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  1. 11 7月, 2015 1 次提交
    • J
      parisc: Fix some PTE/TLB race conditions and optimize __flush_tlb_range based on timing results · 01ab6057
      由 John David Anglin 提交于 
      The increased use of pdtlb/pitlb instructions seemed to increase the
frequency of random segmentation faults building packages. Further, we
had a number of cases where TLB inserts would repeatedly fail and all
forward progress would stop. The Haskell ghc package caused a lot of
trouble in this area. The final indication of a race in pte handling was
this syslog entry on sibaris (C8000):

 swap_free: Unused swap offset entry 00000004
 BUG: Bad page map in process mysqld  pte:00000100 pmd:019bbec5
 addr:00000000ec464000 vm_flags:00100073 anon_vma:0000000221023828 mapping: (null) index:ec464
 CPU: 1 PID: 9176 Comm: mysqld Not tainted 4.0.0-2-parisc64-smp #1 Debian 4.0.5-1
 Backtrace:
  [<0000000040173eb0>] show_stack+0x20/0x38
  [<0000000040444424>] dump_stack+0x9c/0x110
  [<00000000402a0d38>] print_bad_pte+0x1a8/0x278
  [<00000000402a28b8>] unmap_single_vma+0x3d8/0x770
  [<00000000402a4090>] zap_page_range+0xf0/0x198
  [<00000000402ba2a4>] SyS_madvise+0x404/0x8c0

Note that the pte value is 0 except for the accessed bit 0x100. This bit
shouldn't be set without the present bit.

It should be noted that the madvise system call is probably a trigger for many
of the random segmentation faults.

In looking at the kernel code, I found the following problems:

1) The pte_clear define didn't take TLB lock when clearing a pte.
2) We didn't test pte present bit inside lock in exception support.
3) The pte and tlb locks needed to merged in order to ensure consistency
between page table and TLB. This also has the effect of serializing TLB
broadcasts on SMP systems.

The attached change implements the above and a few other tweaks to try
to improve performance. Based on the timing code, TLB purges are very
slow (e.g., ~ 209 cycles per page on rp3440). Thus, I think it
beneficial to test the split_tlb variable to avoid duplicate purges.
Probably, all PA 2.0 machines have combined TLBs.

I dropped using __flush_tlb_range in flush_tlb_mm as I realized all
applications and most threads have a stack size that is too large to
make this useful. I added some comments to this effect.

Since implementing 1 through 3, I haven't had any random segmentation
faults on mx3210 (rp3440) in about one week of building code and running
as a Debian buildd.
Signed-off-by: NJohn David Anglin <dave.anglin@bell.net>
Cc: stable@vger.kernel.org # v3.18+
Signed-off-by: NHelge Deller <deller@gmx.de>
      01ab6057
  3. 25 6月, 2015 2 次提交
    • L
      mm: new mm hook framework · 2ae416b1
      由 Laurent Dufour 提交于 
      CRIU is recreating the process memory layout by remapping the checkpointee
memory area on top of the current process (criu).  This includes remapping
the vDSO to the place it has at checkpoint time.

However some architectures like powerpc are keeping a reference to the
vDSO base address to build the signal return stack frame by calling the
vDSO sigreturn service.  So once the vDSO has been moved, this reference
is no more valid and the signal frame built later are not usable.

This patch serie is introducing a new mm hook framework, and a new
arch_remap hook which is called when mremap is done and the mm lock still
hold.  The next patch is adding the vDSO remap and unmap tracking to the
powerpc architecture.

This patch (of 3):

This patch introduces a new set of header file to manage mm hooks:
- per architecture empty header file (arch/x/include/asm/mm-arch-hooks.h)
- a generic header (include/linux/mm-arch-hooks.h)

The architecture which need to overwrite a hook as to redefine it in its
header file, while architecture which doesn't need have nothing to do.

The default hooks are defined in the generic header and are used in the
case the architecture is not defining it.

