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  1. 21 11月, 2016 4 次提交
  3. 16 11月, 2016 2 次提交
  5. 12 11月, 2016 6 次提交
    • A
      crypto: aesni: shut up -Wmaybe-uninitialized warning · beae2c9e
      由 Arnd Bergmann 提交于 
      The rfc4106 encrypy/decrypt helper functions cause an annoying
false-positive warning in allmodconfig if we turn on
-Wmaybe-uninitialized warnings again:

  arch/x86/crypto/aesni-intel_glue.c: In function ‘helper_rfc4106_decrypt’:
  include/linux/scatterlist.h:67:31: warning: ‘dst_sg_walk.sg’ may be used uninitialized in this function [-Wmaybe-uninitialized]

The problem seems to be that the compiler doesn't track the state of the
'one_entry_in_sg' variable across the kernel_fpu_begin/kernel_fpu_end
section.

This takes the easy way out by adding a bogus initialization, which
should be harmless enough to get the patch into v4.9 so we can turn on
this warning again by default without producing useless output.  A
follow-up patch for v4.10 rearranges the code to make the warning go
away.
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      beae2c9e
    • A
      s390: pci: don't print uninitialized data for debugging · 92dfffee
      由 Arnd Bergmann 提交于 
      gcc correctly warns about an incorrect use of the 'pa' variable in case
we pass an empty scatterlist to __s390_dma_map_sg:

  arch/s390/pci/pci_dma.c: In function '__s390_dma_map_sg':
  arch/s390/pci/pci_dma.c:309:13: warning: 'pa' may be used uninitialized in this function [-Wmaybe-uninitialized]

This adds a bogus initialization to the function to sanitize the debug
output.  I would have preferred a solution without the initialization,
but I only got the report from the kbuild bot after turning on the
warning again, and didn't manage to reproduce it myself.
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Acked-by: NSebastian Ott <sebott@linux.vnet.ibm.com>
Acked-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      92dfffee
    • A
      nios2: fix timer initcall return value · 069013a9
      由 Arnd Bergmann 提交于 
      When called more than twice, the nios2_time_init() function return an
uninitialized value, as detected by gcc -Wmaybe-uninitialized

  arch/nios2/kernel/time.c: warning: 'ret' may be used uninitialized in this function

This makes it return '0' here, matching the comment above the function.
Acked-by: NLey Foon Tan <lftan@altera.com>
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      069013a9
    • A
      x86: apm: avoid uninitialized data · 3a6d8676
      由 Arnd Bergmann 提交于 
      apm_bios_call() can fail, and return a status in its argument structure.
If that status however is zero during a call from
apm_get_power_status(), we end up using data that may have never been
set, as reported by "gcc -Wmaybe-uninitialized":

  arch/x86/kernel/apm_32.c: In function ‘apm’:
  arch/x86/kernel/apm_32.c:1729:17: error: ‘bx’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
  arch/x86/kernel/apm_32.c:1835:5: error: ‘cx’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
  arch/x86/kernel/apm_32.c:1730:17: note: ‘cx’ was declared here
  arch/x86/kernel/apm_32.c:1842:27: error: ‘dx’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
  arch/x86/kernel/apm_32.c:1731:17: note: ‘dx’ was declared here

This changes the function to return "APM_NO_ERROR" here, which makes the
code more robust to broken BIOS versions, and avoids the warning.
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Reviewed-by: NJiri Kosina <jkosina@suse.cz>
Reviewed-by: NLuis R. Rodriguez <mcgrof@kernel.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      3a6d8676
    • A
      Kbuild: enable -Wmaybe-uninitialized warning for "make W=1" · a76bcf55
      由 Arnd Bergmann 提交于 
      Traditionally, we have always had warnings about uninitialized variables
enabled, as this is part of -Wall, and generally a good idea [1], but it
also always produced false positives, mainly because this is a variation
of the halting problem and provably impossible to get right in all cases
[2].

Various people have identified cases that are particularly bad for false
positives, and in commit e74fc973 ("Turn off -Wmaybe-uninitialized
when building with -Os"), I turned off the warning for any build that
was done with CC_OPTIMIZE_FOR_SIZE.  This drastically reduced the number
of false positive warnings in the default build but unfortunately had
the side effect of turning the warning off completely in 'allmodconfig'
builds, which in turn led to a lot of warnings (both actual bugs, and
remaining false positives) to go in unnoticed.

With commit 877417e6 ("Kbuild: change CC_OPTIMIZE_FOR_SIZE
definition") enabled the warning again for allmodconfig builds in v4.7
and in v4.8-rc1, I had finally managed to address all warnings I get in
an ARM allmodconfig build and most other maybe-uninitialized warnings
for ARM randconfig builds.

However, commit 6e8d666e ("Disable "maybe-uninitialized" warning
globally") was merged at the same time and disabled it completely for
all configurations, because of false-positive warnings on x86 that I had
not addressed until then.  This caused a lot of actual bugs to get
merged into mainline, and I sent several dozen patches for these during
the v4.9 development cycle.  Most of these are actual bugs, some are for
correct code that is safe because it is only called under external
constraints that make it impossible to run into the case that gcc sees,
and in a few cases gcc is just stupid and finds something that can
obviously never happen.

I have now done a few thousand randconfig builds on x86 and collected
all patches that I needed to address every single warning I got (I can
provide the combined patch for the other warnings if anyone is
interested), so I hope we can get the warning back and let people catch
the actual bugs earlier.

This reverts the change to disable the warning completely and for now
brings it back at the "make W=1" level, so we can get it merged into
mainline without introducing false positives.  A follow-up patch enables
it on all levels unless some configuration option turns it off because
of false-positives.

Link: https://rusty.ozlabs.org/?p=232 [1]
Link: https://gcc.gnu.org/wiki/Better_Uninitialized_Warnings [2]
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      a76bcf55
    • J
      mm: kmemleak: scan .data.ro_after_init · d7c19b06
      由 Jakub Kicinski 提交于 
      Limit the number of kmemleak false positives by including
.data.ro_after_init in memory scanning.  To achieve this we need to add
symbols for start and end of the section to the linker scripts.

The problem was been uncovered by commit 56989f6d ("genetlink: mark
families as __ro_after_init").

Link: http://lkml.kernel.org/r/1478274173-15218-1-git-send-email-jakub.kicinski@netronome.comReviewed-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NJakub Kicinski <jakub.kicinski@netronome.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Cong Wang <xiyou.wangcong@gmail.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      d7c19b06
  7. 11 11月, 2016 1 次提交
  9. 09 11月, 2016 5 次提交
  11. 08 11月, 2016 2 次提交
    • V
      ARC: timer: rtc: implement read loop in "C" vs. inline asm · 922cc171
      由 Vineet Gupta 提交于 
      The current code doesn't even compile as somehow the inline assembly
can't see the register names defined as ARC_RTC_*
I'm pretty sure It worked when I first got it merged, but the tools were
definitely different then.

So better to write this in "C" anyways.

CC: stable@vger.kernel.org	#4.2+
Acked-by: NDaniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: NVineet Gupta <vgupta@synopsys.com>
      922cc171
    • V
      ARC: change return value of userspace cmpxchg assist syscall · e6e335bf
      由 Vineet Gupta 提交于 
      The original syscall only used to return errno to indicate if cmpxchg
succeeded. It was not returning the "previous" value which typical cmpxchg
callers are interested in to build their slowpaths or retry loops.
Given user preemption in syscall return path etc, it is not wise to
check this in userspace afterwards, but should be what kernel actually
observed in the syscall.

So change the syscall interface to always return the previous value and
additionally set Z flag to indicate whether operation succeeded or not
(just like ARM implementation when they used to have this syscall)
The flag approach avoids having to put_user errno which is nice given
the use case for this syscall cares mostly about the "previous" value.
Signed-off-by: NVineet Gupta <vgupta@synopsys.com>
      e6e335bf
  13. 07 11月, 2016 1 次提交
    • G
      openrisc: Define __ro_after_init to avoid crash · 2c7a5c5c
      由 Guenter Roeck 提交于 
      openrisc qemu tests fail with the following crash.

Unable to handle kernel access at virtual address 0xc0300c34

Oops#: 0001
CPU #: 0
   PC: c016c710    SR: 0000ae67    SP: c1017e04
   GPR00: 00000000 GPR01: c1017e04 GPR02: c0300c34 GPR03: c0300c34
   GPR04: 00000000 GPR05: c0300cb0 GPR06: c0300c34 GPR07: 000000ff
   GPR08: c107f074 GPR09: c0199ef4 GPR10: c1016000 GPR11: 00000000
   GPR12: 00000000 GPR13: c107f044 GPR14: c0473774 GPR15: 07ce0000
   GPR16: 00000000 GPR17: c107ed8a GPR18: 00009600 GPR19: c107f044
   GPR20: c107ee74 GPR21: 00000003 GPR22: c0473770 GPR23: 00000033
   GPR24: 000000bf GPR25: 00000019 GPR26: c046400c GPR27: 00000001
   GPR28: c0464028 GPR29: c1018000 GPR30: 00000006 GPR31: ccf37483
     RES: 00000000 oGPR11: ffffffff
     Process swapper (pid: 1, stackpage=c1001960)

     Stack: Stack dump [0xc1017cf8]:
     sp + 00: 0xc1017e04
     sp + 04: 0xc0300c34
     sp + 08: 0xc0300c34
     sp + 12: 0x00000000
...

Bisect points to commit d2ec3f77 ("pty: make ptmx file ops read-only
after init"). Fix by defining __ro_after_init for the openrisc
architecture, similar to parisc.

Fixes: d2ec3f77 ("pty: make ptmx file ops read-only after init")
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: NGuenter Roeck <linux@roeck-us.net>
Acked-by: NStafford Horne <shorne@gmail.com>
      2c7a5c5c
  15. 06 11月, 2016 1 次提交
  17. 05 11月, 2016 1 次提交
    • M
      arm/arm64: KVM: Perform local TLB invalidation when multiplexing vcpus on a single CPU · 94d0e598
      由 Marc Zyngier 提交于 
      Architecturally, TLBs are private to the (physical) CPU they're
associated with. But when multiple vcpus from the same VM are
being multiplexed on the same CPU, the TLBs are not private
to the vcpus (and are actually shared across the VMID).

Let's consider the following scenario:

- vcpu-0 maps PA to VA
- vcpu-1 maps PA' to VA

If run on the same physical CPU, vcpu-1 can hit TLB entries generated
by vcpu-0 accesses, and access the wrong physical page.

The solution to this is to keep a per-VM map of which vcpu ran last
on each given physical CPU, and invalidate local TLBs when switching
to a different vcpu from the same VM.
Reviewed-by: NChristoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>
      94d0e598
  19. 04 11月, 2016 17 次提交