linux.git/scripts, branch v4.14.34

kbuild: fix linker feature test macros when cross compiling with Clang

2018-03-24T10:01:29+00:00

commit 86a9df597cdd564d2d29c65897bcad42519e3678 upstream.

I was not seeing my linker flags getting added when using ld-option when
cross compiling with Clang. Upon investigation, this seems to be due to
a difference in how GCC vs Clang handle cross compilation.

GCC is configured at build time to support one backend, that is implicit
when compiling.  Clang is explicit via the use of `-target ` and
ships with all supported backends by default.

GNU Make feature test macros that compile then link will always fail
when cross compiling with Clang unless Clang's triple is passed along to
the compiler. For example:

$ clang -x c /dev/null -c -o temp.o
$ aarch64-linux-android/bin/ld -E temp.o
aarch64-linux-android/bin/ld:
unknown architecture of input file `temp.o' is incompatible with
aarch64 output
aarch64-linux-android/bin/ld:
warning: cannot find entry symbol _start; defaulting to
0000000000400078
$ echo $?
1

$ clang -target aarch64-linux-android- -x c /dev/null -c -o temp.o
$ aarch64-linux-android/bin/ld -E temp.o
aarch64-linux-android/bin/ld:
warning: cannot find entry symbol _start; defaulting to 00000000004002e4
$ echo $?
0

This causes conditional checks that invoke $(CC) without the target
triple, then $(LD) on the result, to always fail.

Suggested-by: Masahiro Yamada 
Signed-off-by: Nick Desaulniers 
Reviewed-by: Matthias Kaehlcke 
Signed-off-by: Masahiro Yamada 
Signed-off-by: Greg Hackmann 
Signed-off-by: Greg Kroah-Hartman

objtool, retpolines: Integrate objtool with retpoline support more closely

2018-03-15T09:54:38+00:00

commit d5028ba8ee5a18c9d0bb926d883c28b370f89009 upstream.

Disable retpoline validation in objtool if your compiler sucks, and otherwise
select the validation stuff for CONFIG_RETPOLINE=y (most builds would already
have it set due to ORC).

Signed-off-by: Peter Zijlstra (Intel) 
Acked-by: Thomas Gleixner 
Cc: Andy Lutomirski 
Cc: Arjan van de Ven 
Cc: Borislav Petkov 
Cc: Dan Williams 
Cc: Dave Hansen 
Cc: David Woodhouse 
Cc: Greg Kroah-Hartman 
Cc: Josh Poimboeuf 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Signed-off-by: Ingo Molnar 
Signed-off-by: Greg Kroah-Hartman

objtool: Add module specific retpoline rules

2018-03-15T09:54:38+00:00

commit ca41b97ed9124fd62323a162de5852f6e28f94b8 upstream.

David allowed retpolines in .init.text, except for modules, which will
trip up objtool retpoline validation, fix that.

Requested-by: David Woodhouse 
Signed-off-by: Peter Zijlstra (Intel) 
Acked-by: Thomas Gleixner 
Acked-by: Josh Poimboeuf 
Cc: Andy Lutomirski 
Cc: Arjan van de Ven 
Cc: Borislav Petkov 
Cc: Dan Williams 
Cc: Dave Hansen 
Cc: David Woodhouse 
Cc: Greg Kroah-Hartman 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Signed-off-by: Ingo Molnar 
Signed-off-by: Greg Kroah-Hartman

objtool: Add retpoline validation

2018-03-15T09:54:37+00:00

commit b5bc2231b8ad4387c9641f235ca0ad8cd300b6df upstream.

David requested a objtool validation pass for CONFIG_RETPOLINE=y enabled
builds, where it validates no unannotated indirect  jumps or calls are
left.

Add an additional .discard.retpoline_safe section to allow annotating
the few indirect sites that are required and safe.

Requested-by: David Woodhouse 
Signed-off-by: Peter Zijlstra (Intel) 
Reviewed-by: David Woodhouse 
Acked-by: Thomas Gleixner 
Acked-by: Josh Poimboeuf 
Cc: Andy Lutomirski 
Cc: Arjan van de Ven 
Cc: Borislav Petkov 
Cc: Dan Williams 
Cc: Dave Hansen 
Cc: Greg Kroah-Hartman 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Signed-off-by: Ingo Molnar 
Signed-off-by: Greg Kroah-Hartman

kbuild: Handle builtin dtb file names containing hyphens

2018-03-15T09:54:33+00:00

commit 55fe6da9efba102866e2fb5b40b04b6a4b26c19e upstream.