In a next step, mm hooks defined in include/asm-generic/mm_hooks.h should
be moved here.
Signed-off-by: NLaurent Dufour <ldufour@linux.vnet.ibm.com>
Suggested-by: NAndrew Morton <akpm@linux-foundation.org>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Ingo Molnar <mingo@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      2ae416b1
    • A
      parisc: use for_each_sg() · 210bff6d
      由 Akinobu Mita 提交于 
      This replaces the plain loop over the sglist array with for_each_sg()
macro which consists of sg_next() function calls.  Since parisc doesn't
select ARCH_HAS_SG_CHAIN, it is not necessary to use for_each_sg() in
order to loop over each sg element.  But this can help find problems with
drivers that do not properly initialize their sg tables when
CONFIG_DEBUG_SG is enabled.
Signed-off-by: NAkinobu Mita <akinobu.mita@gmail.com>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Helge Deller <deller@gmx.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      210bff6d
  5. 17 6月, 2015 2 次提交
    • P
      parisc64: don't use module_init for non-modular core perf code · 15becabd
      由 Paul Gortmaker 提交于 
      The perf.c code depends on CONFIG_64BIT, so it is either built-in
or absent.  It will never be modular, so using module_init as an
alias for __initcall is rather misleading.

Fix this up now, so that we can relocate module_init from
init.h into module.h in the future.  If we don't do this, we'd
have to add module.h to obviously non-modular code, and that
would be a worse thing.  Aside from it not making sense, it also
causes a ~10% increase in CPP overhead due to module.h having a
large list of headers itself -- for example compare line counts:

 device_initcall() and <linux/init.h>
	20238 arch/parisc/kernel/perf.i

 module_init() and <linux/module.h>
	22194 arch/parisc/kernel/perf.i

Direct use of __initcall is discouraged, vs prioritized ones.
Use of device_initcall is consistent with what __initcall
maps onto, and hence does not change the init order, making the
impact of this change zero.   Should someone with real hardware
for boot testing want to change it later to arch_initcall or
something different, they can do that at a later date.

Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Helge Deller <deller@gmx.de>
Cc: linux-parisc@vger.kernel.org
Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>
      15becabd
    • P
      parisc: don't use module_init for non-modular core pdc_cons code · aed6850a
      由 Paul Gortmaker 提交于 
      The pdc_cons.c code is always built in.  It will never be modular,
so using module_init as an alias for __initcall is rather
misleading.

Fix this up now, so that we can relocate module_init from
init.h into module.h in the future.  If we don't do this, we'd
have to add module.h to obviously non-modular code, and that
would be a worse thing.

Direct use of __initcall is discouraged, vs prioritized ones.
Use of device_initcall is consistent with what __initcall
maps onto, and hence does not change the init order, making the
impact of this change zero.   Should someone with real hardware
for boot testing want to change it later to arch_initcall or
something different, they can do that at a later date.
Reported-by: Nkbuild test robot <fengguang.wu@intel.com>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Helge Deller <deller@gmx.de>
Cc: linux-parisc@vger.kernel.org
Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>
      aed6850a
  7. 08 6月, 2015 1 次提交
  9. 19 5月, 2015 3 次提交
  11. 13 5月, 2015 2 次提交
    • T
      arch: Remove __ARCH_HAVE_CMPXCHG · a22e5f57
      由 Thomas Gleixner 提交于 
      We removed the only user of this define in the rtmutex code. Get rid
of it.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
      a22e5f57
    • H
      parisc,metag: Fix crashes due to stack randomization on stack-grows-upwards architectures · d045c77c
      由 Helge Deller 提交于 
      On architectures where the stack grows upwards (CONFIG_STACK_GROWSUP=y,
currently parisc and metag only) stack randomization sometimes leads to crashes
when the stack ulimit is set to lower values than STACK_RND_MASK (which is 8 MB
by default if not defined in arch-specific headers).

The problem is, that when the stack vm_area_struct is set up in fs/exec.c, the
additional space needed for the stack randomization (as defined by the value of
STACK_RND_MASK) was not taken into account yet and as such, when the stack
randomization code added a random offset to the stack start, the stack
effectively got smaller than what the user defined via rlimit_max(RLIMIT_STACK)
which then sometimes leads to out-of-stack situations and crashes.

