kernel/arch/unicore32, branch linux-5.1.y

x86/mpx, mm/core: Fix recursive munmap() corruption

2019-05-25T16:16:40Z

commit 5a28fc94c9143db766d1ba5480cae82d856ad080 upstream. This is a bit of a mess, to put it mildly. But, it's a bug that only seems to have showed up in 4.20 but wasn't noticed until now, because nobody uses MPX. MPX has the arch_unmap() hook inside of munmap() because MPX uses bounds tables that protect other areas of memory. When memory is unmapped, there is also a need to unmap the MPX bounds tables. Barring this, unused bounds tables can eat 80% of the address space. But, the recursive do_munmap() that gets called vi arch_unmap() wreaks havoc with __do_munmap()'s state. It can result in freeing populated page tables, accessing bogus VMA state, double-freed VMAs and more. See the "long story" further below for the gory details. To fix this, call arch_unmap() before __do_unmap() has a chance to do anything meaningful. Also, remove the 'vma' argument and force the MPX code to do its own, independent VMA lookup. == UML / unicore32 impact == Remove unused 'vma' argument to arch_unmap(). No functional change. I compile tested this on UML but not unicore32. == powerpc impact == powerpc uses arch_unmap() well to watch for munmap() on the VDSO and zeroes out 'current->mm->context.vdso_base'. Moving arch_unmap() makes this happen earlier in __do_munmap(). But, 'vdso_base' seems to only be used in perf and in the signal delivery that happens near the return to userspace. I can not find any likely impact to powerpc, other than the zeroing happening a little earlier. powerpc does not use the 'vma' argument and is unaffected by its removal. I compile-tested a 64-bit powerpc defconfig. == x86 impact == For the common success case this is functionally identical to what was there before. For the munmap() failure case, it's possible that some MPX tables will be zapped for memory that continues to be in use. But, this is an extraordinarily unlikely scenario and the harm would be that MPX provides no protection since the bounds table got reset (zeroed). I can't imagine anyone doing this: ptr = mmap(); // use ptr ret = munmap(ptr); if (ret) // oh, there was an error, I'll // keep using ptr. Because if you're doing munmap(), you are *done* with the memory. There's probably no good data in there _anyway_. This passes the original reproducer from Richard Biener as well as the existing mpx selftests/. The long story: munmap() has a couple of pieces: 1. Find the affected VMA(s) 2. Split the start/end one(s) if neceesary 3. Pull the VMAs out of the rbtree 4. Actually zap the memory via unmap_region(), including freeing page tables (or queueing them to be freed). 5. Fix up some of the accounting (like fput()) and actually free the VMA itself. This specific ordering was actually introduced by: dd2283f2605e ("mm: mmap: zap pages with read mmap_sem in munmap") during the 4.20 merge window. The previous __do_munmap() code was actually safe because the only thing after arch_unmap() was remove_vma_list(). arch_unmap() could not see 'vma' in the rbtree because it was detached, so it is not even capable of doing operations unsafe for remove_vma_list()'s use of 'vma'. Richard Biener reported a test that shows this in dmesg: [1216548.787498] BUG: Bad rss-counter state mm:0000000017ce560b idx:1 val:551 [1216548.787500] BUG: non-zero pgtables_bytes on freeing mm: 24576 What triggered this was the recursive do_munmap() called via arch_unmap(). It was freeing page tables that has not been properly zapped. But, the problem was bigger than this. For one, arch_unmap() can free VMAs. But, the calling __do_munmap() has variables that *point* to VMAs and obviously can't handle them just getting freed while the pointer is still in use. I tried a couple of things here. First, I tried to fix the page table freeing problem in isolation, but I then found the VMA issue. I also tried having the MPX code return a flag if it modified the rbtree which would force __do_munmap() to re-walk to restart. That spiralled out of control in complexity pretty fast. Just moving arch_unmap() and accepting that the bonkers failure case might eat some bounds tables seems like the simplest viable fix. This was also reported in the following kernel bugzilla entry: https://bugzilla.kernel.org/show_bug.cgi?id=203123 There are some reports that this commit triggered this bug: dd2283f2605 ("mm: mmap: zap pages with read mmap_sem in munmap") While that commit certainly made the issues easier to hit, I believe the fundamental issue has been with us as long as MPX itself, thus the Fixes: tag below is for one of the original MPX commits. [ mingo: Minor edits to the changelog and the patch. ] Reported-by: Richard Biener Reported-by: H.J. Lu Signed-off-by: Dave Hansen Reviewed-by Thomas Gleixner Reviewed-by: Yang Shi Acked-by: Michael Ellerman Cc: Andrew Morton Cc: Andy Lutomirski Cc: Anton Ivanov Cc: Benjamin Herrenschmidt Cc: Borislav Petkov Cc: Guan Xuetao Cc: H. Peter Anvin Cc: Jeff Dike Cc: Linus Torvalds Cc: Michal Hocko Cc: Paul Mackerras Cc: Peter Zijlstra Cc: Richard Weinberger Cc: Rik van Riel Cc: Vlastimil Babka Cc: linux-arch@vger.kernel.org Cc: linux-mm@kvack.org Cc: linux-um@lists.infradead.org Cc: linuxppc-dev@lists.ozlabs.org Cc: stable@vger.kernel.org Fixes: dd2283f2605e ("mm: mmap: zap pages with read mmap_sem in munmap") Link: http://lkml.kernel.org/r/20190419194747.5E1AD6DC@viggo.jf.intel.com Signed-off-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman

KVM: export and iif KVM is supported

2019-03-28T16:27:42Z

I do not see any consistency about headers_install of and . According to my analysis of Linux 5.1-rc1, there are 3 groups: [1] Both and are exported alpha, arm, hexagon, mips, powerpc, s390, sparc, x86 [2] is exported, but is not arc, arm64, c6x, h8300, ia64, m68k, microblaze, nios2, openrisc, parisc, sh, unicore32, xtensa [3] Neither nor is exported csky, nds32, riscv This does not match to the actual KVM support. At least, [2] is half-baked. Nor do arch maintainers look like they care about this. For example, commit 0add53713b1c ("microblaze: Add missing kvm_para.h to Kbuild") exported to user-space in order to fix an in-kernel build error. We have two ways to make this consistent: [A] export both and for all architectures, irrespective of the KVM support [B] Match the header export of and to the KVM support My first attempt was [A] because the code looks cleaner, but Paolo suggested [B]. So, this commit goes with [B]. For most architectures, was moved to the kernel-space. I changed include/uapi/linux/Kbuild so that it checks generated asm/kvm_para.h as well as check-in ones. After this commit, there will be two groups: [1] Both and are exported arm, arm64, mips, powerpc, s390, x86 [2] Neither nor is exported alpha, arc, c6x, csky, h8300, hexagon, ia64, m68k, microblaze, nds32, nios2, openrisc, parisc, riscv, sh, sparc, unicore32, xtensa Signed-off-by: Masahiro Yamada Acked-by: Cornelia Huck Signed-off-by: Paolo Bonzini

kbuild: force all architectures except um to include mandatory-y

2019-03-17T03:56:32Z

Currently, every arch/*/include/uapi/asm/Kbuild explicitly includes the common Kbuild.asm file. Factor out the duplicated include directives to scripts/Makefile.asm-generic so that no architecture would opt out of the mandatory-y mechanism. um is not forced to include mandatory-y since it is a very exceptional case which does not support UAPI. Signed-off-by: Masahiro Yamada

unicore32: simplify linker script generation for decompressor

2019-03-13T17:39:11Z

When I was searching for unneeded $(KCONFIG_CONFIG) usages, I noticed this strange build dependency. It can use $(call if_changed,...) in case ZTEXTADDR and ZBSSADDR are changed, but even a simpler way is to use the pattern rule in scripts/Makefile.build. This is what arch/arm/boot/compressed/Makefile does. I did only build test. I confirmed equivalent vmlinux.lds was generated. Signed-off-by: Masahiro Yamada

treewide: add checks for the return value of memblock_alloc*()