cmd_dt_S_dtb constructs the assembly source to incorporate a devicetree
FDT (that is, the .dtb file) as binary data in the kernel image. This
assembly source contains labels before and after the binary data. The
label names incorporate the file name of the corresponding .dtb file.
Hyphens are not legal characters in labels, so .dtb files built into the
kernel with hyphens in the file name result in errors like the
following:

bcm3368-netgear-cvg834g.dtb.S: Assembler messages:
bcm3368-netgear-cvg834g.dtb.S:5: Error: : no such section
bcm3368-netgear-cvg834g.dtb.S:5: Error: junk at end of line, first unrecognized character is `-'
bcm3368-netgear-cvg834g.dtb.S:6: Error: unrecognized opcode `__dtb_bcm3368-netgear-cvg834g_begin:'
bcm3368-netgear-cvg834g.dtb.S:8: Error: unrecognized opcode `__dtb_bcm3368-netgear-cvg834g_end:'
bcm3368-netgear-cvg834g.dtb.S:9: Error: : no such section
bcm3368-netgear-cvg834g.dtb.S:9: Error: junk at end of line, first unrecognized character is `-'

Fix this by updating cmd_dt_S_dtb to transform all hyphens from the file
name to underscores when constructing the labels.

As of v4.16-rc2, 1139 .dts files across ARM64, ARM, MIPS and PowerPC
contain hyphens in their names, but the issue only currently manifests
on Broadcom MIPS platforms, as that is the only place where such files
are built into the kernel. For example when CONFIG_DT_NETGEAR_CVG834G=y,
or on BMIPS kernels when the dtbs target is used (in the latter case it
admittedly shouldn't really build all the dtb.o files, but thats a
separate issue).

Fixes: 695835511f96 ("MIPS: BMIPS: rename bcm96358nb4ser to bcm6358-neufbox4-sercom")
Signed-off-by: James Hogan 
Reviewed-by: Frank Rowand 
Cc: Rob Herring 
Cc: Michal Marek 
Cc: Ralf Baechle 
Cc: Florian Fainelli 
Cc: Kevin Cernekee 
Cc:  # 4.9+
Signed-off-by: Masahiro Yamada 
Signed-off-by: Greg Kroah-Hartman

scripts/kernel-doc: Don't fail with status != 0 if error encountered with -none

2018-02-25T10:07:58+00:00

[ Upstream commit e814bccbafece52a24e152d2395b5d49eef55841 ]

My bisect scripts starting running into build failures when trying to
compile 4.15-rc1 with the builds failing with things like:

drivers/net/wireless/broadcom/brcm80211/brcmfmac/sdio.c:2078: error: Cannot parse struct or union!

The line in question is actually just a #define, but after some digging
it turns out that my scripts pass W=1 and since commit 3a025e1d1c2ea
("Add optional check for bad kernel-doc comments") that results in
kernel-doc running on each source file. The file in question has a
badly formatted comment immediately before the #define:

/**
 * struct brcmf_skbuff_cb reserves first two bytes in sk_buff::cb for
 * bus layer usage.
 */

which causes the regex in dump_struct to fail (lack of braces following
struct declaration) and kernel-doc returns 1, which causes the build
to fail.

Fix the issue by always returning 0 from kernel-doc when invoked with
-none. It successfully generates no documentation, and prints out any
issues.

Cc: Matthew Wilcox 
Cc: Jonathan Corbet 
Signed-off-by: Will Deacon 
Signed-off-by: Jonathan Corbet 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

kmemcheck: rip it out

2018-02-22T14:42:24+00:00

commit 4675ff05de2d76d167336b368bd07f3fef6ed5a6 upstream.

Fix up makefiles, remove references, and git rm kmemcheck.

Link: http://lkml.kernel.org/r/20171007030159.22241-4-alexander.levin@verizon.com
Signed-off-by: Sasha Levin 
Cc: Steven Rostedt 
Cc: Vegard Nossum 
Cc: Pekka Enberg 
Cc: Michal Hocko 
Cc: Eric W. Biederman 
Cc: Alexander Potapenko 
Cc: Tim Hansen 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

kasan: rework Kconfig settings

2018-02-16T19:23:04+00:00

commit e7c52b84fb18f08ce49b6067ae6285aca79084a8 upstream.

We get a lot of very large stack frames using gcc-7.0.1 with the default
-fsanitize-address-use-after-scope --param asan-stack=1 options, which can
easily cause an overflow of the kernel stack, e.g.

  drivers/gpu/drm/i915/gvt/handlers.c:2434:1: warning: the frame size of 46176 bytes is larger than 3072 bytes
  drivers/net/wireless/ralink/rt2x00/rt2800lib.c:5650:1: warning: the frame size of 23632 bytes is larger than 3072 bytes
  lib/atomic64_test.c:250:1: warning: the frame size of 11200 bytes is larger than 3072 bytes
  drivers/gpu/drm/i915/gvt/handlers.c:2621:1: warning: the frame size of 9208 bytes is larger than 3072 bytes
  drivers/media/dvb-frontends/stv090x.c:3431:1: warning: the frame size of 6816 bytes is larger than 3072 bytes
  fs/fscache/stats.c:287:1: warning: the frame size of 6536 bytes is larger than 3072 bytes

To reduce this risk, -fsanitize-address-use-after-scope is now split out
into a separate CONFIG_KASAN_EXTRA Kconfig option, leading to stack
frames that are smaller than 2 kilobytes most of the time on x86_64.  An
earlier version of this patch also prevented combining KASAN_EXTRA with
KASAN_INLINE, but that is no longer necessary with gcc-7.0.1.

