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  1. 13 12月, 2016 7 次提交
  3. 02 12月, 2016 1 次提交
  5. 15 11月, 2016 1 次提交
    • P
      locking/mutex, drm: Introduce mutex_trylock_recursive() · 0f5225b0
      由 Peter Zijlstra 提交于 
      By popular DRM demand, introduce mutex_trylock_recursive() to fix up the
two GEM users.

Without this it is very easy for these drivers to get stuck in
low-memory situations and trigger OOM. Work is in progress to remove the
need for this in at least i915.
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: David Airlie <airlied@linux.ie>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Ding Tianhong <dingtianhong@huawei.com>
Cc: Imre Deak <imre.deak@intel.com>
Cc: Jason Low <jason.low2@hpe.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@us.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rob Clark <robdclark@gmail.com>
Cc: Terry Rudd <terry.rudd@hpe.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Will Deacon <Will.Deacon@arm.com>
Cc: dri-devel@lists.freedesktop.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NIngo Molnar <mingo@kernel.org>
      0f5225b0
  7. 12 11月, 2016 3 次提交
    • A
      Kbuild: enable -Wmaybe-uninitialized warnings by default · 4324cb23
      由 Arnd Bergmann 提交于 
      Previously the warnings were added back at the W=1 level and above, this
now turns them on again by default, assuming that we have addressed all
warnings and again have a clean build for v4.10.

I found a number of new warnings in linux-next already and submitted
bugfixes for those.  Hopefully they are caught by the 0day builder in
the future as soon as this patch is merged.
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      4324cb23
    • 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
    • A
      scripts/bloat-o-meter: fix SIGPIPE · eef06b82
      由 Alexey Dobriyan 提交于 
      Fix piping output to a program which quickly exits (read: head -n1)

	$ ./scripts/bloat-o-meter ../vmlinux-000 ../obj/vmlinux | head -n1
	add/remove: 0/0 grow/shrink: 9/60 up/down: 124/-305 (-181)
	close failed in file object destructor:
	sys.excepthook is missing
	lost sys.stderr

Link: http://lkml.kernel.org/r/20161028204618.GA29923@avx2Signed-off-by: NAlexey Dobriyan <adobriyan@gmail.com>
Cc: Matt Mackall <mpm@selenic.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      eef06b82
  9. 10 11月, 2016 2 次提交
  11. 01 11月, 2016 3 次提交
  13. 23 10月, 2016 1 次提交
  15. 12 10月, 2016 14 次提交
  17. 11 10月, 2016 3 次提交
    • N
      Coccinelle: flag conditions with no effect · c8990359
      由 Nicholas Mc Guire 提交于 
      Report code constructs where the if and else branch are functionally
identical. In cases where this is intended it really should be
documented - most reported cases probably are bugs.
Signed-off-by: NNicholas Mc Guire <hofrat@osadl.org>
Signed-off-by: NMichal Marek <mmarek@suse.com>
      c8990359
    • M
      scripts/coccicheck: Update reference for the corresponding documentation · 1e01892e
      由 Markus Elfring 提交于 
      Use the current name (in a comment at the beginning of this script) for
the file which was converted to the documentation format "reStructuredText"
in August 2016.

Fixes: 4b9033a3 ("docs: sphinxify coccinelle.txt and add it to dev-tools")
Signed-off-by: NMarkus Elfring <elfring@users.sourceforge.net>
Acked-by: NJulia Lawall <julia.lawall@lip6.fr>
Signed-off-by: NMichal Marek <mmarek@suse.com>
      1e01892e
    • E
      gcc-plugins: Add latent_entropy plugin · 38addce8
      由 Emese Revfy 提交于 
      This adds a new gcc plugin named "latent_entropy". It is designed to
extract as much possible uncertainty from a running system at boot time as
possible, hoping to capitalize on any possible variation in CPU operation
(due to runtime data differences, hardware differences, SMP ordering,
thermal timing variation, cache behavior, etc).

At the very least, this plugin is a much more comprehensive example for
how to manipulate kernel code using the gcc plugin internals.

The need for very-early boot entropy tends to be very architecture or
system design specific, so this plugin is more suited for those sorts
of special cases. The existing kernel RNG already attempts to extract
entropy from reliable runtime variation, but this plugin takes the idea to
a logical extreme by permuting a global variable based on any variation
in code execution (e.g. a different value (and permutation function)
is used to permute the global based on loop count, case statement,
if/then/else branching, etc).

To do this, the plugin starts by inserting a local variable in every
marked function. The plugin then adds logic so that the value of this
variable is modified by randomly chosen operations (add, xor and rol) and
random values (gcc generates separate static values for each location at
compile time and also injects the stack pointer at runtime). The resulting
value depends on the control flow path (e.g., loops and branches taken).

Before the function returns, the plugin mixes this local variable into
the latent_entropy global variable. The value of this global variable
is added to the kernel entropy pool in do_one_initcall() and _do_fork(),
though it does not credit any bytes of entropy to the pool; the contents
of the global are just used to mix the pool.

Additionally, the plugin can pre-initialize arrays with build-time
random contents, so that two different kernel builds running on identical
hardware will not have the same starting values.
Signed-off-by: NEmese Revfy <re.emese@gmail.com>
[kees: expanded commit message and code comments]
Signed-off-by: NKees Cook <keescook@chromium.org>
      38addce8
  19. 08 10月, 2016 2 次提交
  21. 02 10月, 2016 2 次提交
  23. 29 9月, 2016 1 次提交