BMC/Intel-BMC/linux.git/kernel/events/uprobes.c, branch dev-4.6

mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros

2016-04-04T17:41:08+00:00

PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time ago with promise that one day it will be possible to implement page cache with bigger chunks than PAGE_SIZE. This promise never materialized. And unlikely will. We have many places where PAGE_CACHE_SIZE assumed to be equal to PAGE_SIZE. And it's constant source of confusion on whether PAGE_CACHE_* or PAGE_* constant should be used in a particular case, especially on the border between fs and mm. Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much breakage to be doable. Let's stop pretending that pages in page cache are special. They are not. The changes are pretty straight-forward: - << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> ; - >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> ; - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN}; - page_cache_get() -> get_page(); - page_cache_release() -> put_page(); This patch contains automated changes generated with coccinelle using script below. For some reason, coccinelle doesn't patch header files. I've called spatch for them manually. The only adjustment after coccinelle is revert of changes to PAGE_CAHCE_ALIGN definition: we are going to drop it later. There are few places in the code where coccinelle didn't reach. I'll fix them manually in a separate patch. Comments and documentation also will be addressed with the separate patch. virtual patch @@ expression E; @@ - E << (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ expression E; @@ - E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ @@ - PAGE_CACHE_SHIFT + PAGE_SHIFT @@ @@ - PAGE_CACHE_SIZE + PAGE_SIZE @@ @@ - PAGE_CACHE_MASK + PAGE_MASK @@ expression E; @@ - PAGE_CACHE_ALIGN(E) + PAGE_ALIGN(E) @@ expression E; @@ - page_cache_get(E) + get_page(E) @@ expression E; @@ - page_cache_release(E) + put_page(E) Signed-off-by: Kirill A. Shutemov Acked-by: Michal Hocko Signed-off-by: Linus Torvalds

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

2016-03-21T02:08:56+00:00

Pull x86 protection key support from Ingo Molnar: "This tree adds support for a new memory protection hardware feature that is available in upcoming Intel CPUs: 'protection keys' (pkeys). There's a background article at LWN.net: https://lwn.net/Articles/643797/ The gist is that protection keys allow the encoding of user-controllable permission masks in the pte. So instead of having a fixed protection mask in the pte (which needs a system call to change and works on a per page basis), the user can map a (handful of) protection mask variants and can change the masks runtime relatively cheaply, without having to change every single page in the affected virtual memory range. This allows the dynamic switching of the protection bits of large amounts of virtual memory, via user-space instructions. It also allows more precise control of MMU permission bits: for example the executable bit is separate from the read bit (see more about that below). This tree adds the MM infrastructure and low level x86 glue needed for that, plus it adds a high level API to make use of protection keys - if a user-space application calls: mmap(..., PROT_EXEC); or mprotect(ptr, sz, PROT_EXEC); (note PROT_EXEC-only, without PROT_READ/WRITE), the kernel will notice this special case, and will set a special protection key on this memory range. It also sets the appropriate bits in the Protection Keys User Rights (PKRU) register so that the memory becomes unreadable and unwritable. So using protection keys the kernel is able to implement 'true' PROT_EXEC on x86 CPUs: without protection keys PROT_EXEC implies PROT_READ as well. Unreadable executable mappings have security advantages: they cannot be read via information leaks to figure out ASLR details, nor can they be scanned for ROP gadgets - and they cannot be used by exploits for data purposes either. We know about no user-space code that relies on pure PROT_EXEC mappings today, but binary loaders could start making use of this new feature to map binaries and libraries in a more secure fashion. There is other pending pkeys work that offers more high level system call APIs to manage protection keys - but those are not part of this pull request. Right now there's a Kconfig that controls this feature (CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS) that is default enabled (like most x86 CPU feature enablement code that has no runtime overhead), but it's not user-configurable at the moment. If there's any serious problem with this then we can make it configurable and/or flip the default" * 'mm-pkeys-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (38 commits) x86/mm/pkeys: Fix mismerge of protection keys CPUID bits mm/pkeys: Fix siginfo ABI breakage caused by new u64 field x86/mm/pkeys: Fix access_error() denial of writes to write-only VMA mm/core, x86/mm/pkeys: Add execute-only protection keys support x86/mm/pkeys: Create an x86 arch_calc_vm_prot_bits() for VMA flags x86/mm/pkeys: Allow kernel to modify user pkey rights register x86/fpu: Allow setting of XSAVE state x86/mm: Factor out LDT init from context init mm/core, x86/mm/pkeys: Add arch_validate_pkey() mm/core, arch, powerpc: Pass a protection key in to calc_vm_flag_bits() x86/mm/pkeys: Actually enable Memory Protection Keys in the CPU x86/mm/pkeys: Add Kconfig prompt to existing config option x86/mm/pkeys: Dump pkey from VMA in /proc/pid/smaps x86/mm/pkeys: Dump PKRU with other kernel registers mm/core, x86/mm/pkeys: Differentiate instruction fetches x86/mm/pkeys: Optimize fault handling in access_error() mm/core: Do not enforce PKEY permissions on remote mm access um, pkeys: Add UML arch_*_access_permitted() methods mm/gup, x86/mm/pkeys: Check VMAs and PTEs for protection keys x86/mm/gup: Simplify get_user_pages() PTE bit handling ...

uprobes: __create_xol_area() must nullify xol_mapping.fault

2016-02-29T07:47:51+00:00

As Jiri pointed out, this recent commit: f872f5400cc0 ("mm: Add a vm_special_mapping.fault() method") breaks uprobes: __create_xol_area() doesn't initialize the new ->fault() method and this obviously leads to kernel crash when the application tries to execute the probed insn after bp hit. We probably want to add uprobes_special_mapping_fault(), this allows to turn xol_area->xol_mapping into a single instance of vm_special_mapping. But we need a simple fix, so lets change __create_xol() to nullify the new member as Jiri suggests. Suggested-by: Jiri Olsa Reported-by: Jiri Olsa Signed-off-by: Oleg Nesterov Cc: Andy Lutomirski Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Pratyush Anand Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/20160227221128.GA29565@redhat.com Signed-off-by: Ingo Molnar

mm/gup: Introduce get_user_pages_remote()

2016-02-16T09:04:09+00:00

For protection keys, we need to understand whether protections should be enforced in software or not. In general, we enforce protections when working on our own task, but not when on others. We call these "current" and "remote" operations. This patch introduces a new get_user_pages() variant: get_user_pages_remote() Which is a replacement for when get_user_pages() is called on non-current tsk/mm. We also introduce a new gup flag: FOLL_REMOTE which can be used for the "__" gup variants to get this new behavior. The uprobes is_trap_at_addr() location holds mmap_sem and calls get_user_pages(current->mm) on an instruction address. This makes it a pretty unique gup caller. Being an instruction access and also really originating from the kernel (vs. the app), I opted to consider this a 'remote' access where protection keys will not be enforced. Without protection keys, this patch should not change any behavior. Signed-off-by: Dave Hansen Reviewed-by: Thomas Gleixner Cc: Andrea Arcangeli Cc: Andrew Morton Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Dave Hansen Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Kirill A. Shutemov Cc: Linus Torvalds Cc: Naoya Horiguchi Cc: Peter Zijlstra Cc: Rik van Riel Cc: Srikar Dronamraju Cc: Vlastimil Babka Cc: jack@suse.cz Cc: linux-mm@kvack.org Link: http://lkml.kernel.org/r/20160212210154.3F0E51EA@viggo.jf.intel.com Signed-off-by: Ingo Molnar

memcg: adjust to support new THP refcounting

2016-01-16T01:56:32+00:00

As with rmap, with new refcounting we cannot rely on PageTransHuge() to check if we need to charge size of huge page form the cgroup. We need to get information from caller to know whether it was mapped with PMD or PTE. We do uncharge when last reference on the page gone. At that point if we see PageTransHuge() it means we need to unchange whole huge page. The tricky part is partial unmap -- when we try to unmap part of huge page. We don't do a special handing of this situation, meaning we don't uncharge the part of huge page unless last user is gone or split_huge_page() is triggered. In case of cgroup memory pressure happens the partial unmapped page will be split through shrinker. This should be good enough. Signed-off-by: Kirill A. Shutemov Tested-by: Sasha Levin Tested-by: Aneesh Kumar K.V Acked-by: Vlastimil Babka Acked-by: Jerome Marchand Cc: Andrea Arcangeli Cc: Hugh Dickins Cc: Dave Hansen Cc: Mel Gorman Cc: Rik van Riel Cc: Naoya Horiguchi Cc: Steve Capper Cc: Johannes Weiner Cc: Michal Hocko Cc: Christoph Lameter Cc: David Rientjes Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

