linux-stable.git/lib, branch linux-3.18.y

lib/div64.c: off by one in shift

2019-04-27T07:30:29+00:00

[ Upstream commit cdc94a37493135e355dfc0b0e086d84e3eadb50d ]

fls counts bits starting from 1 to 32 (returns 0 for zero argument).  If
we add 1 we shift right one bit more and loose precision from divisor,
what cause function incorect results with some numbers.

Corrected code was tested in user-space, see bugzilla:
   https://bugzilla.kernel.org/show_bug.cgi?id=202391

Link: http://lkml.kernel.org/r/1548686944-11891-1-git-send-email-sgruszka@redhat.com
Fixes: 658716d19f8f ("div64_u64(): improve precision on 32bit platforms")
Signed-off-by: Stanislaw Gruszka 
Reported-by: Siarhei Volkau 
Tested-by: Siarhei Volkau 
Acked-by: Oleg Nesterov 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Sasha Levin

lib/string.c: implement a basic bcmp

2019-04-27T07:30:25+00:00

[ 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 
Reported-by: Nathan Chancellor 
Reported-by: Adhemerval Zanella 
Suggested-by: Arnd Bergmann 
Suggested-by: James Y Knight 
Suggested-by: Masahiro Yamada 
Suggested-by: Nathan Chancellor 
Suggested-by: Rasmus Villemoes 
Acked-by: Steven Rostedt (VMware) 
Reviewed-by: Nathan Chancellor 
Tested-by: Nathan Chancellor 
Reviewed-by: Masahiro Yamada 
Reviewed-by: Andy Shevchenko 
Cc: David Laight 
Cc: Rasmus Villemoes 
Cc: Namhyung Kim 
Cc: Greg Kroah-Hartman 
Cc: Alexander Shishkin 
Cc: Dan Williams 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Sasha Levin

ARM: 8833/1: Ensure that NEON code always compiles with Clang

2019-04-27T07:30:23+00:00

[ Upstream commit de9c0d49d85dc563549972edc5589d195cd5e859 ]

While building arm32 allyesconfig, I ran into the following errors:

  arch/arm/lib/xor-neon.c:17:2: error: You should compile this file with
  '-mfloat-abi=softfp -mfpu=neon'

  In file included from lib/raid6/neon1.c:27:
  /home/nathan/cbl/prebuilt/lib/clang/8.0.0/include/arm_neon.h:28:2:
  error: "NEON support not enabled"

Building V=1 showed NEON_FLAGS getting passed along to Clang but
__ARM_NEON__ was not getting defined. Ultimately, it boils down to Clang
only defining __ARM_NEON__ when targeting armv7, rather than armv6k,
which is the '-march' value for allyesconfig.

>From lib/Basic/Targets/ARM.cpp in the Clang source:

  // This only gets set when Neon instructions are actually available, unlike
  // the VFP define, hence the soft float and arch check. This is subtly
  // different from gcc, we follow the intent which was that it should be set
  // when Neon instructions are actually available.
  if ((FPU & NeonFPU) && !SoftFloat && ArchVersion >= 7) {
    Builder.defineMacro("__ARM_NEON", "1");
    Builder.defineMacro("__ARM_NEON__");
    // current AArch32 NEON implementations do not support double-precision
    // floating-point even when it is present in VFP.
    Builder.defineMacro("__ARM_NEON_FP",
                        "0x" + Twine::utohexstr(HW_FP & ~HW_FP_DP));
  }

Ard Biesheuvel recommended explicitly adding '-march=armv7-a' at the
beginning of the NEON_FLAGS definitions so that __ARM_NEON__ always gets
definined by Clang. This doesn't functionally change anything because
that code will only run where NEON is supported, which is implicitly
armv7.

Link: https://github.com/ClangBuiltLinux/linux/issues/287

Suggested-by: Ard Biesheuvel 
Signed-off-by: Nathan Chancellor 
Acked-by: Nicolas Pitre 
Reviewed-by: Nick Desaulniers 
Reviewed-by: Stefan Agner 
Signed-off-by: Russell King 
Signed-off-by: Sasha Levin

kprobes: Prohibit probing on bsearch()

2019-04-27T07:30:23+00:00

[ Upstream commit 02106f883cd745523f7766d90a739f983f19e650 ]

Since kprobe breakpoing handler is using bsearch(), probing on this
routine can cause recursive breakpoint problem.

int3
 ->do_int3()
   ->ftrace_int3_handler()
     ->ftrace_location()
       ->ftrace_location_range()
         ->bsearch() -> int3

Prohibit probing on bsearch().

