linux_dsm_epyc7002/arch/x86/boot/compressed
Andrey Ryabinin c6d308534a UBSAN: run-time undefined behavior sanity checker
UBSAN uses compile-time instrumentation to catch undefined behavior
(UB).  Compiler inserts code that perform certain kinds of checks before
operations that could cause UB.  If check fails (i.e.  UB detected)
__ubsan_handle_* function called to print error message.

So the most of the work is done by compiler.  This patch just implements
ubsan handlers printing errors.

GCC has this capability since 4.9.x [1] (see -fsanitize=undefined
option and its suboptions).
However GCC 5.x has more checkers implemented [2].
Article [3] has a bit more details about UBSAN in the GCC.

[1] - https://gcc.gnu.org/onlinedocs/gcc-4.9.0/gcc/Debugging-Options.html
[2] - https://gcc.gnu.org/onlinedocs/gcc/Debugging-Options.html
[3] - http://developerblog.redhat.com/2014/10/16/gcc-undefined-behavior-sanitizer-ubsan/

Issues which UBSAN has found thus far are:

Found bugs:

 * out-of-bounds access - 97840cb67f ("netfilter: nfnetlink: fix
   insufficient validation in nfnetlink_bind")

undefined shifts:

 * d48458d4a7 ("jbd2: use a better hash function for the revoke
   table")

 * 10632008b9 ("clockevents: Prevent shift out of bounds")

 * 'x << -1' shift in ext4 -
   http://lkml.kernel.org/r/<5444EF21.8020501@samsung.com>

 * undefined rol32(0) -
   http://lkml.kernel.org/r/<1449198241-20654-1-git-send-email-sasha.levin@oracle.com>

 * undefined dirty_ratelimit calculation -
   http://lkml.kernel.org/r/<566594E2.3050306@odin.com>

 * undefined roundown_pow_of_two(0) -
   http://lkml.kernel.org/r/<1449156616-11474-1-git-send-email-sasha.levin@oracle.com>

 * [WONTFIX] undefined shift in __bpf_prog_run -
   http://lkml.kernel.org/r/<CACT4Y+ZxoR3UjLgcNdUm4fECLMx2VdtfrENMtRRCdgHB2n0bJA@mail.gmail.com>

   WONTFIX here because it should be fixed in bpf program, not in kernel.

signed overflows:

 * 32a8df4e0b ("sched: Fix odd values in effective_load()
   calculations")

 * mul overflow in ntp -
   http://lkml.kernel.org/r/<1449175608-1146-1-git-send-email-sasha.levin@oracle.com>

 * incorrect conversion into rtc_time in rtc_time64_to_tm() -
   http://lkml.kernel.org/r/<1449187944-11730-1-git-send-email-sasha.levin@oracle.com>

 * unvalidated timespec in io_getevents() -
   http://lkml.kernel.org/r/<CACT4Y+bBxVYLQ6LtOKrKtnLthqLHcw-BMp3aqP3mjdAvr9FULQ@mail.gmail.com>

 * [NOTABUG] signed overflow in ktime_add_safe() -
   http://lkml.kernel.org/r/<CACT4Y+aJ4muRnWxsUe1CMnA6P8nooO33kwG-c8YZg=0Xc8rJqw@mail.gmail.com>

[akpm@linux-foundation.org: fix unused local warning]
[akpm@linux-foundation.org: fix __int128 build woes]
Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Michal Marek <mmarek@suse.cz>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Yury Gribov <y.gribov@samsung.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Kostya Serebryany <kcc@google.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-01-20 17:09:18 -08:00
..
.gitignore x86, boot: add new generated files to the appropriate .gitignore files 2009-06-02 21:13:30 -07:00
aslr.c x86/asm/tsc: Rename native_read_tsc() to rdtsc() 2015-07-06 15:23:28 +02:00
cmdline.c x86, kaslr: Return location from decompress_kernel 2013-10-13 03:12:07 -07:00
cpuflags.c x86, boot: Rename get_flags() and check_flags() to *_cpuflags() 2013-10-13 04:08:56 -07:00
early_serial_console.c x86, boot: Don't compile early_serial_console.c when !CONFIG_EARLY_PRINTK 2014-08-17 14:58:24 -07:00
eboot.c * Make the EFI System Resource Table (ESRT) driver explicitly 2015-10-14 16:51:34 +02:00
eboot.h efi/x86: Move x86 back to libstub 2014-11-11 22:23:11 +00:00
efi_stub_32.S x86, efi: EFI boot stub support 2011-12-12 14:26:10 -08:00
efi_stub_64.S x86/efi: Avoid triple faults during EFI mixed mode calls 2015-02-13 15:42:56 +00:00
efi_thunk_64.S x86/efi: Avoid triple faults during EFI mixed mode calls 2015-02-13 15:42:56 +00:00
head_32.S x86/asm/boot: Use already defined KEEP_SEGMENTS macro in head_{32,64}.S 2015-02-19 10:05:04 +01:00
head_64.S x86/asm/boot/64: Use __BOOT_TSS instead of literal $0x20 2015-04-02 12:00:20 +02:00
Makefile UBSAN: run-time undefined behavior sanity checker 2016-01-20 17:09:18 -08:00
misc.c lib/decompressors: use real out buf size for gunzip with kernel 2015-09-10 13:29:01 -07:00
misc.h x86/boot: Add hex output for debugging 2015-07-07 08:59:05 +02:00
mkpiggy.c x86, kaslr: Prevent .bss from overlaping initrd 2014-11-01 22:20:50 +01:00
string.c x86, boot: Remove misc.h inclusion from compressed/string.c 2014-05-08 08:00:06 -07:00
vmlinux.lds.S x86, setup: Allow global variables and functions in the decompressor 2010-08-02 15:34:44 -07:00