rmap: add argument to charge compound page

2016-01-16T01:56:32+00:00

We're going to allow mapping of individual 4k pages of THP compound page. It means we cannot rely on PageTransHuge() check to decide if map/unmap small page or THP. The patch adds new argument to rmap functions to indicate whether we want to operate on whole compound page or only the small page. [n-horiguchi@ah.jp.nec.com: fix mapcount mismatch in hugepage migration] Signed-off-by: Kirill A. Shutemov Tested-by: Sasha Levin Tested-by: Aneesh Kumar K.V Acked-by: Vlastimil Babka Acked-by: Jerome Marchand Cc: Andrea Arcangeli Cc: Hugh Dickins Cc: Dave Hansen Cc: Mel Gorman Cc: Rik van Riel Cc: Steve Capper Cc: Johannes Weiner Cc: Michal Hocko Cc: Christoph Lameter Cc: David Rientjes Signed-off-by: Naoya Horiguchi Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm, shmem: add internal shmem resident memory accounting

2016-01-15T00:00:49+00:00

Currently looking at /proc//status or statm, there is no way to distinguish shmem pages from pages mapped to a regular file (shmem pages are mapped to /dev/zero), even though their implication in actual memory use is quite different. The internal accounting currently counts shmem pages together with regular files. As a preparation to extend the userspace interfaces, this patch adds MM_SHMEMPAGES counter to mm_rss_stat to account for shmem pages separately from MM_FILEPAGES. The next patch will expose it to userspace - this patch doesn't change the exported values yet, by adding up MM_SHMEMPAGES to MM_FILEPAGES at places where MM_FILEPAGES was used before. The only user-visible change after this patch is the OOM killer message that separates the reported "shmem-rss" from "file-rss". [vbabka@suse.cz: forward-porting, tweak changelog] Signed-off-by: Jerome Marchand Signed-off-by: Vlastimil Babka Acked-by: Konstantin Khlebnikov Acked-by: Michal Hocko Acked-by: Hugh Dickins Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

treewide: Remove old email address

2015-11-23T08:44:58+00:00

There were still a number of references to my old Red Hat email address in the kernel source. Remove these while keeping the Red Hat copyright notices intact. Signed-off-by: Peter Zijlstra (Intel) Cc: Arnaldo Carvalho de Melo Cc: Jiri Olsa Cc: Linus Torvalds Cc: Mike Galbraith Cc: Peter Zijlstra Cc: Stephane Eranian Cc: Thomas Gleixner Cc: Vince Weaver Signed-off-by: Ingo Molnar

uprobes: Fix the waitqueue_active() check in xol_free_insn_slot()

2015-07-31T08:38:07+00:00

The xol_free_insn_slot()->waitqueue_active() check is buggy. We need mb() after we set the conditon for wait_event(), or xol_take_insn_slot() can miss the wakeup. Signed-off-by: Oleg Nesterov Cc: Andy Lutomirski Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Pratyush Anand Cc: Srikar Dronamraju Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/20150721134036.GA4799@redhat.com Signed-off-by: Ingo Molnar

uprobes: Use vm_special_mapping to name the XOL vma

2015-07-31T08:38:06+00:00

Change xol_add_vma() to use _install_special_mapping(), this way we can name the vma installed by uprobes. Currently it looks like private anonymous mapping, this is confusing and complicates the debugging. With this change /proc/$pid/maps reports "[uprobes]". As a side effect this will cause core dumps to include the XOL vma and I think this is good; this can help to debug the problem if the app crashed because it was probed. Signed-off-by: Oleg Nesterov Cc: Andy Lutomirski Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Pratyush Anand Cc: Srikar Dronamraju Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/20150721134033.GA4796@redhat.com Signed-off-by: Ingo Molnar