2019-03-12T17:04:02Z

Add check for the return value of memblock_alloc*() functions and call panic() in case of error. The panic message repeats the one used by panicing memblock allocators with adjustment of parameters to include only relevant ones. The replacement was mostly automated with semantic patches like the one below with manual massaging of format strings. @@ expression ptr, size, align; @@ ptr = memblock_alloc(size, align); + if (!ptr) + panic("%s: Failed to allocate %lu bytes align=0x%lx\n", __func__, size, align); [anders.roxell@linaro.org: use '%pa' with 'phys_addr_t' type] Link: http://lkml.kernel.org/r/20190131161046.21886-1-anders.roxell@linaro.org [rppt@linux.ibm.com: fix format strings for panics after memblock_alloc] Link: http://lkml.kernel.org/r/1548950940-15145-1-git-send-email-rppt@linux.ibm.com [rppt@linux.ibm.com: don't panic if the allocation in sparse_buffer_init fails] Link: http://lkml.kernel.org/r/20190131074018.GD28876@rapoport-lnx [akpm@linux-foundation.org: fix xtensa printk warning] Link: http://lkml.kernel.org/r/1548057848-15136-20-git-send-email-rppt@linux.ibm.com Signed-off-by: Mike Rapoport Signed-off-by: Anders Roxell Reviewed-by: Guo Ren [c-sky] Acked-by: Paul Burton [MIPS] Acked-by: Heiko Carstens [s390] Reviewed-by: Juergen Gross [Xen] Reviewed-by: Geert Uytterhoeven [m68k] Acked-by: Max Filippov [xtensa] Cc: Catalin Marinas Cc: Christophe Leroy Cc: Christoph Hellwig Cc: "David S. Miller" Cc: Dennis Zhou Cc: Greentime Hu Cc: Greg Kroah-Hartman Cc: Guan Xuetao Cc: Guo Ren Cc: Mark Salter Cc: Matt Turner Cc: Michael Ellerman Cc: Michal Simek Cc: Petr Mladek Cc: Richard Weinberger Cc: Rich Felker Cc: Rob Herring Cc: Rob Herring Cc: Russell King Cc: Stafford Horne Cc: Tony Luck Cc: Vineet Gupta Cc: Yoshinori Sato Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

Merge tag 'dma-mapping-5.1' of git://git.infradead.org/users/hch/dma-mapping

2019-03-10T18:54:48Z

Pull DMA mapping updates from Christoph Hellwig: - add debugfs support for dumping dma-debug information (Corentin Labbe) - Kconfig cleanups (Andy Shevchenko and me) - debugfs cleanups (Greg Kroah-Hartman) - improve dma_map_resource and use it in the media code - arch_setup_dma_ops / arch_teardown_dma_ops cleanups - various small cleanups and improvements for the per-device coherent allocator - make the DMA mask an upper bound and don't fail "too large" dma mask in the remaning two architectures - this will allow big driver cleanups in the following merge windows * tag 'dma-mapping-5.1' of git://git.infradead.org/users/hch/dma-mapping: (21 commits) Documentation/DMA-API-HOWTO: update dma_mask sections sparc64/pci_sun4v: allow large DMA masks sparc64/iommu: allow large DMA masks sparc64: refactor the ali DMA quirk ccio: allow large DMA masks dma-mapping: remove the DMA_MEMORY_EXCLUSIVE flag dma-mapping: remove dma_mark_declared_memory_occupied dma-mapping: move CONFIG_DMA_CMA to kernel/dma/Kconfig dma-mapping: improve selection of dma_declare_coherent availability dma-mapping: remove an incorrect __iommem annotation of: select OF_RESERVED_MEM automatically device.h: dma_mem is only needed for HAVE_GENERIC_DMA_COHERENT mfd/sm501: depend on HAS_DMA dma-mapping: add a kconfig symbol for arch_teardown_dma_ops availability dma-mapping: add a kconfig symbol for arch_setup_dma_ops availability dma-mapping: move debug configuration options to kernel/dma dma-debug: add dumping facility via debugfs dma: debug: no need to check return value of debugfs_create functions videobuf2: replace a layering violation with dma_map_resource dma-mapping: don't BUG when calling dma_map_resource on RAM ...

unicore32: stop printing the virtual memory layout

2019-03-08T02:32:03Z

Since commit ad67b74d2469 ("printk: hash addresses printed with %p"), the virtual memory layout printed during boot up contains "ptrval" instead of actual addresses. Instead of changing the printing to "%px", and leaking virtual memory layout information again, just remove the printing completely, cfr. e.g. commits 071929dbdd86 ("arm64: Stop printing the virtual memory layout") and 31833332f798 ("m68k/mm: Stop printing the virtual memory layout"). All interesting information (actual section sizes) is already printed by mem_init_print_info() just above anyway. Link: http://lkml.kernel.org/r/20190121152254.29079-1-geert+renesas@glider.be Signed-off-by: Geert Uytterhoeven Reviewed-by: Kees Cook Cc: Guan Xuetao Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

arm, s390, unicore32: remove oneliner wrappers for memblock_alloc()

2019-03-08T02:32:03Z

arm, s390 and unicore32 use oneliner wrappers for memblock_alloc(). Replace their usage with direct call to memblock_alloc(). Link: http://lkml.kernel.org/r/1546248566-14910-7-git-send-email-rppt@linux.ibm.com Signed-off-by: Mike Rapoport Suggested-by: Christoph Hellwig Cc: Arnd Bergmann Cc: Benjamin Herrenschmidt Cc: "David S. Miller" Cc: Greentime Hu Cc: Guan Xuetao Cc: Heiko Carstens Cc: Jonas Bonn Cc: Mark Salter Cc: Martin Schwidefsky Cc: Michael Ellerman Cc: Michal Hocko Cc: Michal Simek Cc: Michal Simek Cc: Paul Mackerras Cc: Rich Felker Cc: Russell King Cc: Stafford Horne Cc: Stefan Kristiansson Cc: Vincent Chen Cc: Yoshinori Sato Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

arch: simplify several early memory allocations

2019-03-08T02:32:03Z

There are several early memory allocations in arch/ code that use memblock_phys_alloc() to allocate memory, convert the returned physical address to the virtual address and then set the allocated memory to zero. Exactly the same behaviour can be achieved simply by calling memblock_alloc(): it allocates the memory in the same way as memblock_phys_alloc(), then it performs the phys_to_virt() conversion and clears the allocated memory. Replace the longer sequence with a simpler call to memblock_alloc(). Link: http://lkml.kernel.org/r/1546248566-14910-6-git-send-email-rppt@linux.ibm.com Signed-off-by: Mike Rapoport Cc: Arnd Bergmann Cc: Benjamin Herrenschmidt Cc: Christoph Hellwig Cc: "David S. Miller" Cc: Greentime Hu Cc: Guan Xuetao Cc: Heiko Carstens Cc: Jonas Bonn Cc: Mark Salter Cc: Martin Schwidefsky Cc: Michael Ellerman Cc: Michal Hocko Cc: Michal Simek Cc: Michal Simek Cc: Paul Mackerras Cc: Rich Felker Cc: Russell King Cc: Stafford Horne Cc: Stefan Kristiansson Cc: Vincent Chen Cc: Yoshinori Sato Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

Merge tag 'y2038-syscall-abi' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/playground into timers/2038

2019-02-27T20:45:27Z

Pull additional syscall ABI cleanup for y2038 from Arnd Bergmann: This is a follow-up to the y2038 syscall patches already merged in the tip tree. As the final 32-bit RISC-V syscall ABI is still being decided on, this is the last chance to make a few corrections to leave out interfaces based on 32-bit time_t along with the old off_t and rlimit types. The series achieves this in a few steps: - A couple of bug fixes for minor regressions I introduced in the original series - A couple of older patches from Yury Norov that I had never merged in the past, these fix up the openat/open_by_handle_at and getrlimit/setrlimit syscalls to disallow the old versions of off_t and rlimit. - Hiding the deprecated system calls behind an #ifdef in include/uapi/asm-generic/unistd.h - Change arch/riscv to drop all these ABIs. Originally, the plan was to also leave these out on C-Sky, but that now has a glibc port that uses the older interfaces, so we need to leave them in place.