This patch fixes it by adding the maximum possible amount of memory (based on
STACK_RND_MASK) which theoretically could be added by the stack randomization
code to the initial stack size. That way, the user-defined stack size is always
guaranteed to be at minimum what is defined via rlimit_max(RLIMIT_STACK).

This bug is currently not visible on the metag architecture, because on metag
STACK_RND_MASK is defined to 0 which effectively disables stack randomization.

The changes to fs/exec.c are inside an "#ifdef CONFIG_STACK_GROWSUP"
section, so it does not affect other platformws beside those where the
stack grows upwards (parisc and metag).
Signed-off-by: NHelge Deller <deller@gmx.de>
Cc: linux-parisc@vger.kernel.org
Cc: James Hogan <james.hogan@imgtec.com>
Cc: linux-metag@vger.kernel.org
Cc: stable@vger.kernel.org # v3.16+
      d045c77c
  13. 06 5月, 2015 1 次提交
  15. 24 4月, 2015 1 次提交
  17. 22 4月, 2015 2 次提交
  19. 17 4月, 2015 1 次提交
  21. 15 4月, 2015 1 次提交
  23. 13 4月, 2015 1 次提交
  25. 23 3月, 2015 3 次提交
  27. 05 3月, 2015 1 次提交
  29. 01 3月, 2015 1 次提交
    • K
      mm: add missing __PAGETABLE_{PUD,PMD}_FOLDED defines · c07af4f1
      由 Kirill A. Shutemov 提交于 
      Core mm expects __PAGETABLE_{PUD,PMD}_FOLDED to be defined if these page
table levels folded.  Usually, these defines are provided by
<asm-generic/pgtable-nopmd.h> and <asm-generic/pgtable-nopud.h>.

But some architectures fold page table levels in a custom way.  They
need to define these macros themself.  This patch adds missing defines.

The patch fixes mm->nr_pmds underflow and eliminates dead __pmd_alloc()
and __pud_alloc() on architectures without these page table levels.
Signed-off-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Aaro Koskinen <aaro.koskinen@iki.fi>
Cc: David Howells <dhowells@redhat.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Koichi Yasutake <yasutake.koichi@jp.panasonic.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      c07af4f1
  31. 17 2月, 2015 10 次提交
  33. 14 2月, 2015 1 次提交
    • A
      mm: vmalloc: pass additional vm_flags to __vmalloc_node_range() · cb9e3c29
      由 Andrey Ryabinin 提交于 
      For instrumenting global variables KASan will shadow memory backing memory
for modules.  So on module loading we will need to allocate memory for
shadow and map it at address in shadow that corresponds to the address
allocated in module_alloc().

__vmalloc_node_range() could be used for this purpose, except it puts a
guard hole after allocated area.  Guard hole in shadow memory should be a
problem because at some future point we might need to have a shadow memory
at address occupied by guard hole.  So we could fail to allocate shadow
for module_alloc().

Now we have VM_NO_GUARD flag disabling guard page, so we need to pass into
__vmalloc_node_range().  Add new parameter 'vm_flags' to
__vmalloc_node_range() function.
Signed-off-by: NAndrey Ryabinin <a.ryabinin@samsung.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Konstantin Serebryany <kcc@google.com>
Cc: Dmitry Chernenkov <dmitryc@google.com>
Signed-off-by: NAndrey Konovalov <adech.fo@gmail.com>
Cc: Yuri Gribov <tetra2005@gmail.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      cb9e3c29
  35. 13 2月, 2015 1 次提交
    • A
      all arches, signal: move restart_block to struct task_struct · f56141e3
      由 Andy Lutomirski 提交于 
      If an attacker can cause a controlled kernel stack overflow, overwriting
the restart block is a very juicy exploit target.  This is because the
restart_block is held in the same memory allocation as the kernel stack.

Moving the restart block to struct task_struct prevents this exploit by
making the restart_block harder to locate.

Note that there are other fields in thread_info that are also easy
targets, at least on some architectures.

It's also a decent simplification, since the restart code is more or less
identical on all architectures.