All patches to get the frame size below 2048 bytes with CONFIG_KASAN=y
and CONFIG_KASAN_EXTRA=n have been merged by maintainers now, so we can
bring back that default now.  KASAN_EXTRA=y still causes lots of
warnings but now defaults to !COMPILE_TEST to disable it in
allmodconfig, and it remains disabled in all other defconfigs since it
is a new option.  I arbitrarily raise the warning limit for KASAN_EXTRA
to 3072 to reduce the noise, but an allmodconfig kernel still has around
50 warnings on gcc-7.

I experimented a bit more with smaller stack frames and have another
follow-up series that reduces the warning limit for 64-bit architectures
to 1280 bytes (without CONFIG_KASAN).

With earlier versions of this patch series, I also had patches to address
the warnings we get with KASAN and/or KASAN_EXTRA, using a
"noinline_if_stackbloat" annotation.

That annotation now got replaced with a gcc-8 bugfix (see
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81715) and a workaround for
older compilers, which means that KASAN_EXTRA is now just as bad as
before and will lead to an instant stack overflow in a few extreme
cases.

This reverts parts of commit 3f181b4d8652 ("lib/Kconfig.debug: disable
-Wframe-larger-than warnings with KASAN=y").  Two patches in linux-next
should be merged first to avoid introducing warnings in an allmodconfig
build:
  3cd890dbe2a4 ("media: dvb-frontends: fix i2c access helpers for KASAN")
  16c3ada89cff ("media: r820t: fix r820t_write_reg for KASAN")

Do we really need to backport this?

I think we do: without this patch, enabling KASAN will lead to
unavoidable kernel stack overflow in certain device drivers when built
with gcc-7 or higher on linux-4.10+ or any version that contains a
backport of commit c5caf21ab0cf8.  Most people are probably still on
older compilers, but it will get worse over time as they upgrade their
distros.

The warnings we get on kernels older than this should all be for code
that uses dangerously large stack frames, though most of them do not
cause an actual stack overflow by themselves.The asan-stack option was
added in linux-4.0, and commit 3f181b4d8652 ("lib/Kconfig.debug:
disable -Wframe-larger-than warnings with KASAN=y") effectively turned
off the warning for allmodconfig kernels, so I would like to see this
fix backported to any kernels later than 4.0.

I have done dozens of fixes for individual functions with stack frames
larger than 2048 bytes with asan-stack, and I plan to make sure that
all those fixes make it into the stable kernels as well (most are
already there).

Part of the complication here is that asan-stack (from 4.0) was
originally assumed to always require much larger stacks, but that
turned out to be a combination of multiple gcc bugs that we have now
worked around and fixed, but sanitize-address-use-after-scope (from
v4.10) has a much higher inherent stack usage and also suffers from at
least three other problems that we have analyzed but not yet fixed
upstream, each of them makes the stack usage more severe than it should
be.

Link: http://lkml.kernel.org/r/20171221134744.2295529-1-arnd@arndb.de
Signed-off-by: Arnd Bergmann 
Acked-by: Andrey Ryabinin 
Cc: Mauro Carvalho Chehab 
Cc: Andrey Ryabinin 
Cc: Alexander Potapenko 
Cc: Dmitry Vyukov 
Cc: Andrey Konovalov 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

kasan: don't emit builtin calls when sanitization is off

2018-02-16T19:23:04+00:00

commit 0e410e158e5baa1300bdf678cea4f4e0cf9d8b94 upstream.

With KASAN enabled the kernel has two different memset() functions, one
with KASAN checks (memset) and one without (__memset).  KASAN uses some
macro tricks to use the proper version where required.  For example
memset() calls in mm/slub.c are without KASAN checks, since they operate
on poisoned slab object metadata.

The issue is that clang emits memset() calls even when there is no
memset() in the source code.  They get linked with improper memset()
implementation and the kernel fails to boot due to a huge amount of KASAN
reports during early boot stages.

The solution is to add -fno-builtin flag for files with KASAN_SANITIZE :=
n marker.

Link: http://lkml.kernel.org/r/8ffecfffe04088c52c42b92739c2bd8a0bcb3f5e.1516384594.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov 
Acked-by: Nick Desaulniers 
Cc: Masahiro Yamada 
Cc: Michal Marek 
Cc: Andrey Ryabinin 
Cc: Alexander Potapenko 
Cc: Dmitry Vyukov 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

kbuild: rpm-pkg: keep spec file until make mrproper

2018-02-13T09:19:46+00:00

commit af60e207087975d069858741c44ed4f450330ac4 upstream.

If build fails during (bin)rpm-pkg, the spec file is not cleaned by
anyone until the next successful build of the package.

We do not have to immediately delete the spec file in case somebody
may want to take a look at it.  Instead, make them ignored by git,
and cleaned up by make mrproper.

Signed-off-by: Masahiro Yamada 
Signed-off-by: Greg Kroah-Hartman