kernel/linux.git/arch/x86/mm, branch linux-4.16.y

x86/mm: Do not forbid _PAGE_RW before init for __ro_after_init

2018-05-30T06:17:20+00:00

[ Upstream commit 639d6aafe437a7464399d2a77d006049053df06f ] __ro_after_init data gets stuck in the .rodata section. That's normally fine because the kernel itself manages the R/W properties. But, if we run __change_page_attr() on an area which is __ro_after_init, the .rodata checks will trigger and force the area to be immediately read-only, even if it is early-ish in boot. This caused problems when trying to clear the _PAGE_GLOBAL bit for these area in the PTI code: it cleared _PAGE_GLOBAL like I asked, but also took it up on itself to clear _PAGE_RW. The kernel then oopses the next time it wrote to a __ro_after_init data structure. To fix this, add the kernel_set_to_readonly check, just like we have for kernel text, just a few lines below in this function. Signed-off-by: Dave Hansen Acked-by: Kees Cook Cc: Andrea Arcangeli Cc: Andy Lutomirski Cc: Arjan van de Ven Cc: Borislav Petkov Cc: Dan Williams Cc: David Woodhouse Cc: Greg Kroah-Hartman Cc: Hugh Dickins Cc: Josh Poimboeuf Cc: Juergen Gross Cc: Linus Torvalds Cc: Nadav Amit Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-mm@kvack.org Link: http://lkml.kernel.org/r/20180406205514.8D898241@viggo.jf.intel.com Signed-off-by: Ingo Molnar Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

x86/pgtable: Don't set huge PUD/PMD on non-leaf entries

2018-05-30T06:17:20+00:00

[ Upstream commit e3e288121408c3abeed5af60b87b95c847143845 ] The pmd_set_huge() and pud_set_huge() functions are used from the generic ioremap() code to establish large mappings where this is possible. But the generic ioremap() code does not check whether the PMD/PUD entries are already populated with a non-leaf entry, so that any page-table pages these entries point to will be lost. Further, on x86-32 with SHARED_KERNEL_PMD=0, this causes a BUG_ON() in vmalloc_sync_one() when PMD entries are synced from swapper_pg_dir to the current page-table. This happens because the PMD entry from swapper_pg_dir was promoted to a huge-page entry while the current PGD still contains the non-leaf entry. Because both entries are present and point to a different page, the BUG_ON() triggers. This was actually triggered with pti-x32 enabled in a KVM virtual machine by the graphics driver. A real and better fix for that would be to improve the page-table handling in the generic ioremap() code. But that is out-of-scope for this patch-set and left for later work. Reported-by: David H. Gutteridge Signed-off-by: Joerg Roedel Reviewed-by: Thomas Gleixner Cc: Andrea Arcangeli Cc: Andy Lutomirski Cc: Boris Ostrovsky Cc: Borislav Petkov Cc: Brian Gerst Cc: Dave Hansen Cc: David Laight Cc: Denys Vlasenko Cc: Eduardo Valentin Cc: Greg KH Cc: Jiri Kosina Cc: Josh Poimboeuf Cc: Juergen Gross Cc: Linus Torvalds Cc: Pavel Machek Cc: Peter Zijlstra Cc: Waiman Long Cc: Will Deacon Cc: aliguori@amazon.com Cc: daniel.gruss@iaik.tugraz.at Cc: hughd@google.com Cc: keescook@google.com Cc: linux-mm@kvack.org Link: http://lkml.kernel.org/r/20180411152437.GC15462@8bytes.org Signed-off-by: Ingo Molnar Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

x86/pkeys: Override pkey when moving away from PROT_EXEC

2018-05-22T16:56:24+00:00

commit 0a0b152083cfc44ec1bb599b57b7aab41327f998 upstream. I got a bug report that the following code (roughly) was causing a SIGSEGV: mprotect(ptr, size, PROT_EXEC); mprotect(ptr, size, PROT_NONE); mprotect(ptr, size, PROT_READ); *ptr = 100; The problem is hit when the mprotect(PROT_EXEC) is implicitly assigned a protection key to the VMA, and made that key ACCESS_DENY|WRITE_DENY. The PROT_NONE mprotect() failed to remove the protection key, and the PROT_NONE-> PROT_READ left the PTE usable, but the pkey still in place and left the memory inaccessible. To fix this, we ensure that we always "override" the pkee at mprotect() if the VMA does not have execute-only permissions, but the VMA has the execute-only pkey. We had a check for PROT_READ/WRITE, but it did not work for PROT_NONE. This entirely removes the PROT_* checks, which ensures that PROT_NONE now works. Reported-by: Shakeel Butt Signed-off-by: Dave Hansen Cc: Andrew Morton Cc: Dave Hansen Cc: Linus Torvalds Cc: Michael Ellermen Cc: Peter Zijlstra Cc: Ram Pai Cc: Shuah Khan Cc: Thomas Gleixner Cc: linux-mm@kvack.org Cc: stable@vger.kernel.org Fixes: 62b5f7d013f ("mm/core, x86/mm/pkeys: Add execute-only protection keys support") Link: http://lkml.kernel.org/r/20180509171351.084C5A71@viggo.jf.intel.com Signed-off-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman

Merge branch 'akpm' (patches from Andrew)

2018-03-23T01:48:43+00:00

Merge misc fixes from Andrew Morton: "13 fixes" * emailed patches from Andrew Morton : mm, thp: do not cause memcg oom for thp mm/vmscan: wake up flushers for legacy cgroups too Revert "mm: page_alloc: skip over regions of invalid pfns where possible" mm/shmem: do not wait for lock_page() in shmem_unused_huge_shrink() mm/thp: do not wait for lock_page() in deferred_split_scan() mm/khugepaged.c: convert VM_BUG_ON() to collapse fail x86/mm: implement free pmd/pte page interfaces mm/vmalloc: add interfaces to free unmapped page table h8300: remove extraneous __BIG_ENDIAN definition hugetlbfs: check for pgoff value overflow lockdep: fix fs_reclaim warning MAINTAINERS: update Mark Fasheh's e-mail mm/mempolicy.c: avoid use uninitialized preferred_node

Merge branch 'libnvdimm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm

2018-03-23T01:37:49+00:00

Pull libnvdimm fixes from Dan Williams: "Two regression fixes, two bug fixes for older issues, two fixes for new functionality added this cycle that have userspace ABI concerns, and a small cleanup. These have appeared in a linux-next release and have a build success report from the 0day robot. * The 4.16 rework of altmap handling led to some configurations leaking page table allocations due to freeing from the altmap reservation rather than the page allocator. The impact without the fix is leaked memory and a WARN() message when tearing down libnvdimm namespaces. The rework also missed a place where error handling code needed to be removed that can lead to a crash if devm_memremap_pages() fails. * acpi_map_pxm_to_node() had a latent bug whereby it could misidentify the closest online node to a given proximity domain. * Block integrity handling was reworked several kernels back to allow calling add_disk() after setting up the integrity profile. The nd_btt and nd_blk drivers are just now catching up to fix automatic partition detection at driver load time. * The new peristence_domain attribute, a platform indicator of whether cpu caches are powerfail protected for example, is meant to be a single value enum and not a set of flags. This oversight was caught while reviewing new userspace code in libndctl to communicate the attribute. Fix this new enabling up so that we are not stuck with an unwanted userspace ABI" * 'libnvdimm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm: libnvdimm, nfit: fix persistence domain reporting libnvdimm, region: hide persistence_domain when unknown acpi, numa: fix pxm to online numa node associations x86, memremap: fix altmap accounting at free libnvdimm: remove redundant assignment to pointer 'dev' libnvdimm, {btt, blk}: do integrity setup before add_disk() kernel/memremap: Remove stale devres_free() call

x86/mm: implement free pmd/pte page interfaces

2018-03-23T00:07:01+00:00

Implement pud_free_pmd_page() and pmd_free_pte_page() on x86, which clear a given pud/pmd entry and free up lower level page table(s). The address range associated with the pud/pmd entry must have been purged by INVLPG. Link: http://lkml.kernel.org/r/20180314180155.19492-3-toshi.kani@hpe.com Fixes: e61ce6ade404e ("mm: change ioremap to set up huge I/O mappings") Signed-off-by: Toshi Kani Reported-by: Lei Li Cc: Michal Hocko Cc: Thomas Gleixner Cc: Ingo Molnar Cc: "H. Peter Anvin" Cc: Borislav Petkov Cc: Matthew Wilcox Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm/vmalloc: add interfaces to free unmapped page table

2018-03-23T00:07:01+00:00

On architectures with CONFIG_HAVE_ARCH_HUGE_VMAP set, ioremap() may create pud/pmd mappings. A kernel panic was observed on arm64 systems with Cortex-A75 in the following steps as described by Hanjun Guo. 1. ioremap a 4K size, valid page table will build, 2. iounmap it, pte0 will set to 0; 3. ioremap the same address with 2M size, pgd/pmd is unchanged, then set the a new value for pmd; 4. pte0 is leaked; 5. CPU may meet exception because the old pmd is still in TLB, which will lead to kernel panic. This panic is not reproducible on x86. INVLPG, called from iounmap, purges all levels of entries associated with purged address on x86. x86 still has memory leak. The patch changes the ioremap path to free unmapped page table(s) since doing so in the unmap path has the following issues: - The iounmap() path is shared with vunmap(). Since vmap() only supports pte mappings, making vunmap() to free a pte page is an overhead for regular vmap users as they do not need a pte page freed up. - Checking if all entries in a pte page are cleared in the unmap path is racy, and serializing this check is expensive. - The unmap path calls free_vmap_area_noflush() to do lazy TLB purges. Clearing a pud/pmd entry before the lazy TLB purges needs extra TLB purge. Add two interfaces, pud_free_pmd_page() and pmd_free_pte_page(), which clear a given pud/pmd entry and free up a page for the lower level entries. This patch implements their stub functions on x86 and arm64, which work as workaround. [akpm@linux-foundation.org: fix typo in pmd_free_pte_page() stub] Link: http://lkml.kernel.org/r/20180314180155.19492-2-toshi.kani@hpe.com Fixes: e61ce6ade404e ("mm: change ioremap to set up huge I/O mappings") Reported-by: Lei Li Signed-off-by: Toshi Kani Cc: Catalin Marinas Cc: Wang Xuefeng Cc: Will Deacon Cc: Hanjun Guo Cc: Michal Hocko Cc: Thomas Gleixner Cc: Ingo Molnar Cc: "H. Peter Anvin" Cc: Borislav Petkov Cc: Matthew Wilcox Cc: Chintan Pandya Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

x86, memremap: fix altmap accounting at free

2018-03-14T21:46:23+00:00

Commit 24b6d4164348 "mm: pass the vmem_altmap to vmemmap_free" converted the vmemmap_free() path to pass the altmap argument all the way through the call chain rather than looking it up based on the page. Unfortunately that ends up over freeing altmap allocated pages in some cases since free_pagetable() is used to free both memmap space and pte space, where only the memmap stored in huge pages uses altmap allocations. Given that altmap allocations for memmap space are special cased in vmemmap_populate_hugepages() add a symmetric / special case free_hugepage_table() to handle altmap freeing, and cleanup the unneeded passing of altmap to leaf functions that do not require it. Without this change the sanity check accounting in devm_memremap_pages_release() will throw a warning with the following signature. nd_pmem pfn10.1: devm_memremap_pages_release: failed to free all reserved pages WARNING: CPU: 44 PID: 3539 at kernel/memremap.c:310 devm_memremap_pages_release+0x1c7/0x220 CPU: 44 PID: 3539 Comm: ndctl Tainted: G L 4.16.0-rc1-linux-stable #7 RIP: 0010:devm_memremap_pages_release+0x1c7/0x220 [..] Call Trace: release_nodes+0x225/0x270 device_release_driver_internal+0x15d/0x210 bus_remove_device+0xe2/0x160 device_del+0x130/0x310 ? klist_release+0x56/0x100 ? nd_region_notify+0xc0/0xc0 [libnvdimm] device_unregister+0x16/0x60 This was missed in testing since not all configurations will trigger this warning. Fixes: 24b6d4164348 ("mm: pass the vmem_altmap to vmemmap_free") Reported-by: Jane Chu Cc: Ross Zwisler Reviewed-by: Christoph Hellwig Signed-off-by: Dan Williams

x86/mm: Fix vmalloc_fault to use pXd_large

2018-03-14T19:22:42+00:00

Gratian Crisan reported that vmalloc_fault() crashes when CONFIG_HUGETLBFS is not set since the function inadvertently uses pXn_huge(), which always return 0 in this case. ioremap() does not depend on CONFIG_HUGETLBFS. Fix vmalloc_fault() to call pXd_large() instead. Fixes: f4eafd8bcd52 ("x86/mm: Fix vmalloc_fault() to handle large pages properly") Reported-by: Gratian Crisan Signed-off-by: Toshi Kani Signed-off-by: Thomas Gleixner Cc: stable@vger.kernel.org Cc: linux-mm@kvack.org Cc: Borislav Petkov Cc: Andy Lutomirski Link: https://lkml.kernel.org/r/20180313170347.3829-2-toshi.kani@hpe.com

Merge branch 'x86-pti-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2018-03-11T21:59:23+00:00

Pull x86/pti updates from Thomas Gleixner: "Yet another pile of melted spectrum related updates: - Drop native vsyscall support finally as it causes more trouble than benefit. - Make microcode loading more robust. There were a few issues especially related to late loading which are now surfacing because late loading of the IB* microcodes addressing spectre issues has become more widely used. - Simplify and robustify the syscall handling in the entry code - Prevent kprobes on the entry trampoline code which lead to kernel crashes when the probe hits before CR3 is updated - Don't check microcode versions when running on hypervisors as they are considered as lying anyway. - Fix the 32bit objtool build and a coment typo" * 'x86-pti-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/kprobes: Fix kernel crash when probing .entry_trampoline code x86/pti: Fix a comment typo x86/microcode: Synchronize late microcode loading x86/microcode: Request microcode on the BSP x86/microcode/intel: Look into the patch cache first x86/microcode: Do not upload microcode if CPUs are offline x86/microcode/intel: Writeback and invalidate caches before updating microcode x86/microcode/intel: Check microcode revision before updating sibling threads x86/microcode: Get rid of struct apply_microcode_ctx x86/spectre_v2: Don't check microcode versions when running under hypervisors x86/vsyscall/64: Drop "native" vsyscalls x86/entry/64/compat: Save one instruction in entry_INT80_compat() x86/entry: Do not special-case clone(2) in compat entry x86/syscalls: Use COMPAT_SYSCALL_DEFINEx() macros for x86-only compat syscalls x86/syscalls: Use proper syscall definition for sys_ioperm() x86/entry: Remove stale syscall prototype x86/syscalls/32: Simplify $entry == $compat entries objtool: Fix 32-bit build