[james.hogan@imgtec.com: metag: align thread_info::supervisor_stack]
Signed-off-by: NAndy Lutomirski <luto@amacapital.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: David Miller <davem@davemloft.net>
Acked-by: NRichard Weinberger <richard@nod.at>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Haavard Skinnemoen <hskinnemoen@gmail.com>
Cc: Hans-Christian Egtvedt <egtvedt@samfundet.no>
Cc: Steven Miao <realmz6@gmail.com>
Cc: Mark Salter <msalter@redhat.com>
Cc: Aurelien Jacquiot <a-jacquiot@ti.com>
Cc: Mikael Starvik <starvik@axis.com>
Cc: Jesper Nilsson <jesper.nilsson@axis.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Richard Kuo <rkuo@codeaurora.org>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Helge Deller <deller@gmx.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Tested-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Chen Liqin <liqin.linux@gmail.com>
Cc: Lennox Wu <lennox.wu@gmail.com>
Cc: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Guan Xuetao <gxt@mprc.pku.edu.cn>
Cc: Chris Zankel <chris@zankel.net>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: NJames Hogan <james.hogan@imgtec.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      f56141e3
  37. 12 2月, 2015 1 次提交
  39. 11 2月, 2015 1 次提交
  41. 30 1月, 2015 1 次提交
    • L
      vm: add VM_FAULT_SIGSEGV handling support · 33692f27
      由 Linus Torvalds 提交于 
      The core VM already knows about VM_FAULT_SIGBUS, but cannot return a
"you should SIGSEGV" error, because the SIGSEGV case was generally
handled by the caller - usually the architecture fault handler.

That results in lots of duplication - all the architecture fault
handlers end up doing very similar "look up vma, check permissions, do
retries etc" - but it generally works.  However, there are cases where
the VM actually wants to SIGSEGV, and applications _expect_ SIGSEGV.

In particular, when accessing the stack guard page, libsigsegv expects a
SIGSEGV.  And it usually got one, because the stack growth is handled by
that duplicated architecture fault handler.

However, when the generic VM layer started propagating the error return
from the stack expansion in commit fee7e49d ("mm: propagate error
from stack expansion even for guard page"), that now exposed the
existing VM_FAULT_SIGBUS result to user space.  And user space really
expected SIGSEGV, not SIGBUS.

To fix that case, we need to add a VM_FAULT_SIGSEGV, and teach all those
duplicate architecture fault handlers about it.  They all already have
the code to handle SIGSEGV, so it's about just tying that new return
value to the existing code, but it's all a bit annoying.

This is the mindless minimal patch to do this.  A more extensive patch
would be to try to gather up the mostly shared fault handling logic into
one generic helper routine, and long-term we really should do that
cleanup.

Just from this patch, you can generally see that most architectures just
copied (directly or indirectly) the old x86 way of doing things, but in
the meantime that original x86 model has been improved to hold the VM
semaphore for shorter times etc and to handle VM_FAULT_RETRY and other
"newer" things, so it would be a good idea to bring all those
improvements to the generic case and teach other architectures about
them too.
Reported-and-tested-by: NTakashi Iwai <tiwai@suse.de>
Tested-by: NJan Engelhardt <jengelh@inai.de>
Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com> # "s390 still compiles and boots"
Cc: linux-arch@vger.kernel.org
Cc: stable@vger.kernel.org
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      33692f27
  43. 20 1月, 2015 1 次提交
    • R
      module_arch_freeing_init(): new hook for archs before module->module_init freed. · d453cded
      由 Rusty Russell 提交于 
      Archs have been abusing module_free() to clean up their arch-specific
allocations.  Since module_free() is also (ab)used by BPF and trace code,
let's keep it to simple allocations, and provide a hook called before
that.

This means that avr32, ia64, parisc and s390 no longer need to implement
their own module_free() at all.  avr32 doesn't need module_finalize()
either.
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
Cc: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Haavard Skinnemoen <hskinnemoen@gmail.com>
Cc: Hans-Christian Egtvedt <egtvedt@samfundet.no>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Helge Deller <deller@gmx.de>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: linux-kernel@vger.kernel.org
Cc: linux-ia64@vger.kernel.org
Cc: linux-parisc@vger.kernel.org
Cc: linux-s390@vger.kernel.org
      d453cded
  45. 13 1月, 2015 1 次提交