user/sven/linux.git/kernel/fork.c, branch v4.14.5

kmemleak: clear stale pointers from task stacks

2017-10-13T23:18:33Z

Kmemleak considers any pointers on task stacks as references. This patch clears newly allocated and reused vmap stacks. Link: http://lkml.kernel.org/r/150728990124.744199.8403409836394318684.stgit@buzz Signed-off-by: Konstantin Khlebnikov Acked-by: Catalin Marinas Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

android: binder: drop lru lock in isolate callback

2017-10-04T00:54:24Z

Drop the global lru lock in isolate callback before calling zap_page_range which calls cond_resched, and re-acquire the global lru lock before returning. Also change return code to LRU_REMOVED_RETRY. Use mmput_async when fail to acquire mmap sem in an atomic context. Fix "BUG: sleeping function called from invalid context" errors when CONFIG_DEBUG_ATOMIC_SLEEP is enabled. Also restore mmput_async, which was initially introduced in commit ec8d7c14ea14 ("mm, oom_reaper: do not mmput synchronously from the oom reaper context"), and was removed in commit 212925802454 ("mm: oom: let oom_reap_task and exit_mmap run concurrently"). Link: http://lkml.kernel.org/r/20170914182231.90908-1-sherryy@android.com Fixes: f2517eb76f1f2 ("android: binder: Add global lru shrinker to binder") Signed-off-by: Sherry Yang Signed-off-by: Greg Kroah-Hartman Reported-by: Kyle Yan Acked-by: Arve Hjønnevåg Acked-by: Michal Hocko Cc: Martijn Coenen Cc: Todd Kjos Cc: Riley Andrews Cc: Ingo Molnar Cc: Vlastimil Babka Cc: Hillf Danton Cc: Peter Zijlstra Cc: Andrea Arcangeli Cc: Thomas Gleixner Cc: Andy Lutomirski Cc: Oleg Nesterov Cc: Hoeun Ryu Cc: Christopher Lameter Cc: Vegard Nossum Cc: Frederic Weisbecker Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

Merge tag 'selinux-pr-20170831' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux

2017-09-12T20:21:00Z

Pull selinux updates from Paul Moore: "A relatively quiet period for SELinux, 11 patches with only two/three having any substantive changes. These noteworthy changes include another tweak to the NNP/nosuid handling, per-file labeling for cgroups, and an object class fix for AF_UNIX/SOCK_RAW sockets; the rest of the changes are minor tweaks or administrative updates (Stephen's email update explains the file explosion in the diffstat). Everything passes the selinux-testsuite" [ Also a couple of small patches from the security tree from Tetsuo Handa for Tomoyo and LSM cleanup. The separation of security policy updates wasn't all that clean - Linus ] * tag 'selinux-pr-20170831' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux: selinux: constify nf_hook_ops selinux: allow per-file labeling for cgroupfs lsm_audit: update my email address selinux: update my email address MAINTAINERS: update the NetLabel and Labeled Networking information selinux: use GFP_NOWAIT in the AVC kmem_caches selinux: Generalize support for NNP/nosuid SELinux domain transitions selinux: genheaders should fail if too many permissions are defined selinux: update the selinux info in MAINTAINERS credits: update Paul Moore's info selinux: Assign proper class to PF_UNIX/SOCK_RAW sockets tomoyo: Update URLs in Documentation/admin-guide/LSM/tomoyo.rst LSM: Remove security_task_create() hook.

locking/rtmutex: replace top-waiter and pi_waiters leftmost caching

2017-09-09T01:26:49Z

... with the generic rbtree flavor instead. No changes in semantics whatsoever. Link: http://lkml.kernel.org/r/20170719014603.19029-10-dave@stgolabs.net Signed-off-by: Davidlohr Bueso Acked-by: Peter Zijlstra (Intel) Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm/hmm: heterogeneous memory management (HMM for short)

2017-09-09T01:26:45Z

HMM provides 3 separate types of functionality: - Mirroring: synchronize CPU page table and device page table - Device memory: allocating struct page for device memory - Migration: migrating regular memory to device memory This patch introduces some common helpers and definitions to all of those 3 functionality. Link: http://lkml.kernel.org/r/20170817000548.32038-3-jglisse@redhat.com Signed-off-by: Jérôme Glisse Signed-off-by: Evgeny Baskakov Signed-off-by: John Hubbard Signed-off-by: Mark Hairgrove Signed-off-by: Sherry Cheung Signed-off-by: Subhash Gutti Cc: Aneesh Kumar Cc: Balbir Singh Cc: Benjamin Herrenschmidt Cc: Dan Williams Cc: David Nellans Cc: Johannes Weiner Cc: Kirill A. Shutemov Cc: Michal Hocko Cc: Paul E. McKenney Cc: Ross Zwisler Cc: Vladimir Davydov Cc: Bob Liu Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm,fork: introduce MADV_WIPEONFORK

2017-09-07T00:27:30Z

Introduce MADV_WIPEONFORK semantics, which result in a VMA being empty in the child process after fork. This differs from MADV_DONTFORK in one important way. If a child process accesses memory that was MADV_WIPEONFORK, it will get zeroes. The address ranges are still valid, they are just empty. If a child process accesses memory that was MADV_DONTFORK, it will get a segmentation fault, since those address ranges are no longer valid in the child after fork. Since MADV_DONTFORK also seems to be used to allow very large programs to fork in systems with strict memory overcommit restrictions, changing the semantics of MADV_DONTFORK might break existing programs. MADV_WIPEONFORK only works on private, anonymous VMAs. The use case is libraries that store or cache information, and want to know that they need to regenerate it in the child process after fork. Examples of this would be: - systemd/pulseaudio API checks (fail after fork) (replacing a getpid check, which is too slow without a PID cache) - PKCS#11 API reinitialization check (mandated by specification) - glibc's upcoming PRNG (reseed after fork) - OpenSSL PRNG (reseed after fork) The security benefits of a forking server having a re-inialized PRNG in every child process are pretty obvious. However, due to libraries having all kinds of internal state, and programs getting compiled with many different versions of each library, it is unreasonable to expect calling programs to re-initialize everything manually after fork. A further complication is the proliferation of clone flags, programs bypassing glibc's functions to call clone directly, and programs calling unshare, causing the glibc pthread_atfork hook to not get called. It would be better to have the kernel take care of this automatically. The patch also adds MADV_KEEPONFORK, to undo the effects of a prior MADV_WIPEONFORK. This is similar to the OpenBSD minherit syscall with MAP_INHERIT_ZERO: https://man.openbsd.org/minherit.2 [akpm@linux-foundation.org: numerically order arch/parisc/include/uapi/asm/mman.h #defines] Link: http://lkml.kernel.org/r/20170811212829.29186-3-riel@redhat.com Signed-off-by: Rik van Riel Reported-by: Florian Weimer Reported-by: Colm MacCártaigh Reviewed-by: Mike Kravetz Cc: "H. Peter Anvin" Cc: "Kirill A. Shutemov" Cc: Andy Lutomirski Cc: Dave Hansen Cc: Ingo Molnar Cc: Helge Deller Cc: Kees Cook Cc: Matthew Wilcox Cc: Thomas Gleixner Cc: Will Drewry Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm: oom: let oom_reap_task and exit_mmap run concurrently

