user/sven/linux.git/include/linux/mm.h, branch v3.14.36

mm: propagate error from stack expansion even for guard page

2015-01-16T14:59:35Z

commit fee7e49d45149fba60156f5b59014f764d3e3728 upstream. Jay Foad reports that the address sanitizer test (asan) sometimes gets confused by a stack pointer that ends up being outside the stack vma that is reported by /proc/maps. This happens due to an interaction between RLIMIT_STACK and the guard page: when we do the guard page check, we ignore the potential error from the stack expansion, which effectively results in a missing guard page, since the expected stack expansion won't have been done. And since /proc/maps explicitly ignores the guard page (commit d7824370e263: "mm: fix up some user-visible effects of the stack guard page"), the stack pointer ends up being outside the reported stack area. This is the minimal patch: it just propagates the error. It also effectively makes the guard page part of the stack limit, which in turn measn that the actual real stack is one page less than the stack limit. Let's see if anybody notices. We could teach acct_stack_growth() to allow an extra page for a grow-up/grow-down stack in the rlimit test, but I don't want to add more complexity if it isn't needed. Reported-and-tested-by: Jay Foad Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

mm/readahead.c: inline ra_submit

2014-11-21T17:23:06Z

commit 29f175d125f0f3a9503af8a5596f93d714cceb08 upstream. Commit f9acc8c7b35a ("readahead: sanify file_ra_state names") left ra_submit with a single function call. Move ra_submit to internal.h and inline it to save some stack. Thanks to Andrew Morton for commenting different versions. Signed-off-by: Fabian Frederick Suggested-by: Andrew Morton Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Mel Gorman Signed-off-by: Greg Kroah-Hartman

mm + fs: prepare for non-page entries in page cache radix trees

2014-11-21T17:23:06Z

commit 0cd6144aadd2afd19d1aca880153530c52957604 upstream. shmem mappings already contain exceptional entries where swap slot information is remembered. To be able to store eviction information for regular page cache, prepare every site dealing with the radix trees directly to handle entries other than pages. The common lookup functions will filter out non-page entries and return NULL for page cache holes, just as before. But provide a raw version of the API which returns non-page entries as well, and switch shmem over to use it. Signed-off-by: Johannes Weiner Reviewed-by: Rik van Riel Reviewed-by: Minchan Kim Cc: Andrea Arcangeli Cc: Bob Liu Cc: Christoph Hellwig Cc: Dave Chinner Cc: Greg Thelen Cc: Hugh Dickins Cc: Jan Kara Cc: KOSAKI Motohiro Cc: Luigi Semenzato Cc: Mel Gorman Cc: Metin Doslu Cc: Michel Lespinasse Cc: Ozgun Erdogan Cc: Peter Zijlstra Cc: Roman Gushchin Cc: Ryan Mallon Cc: Tejun Heo Cc: Vlastimil Babka Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Mel Gorman Signed-off-by: Greg Kroah-Hartman

vfs: fix data corruption when blocksize < pagesize for mmaped data

2014-11-14T16:59:47Z

commit 90a8020278c1598fafd071736a0846b38510309c upstream. ->page_mkwrite() is used by filesystems to allocate blocks under a page which is becoming writeably mmapped in some process' address space. This allows a filesystem to return a page fault if there is not enough space available, user exceeds quota or similar problem happens, rather than silently discarding data later when writepage is called. However VFS fails to call ->page_mkwrite() in all the cases where filesystems need it when blocksize < pagesize. For example when blocksize = 1024, pagesize = 4096 the following is problematic: ftruncate(fd, 0); pwrite(fd, buf, 1024, 0); map = mmap(NULL, 1024, PROT_WRITE, MAP_SHARED, fd, 0); map[0] = 'a'; ----> page_mkwrite() for index 0 is called ftruncate(fd, 10000); /* or even pwrite(fd, buf, 1, 10000) */ mremap(map, 1024, 10000, 0); map[4095] = 'a'; ----> no page_mkwrite() called At the moment ->page_mkwrite() is called, filesystem can allocate only one block for the page because i_size == 1024. Otherwise it would create blocks beyond i_size which is generally undesirable. But later at ->writepage() time, we also need to store data at offset 4095 but we don't have block allocated for it. This patch introduces a helper function filesystems can use to have ->page_mkwrite() called at all the necessary moments. Signed-off-by: Jan Kara Signed-off-by: Theodore Ts'o Signed-off-by: Greg Kroah-Hartman

mm: numa: bugfix for LAST_CPUPID_NOT_IN_PAGE_FLAGS

2014-03-04T15:55:50Z

When doing some numa tests on powerpc, I triggered an oops bug. I find it is caused by using page->_last_cpupid. It should be initialized as "-1 & LAST_CPUPID_MASK", but not "-1". Otherwise, in task_numa_fault(), we will miss the checking (last_cpupid == (-1 & LAST_CPUPID_MASK)). And finally cause an oops bug in task_numa_group(), since the online cpu is less than possible cpu. This happen with CONFIG_SPARSE_VMEMMAP disabled Call trace: SMP NR_CPUS=64 NUMA PowerNV Modules linked in: CPU: 24 PID: 804 Comm: systemd-udevd Not tainted3.13.0-rc1+ #32 task: c000001e2746aa80 ti: c000001e32c50000 task.ti:c000001e32c50000 REGS: c000001e32c53510 TRAP: 0300 Not tainted(3.13.0-rc1+) MSR: 9000000000009032 CR:28024424 XER: 20000000 CFAR: c000000000009324 DAR: 7265717569726857 DSISR:40000000 SOFTE: 1 NIP .task_numa_fault+0x1470/0x2370 LR .task_numa_fault+0x1468/0x2370 Call Trace: .task_numa_fault+0x1468/0x2370 (unreliable) .do_numa_page+0x480/0x4a0 .handle_mm_fault+0x4ec/0xc90 .do_page_fault+0x3a8/0x890 handle_page_fault+0x10/0x30 Instruction dump: 3c82fefb 3884b138 48d9cff1 60000000 48000574 3c62fefb3863af78 3c82fefb 3884b138 48d9cfd5 60000000 e93f0100 <812902e4> 7d2907b45529063e 7d2a07b4 ---[ end trace 15f2510da5ae07cf ]--- Signed-off-by: Liu Ping Fan Signed-off-by: Aneesh Kumar K.V Acked-by: Peter Zijlstra Cc: Benjamin Herrenschmidt Cc: Paul Mackerras Cc: Mel Gorman Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm: include VM_MIXEDMAP flag in the VM_SPECIAL list to avoid m(un)locking

2014-03-04T15:55:48Z

Daniel Borkmann reported a VM_BUG_ON assertion failing: ------------[ cut here ]------------ kernel BUG at mm/mlock.c:528! invalid opcode: 0000 [#1] SMP Modules linked in: ccm arc4 iwldvm [...] video CPU: 3 PID: 2266 Comm: netsniff-ng Not tainted 3.14.0-rc2+ #8 Hardware name: LENOVO 2429BP3/2429BP3, BIOS G4ET37WW (1.12 ) 05/29/2012 task: ffff8801f87f9820 ti: ffff88002cb44000 task.ti: ffff88002cb44000 RIP: 0010:[] [] munlock_vma_pages_range+0x2e0/0x2f0 Call Trace: do_munmap+0x18f/0x3b0 vm_munmap+0x41/0x60 SyS_munmap+0x22/0x30 system_call_fastpath+0x1a/0x1f RIP munlock_vma_pages_range+0x2e0/0x2f0 ---[ end trace a0088dcf07ae10f2 ]--- because munlock_vma_pages_range() thinks it's unexpectedly in the middle of a THP page. This can be reproduced with default config since 3.11 kernels. A reproducer can be found in the kernel's selftest directory for networking by running ./psock_tpacket. The problem is that an order=2 compound page (allocated by alloc_one_pg_vec_page() is part of the munlocked VM_MIXEDMAP vma (mapped by packet_mmap()) and mistaken for a THP page and assumed to be order=9. The checks for THP in munlock came with commit ff6a6da60b89 ("mm: accelerate munlock() treatment of THP pages"), i.e. since 3.9, but did not trigger a bug. It just makes munlock_vma_pages_range() skip such compound pages until the next 512-pages-aligned page, when it encounters a head page. This is however not a problem for vma's where mlocking has no effect anyway, but it can distort the accounting. Since commit 7225522bb429 ("mm: munlock: batch non-THP page isolation and munlock+putback using pagevec") this can trigger a VM_BUG_ON in PageTransHuge() check. This patch fixes the issue by adding VM_MIXEDMAP flag to VM_SPECIAL, a list of flags that make vma's non-mlockable and non-mergeable. The reasoning is that VM_MIXEDMAP vma's are similar to VM_PFNMAP, which is already on the VM_SPECIAL list, and both are intended for non-LRU pages where mlocking makes no sense anyway. Related Lkml discussion can be found in [2]. [1] tools/testing/selftests/net/psock_tpacket [2] https://lkml.org/lkml/2014/1/10/427 Signed-off-by: Vlastimil Babka Signed-off-by: Daniel Borkmann Reported-by: Daniel Borkmann Tested-by: Daniel Borkmann Cc: Thomas Hellstrom Cc: John David Anglin Cc: HATAYAMA Daisuke Cc: Konstantin Khlebnikov Cc: Carsten Otte Cc: Jared Hulbert Tested-by: Hannes Frederic Sowa Cc: Kirill A. Shutemov Acked-by: Rik van Riel Cc: Andrea Arcangeli Cc: [3.11.x+] Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm: close PageTail race

2014-03-04T15:55:47Z

Commit bf6bddf1924e ("mm: introduce compaction and migration for ballooned pages") introduces page_count(page) into memory compaction which dereferences page->first_page if PageTail(page). This results in a very rare NULL pointer dereference on the aforementioned page_count(page). Indeed, anything that does compound_head(), including page_count() is susceptible to racing with prep_compound_page() and seeing a NULL or dangling page->first_page pointer. This patch uses Andrea's implementation of compound_trans_head() that deals with such a race and makes it the default compound_head() implementation. This includes a read memory barrier that ensures that if PageTail(head) is true that we return a head page that is neither NULL nor dangling. The patch then adds a store memory barrier to prep_compound_page() to ensure page->first_page is set. This is the safest way to ensure we see the head page that we are expecting, PageTail(page) is already in the unlikely() path and the memory barriers are unfortunately required. Hugetlbfs is the exception, we don't enforce a store memory barrier during init since no race is possible. Signed-off-by: David Rientjes Cc: Holger Kiehl Cc: Christoph Lameter Cc: Rafael Aquini Cc: Vlastimil Babka Cc: Michal Hocko Cc: Mel Gorman Cc: Andrea Arcangeli Cc: Rik van Riel Cc: "Kirill A. Shutemov" Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc

2014-01-28T05:11:26Z

Pull powerpc updates from Ben Herrenschmidt: "So here's my next branch for powerpc. A bit late as I was on vacation last week. It's mostly the same stuff that was in next already, I just added two patches today which are the wiring up of lockref for powerpc, which for some reason fell through the cracks last time and is trivial. The highlights are, in addition to a bunch of bug fixes: - Reworked Machine Check handling on kernels running without a hypervisor (or acting as a hypervisor). Provides hooks to handle some errors in real mode such as TLB errors, handle SLB errors, etc... - Support for retrieving memory error information from the service processor on IBM servers running without a hypervisor and routing them to the memory poison infrastructure. - _PAGE_NUMA support on server processors - 32-bit BookE relocatable kernel support - FSL e6500 hardware tablewalk support - A bunch of new/revived board support - FSL e6500 deeper idle states and altivec powerdown support You'll notice a generic mm change here, it has been acked by the relevant authorities and is a pre-req for our _PAGE_NUMA support" * 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc: (121 commits) powerpc: Implement arch_spin_is_locked() using arch_spin_value_unlocked() powerpc: Add support for the optimised lockref implementation powerpc/powernv: Call OPAL sync before kexec'ing powerpc/eeh: Escalate error on non-existing PE powerpc/eeh: Handle multiple EEH errors powerpc: Fix transactional FP/VMX/VSX unavailable handlers powerpc: Don't corrupt transactional state when using FP/VMX in kernel powerpc: Reclaim two unused thread_info flag bits powerpc: Fix races with irq_work Move precessing of MCE queued event out from syscall exit path. pseries/cpuidle: Remove redundant call to ppc64_runlatch_off() in cpu idle routines powerpc: Make add_system_ram_resources() __init powerpc: add SATA_MV to ppc64_defconfig powerpc/powernv: Increase candidate fw image size powerpc: Add debug checks to catch invalid cpu-to-node mappings powerpc: Fix the setup of CPU-to-Node mappings during CPU online powerpc/iommu: Don't detach device without IOMMU group powerpc/eeh: Hotplug improvement powerpc/eeh: Call opal_pci_reinit() on powernv for restoring config space powerpc/eeh: Add restore_config operation ...

mm: dump page when hitting a VM_BUG_ON using VM_BUG_ON_PAGE

2014-01-24T00:36:50Z

Most of the VM_BUG_ON assertions are performed on a page. Usually, when one of these assertions fails we'll get a BUG_ON with a call stack and the registers. I've recently noticed based on the requests to add a small piece of code that dumps the page to various VM_BUG_ON sites that the page dump is quite useful to people debugging issues in mm. This patch adds a VM_BUG_ON_PAGE(cond, page) which beyond doing what VM_BUG_ON() does, also dumps the page before executing the actual BUG_ON. [akpm@linux-foundation.org: fix up includes] Signed-off-by: Sasha Levin Cc: "Kirill A. Shutemov" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm: print more details for bad_page()

2014-01-24T00:36:50Z

bad_page() is cool in that it prints out a bunch of data about the page. But, I can never remember which page flags are good and which are bad, or whether ->index or ->mapping is required to be NULL. This patch allows bad/dump_page() callers to specify a string about why they are dumping the page and adds explanation strings to a number of places. It also adds a 'bad_flags' argument to bad_page(), which it then dumps out separately from the flags which are actually set. This way, the messages will show specifically why the page was bad, *specifically* which flags it is complaining about, if it was a page flag combination which was the problem. [akpm@linux-foundation.org: switch to pr_alert] Signed-off-by: Dave Hansen Reviewed-by: Christoph Lameter Cc: Andi Kleen Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds