<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/include, branch v5.0.8</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>virtio: Honour 'may_reduce_num' in vring_create_virtqueue</title>
<updated>2019-04-17T06:39:50+00:00</updated>
<author>
<name>Cornelia Huck</name>
<email>cohuck@redhat.com</email>
</author>
<published>2019-04-08T12:33:22+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=88fa815395e3e082be1961fdf6c606ba1e23b342'/>
<id>88fa815395e3e082be1961fdf6c606ba1e23b342</id>
<content type='text'>
commit cf94db21905333e610e479688add629397a4b384 upstream.

vring_create_virtqueue() allows the caller to specify via the
may_reduce_num parameter whether the vring code is allowed to
allocate a smaller ring than specified.

However, the split ring allocation code tries to allocate a
smaller ring on allocation failure regardless of what the
caller specified. This may cause trouble for e.g. virtio-pci
in legacy mode, which does not support ring resizing. (The
packed ring code does not resize in any case.)

Let's fix this by bailing out immediately in the split ring code
if the requested size cannot be allocated and may_reduce_num has
not been specified.

While at it, fix a typo in the usage instructions.

Fixes: 2a2d1382fe9d ("virtio: Add improved queue allocation API")
Cc: stable@vger.kernel.org # v4.6+
Signed-off-by: Cornelia Huck &lt;cohuck@redhat.com&gt;
Signed-off-by: Michael S. Tsirkin &lt;mst@redhat.com&gt;
Reviewed-by: Halil Pasic &lt;pasic@linux.ibm.com&gt;
Reviewed-by: Jens Freimann &lt;jfreimann@redhat.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit cf94db21905333e610e479688add629397a4b384 upstream.

vring_create_virtqueue() allows the caller to specify via the
may_reduce_num parameter whether the vring code is allowed to
allocate a smaller ring than specified.

However, the split ring allocation code tries to allocate a
smaller ring on allocation failure regardless of what the
caller specified. This may cause trouble for e.g. virtio-pci
in legacy mode, which does not support ring resizing. (The
packed ring code does not resize in any case.)

Let's fix this by bailing out immediately in the split ring code
if the requested size cannot be allocated and may_reduce_num has
not been specified.

While at it, fix a typo in the usage instructions.

Fixes: 2a2d1382fe9d ("virtio: Add improved queue allocation API")
Cc: stable@vger.kernel.org # v4.6+
Signed-off-by: Cornelia Huck &lt;cohuck@redhat.com&gt;
Signed-off-by: Michael S. Tsirkin &lt;mst@redhat.com&gt;
Reviewed-by: Halil Pasic &lt;pasic@linux.ibm.com&gt;
Reviewed-by: Jens Freimann &lt;jfreimann@redhat.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>mm: writeback: use exact memcg dirty counts</title>
<updated>2019-04-17T06:39:49+00:00</updated>
<author>
<name>Greg Thelen</name>
<email>gthelen@google.com</email>
</author>
<published>2019-04-06T01:39:18+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=3859d8fae2d83df3c3d8b65ca90ab061a7f8ef6c'/>
<id>3859d8fae2d83df3c3d8b65ca90ab061a7f8ef6c</id>
<content type='text'>
commit 0b3d6e6f2dd0a7b697b1aa8c167265908940624b upstream.

Since commit a983b5ebee57 ("mm: memcontrol: fix excessive complexity in
memory.stat reporting") memcg dirty and writeback counters are managed
as:

 1) per-memcg per-cpu values in range of [-32..32]

 2) per-memcg atomic counter

When a per-cpu counter cannot fit in [-32..32] it's flushed to the
atomic.  Stat readers only check the atomic.  Thus readers such as
balance_dirty_pages() may see a nontrivial error margin: 32 pages per
cpu.

Assuming 100 cpus:
   4k x86 page_size:  13 MiB error per memcg
  64k ppc page_size: 200 MiB error per memcg

Considering that dirty+writeback are used together for some decisions the
errors double.

This inaccuracy can lead to undeserved oom kills.  One nasty case is
when all per-cpu counters hold positive values offsetting an atomic
negative value (i.e.  per_cpu[*]=32, atomic=n_cpu*-32).
balance_dirty_pages() only consults the atomic and does not consider
throttling the next n_cpu*32 dirty pages.  If the file_lru is in the
13..200 MiB range then there's absolutely no dirty throttling, which
burdens vmscan with only dirty+writeback pages thus resorting to oom
kill.

It could be argued that tiny containers are not supported, but it's more
subtle.  It's the amount the space available for file lru that matters.
If a container has memory.max-200MiB of non reclaimable memory, then it
will also suffer such oom kills on a 100 cpu machine.

The following test reliably ooms without this patch.  This patch avoids
oom kills.

  $ cat test
  mount -t cgroup2 none /dev/cgroup
  cd /dev/cgroup
  echo +io +memory &gt; cgroup.subtree_control
  mkdir test
  cd test
  echo 10M &gt; memory.max
  (echo $BASHPID &gt; cgroup.procs &amp;&amp; exec /memcg-writeback-stress /foo)
  (echo $BASHPID &gt; cgroup.procs &amp;&amp; exec dd if=/dev/zero of=/foo bs=2M count=100)

  $ cat memcg-writeback-stress.c
  /*
   * Dirty pages from all but one cpu.
   * Clean pages from the non dirtying cpu.
   * This is to stress per cpu counter imbalance.
   * On a 100 cpu machine:
   * - per memcg per cpu dirty count is 32 pages for each of 99 cpus
   * - per memcg atomic is -99*32 pages
   * - thus the complete dirty limit: sum of all counters 0
   * - balance_dirty_pages() only sees atomic count -99*32 pages, which
   *   it max()s to 0.
   * - So a workload can dirty -99*32 pages before balance_dirty_pages()
   *   cares.
   */
  #define _GNU_SOURCE
  #include &lt;err.h&gt;
  #include &lt;fcntl.h&gt;
  #include &lt;sched.h&gt;
  #include &lt;stdlib.h&gt;
  #include &lt;stdio.h&gt;
  #include &lt;sys/stat.h&gt;
  #include &lt;sys/sysinfo.h&gt;
  #include &lt;sys/types.h&gt;
  #include &lt;unistd.h&gt;

  static char *buf;
  static int bufSize;

  static void set_affinity(int cpu)
  {
  	cpu_set_t affinity;

  	CPU_ZERO(&amp;affinity);
  	CPU_SET(cpu, &amp;affinity);
  	if (sched_setaffinity(0, sizeof(affinity), &amp;affinity))
  		err(1, "sched_setaffinity");
  }

  static void dirty_on(int output_fd, int cpu)
  {
  	int i, wrote;

  	set_affinity(cpu);
  	for (i = 0; i &lt; 32; i++) {
  		for (wrote = 0; wrote &lt; bufSize; ) {
  			int ret = write(output_fd, buf+wrote, bufSize-wrote);
  			if (ret == -1)
  				err(1, "write");
  			wrote += ret;
  		}
  	}
  }

  int main(int argc, char **argv)
  {
  	int cpu, flush_cpu = 1, output_fd;
  	const char *output;

  	if (argc != 2)
  		errx(1, "usage: output_file");

  	output = argv[1];
  	bufSize = getpagesize();
  	buf = malloc(getpagesize());
  	if (buf == NULL)
  		errx(1, "malloc failed");

  	output_fd = open(output, O_CREAT|O_RDWR);
  	if (output_fd == -1)
  		err(1, "open(%s)", output);

  	for (cpu = 0; cpu &lt; get_nprocs(); cpu++) {
  		if (cpu != flush_cpu)
  			dirty_on(output_fd, cpu);
  	}

  	set_affinity(flush_cpu);
  	if (fsync(output_fd))
  		err(1, "fsync(%s)", output);
  	if (close(output_fd))
  		err(1, "close(%s)", output);
  	free(buf);
  }

Make balance_dirty_pages() and wb_over_bg_thresh() work harder to
collect exact per memcg counters.  This avoids the aforementioned oom
kills.

This does not affect the overhead of memory.stat, which still reads the
single atomic counter.

Why not use percpu_counter? memcg already handles cpus going offline, so
no need for that overhead from percpu_counter.  And the percpu_counter
spinlocks are more heavyweight than is required.

It probably also makes sense to use exact dirty and writeback counters
in memcg oom reports.  But that is saved for later.

Link: http://lkml.kernel.org/r/20190329174609.164344-1-gthelen@google.com
Signed-off-by: Greg Thelen &lt;gthelen@google.com&gt;
Reviewed-by: Roman Gushchin &lt;guro@fb.com&gt;
Acked-by: Johannes Weiner &lt;hannes@cmpxchg.org&gt;
Cc: Michal Hocko &lt;mhocko@kernel.org&gt;
Cc: Vladimir Davydov &lt;vdavydov.dev@gmail.com&gt;
Cc: Tejun Heo &lt;tj@kernel.org&gt;
Cc: &lt;stable@vger.kernel.org&gt;	[4.16+]
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 0b3d6e6f2dd0a7b697b1aa8c167265908940624b upstream.

Since commit a983b5ebee57 ("mm: memcontrol: fix excessive complexity in
memory.stat reporting") memcg dirty and writeback counters are managed
as:

 1) per-memcg per-cpu values in range of [-32..32]

 2) per-memcg atomic counter

When a per-cpu counter cannot fit in [-32..32] it's flushed to the
atomic.  Stat readers only check the atomic.  Thus readers such as
balance_dirty_pages() may see a nontrivial error margin: 32 pages per
cpu.

Assuming 100 cpus:
   4k x86 page_size:  13 MiB error per memcg
  64k ppc page_size: 200 MiB error per memcg

Considering that dirty+writeback are used together for some decisions the
errors double.

This inaccuracy can lead to undeserved oom kills.  One nasty case is
when all per-cpu counters hold positive values offsetting an atomic
negative value (i.e.  per_cpu[*]=32, atomic=n_cpu*-32).
balance_dirty_pages() only consults the atomic and does not consider
throttling the next n_cpu*32 dirty pages.  If the file_lru is in the
13..200 MiB range then there's absolutely no dirty throttling, which
burdens vmscan with only dirty+writeback pages thus resorting to oom
kill.

It could be argued that tiny containers are not supported, but it's more
subtle.  It's the amount the space available for file lru that matters.
If a container has memory.max-200MiB of non reclaimable memory, then it
will also suffer such oom kills on a 100 cpu machine.

The following test reliably ooms without this patch.  This patch avoids
oom kills.

  $ cat test
  mount -t cgroup2 none /dev/cgroup
  cd /dev/cgroup
  echo +io +memory &gt; cgroup.subtree_control
  mkdir test
  cd test
  echo 10M &gt; memory.max
  (echo $BASHPID &gt; cgroup.procs &amp;&amp; exec /memcg-writeback-stress /foo)
  (echo $BASHPID &gt; cgroup.procs &amp;&amp; exec dd if=/dev/zero of=/foo bs=2M count=100)

  $ cat memcg-writeback-stress.c
  /*
   * Dirty pages from all but one cpu.
   * Clean pages from the non dirtying cpu.
   * This is to stress per cpu counter imbalance.
   * On a 100 cpu machine:
   * - per memcg per cpu dirty count is 32 pages for each of 99 cpus
   * - per memcg atomic is -99*32 pages
   * - thus the complete dirty limit: sum of all counters 0
   * - balance_dirty_pages() only sees atomic count -99*32 pages, which
   *   it max()s to 0.
   * - So a workload can dirty -99*32 pages before balance_dirty_pages()
   *   cares.
   */
  #define _GNU_SOURCE
  #include &lt;err.h&gt;
  #include &lt;fcntl.h&gt;
  #include &lt;sched.h&gt;
  #include &lt;stdlib.h&gt;
  #include &lt;stdio.h&gt;
  #include &lt;sys/stat.h&gt;
  #include &lt;sys/sysinfo.h&gt;
  #include &lt;sys/types.h&gt;
  #include &lt;unistd.h&gt;

  static char *buf;
  static int bufSize;

  static void set_affinity(int cpu)
  {
  	cpu_set_t affinity;

  	CPU_ZERO(&amp;affinity);
  	CPU_SET(cpu, &amp;affinity);
  	if (sched_setaffinity(0, sizeof(affinity), &amp;affinity))
  		err(1, "sched_setaffinity");
  }

  static void dirty_on(int output_fd, int cpu)
  {
  	int i, wrote;

  	set_affinity(cpu);
  	for (i = 0; i &lt; 32; i++) {
  		for (wrote = 0; wrote &lt; bufSize; ) {
  			int ret = write(output_fd, buf+wrote, bufSize-wrote);
  			if (ret == -1)
  				err(1, "write");
  			wrote += ret;
  		}
  	}
  }

  int main(int argc, char **argv)
  {
  	int cpu, flush_cpu = 1, output_fd;
  	const char *output;

  	if (argc != 2)
  		errx(1, "usage: output_file");

  	output = argv[1];
  	bufSize = getpagesize();
  	buf = malloc(getpagesize());
  	if (buf == NULL)
  		errx(1, "malloc failed");

  	output_fd = open(output, O_CREAT|O_RDWR);
  	if (output_fd == -1)
  		err(1, "open(%s)", output);

  	for (cpu = 0; cpu &lt; get_nprocs(); cpu++) {
  		if (cpu != flush_cpu)
  			dirty_on(output_fd, cpu);
  	}

  	set_affinity(flush_cpu);
  	if (fsync(output_fd))
  		err(1, "fsync(%s)", output);
  	if (close(output_fd))
  		err(1, "close(%s)", output);
  	free(buf);
  }

Make balance_dirty_pages() and wb_over_bg_thresh() work harder to
collect exact per memcg counters.  This avoids the aforementioned oom
kills.

This does not affect the overhead of memory.stat, which still reads the
single atomic counter.

Why not use percpu_counter? memcg already handles cpus going offline, so
no need for that overhead from percpu_counter.  And the percpu_counter
spinlocks are more heavyweight than is required.

It probably also makes sense to use exact dirty and writeback counters
in memcg oom reports.  But that is saved for later.

Link: http://lkml.kernel.org/r/20190329174609.164344-1-gthelen@google.com
Signed-off-by: Greg Thelen &lt;gthelen@google.com&gt;
Reviewed-by: Roman Gushchin &lt;guro@fb.com&gt;
Acked-by: Johannes Weiner &lt;hannes@cmpxchg.org&gt;
Cc: Michal Hocko &lt;mhocko@kernel.org&gt;
Cc: Vladimir Davydov &lt;vdavydov.dev@gmail.com&gt;
Cc: Tejun Heo &lt;tj@kernel.org&gt;
Cc: &lt;stable@vger.kernel.org&gt;	[4.16+]
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>include/linux/bitrev.h: fix constant bitrev</title>
<updated>2019-04-17T06:39:49+00:00</updated>
<author>
<name>Arnd Bergmann</name>
<email>arnd@arndb.de</email>
</author>
<published>2019-04-06T01:38:53+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=c4727317b4e527b3720fb289d3f1eb139730083c'/>
<id>c4727317b4e527b3720fb289d3f1eb139730083c</id>
<content type='text'>
commit 6147e136ff5071609b54f18982dea87706288e21 upstream.

clang points out with hundreds of warnings that the bitrev macros have a
problem with constant input:

  drivers/hwmon/sht15.c:187:11: error: variable '__x' is uninitialized when used within its own initialization
        [-Werror,-Wuninitialized]
          u8 crc = bitrev8(data-&gt;val_status &amp; 0x0F);
                   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  include/linux/bitrev.h:102:21: note: expanded from macro 'bitrev8'
          __constant_bitrev8(__x) :                       \
          ~~~~~~~~~~~~~~~~~~~^~~~
  include/linux/bitrev.h:67:11: note: expanded from macro '__constant_bitrev8'
          u8 __x = x;                     \
             ~~~   ^

Both the bitrev and the __constant_bitrev macros use an internal
variable named __x, which goes horribly wrong when passing one to the
other.

The obvious fix is to rename one of the variables, so this adds an extra
'_'.

It seems we got away with this because

 - there are only a few drivers using bitrev macros

 - usually there are no constant arguments to those

 - when they are constant, they tend to be either 0 or (unsigned)-1
   (drivers/isdn/i4l/isdnhdlc.o, drivers/iio/amplifiers/ad8366.c) and
   give the correct result by pure chance.

In fact, the only driver that I could find that gets different results
with this is drivers/net/wan/slic_ds26522.c, which in turn is a driver
for fairly rare hardware (adding the maintainer to Cc for testing).

Link: http://lkml.kernel.org/r/20190322140503.123580-1-arnd@arndb.de
Fixes: 556d2f055bf6 ("ARM: 8187/1: add CONFIG_HAVE_ARCH_BITREVERSE to support rbit instruction")
Signed-off-by: Arnd Bergmann &lt;arnd@arndb.de&gt;
Reviewed-by: Nick Desaulniers &lt;ndesaulniers@google.com&gt;
Cc: Zhao Qiang &lt;qiang.zhao@nxp.com&gt;
Cc: Yalin Wang &lt;yalin.wang@sonymobile.com&gt;
Cc: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 6147e136ff5071609b54f18982dea87706288e21 upstream.

clang points out with hundreds of warnings that the bitrev macros have a
problem with constant input:

  drivers/hwmon/sht15.c:187:11: error: variable '__x' is uninitialized when used within its own initialization
        [-Werror,-Wuninitialized]
          u8 crc = bitrev8(data-&gt;val_status &amp; 0x0F);
                   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  include/linux/bitrev.h:102:21: note: expanded from macro 'bitrev8'
          __constant_bitrev8(__x) :                       \
          ~~~~~~~~~~~~~~~~~~~^~~~
  include/linux/bitrev.h:67:11: note: expanded from macro '__constant_bitrev8'
          u8 __x = x;                     \
             ~~~   ^

Both the bitrev and the __constant_bitrev macros use an internal
variable named __x, which goes horribly wrong when passing one to the
other.

The obvious fix is to rename one of the variables, so this adds an extra
'_'.

It seems we got away with this because

 - there are only a few drivers using bitrev macros

 - usually there are no constant arguments to those

 - when they are constant, they tend to be either 0 or (unsigned)-1
   (drivers/isdn/i4l/isdnhdlc.o, drivers/iio/amplifiers/ad8366.c) and
   give the correct result by pure chance.

In fact, the only driver that I could find that gets different results
with this is drivers/net/wan/slic_ds26522.c, which in turn is a driver
for fairly rare hardware (adding the maintainer to Cc for testing).

Link: http://lkml.kernel.org/r/20190322140503.123580-1-arnd@arndb.de
Fixes: 556d2f055bf6 ("ARM: 8187/1: add CONFIG_HAVE_ARCH_BITREVERSE to support rbit instruction")
Signed-off-by: Arnd Bergmann &lt;arnd@arndb.de&gt;
Reviewed-by: Nick Desaulniers &lt;ndesaulniers@google.com&gt;
Cc: Zhao Qiang &lt;qiang.zhao@nxp.com&gt;
Cc: Yalin Wang &lt;yalin.wang@sonymobile.com&gt;
Cc: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>lib/string.c: implement a basic bcmp</title>
<updated>2019-04-17T06:39:44+00:00</updated>
<author>
<name>Nick Desaulniers</name>
<email>ndesaulniers@google.com</email>
</author>
<published>2019-04-06T01:38:45+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=62a23bbaee095e935af50c82ff23da7a57eefa5c'/>
<id>62a23bbaee095e935af50c82ff23da7a57eefa5c</id>
<content type='text'>
[ Upstream commit 5f074f3e192f10c9fade898b9b3b8812e3d83342 ]

A recent optimization in Clang (r355672) lowers comparisons of the
return value of memcmp against zero to comparisons of the return value
of bcmp against zero.  This helps some platforms that implement bcmp
more efficiently than memcmp.  glibc simply aliases bcmp to memcmp, but
an optimized implementation is in the works.

This results in linkage failures for all targets with Clang due to the
undefined symbol.  For now, just implement bcmp as a tailcail to memcmp
to unbreak the build.  This routine can be further optimized in the
future.

Other ideas discussed:

 * A weak alias was discussed, but breaks for architectures that define
   their own implementations of memcmp since aliases to declarations are
   not permitted (only definitions). Arch-specific memcmp
   implementations typically declare memcmp in C headers, but implement
   them in assembly.

 * -ffreestanding also is used sporadically throughout the kernel.

 * -fno-builtin-bcmp doesn't work when doing LTO.

Link: https://bugs.llvm.org/show_bug.cgi?id=41035
Link: https://code.woboq.org/userspace/glibc/string/memcmp.c.html#bcmp
Link: https://github.com/llvm/llvm-project/commit/8e16d73346f8091461319a7dfc4ddd18eedcff13
Link: https://github.com/ClangBuiltLinux/linux/issues/416
Link: http://lkml.kernel.org/r/20190313211335.165605-1-ndesaulniers@google.com
Signed-off-by: Nick Desaulniers &lt;ndesaulniers@google.com&gt;
Reported-by: Nathan Chancellor &lt;natechancellor@gmail.com&gt;
Reported-by: Adhemerval Zanella &lt;adhemerval.zanella@linaro.org&gt;
Suggested-by: Arnd Bergmann &lt;arnd@arndb.de&gt;
Suggested-by: James Y Knight &lt;jyknight@google.com&gt;
Suggested-by: Masahiro Yamada &lt;yamada.masahiro@socionext.com&gt;
Suggested-by: Nathan Chancellor &lt;natechancellor@gmail.com&gt;
Suggested-by: Rasmus Villemoes &lt;linux@rasmusvillemoes.dk&gt;
Acked-by: Steven Rostedt (VMware) &lt;rostedt@goodmis.org&gt;
Reviewed-by: Nathan Chancellor &lt;natechancellor@gmail.com&gt;
Tested-by: Nathan Chancellor &lt;natechancellor@gmail.com&gt;
Reviewed-by: Masahiro Yamada &lt;yamada.masahiro@socionext.com&gt;
Reviewed-by: Andy Shevchenko &lt;andriy.shevchenko@linux.intel.com&gt;
Cc: David Laight &lt;David.Laight@ACULAB.COM&gt;
Cc: Rasmus Villemoes &lt;linux@rasmusvillemoes.dk&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Dan Williams &lt;dan.j.williams@intel.com&gt;
Cc: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 5f074f3e192f10c9fade898b9b3b8812e3d83342 ]

A recent optimization in Clang (r355672) lowers comparisons of the
return value of memcmp against zero to comparisons of the return value
of bcmp against zero.  This helps some platforms that implement bcmp
more efficiently than memcmp.  glibc simply aliases bcmp to memcmp, but
an optimized implementation is in the works.

This results in linkage failures for all targets with Clang due to the
undefined symbol.  For now, just implement bcmp as a tailcail to memcmp
to unbreak the build.  This routine can be further optimized in the
future.

Other ideas discussed:

 * A weak alias was discussed, but breaks for architectures that define
   their own implementations of memcmp since aliases to declarations are
   not permitted (only definitions). Arch-specific memcmp
   implementations typically declare memcmp in C headers, but implement
   them in assembly.

 * -ffreestanding also is used sporadically throughout the kernel.

 * -fno-builtin-bcmp doesn't work when doing LTO.

Link: https://bugs.llvm.org/show_bug.cgi?id=41035
Link: https://code.woboq.org/userspace/glibc/string/memcmp.c.html#bcmp
Link: https://github.com/llvm/llvm-project/commit/8e16d73346f8091461319a7dfc4ddd18eedcff13
Link: https://github.com/ClangBuiltLinux/linux/issues/416
Link: http://lkml.kernel.org/r/20190313211335.165605-1-ndesaulniers@google.com
Signed-off-by: Nick Desaulniers &lt;ndesaulniers@google.com&gt;
Reported-by: Nathan Chancellor &lt;natechancellor@gmail.com&gt;
Reported-by: Adhemerval Zanella &lt;adhemerval.zanella@linaro.org&gt;
Suggested-by: Arnd Bergmann &lt;arnd@arndb.de&gt;
Suggested-by: James Y Knight &lt;jyknight@google.com&gt;
Suggested-by: Masahiro Yamada &lt;yamada.masahiro@socionext.com&gt;
Suggested-by: Nathan Chancellor &lt;natechancellor@gmail.com&gt;
Suggested-by: Rasmus Villemoes &lt;linux@rasmusvillemoes.dk&gt;
Acked-by: Steven Rostedt (VMware) &lt;rostedt@goodmis.org&gt;
Reviewed-by: Nathan Chancellor &lt;natechancellor@gmail.com&gt;
Tested-by: Nathan Chancellor &lt;natechancellor@gmail.com&gt;
Reviewed-by: Masahiro Yamada &lt;yamada.masahiro@socionext.com&gt;
Reviewed-by: Andy Shevchenko &lt;andriy.shevchenko@linux.intel.com&gt;
Cc: David Laight &lt;David.Laight@ACULAB.COM&gt;
Cc: Rasmus Villemoes &lt;linux@rasmusvillemoes.dk&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Dan Williams &lt;dan.j.williams@intel.com&gt;
Cc: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>net/mlx5e: Add a lock on tir list</title>
<updated>2019-04-17T06:39:40+00:00</updated>
<author>
<name>Yuval Avnery</name>
<email>yuvalav@mellanox.com</email>
</author>
<published>2019-03-11T04:18:24+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=6fc42565470ab355097ab7b5091da390468ba55b'/>
<id>6fc42565470ab355097ab7b5091da390468ba55b</id>
<content type='text'>
[ Upstream commit 80a2a9026b24c6bd34b8d58256973e22270bedec ]

Refresh tirs is looping over a global list of tirs while netdevs are
adding and removing tirs from that list. That is why a lock is
required.

Fixes: 724b2aa15126 ("net/mlx5e: TIRs management refactoring")
Signed-off-by: Yuval Avnery &lt;yuvalav@mellanox.com&gt;
Signed-off-by: Saeed Mahameed &lt;saeedm@mellanox.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 80a2a9026b24c6bd34b8d58256973e22270bedec ]

Refresh tirs is looping over a global list of tirs while netdevs are
adding and removing tirs from that list. That is why a lock is
required.

Fixes: 724b2aa15126 ("net/mlx5e: TIRs management refactoring")
Signed-off-by: Yuval Avnery &lt;yuvalav@mellanox.com&gt;
Signed-off-by: Saeed Mahameed &lt;saeedm@mellanox.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>vrf: check accept_source_route on the original netdevice</title>
<updated>2019-04-17T06:39:40+00:00</updated>
<author>
<name>Stephen Suryaputra</name>
<email>ssuryaextr@gmail.com</email>
</author>
<published>2019-04-01T13:17:32+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=59c5f595a120808cf26f426af162fc9237b57f9b'/>
<id>59c5f595a120808cf26f426af162fc9237b57f9b</id>
<content type='text'>
[ Upstream commit 8c83f2df9c6578ea4c5b940d8238ad8a41b87e9e ]

Configuration check to accept source route IP options should be made on
the incoming netdevice when the skb-&gt;dev is an l3mdev master. The route
lookup for the source route next hop also needs the incoming netdev.

v2-&gt;v3:
- Simplify by passing the original netdevice down the stack (per David
  Ahern).

Signed-off-by: Stephen Suryaputra &lt;ssuryaextr@gmail.com&gt;
Reviewed-by: David Ahern &lt;dsahern@gmail.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 8c83f2df9c6578ea4c5b940d8238ad8a41b87e9e ]

Configuration check to accept source route IP options should be made on
the incoming netdevice when the skb-&gt;dev is an l3mdev master. The route
lookup for the source route next hop also needs the incoming netdev.

v2-&gt;v3:
- Simplify by passing the original netdevice down the stack (per David
  Ahern).

Signed-off-by: Stephen Suryaputra &lt;ssuryaextr@gmail.com&gt;
Reviewed-by: David Ahern &lt;dsahern@gmail.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>netns: provide pure entropy for net_hash_mix()</title>
<updated>2019-04-17T06:39:38+00:00</updated>
<author>
<name>Eric Dumazet</name>
<email>edumazet@google.com</email>
</author>
<published>2019-03-27T15:21:30+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=ec7aeb6a0709855c6b76bc10e8a218e84d80fc68'/>
<id>ec7aeb6a0709855c6b76bc10e8a218e84d80fc68</id>
<content type='text'>
[ Upstream commit 355b98553789b646ed97ad801a619ff898471b92 ]

net_hash_mix() currently uses kernel address of a struct net,
and is used in many places that could be used to reveal this
address to a patient attacker, thus defeating KASLR, for
the typical case (initial net namespace, &amp;init_net is
not dynamically allocated)

I believe the original implementation tried to avoid spending
too many cycles in this function, but security comes first.

Also provide entropy regardless of CONFIG_NET_NS.

Fixes: 0b4419162aa6 ("netns: introduce the net_hash_mix "salt" for hashes")
Signed-off-by: Eric Dumazet &lt;edumazet@google.com&gt;
Reported-by: Amit Klein &lt;aksecurity@gmail.com&gt;
Reported-by: Benny Pinkas &lt;benny@pinkas.net&gt;
Cc: Pavel Emelyanov &lt;xemul@openvz.org&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 355b98553789b646ed97ad801a619ff898471b92 ]

net_hash_mix() currently uses kernel address of a struct net,
and is used in many places that could be used to reveal this
address to a patient attacker, thus defeating KASLR, for
the typical case (initial net namespace, &amp;init_net is
not dynamically allocated)

I believe the original implementation tried to avoid spending
too many cycles in this function, but security comes first.

Also provide entropy regardless of CONFIG_NET_NS.

Fixes: 0b4419162aa6 ("netns: introduce the net_hash_mix "salt" for hashes")
Signed-off-by: Eric Dumazet &lt;edumazet@google.com&gt;
Reported-by: Amit Klein &lt;aksecurity@gmail.com&gt;
Reported-by: Benny Pinkas &lt;benny@pinkas.net&gt;
Cc: Pavel Emelyanov &lt;xemul@openvz.org&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>netfilter: nft_compat: use .release_ops and remove list of extension</title>
<updated>2019-04-17T06:39:36+00:00</updated>
<author>
<name>Pablo Neira Ayuso</name>
<email>pablo@netfilter.org</email>
</author>
<published>2019-02-13T12:18:36+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=43154d5c868cc9b2bdae8a55cdebcff3da0d34e3'/>
<id>43154d5c868cc9b2bdae8a55cdebcff3da0d34e3</id>
<content type='text'>
[ Upstream commit b8e204006340b7aaf32bd2b9806c692f6e0cb38a ]

Add .release_ops, that is called in case of error at a later stage in
the expression initialization path, ie. .select_ops() has been already
set up operations and that needs to be undone. This allows us to unwind
.select_ops from the error path, ie. release the dynamic operations for
this extension.

Moreover, allocate one single operation instead of recycling them, this
comes at the cost of consuming a bit more memory per rule, but it
simplifies the infrastructure.

Signed-off-by: Pablo Neira Ayuso &lt;pablo@netfilter.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit b8e204006340b7aaf32bd2b9806c692f6e0cb38a ]

Add .release_ops, that is called in case of error at a later stage in
the expression initialization path, ie. .select_ops() has been already
set up operations and that needs to be undone. This allows us to unwind
.select_ops from the error path, ie. release the dynamic operations for
this extension.

Moreover, allocate one single operation instead of recycling them, this
comes at the cost of consuming a bit more memory per rule, but it
simplifies the infrastructure.

Signed-off-by: Pablo Neira Ayuso &lt;pablo@netfilter.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>appletalk: Fix compile regression</title>
<updated>2019-04-05T20:34:53+00:00</updated>
<author>
<name>Arnd Bergmann</name>
<email>arnd@arndb.de</email>
</author>
<published>2019-03-06T10:52:36+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=ae42fc868cd5fca29f6f31487dc7d016c923f8fa'/>
<id>ae42fc868cd5fca29f6f31487dc7d016c923f8fa</id>
<content type='text'>
[ Upstream commit 27da0d2ef998e222a876c0cec72aa7829a626266 ]

A bugfix just broke compilation of appletalk when CONFIG_SYSCTL
is disabled:

In file included from net/appletalk/ddp.c:65:
net/appletalk/ddp.c: In function 'atalk_init':
include/linux/atalk.h:164:34: error: expected expression before 'do'
 #define atalk_register_sysctl()  do { } while(0)
                                  ^~
net/appletalk/ddp.c:1934:7: note: in expansion of macro 'atalk_register_sysctl'
  rc = atalk_register_sysctl();

This is easier to avoid by using conventional inline functions
as stubs rather than macros. The header already has inline
functions for other purposes, so I'm changing over all the
macros for consistency.

Fixes: 6377f787aeb9 ("appletalk: Fix use-after-free in atalk_proc_exit")
Signed-off-by: Arnd Bergmann &lt;arnd@arndb.de&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 27da0d2ef998e222a876c0cec72aa7829a626266 ]

A bugfix just broke compilation of appletalk when CONFIG_SYSCTL
is disabled:

In file included from net/appletalk/ddp.c:65:
net/appletalk/ddp.c: In function 'atalk_init':
include/linux/atalk.h:164:34: error: expected expression before 'do'
 #define atalk_register_sysctl()  do { } while(0)
                                  ^~
net/appletalk/ddp.c:1934:7: note: in expansion of macro 'atalk_register_sysctl'
  rc = atalk_register_sysctl();

This is easier to avoid by using conventional inline functions
as stubs rather than macros. The header already has inline
functions for other purposes, so I'm changing over all the
macros for consistency.

Fixes: 6377f787aeb9 ("appletalk: Fix use-after-free in atalk_proc_exit")
Signed-off-by: Arnd Bergmann &lt;arnd@arndb.de&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>netfilter: physdev: relax br_netfilter dependency</title>
<updated>2019-04-05T20:34:50+00:00</updated>
<author>
<name>Florian Westphal</name>
<email>fw@strlen.de</email>
</author>
<published>2019-01-11T13:46:15+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=ebd0f3066c35bd27d3a4b224135e638eeaf70b8d'/>
<id>ebd0f3066c35bd27d3a4b224135e638eeaf70b8d</id>
<content type='text'>
[ Upstream commit 8e2f311a68494a6677c1724bdcb10bada21af37c ]

Following command:
  iptables -D FORWARD -m physdev ...
causes connectivity loss in some setups.

Reason is that iptables userspace will probe kernel for the module revision
of the physdev patch, and physdev has an artificial dependency on
br_netfilter (xt_physdev use makes no sense unless a br_netfilter module
is loaded).

This causes the "phydev" module to be loaded, which in turn enables the
"call-iptables" infrastructure.

bridged packets might then get dropped by the iptables ruleset.

The better fix would be to change the "call-iptables" defaults to 0 and
enforce explicit setting to 1, but that breaks backwards compatibility.

This does the next best thing: add a request_module call to checkentry.
This was a stray '-D ... -m physdev' won't activate br_netfilter
anymore.

Signed-off-by: Florian Westphal &lt;fw@strlen.de&gt;
Signed-off-by: Pablo Neira Ayuso &lt;pablo@netfilter.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 8e2f311a68494a6677c1724bdcb10bada21af37c ]

Following command:
  iptables -D FORWARD -m physdev ...
causes connectivity loss in some setups.

Reason is that iptables userspace will probe kernel for the module revision
of the physdev patch, and physdev has an artificial dependency on
br_netfilter (xt_physdev use makes no sense unless a br_netfilter module
is loaded).

This causes the "phydev" module to be loaded, which in turn enables the
"call-iptables" infrastructure.

bridged packets might then get dropped by the iptables ruleset.

The better fix would be to change the "call-iptables" defaults to 0 and
enforce explicit setting to 1, but that breaks backwards compatibility.

This does the next best thing: add a request_module call to checkentry.
This was a stray '-D ... -m physdev' won't activate br_netfilter
anymore.

Signed-off-by: Florian Westphal &lt;fw@strlen.de&gt;
Signed-off-by: Pablo Neira Ayuso &lt;pablo@netfilter.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
</feed>
