[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <CAGXu5jKyZ954aRHg_7xhXP0CJBiJ8TV7y-dH5viwzfEj8+D6_w@mail.gmail.com>
Date: Thu, 27 Apr 2017 13:22:05 -0700
From: Kees Cook <keescook@...omium.org>
To: Josh Poimboeuf <jpoimboe@...hat.com>
Cc: LKML <linux-kernel@...r.kernel.org>, Peter Zijlstra <peterz@...radead.org>,
PaX Team <pageexec@...email.hu>, Jann Horn <jannh@...gle.com>,
Eric Biggers <ebiggers3@...il.com>, Christoph Hellwig <hch@...radead.org>,
"axboe@...nel.dk" <axboe@...nel.dk>, James Bottomley <James.Bottomley@...senpartnership.com>,
Elena Reshetova <elena.reshetova@...el.com>, Hans Liljestrand <ishkamiel@...il.com>,
David Windsor <dwindsor@...il.com>, "x86@...nel.org" <x86@...nel.org>, Ingo Molnar <mingo@...nel.org>,
Arnd Bergmann <arnd@...db.de>, Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
"David S. Miller" <davem@...emloft.net>, Rik van Riel <riel@...hat.com>,
linux-arch <linux-arch@...r.kernel.org>,
"kernel-hardening@...ts.openwall.com" <kernel-hardening@...ts.openwall.com>
Subject: Re: [PATCH v2 2/2] x86, refcount: Implement fast refcount overflow protection
On Wed, Apr 26, 2017 at 6:31 PM, kbuild test robot <lkp@...el.com> wrote:
> Hi Kees,
>
> [auto build test WARNING on next-20170424]
> [cannot apply to tip/x86/core linus/master linux/master v4.9-rc8 v4.9-rc7 v4.9-rc6 v4.11-rc8]
> [if your patch is applied to the wrong git tree, please drop us a note to help improve the system]
>
> url: https://github.com/0day-ci/linux/commits/Kees-Cook/x86-refcount-Implement-fast-refcount-overflow/20170426-210530
> config: x86_64-allmodconfig (attached as .config)
> compiler: gcc-6 (Debian 6.2.0-3) 6.2.0 20160901
> reproduce:
> # save the attached .config to linux build tree
> make ARCH=x86_64
>
> All warnings (new ones prefixed by >>):
>
>>> drivers//scsi/scsi_scan.o: warning: objtool: .text.refcount_overflow+0x5: special: can't find orig instruction
Hi Josh,
I'm seeing this error being generated on areas that are using a
cross-section exception handler. I can't quite see why the .o checker
is unhappy, so I figured I'd ask you first. :)
The code is generated with calls to __REFCOUNT_CHECK() which is
defined like this:
+#define __REFCOUNT_EXCEPTION(size) \
+ ".if "__stringify(size)" == 4\n\t" \
+ ".pushsection .text.refcount_overflow\n" \
+ ".elseif "__stringify(size)" == -4\n\t" \
+ ".pushsection .text.refcount_underflow\n" \
+ ".else\n" \
+ ".error \"invalid size\"\n" \
+ ".endif\n" \
+ "111:\tlea %[counter],%%"_ASM_CX"\n\t" \
+ "int $"__stringify(X86_REFCOUNT_VECTOR)"\n" \
+ "222:\n\t" \
+ ".popsection\n" \
+ "333:\n" \
+ _ASM_EXTABLE(222b, 333b)
+
+#define __REFCOUNT_CHECK(size) \
+ "js 111f\n" \
+ __REFCOUNT_EXCEPTION(size)
+
+#define __REFCOUNT_ERROR(size) \
+ "jmp 111f\n" \
+ __REFCOUNT_EXCEPTION(size)
I assume it doesn't like seeing an exception split across .text and
.text.refcount_overflow, but I haven't been able to figure out how
that distinction would be made by the checker. :P
Thanks!
-Kees
> --
> /kbuild/src/consumer/include/linux/compiler.h:264:8: sparse: attribute 'no_sanitize_address': unknown attribute
>>> drivers/scsi/qla2xxx/qla_target.o: warning: objtool: .text.refcount_overflow+0x23: special: can't find orig instruction
> --
> /kbuild/src/consumer/include/linux/compiler.h:264:8: sparse: attribute 'no_sanitize_address': unknown attribute
>>> drivers/nvme/target/core.o: warning: objtool: .text.refcount_overflow+0x19: special: can't find orig instruction
> --
> /kbuild/src/consumer/include/linux/compiler.h:264:8: sparse: attribute 'no_sanitize_address': unknown attribute
>>> drivers/nvme/target/rdma.o: warning: objtool: .text.refcount_overflow+0x5: special: can't find orig instruction
> --
> /kbuild/src/consumer/include/linux/compiler.h:264:8: sparse: attribute 'no_sanitize_address': unknown attribute
>>> drivers/nvme/target/fcloop.o: warning: objtool: .text.refcount_overflow+0x6: special: can't find orig instruction
> --
> /kbuild/src/consumer/include/linux/compiler.h:264:8: sparse: attribute 'no_sanitize_address': unknown attribute
>>> net/batman-adv/bat_v.o: warning: objtool: .text.refcount_underflow+0xc: special: can't find orig instruction
> --
> /kbuild/src/consumer/include/linux/compiler.h:264:8: sparse: attribute 'no_sanitize_address': unknown attribute
>>> net/batman-adv/bat_v_elp.o: warning: objtool: .text.refcount_overflow+0xa: special: can't find orig instruction
> --
> /kbuild/src/consumer/include/linux/compiler.h:264:8: sparse: attribute 'no_sanitize_address': unknown attribute
>>> net/batman-adv/fragmentation.o: warning: objtool: .text.refcount_overflow+0xa: special: can't find orig instruction
> --
> /kbuild/src/consumer/include/linux/compiler.h:264:8: sparse: attribute 'no_sanitize_address': unknown attribute
>>> net/batman-adv/icmp_socket.o: warning: objtool: .text.refcount_overflow+0xb: special: can't find orig instruction
> --
> /kbuild/src/consumer/include/linux/compiler.h:264:8: sparse: attribute 'no_sanitize_address': unknown attribute
>>> net/batman-adv/main.o: warning: objtool: .text.refcount_overflow+0xb: special: can't find orig instruction
> --
> /kbuild/src/consumer/include/linux/compiler.h:264:8: sparse: attribute 'no_sanitize_address': unknown attribute
>>> net/batman-adv/multicast.o: warning: objtool: .text.refcount_overflow+0xf: special: can't find orig instruction
> ..
>
> ---
> 0-DAY kernel test infrastructure Open Source Technology Center
> https://lists.01.org/pipermail/kbuild-all Intel Corporation
--
Kees Cook
Pixel Security
Powered by blists - more mailing lists
Confused about mailing lists and their use?
Read about mailing lists on Wikipedia
and check out these
guidelines on proper formatting of your messages.