2017-09-07T00:27:30Z

This is purely required because exit_aio() may block and exit_mmap() may never start, if the oom_reap_task cannot start running on a mm with mm_users == 0. At the same time if the OOM reaper doesn't wait at all for the memory of the current OOM candidate to be freed by exit_mmap->unmap_vmas, it would generate a spurious OOM kill. If it wasn't because of the exit_aio or similar blocking functions in the last mmput, it would be enough to change the oom_reap_task() in the case it finds mm_users == 0, to wait for a timeout or to wait for __mmput to set MMF_OOM_SKIP itself, but it's not just exit_mmap the problem here so the concurrency of exit_mmap and oom_reap_task is apparently warranted. It's a non standard runtime, exit_mmap() runs without mmap_sem, and oom_reap_task runs with the mmap_sem for reading as usual (kind of MADV_DONTNEED). The race between the two is solved with a combination of tsk_is_oom_victim() (serialized by task_lock) and MMF_OOM_SKIP (serialized by a dummy down_write/up_write cycle on the same lines of the ksm_exit method). If the oom_reap_task() may be running concurrently during exit_mmap, exit_mmap will wait it to finish in down_write (before taking down mm structures that would make the oom_reap_task fail with use after free). If exit_mmap comes first, oom_reap_task() will skip the mm if MMF_OOM_SKIP is already set and in turn all memory is already freed and furthermore the mm data structures may already have been taken down by free_pgtables. [aarcange@redhat.com: incremental one liner] Link: http://lkml.kernel.org/r/20170726164319.GC29716@redhat.com [rientjes@google.com: remove unused mmput_async] Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1708141733130.50317@chino.kir.corp.google.com [aarcange@redhat.com: microoptimization] Link: http://lkml.kernel.org/r/20170817171240.GB5066@redhat.com Link: http://lkml.kernel.org/r/20170726162912.GA29716@redhat.com Fixes: 26db62f179d1 ("oom: keep mm of the killed task available") Signed-off-by: Andrea Arcangeli Signed-off-by: David Rientjes Reported-by: David Rientjes Tested-by: David Rientjes Reviewed-by: Michal Hocko Cc: Tetsuo Handa Cc: Oleg Nesterov Cc: Hugh Dickins Cc: "Kirill A. Shutemov" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux

2017-09-05T16:53:37Z

Pull arm64 updates from Catalin Marinas: - VMAP_STACK support, allowing the kernel stacks to be allocated in the vmalloc space with a guard page for trapping stack overflows. One of the patches introduces THREAD_ALIGN and changes the generic alloc_thread_stack_node() to use this instead of THREAD_SIZE (no functional change for other architectures) - Contiguous PTE hugetlb support re-enabled (after being reverted a couple of times). We now have the semantics agreed in the generic mm layer together with API improvements so that the architecture code can detect between contiguous and non-contiguous huge PTEs - Initial support for persistent memory on ARM: DC CVAP instruction exposed to user space (HWCAP) and the in-kernel pmem API implemented - raid6 improvements for arm64: faster algorithm for the delta syndrome and implementation of the recovery routines using Neon - FP/SIMD refactoring and removal of support for Neon in interrupt context. This is in preparation for full SVE support - PTE accessors converted from inline asm to cmpxchg so that we can use LSE atomics if available (ARMv8.1) - Perf support for Cortex-A35 and A73 - Non-urgent fixes and cleanups * tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (75 commits) arm64: cleanup {COMPAT_,}SET_PERSONALITY() macro arm64: introduce separated bits for mm_context_t flags arm64: hugetlb: Cleanup setup_hugepagesz arm64: Re-enable support for contiguous hugepages arm64: hugetlb: Override set_huge_swap_pte_at() to support contiguous hugepages arm64: hugetlb: Override huge_pte_clear() to support contiguous hugepages arm64: hugetlb: Handle swap entries in huge_pte_offset() for contiguous hugepages arm64: hugetlb: Add break-before-make logic for contiguous entries arm64: hugetlb: Spring clean huge pte accessors arm64: hugetlb: Introduce pte_pgprot helper arm64: hugetlb: set_huge_pte_at Add WARN_ON on !pte_present arm64: kexec: have own crash_smp_send_stop() for crash dump for nonpanic cores arm64: dma-mapping: Mark atomic_pool as __ro_after_init arm64: dma-mapping: Do not pass data to gen_pool_set_algo() arm64: Remove the !CONFIG_ARM64_HW_AFDBM alternative code paths arm64: Ignore hardware dirty bit updates in ptep_set_wrprotect() arm64: Move PTE_RDONLY bit handling out of set_pte_at() kvm: arm64: Convert kvm_set_s2pte_readonly() from inline asm to cmpxchg() arm64: Convert pte handling from inline asm to using (cmp)xchg arm64: neon/efi: Make EFI fpsimd save/restore variables static ...

Merge branch 'linus' into locking/core, to fix up conflicts

2017-09-04T09:01:18Z

Conflicts: mm/page_alloc.c Signed-off-by: Ingo Molnar

mm, uprobes: fix multiple free of ->uprobes_state.xol_area

2017-08-31T23:33:15Z

Commit 7c051267931a ("mm, fork: make dup_mmap wait for mmap_sem for write killable") made it possible to kill a forking task while it is waiting to acquire its ->mmap_sem for write, in dup_mmap(). However, it was overlooked that this introduced an new error path before the new mm_struct's ->uprobes_state.xol_area has been set to NULL after being copied from the old mm_struct by the memcpy in dup_mm(). For a task that has previously hit a uprobe tracepoint, this resulted in the 'struct xol_area' being freed multiple times if the task was killed at just the right time while forking. Fix it by setting ->uprobes_state.xol_area to NULL in mm_init() rather than in uprobe_dup_mmap(). With CONFIG_UPROBE_EVENTS=y, the bug can be reproduced by the same C program given by commit 2b7e8665b4ff ("fork: fix incorrect fput of ->exe_file causing use-after-free"), provided that a uprobe tracepoint has been set on the fork_thread() function. For example: $ gcc reproducer.c -o reproducer -lpthread $ nm reproducer | grep fork_thread 0000000000400719 t fork_thread $ echo "p $PWD/reproducer:0x719" > /sys/kernel/debug/tracing/uprobe_events $ echo 1 > /sys/kernel/debug/tracing/events/uprobes/enable $ ./reproducer Here is the use-after-free reported by KASAN: BUG: KASAN: use-after-free in uprobe_clear_state+0x1c4/0x200 Read of size 8 at addr ffff8800320a8b88 by task reproducer/198 CPU: 1 PID: 198 Comm: reproducer Not tainted 4.13.0-rc7-00015-g36fde05f3fb5 #255 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-20170228_101828-anatol 04/01/2014 Call Trace: dump_stack+0xdb/0x185 print_address_description+0x7e/0x290 kasan_report+0x23b/0x350 __asan_report_load8_noabort+0x19/0x20 uprobe_clear_state+0x1c4/0x200 mmput+0xd6/0x360 do_exit+0x740/0x1670 do_group_exit+0x13f/0x380 get_signal+0x597/0x17d0 do_signal+0x99/0x1df0 exit_to_usermode_loop+0x166/0x1e0 syscall_return_slowpath+0x258/0x2c0 entry_SYSCALL_64_fastpath+0xbc/0xbe ... Allocated by task 199: save_stack_trace+0x1b/0x20 kasan_kmalloc+0xfc/0x180 kmem_cache_alloc_trace+0xf3/0x330 __create_xol_area+0x10f/0x780 uprobe_notify_resume+0x1674/0x2210 exit_to_usermode_loop+0x150/0x1e0 prepare_exit_to_usermode+0x14b/0x180 retint_user+0x8/0x20 Freed by task 199: save_stack_trace+0x1b/0x20 kasan_slab_free+0xa8/0x1a0 kfree+0xba/0x210 uprobe_clear_state+0x151/0x200 mmput+0xd6/0x360 copy_process.part.8+0x605f/0x65d0 _do_fork+0x1a5/0xbd0 SyS_clone+0x19/0x20 do_syscall_64+0x22f/0x660 return_from_SYSCALL_64+0x0/0x7a Note: without KASAN, you may instead see a "Bad page state" message, or simply a general protection fault. Link: http://lkml.kernel.org/r/20170830033303.17927-1-ebiggers3@gmail.com Fixes: 7c051267931a ("mm, fork: make dup_mmap wait for mmap_sem for write killable") Signed-off-by: Eric Biggers Reported-by: Oleg Nesterov Acked-by: Oleg Nesterov Cc: Alexander Shishkin Cc: Arnaldo Carvalho de Melo Cc: Dmitry Vyukov Cc: Ingo Molnar Cc: Konstantin Khlebnikov Cc: Mark Rutland Cc: Michal Hocko Cc: Peter Zijlstra Cc: Vlastimil Babka Cc: [4.7+] Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds