1. 19 6月, 2017 1 次提交
    • H
      mm: larger stack guard gap, between vmas · 1be7107f
      Hugh Dickins 提交于
      Stack guard page is a useful feature to reduce a risk of stack smashing
      into a different mapping. We have been using a single page gap which
      is sufficient to prevent having stack adjacent to a different mapping.
      But this seems to be insufficient in the light of the stack usage in
      userspace. E.g. glibc uses as large as 64kB alloca() in many commonly
      used functions. Others use constructs liks gid_t buffer[NGROUPS_MAX]
      which is 256kB or stack strings with MAX_ARG_STRLEN.
      
      This will become especially dangerous for suid binaries and the default
      no limit for the stack size limit because those applications can be
      tricked to consume a large portion of the stack and a single glibc call
      could jump over the guard page. These attacks are not theoretical,
      unfortunatelly.
      
      Make those attacks less probable by increasing the stack guard gap
      to 1MB (on systems with 4k pages; but make it depend on the page size
      because systems with larger base pages might cap stack allocations in
      the PAGE_SIZE units) which should cover larger alloca() and VLA stack
      allocations. It is obviously not a full fix because the problem is
      somehow inherent, but it should reduce attack space a lot.
      
      One could argue that the gap size should be configurable from userspace,
      but that can be done later when somebody finds that the new 1MB is wrong
      for some special case applications.  For now, add a kernel command line
      option (stack_guard_gap) to specify the stack gap size (in page units).
      
      Implementation wise, first delete all the old code for stack guard page:
      because although we could get away with accounting one extra page in a
      stack vma, accounting a larger gap can break userspace - case in point,
      a program run with "ulimit -S -v 20000" failed when the 1MB gap was
      counted for RLIMIT_AS; similar problems could come with RLIMIT_MLOCK
      and strict non-overcommit mode.
      
      Instead of keeping gap inside the stack vma, maintain the stack guard
      gap as a gap between vmas: using vm_start_gap() in place of vm_start
      (or vm_end_gap() in place of vm_end if VM_GROWSUP) in just those few
      places which need to respect the gap - mainly arch_get_unmapped_area(),
      and and the vma tree's subtree_gap support for that.
      Original-patch-by: NOleg Nesterov <oleg@redhat.com>
      Original-patch-by: NMichal Hocko <mhocko@suse.com>
      Signed-off-by: NHugh Dickins <hughd@google.com>
      Acked-by: NMichal Hocko <mhocko@suse.com>
      Tested-by: Helge Deller <deller@gmx.de> # parisc
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      1be7107f
  2. 03 6月, 2017 1 次提交
  3. 10 5月, 2017 1 次提交
    • N
      uapi: export all headers under uapi directories · fcc8487d
      Nicolas Dichtel 提交于
      Regularly, when a new header is created in include/uapi/, the developer
      forgets to add it in the corresponding Kbuild file. This error is usually
      detected after the release is out.
      
      In fact, all headers under uapi directories should be exported, thus it's
      useless to have an exhaustive list.
      
      After this patch, the following files, which were not exported, are now
      exported (with make headers_install_all):
      asm-arc/kvm_para.h
      asm-arc/ucontext.h
      asm-blackfin/shmparam.h
      asm-blackfin/ucontext.h
      asm-c6x/shmparam.h
      asm-c6x/ucontext.h
      asm-cris/kvm_para.h
      asm-h8300/shmparam.h
      asm-h8300/ucontext.h
      asm-hexagon/shmparam.h
      asm-m32r/kvm_para.h
      asm-m68k/kvm_para.h
      asm-m68k/shmparam.h
      asm-metag/kvm_para.h
      asm-metag/shmparam.h
      asm-metag/ucontext.h
      asm-mips/hwcap.h
      asm-mips/reg.h
      asm-mips/ucontext.h
      asm-nios2/kvm_para.h
      asm-nios2/ucontext.h
      asm-openrisc/shmparam.h
      asm-parisc/kvm_para.h
      asm-powerpc/perf_regs.h
      asm-sh/kvm_para.h
      asm-sh/ucontext.h
      asm-tile/shmparam.h
      asm-unicore32/shmparam.h
      asm-unicore32/ucontext.h
      asm-x86/hwcap2.h
      asm-xtensa/kvm_para.h
      drm/armada_drm.h
      drm/etnaviv_drm.h
      drm/vgem_drm.h
      linux/aspeed-lpc-ctrl.h
      linux/auto_dev-ioctl.h
      linux/bcache.h
      linux/btrfs_tree.h
      linux/can/vxcan.h
      linux/cifs/cifs_mount.h
      linux/coresight-stm.h
      linux/cryptouser.h
      linux/fsmap.h
      linux/genwqe/genwqe_card.h
      linux/hash_info.h
      linux/kcm.h
      linux/kcov.h
      linux/kfd_ioctl.h
      linux/lightnvm.h
      linux/module.h
      linux/nbd-netlink.h
      linux/nilfs2_api.h
      linux/nilfs2_ondisk.h
      linux/nsfs.h
      linux/pr.h
      linux/qrtr.h
      linux/rpmsg.h
      linux/sched/types.h
      linux/sed-opal.h
      linux/smc.h
      linux/smc_diag.h
      linux/stm.h
      linux/switchtec_ioctl.h
      linux/vfio_ccw.h
      linux/wil6210_uapi.h
      rdma/bnxt_re-abi.h
      
      Note that I have removed from this list the files which are generated in every
      exported directories (like .install or .install.cmd).
      
      Thanks to Julien Floret <julien.floret@6wind.com> for the tip to get all
      subdirs with a pure makefile command.
      
      For the record, note that exported files for asm directories are a mix of
      files listed by:
       - include/uapi/asm-generic/Kbuild.asm;
       - arch/<arch>/include/uapi/asm/Kbuild;
       - arch/<arch>/include/asm/Kbuild.
      Signed-off-by: NNicolas Dichtel <nicolas.dichtel@6wind.com>
      Acked-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
      Acked-by: NRussell King <rmk+kernel@armlinux.org.uk>
      Acked-by: NMark Salter <msalter@redhat.com>
      Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
      Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
      fcc8487d
  4. 27 4月, 2017 1 次提交
  5. 19 4月, 2017 1 次提交
  6. 08 4月, 2017 1 次提交
  7. 03 4月, 2017 1 次提交
    • P
      debug: Fix __bug_table[] in arch linker scripts · b5effd38
      Peter Zijlstra 提交于
      The kbuild test robot reported this build failure on a number
      of architectures:
      
       >         make.cross ARCH=arm
       >    lib/lib.a(bug.o): In function `find_bug':
       > >> lib/bug.c:135: undefined reference to `__start___bug_table'
       > >> lib/bug.c:135: undefined reference to `__stop___bug_table'
      
      Caused by:
      
        19d43626 ("debug: Add _ONCE() logic to report_bug()")
      
      Which moved the BUG_TABLE from RO_DATA_SECTION() to RW_DATA_SECTION(),
      but a number of architectures don't use RW_DATA_SECTION(), so they
      ended up with no __bug_table[] ...
      
      Ideally all those would use RW_DATA_SECTION() in their linker scripts,
      but that's for another day.
      Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: kbuild test robot <fengguang.wu@intel.com>
      Cc: kbuild-all@01.org
      Cc: tipbuild@zytor.com
      Link: http://lkml.kernel.org/r/20170330154927.o6qmgfp4bdhrajbm@hirez.programming.kicks-ass.netSigned-off-by: NIngo Molnar <mingo@kernel.org>
      b5effd38
  8. 29 3月, 2017 2 次提交
  9. 25 3月, 2017 1 次提交
  10. 23 3月, 2017 1 次提交
  11. 10 3月, 2017 1 次提交
  12. 06 3月, 2017 2 次提交
  13. 02 3月, 2017 7 次提交
  14. 28 2月, 2017 2 次提交
  15. 25 2月, 2017 1 次提交
  16. 01 2月, 2017 1 次提交
    • F
      sched/cputime: Remove generic asm headers · b672592f
      Frederic Weisbecker 提交于
      cputime_t is now only used by two architectures:
      
      	* powerpc (when CONFIG_VIRT_CPU_ACCOUNTING_NATIVE=y)
      	* s390
      
      And since the core doesn't use it anymore, we don't need any arch support
      from the others. So we can remove their stub implementations.
      
      A final cleanup would be to provide an efficient pure arch
      implementation of cputime_to_nsec() for s390 and powerpc and finally
      remove include/linux/cputime.h .
      Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
      Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
      Cc: Fenghua Yu <fenghua.yu@intel.com>
      Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
      Cc: Michael Ellerman <mpe@ellerman.id.au>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Rik van Riel <riel@redhat.com>
      Cc: Stanislaw Gruszka <sgruszka@redhat.com>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Tony Luck <tony.luck@intel.com>
      Cc: Wanpeng Li <wanpeng.li@hotmail.com>
      Link: http://lkml.kernel.org/r/1485832191-26889-36-git-send-email-fweisbec@gmail.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
      b672592f
  17. 25 1月, 2017 5 次提交
  18. 25 12月, 2016 1 次提交
  19. 15 12月, 2016 1 次提交
  20. 30 11月, 2016 1 次提交
    • F
      tcp: SOF_TIMESTAMPING_OPT_STATS option for SO_TIMESTAMPING · 1c885808
      Francis Yan 提交于
      This patch exports the sender chronograph stats via the socket
      SO_TIMESTAMPING channel. Currently we can instrument how long a
      particular application unit of data was queued in TCP by tracking
      SOF_TIMESTAMPING_TX_SOFTWARE and SOF_TIMESTAMPING_TX_SCHED. Having
      these sender chronograph stats exported simultaneously along with
      these timestamps allow further breaking down the various sender
      limitation.  For example, a video server can tell if a particular
      chunk of video on a connection takes a long time to deliver because
      TCP was experiencing small receive window. It is not possible to
      tell before this patch without packet traces.
      
      To prepare these stats, the user needs to set
      SOF_TIMESTAMPING_OPT_STATS and SOF_TIMESTAMPING_OPT_TSONLY flags
      while requesting other SOF_TIMESTAMPING TX timestamps. When the
      timestamps are available in the error queue, the stats are returned
      in a separate control message of type SCM_TIMESTAMPING_OPT_STATS,
      in a list of TLVs (struct nlattr) of types: TCP_NLA_BUSY_TIME,
      TCP_NLA_RWND_LIMITED, TCP_NLA_SNDBUF_LIMITED. Unit is microsecond.
      Signed-off-by: NFrancis Yan <francisyyan@gmail.com>
      Signed-off-by: NYuchung Cheng <ycheng@google.com>
      Signed-off-by: NSoheil Hassas Yeganeh <soheil@google.com>
      Acked-by: NNeal Cardwell <ncardwell@google.com>
      Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      1c885808
  21. 17 11月, 2016 1 次提交
  22. 16 11月, 2016 2 次提交
    • C
      locking/core, arch: Remove cpu_relax_lowlatency() · 5bd0b85b
      Christian Borntraeger 提交于
      As there are no users left, we can remove cpu_relax_lowlatency()
      implementations from every architecture.
      Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>
      Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
      Cc: Catalin Marinas <catalin.marinas@arm.com>
      Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
      Cc: Nicholas Piggin <npiggin@gmail.com>
      Cc: Noam Camus <noamc@ezchip.com>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Russell King <linux@armlinux.org.uk>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Will Deacon <will.deacon@arm.com>
      Cc: linuxppc-dev@lists.ozlabs.org
      Cc: virtualization@lists.linux-foundation.org
      Cc: xen-devel@lists.xenproject.org
      Cc: <linux-arch@vger.kernel.org>
      Link: http://lkml.kernel.org/r/1477386195-32736-6-git-send-email-borntraeger@de.ibm.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
      5bd0b85b
    • C
      locking/core: Introduce cpu_relax_yield() · 79ab11cd
      Christian Borntraeger 提交于
      For spinning loops people do often use barrier() or cpu_relax().
      For most architectures cpu_relax and barrier are the same, but on
      some architectures cpu_relax can add some latency.
      For example on power,sparc64 and arc, cpu_relax can shift the CPU
      towards other hardware threads in an SMT environment.
      On s390 cpu_relax does even more, it uses an hypercall to the
      hypervisor to give up the timeslice.
      In contrast to the SMT yielding this can result in larger latencies.
      In some places this latency is unwanted, so another variant
      "cpu_relax_lowlatency" was introduced. Before this is used in more
      and more places, lets revert the logic and provide a cpu_relax_yield
      that can be called in places where yielding is more important than
      latency. By default this is the same as cpu_relax on all architectures.
      Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>
      Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
      Cc: Catalin Marinas <catalin.marinas@arm.com>
      Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
      Cc: Nicholas Piggin <npiggin@gmail.com>
      Cc: Noam Camus <noamc@ezchip.com>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Russell King <linux@armlinux.org.uk>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Will Deacon <will.deacon@arm.com>
      Cc: linuxppc-dev@lists.ozlabs.org
      Cc: virtualization@lists.linux-foundation.org
      Cc: xen-devel@lists.xenproject.org
      Link: http://lkml.kernel.org/r/1477386195-32736-2-git-send-email-borntraeger@de.ibm.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
      79ab11cd
  23. 25 10月, 2016 1 次提交
  24. 08 10月, 2016 1 次提交
  25. 28 9月, 2016 2 次提交