vector registers Thanks to Aneesh Kumar K.V, Breno Leitao, Christophe Leroy, Frederic Barrat, Madhavan Srinivasan, Michael Bringmann, Nicholas Piggin, Vaibhav Jain" * tag 'powerpc-4.12-5' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: powerpc/book3s64: Move PPC_DT_CPU_FTRs and enable it by default powerpc/mm/4k: Limit 4k page size config to 64TB virtual address space cxl: Fix error path on bad ioctl powerpc/perf: Fix Power9 test_adder fields powerpc/numa: Fix percpu allocations to be NUMA aware cxl: Avoid double free_irq() for psl,slice interrupts powerpc/kernel: Initialize load_tm on task creation powerpc/kernel: Fix FP and vector register restoration powerpc/64: Reclaim CPU_FTR_SUBCORE powerpc/hotplug-mem: Fix missing endian conversion of aa_index powerpc/sysdev/simple_gpio: Fix oops in gpio save_regs function powerpc/spufs: Fix coredump of SPU contexts powerpc/64s: Add dt_cpu_ftrs boot time setup option

powerpc/64s: Add dt_cpu_ftrs boot time setup option

2017-06-01T09:54:33+00:00

Provide a dt_cpu_ftrs= cmdline option to disable the dt_cpu_ftrs CPU feature discovery, and fall back to the "cputable" based version. Also allow control of advertising unknown features to userspace and with this parameter, and remove the clunky CONFIG option. Signed-off-by: Nicholas Piggin [mpe: Add explicit early check of bootargs in dt_cpu_ftrs_init()] Signed-off-by: Michael Ellerman

cpufreq: intel_pstate: Document the current behavior and user interface

2017-05-14T00:06:03+00:00

Add a document describing the current behavior and user space interface of the intel_pstate driver in the RST format and drop the existing outdated intel_pstate.txt document. Also update admin-guide/pm/cpufreq.rst with proper RST references to the new intel_pstate.rst document. Signed-off-by: Rafael J. Wysocki

Merge tag 'docs-4.12-2' of git://git.lwn.net/linux

2017-05-11T18:29:52+00:00

Pull more documentation updates from Jonathan Corbet: "Connect the newly RST-formatted documentation to the rest; this had to wait until the input pull was done. There's also a few small fixes that wandered in" * tag 'docs-4.12-2' of git://git.lwn.net/linux: doc: replace FTP URL to kernel.org with HTTPS one docs: update references to the device io book Documentation: earlycon: fix Marvell Armada 3700 UART name docs-rst: add input docs at main index and use kernel-figure

doc: replace FTP URL to kernel.org with HTTPS one

2017-05-11T17:52:52+00:00

FTP services were shutdown some weeks ago, so the FTP URL does not work anymore. Fix this by replacing it with corresponding HTTPS URL. Signed-off-by: Michael Heimpold Signed-off-by: Jonathan Corbet

Merge tag 'nfs-for-4.12-1' of git://git.linux-nfs.org/projects/trondmy/linux-nfs

2017-05-10T20:03:38+00:00

Pull NFS client updates from Trond Myklebust: "Highlights include: Stable bugfixes: - Fix use after free in write error path - Use GFP_NOIO for two allocations in writeback - Fix a hang in OPEN related to server reboot - Check the result of nfs4_pnfs_ds_connect - Fix an rcu lock leak Features: - Removal of the unmaintained and unused OSD pNFS layout - Cleanup and removal of lots of unnecessary dprintk()s - Cleanup and removal of some memory failure paths now that GFP_NOFS is guaranteed to never fail. - Remove the v3-only data server limitation on pNFS/flexfiles Bugfixes: - RPC/RDMA connection handling bugfixes - Copy offload: fixes to ensure the copied data is COMMITed to disk. - Readdir: switch back to using the ->iterate VFS interface - File locking fixes from Ben Coddington - Various use-after-free and deadlock issues in pNFS - Write path bugfixes" * tag 'nfs-for-4.12-1' of git://git.linux-nfs.org/projects/trondmy/linux-nfs: (89 commits) pNFS/flexfiles: Always attempt to call layoutstats when flexfiles is enabled NFSv4.1: Work around a Linux server bug... NFS append COMMIT after synchronous COPY NFSv4: Fix exclusive create attributes encoding NFSv4: Fix an rcu lock leak nfs: use kmap/kunmap directly NFS: always treat the invocation of nfs_getattr as cache hit when noac is on Fix nfs_client refcounting if kmalloc fails in nfs4_proc_exchange_id and nfs4_proc_async_renew NFSv4.1: RECLAIM_COMPLETE must handle NFS4ERR_CONN_NOT_BOUND_TO_SESSION pNFS: Fix NULL dereference in pnfs_generic_alloc_ds_commits pNFS: Fix a typo in pnfs_generic_alloc_ds_commits pNFS: Fix a deadlock when coalescing writes and returning the layout pNFS: Don't clear the layout return info if there are segments to return pNFS: Ensure we commit the layout if it has been invalidated pNFS: Don't send COMMITs to the DSes if the server invalidated our layout pNFS/flexfiles: Fix up the ff_layout_write_pagelist failure path pNFS: Ensure we check layout validity before marking it for return NFS4.1 handle interrupted slot reuse from ERR_DELAY NFSv4: check return value of xdr_inline_decode nfs/filelayout: fix NULL pointer dereference in fl_pnfs_update_layout() ...

Merge branch 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2017-05-10T17:30:46+00:00

Pull RCU updates from Ingo Molnar: "The main changes are: - Debloat RCU headers - Parallelize SRCU callback handling (plus overlapping patches) - Improve the performance of Tree SRCU on a CPU-hotplug stress test - Documentation updates - Miscellaneous fixes" * 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (74 commits) rcu: Open-code the rcu_cblist_n_lazy_cbs() function rcu: Open-code the rcu_cblist_n_cbs() function rcu: Open-code the rcu_cblist_empty() function rcu: Separately compile large rcu_segcblist functions srcu: Debloat the header srcu: Adjust default auto-expediting holdoff srcu: Specify auto-expedite holdoff time srcu: Expedite first synchronize_srcu() when idle srcu: Expedited grace periods with reduced memory contention srcu: Make rcutorture writer stalls print SRCU GP state srcu: Exact tracking of srcu_data structures containing callbacks srcu: Make SRCU be built by default srcu: Fix Kconfig botch when SRCU not selected rcu: Make non-preemptive schedule be Tasks RCU quiescent state srcu: Expedite srcu_schedule_cbs_snp() callback invocation srcu: Parallelize callback handling kvm: Move srcu_struct fields to end of struct kvm rcu: Fix typo in PER_RCU_NODE_PERIOD header comment rcu: Use true/false in assignment to bool rcu: Use bool value directly ...

Merge tag 'iommu-updates-v4.12' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu

2017-05-09T22:15:47+00:00

Pull IOMMU updates from Joerg Roedel: - code optimizations for the Intel VT-d driver - ability to switch off a previously enabled Intel IOMMU - support for 'struct iommu_device' for OMAP, Rockchip and Mediatek IOMMUs - header optimizations for IOMMU core code headers and a few fixes that became necessary in other parts of the kernel because of that - ACPI/IORT updates and fixes - Exynos IOMMU optimizations - updates for the IOMMU dma-api code to bring it closer to use per-cpu iova caches - new command-line option to set default domain type allocated by the iommu core code - another command line option to allow the Intel IOMMU switched off in a tboot environment - ARM/SMMU: TLB sync optimisations for SMMUv2, Support for using an IDENTITY domain in conjunction with DMA ops, Support for SMR masking, Support for 16-bit ASIDs (was previously broken) - various other small fixes and improvements * tag 'iommu-updates-v4.12' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu: (63 commits) soc/qbman: Move dma-mapping.h include to qman_priv.h soc/qbman: Fix implicit header dependency now causing build fails iommu: Remove trace-events include from iommu.h iommu: Remove pci.h include from trace/events/iommu.h arm: dma-mapping: Don't override dma_ops in arch_setup_dma_ops() ACPI/IORT: Fix CONFIG_IOMMU_API dependency iommu/vt-d: Don't print the failure message when booting non-kdump kernel iommu: Move report_iommu_fault() to iommu.c iommu: Include device.h in iommu.h x86, iommu/vt-d: Add an option to disable Intel IOMMU force on iommu/arm-smmu: Return IOVA in iova_to_phys when SMMU is bypassed iommu/arm-smmu: Correct sid to mask iommu/amd: Fix incorrect error handling in amd_iommu_bind_pasid() iommu: Make iommu_bus_notifier return NOTIFY_DONE rather than error code omap3isp: Remove iommu_group related code iommu/omap: Add iommu-group support iommu/omap: Make use of 'struct iommu_device' iommu/omap: Store iommu_dev pointer in arch_data iommu/omap: Move data structures to omap-iommu.h iommu/omap: Drop legacy-style device support ...

Documentation: earlycon: fix Marvell Armada 3700 UART name

2017-05-09T19:43:39+00:00

The Marvell Armada 3700 UART uses "ar3700_uart" for its earlycon name. Adjust documentation to match the code. Signed-off-by: Andre Przywara Signed-off-by: Jonathan Corbet