Signed-off-by: Andrea Righi 
Acked-by: Masami Hiramatsu 
Cc: Alexander Shishkin 
Cc: Arnaldo Carvalho de Melo 
Cc: Jiri Olsa 
Cc: Linus Torvalds 
Cc: Mathieu Desnoyers 
Cc: Peter Zijlstra 
Cc: Steven Rostedt 
Cc: Thomas Gleixner 
Link: http://lkml.kernel.org/r/154998813406.31052.8791425358974650922.stgit@devbox
Signed-off-by: Ingo Molnar 
Signed-off-by: Sasha Levin

assoc_array: Fix shortcut creation

2019-03-23T07:19:00+00:00

[ Upstream commit bb2ba2d75a2d673e76ddaf13a9bd30d6a8b1bb08 ]

Fix the creation of shortcuts for which the length of the index key value
is an exact multiple of the machine word size.  The problem is that the
code that blanks off the unused bits of the shortcut value malfunctions if
the number of bits in the last word equals machine word size.  This is due
to the "<<" operator being given a shift of zero in this case, and so the
mask that should be all zeros is all ones instead.  This causes the
subsequent masking operation to clear everything rather than clearing
nothing.

Ordinarily, the presence of the hash at the beginning of the tree index key
makes the issue very hard to test for, but in this case, it was encountered
due to a development mistake that caused the hash output to be either 0
(keyring) or 1 (non-keyring) only.  This made it susceptible to the
keyctl/unlink/valid test in the keyutils package.

The fix is simply to skip the blanking if the shift would be 0.  For
example, an index key that is 64 bits long would produce a 0 shift and thus
a 'blank' of all 1s.  This would then be inverted and AND'd onto the
index_key, incorrectly clearing the entire last word.

Fixes: 3cb989501c26 ("Add a generic associative array implementation.")
Signed-off-by: David Howells 
Signed-off-by: James Morris 
Signed-off-by: Sasha Levin

swiotlb: clean up reporting

2018-12-21T13:08:49+00:00

commit 7d63fb3af87aa67aa7d24466e792f9d7c57d8e79 upstream.

This removes needless use of '%p', and refactors the printk calls to
use pr_*() helpers instead.

Signed-off-by: Kees Cook 
Reviewed-by: Konrad Rzeszutek Wilk 
Signed-off-by: Christoph Hellwig 
[bwh: Backported to 4.4:
 - Adjust filename
 - Remove "swiotlb: " prefix from an additional log message]
Signed-off-by: Ben Hutchings 
Signed-off-by: Greg Kroah-Hartman

lib/interval_tree_test.c: allow users to limit scope of endpoint

2018-12-21T13:08:47+00:00

[ Upstream commit a8ec14d4f6aa8e245efacc992c8ee6ea0464ce2a ]

Add a 'max_endpoint' parameter such that users may easily limit the size
of the intervals that are randomly generated.

Link: http://lkml.kernel.org/r/20170518174936.20265-4-dave@stgolabs.net
Signed-off-by: Davidlohr Bueso 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Sasha Levin

lib/rbtree-test: lower default params

2018-12-21T13:08:47+00:00

[ Upstream commit 0b548e33e6cb2bff240fdaf1783783be15c29080 ]

Fengguang reported soft lockups while running the rbtree and interval
tree test modules.  The logic for these tests all occur in init phase,
and we currently are pounding with the default values for number of
nodes and number of iterations of each test.  Reduce the latter by two
orders of magnitude.  This does not influence the value of the tests in
that one thousand times by default is enough to get the picture.

Link: http://lkml.kernel.org/r/20171109161715.xai2dtwqw2frhkcm@linux-n805
Signed-off-by: Davidlohr Bueso 
Reported-by: Fengguang Wu 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Sasha Levin

lib/rbtree_test.c: make input module parameters

2018-12-21T13:08:47+00:00

[ Upstream commit 223f8911eace60c787f8767c25148b80ece9732a ]

Allows for more flexible debugging.

Link: http://lkml.kernel.org/r/20170719014603.19029-5-dave@stgolabs.net
Signed-off-by: Davidlohr Bueso 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Sasha Levin

lib/interval_tree_test.c: allow full tree search

2018-12-21T13:08:47+00:00

[ Upstream commit c46ecce431ebe6b1a9551d1f530eb432dae5c39b ]

...  such that a user can specify visiting all the nodes in the tree
(intersects with the world).  This is a nice opposite from the very
basic default query which is a single point.

Link: http://lkml.kernel.org/r/20170518174936.20265-5-dave@stgolabs.net
Signed-off-by: Davidlohr Bueso 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Sasha Levin