linux/lib
Kees Cook 1b4cfe3c0a lib/bug.c: exclude non-BUG/WARN exceptions from report_bug()
Commit b8347c2196 ("x86/debug: Handle warnings before the notifier
chain, to fix KGDB crash") changed the ordering of fixups, and did not
take into account the case of x86 processing non-WARN() and non-BUG()
exceptions.  This would lead to output of a false BUG line with no other
information.

In the case of a refcount exception, it would be immediately followed by
the refcount WARN(), producing very strange double-"cut here":

  lkdtm: attempting bad refcount_inc() overflow
  ------------[ cut here ]------------
  Kernel BUG at 0000000065f29de5 [verbose debug info unavailable]
  ------------[ cut here ]------------
  refcount_t overflow at lkdtm_REFCOUNT_INC_OVERFLOW+0x6b/0x90 in cat[3065], uid/euid: 0/0
  WARNING: CPU: 0 PID: 3065 at kernel/panic.c:657 refcount_error_report+0x9a/0xa4
  ...

In the prior ordering, exceptions were searched first:

   do_trap_no_signal(struct task_struct *tsk, int trapnr, char *str,
   ...
                if (fixup_exception(regs, trapnr))
                        return 0;

  -               if (fixup_bug(regs, trapnr))
  -                       return 0;
  -

As a result, fixup_bugs()'s is_valid_bugaddr() didn't take into account
needing to search the exception list first, since that had already
happened.

So, instead of searching the exception list twice (once in
is_valid_bugaddr() and then again in fixup_exception()), just add a
simple sanity check to report_bug() that will immediately bail out if a
BUG() (or WARN()) entry is not found.

Link: http://lkml.kernel.org/r/20180301225934.GA34350@beast
Fixes: b8347c2196 ("x86/debug: Handle warnings before the notifier chain, to fix KGDB crash")
Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Richard Weinberger <richard.weinberger@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-03-09 16:40:01 -08:00
..
842 License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
fonts License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
lz4 lib/lz4: make arrays static const, reduces object code size 2017-10-03 17:54:25 -07:00
lzo License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
mpi lib/mpi: Fix umul_ppmm() for MIPS64r6 2017-12-22 19:39:09 +11:00
raid6 License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
reed_solomon
xz lib/xz: Add fall-through comments to a switch statement 2017-10-12 15:10:12 +02:00
zlib_deflate
zlib_inflate lib/zlib_inflate/inftrees.c: fix potential buffer overflow 2017-05-08 17:15:12 -07:00
zstd lib: Add zstd modules 2017-08-15 09:02:08 -07:00
.gitignore
argv_split.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
ashldi3.c move libgcc.h to include/linux 2017-12-01 13:09:40 -08:00
ashrdi3.c move libgcc.h to include/linux 2017-12-01 13:09:40 -08:00
asn1_decoder.c ASN.1: check for error from ASN1_OP_END__ACT actions 2017-12-08 15:13:27 +00:00
assoc_array.c lib/assoc_array: Remove smp_read_barrier_depends() 2017-12-04 10:52:56 -08:00
atomic64_test.c lib/atomic64_test.c: add a test that atomic64_inc_not_zero() returns an int 2017-07-14 15:05:13 -07:00
atomic64.c locking/atomic: Implement atomic{,64,_long}_fetch_{add,sub,and,andnot,or,xor}{,_relaxed,_acquire,_release}() 2016-06-16 10:48:32 +02:00
audit.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
bcd.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
bch.c
bitmap.c bitmap: replace bitmap_{from,to}_u32array 2018-02-06 18:32:44 -08:00
bitrev.c
bsearch.c lib/bsearch.c: micro-optimize pivot position calculation 2017-07-10 16:32:35 -07:00
btree.c
bucket_locks.c spinlock: Add library function to allocate spinlock buckets array 2017-12-11 09:58:39 -05:00
bug.c lib/bug.c: exclude non-BUG/WARN exceptions from report_bug() 2018-03-09 16:40:01 -08:00
build_OID_registry
bust_spinlocks.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
chacha20.c crypto: chacha20 - use rol32() macro from bitops.h 2018-01-12 23:03:01 +11:00
check_signature.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
checksum.c
clz_ctz.c
clz_tab.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
cmdline.c lib/cmdline.c: remove meaningless comment 2017-09-08 18:26:49 -07:00
cmpdi2.c move libgcc.h to include/linux 2017-12-01 13:09:40 -08:00
compat_audit.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
cordic.c
cpu_rmap.c
cpumask.c lib: optimize cpumask_next_and() 2018-02-06 18:32:44 -08:00
crc4.c docs: clean up and add rest of CRC functions to kernel-api.rst 2017-09-26 15:01:20 -06:00
crc7.c
crc8.c docs: clean up and add rest of CRC functions to kernel-api.rst 2017-09-26 15:01:20 -06:00
crc16.c
crc32.c docs: clean up and add rest of CRC functions to kernel-api.rst 2017-09-26 15:01:20 -06:00
crc32defs.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
crc32test.c lib: add module support to crc32 tests 2017-02-24 17:46:57 -08:00
crc-ccitt.c lib/crc-ccitt: Add CCITT-FALSE CRC16 variant 2018-01-08 10:08:33 +00:00
crc-itu-t.c
crc-t10dif.c
ctype.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
debug_info.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
debug_locks.c
debugobjects.c debugobjects: Make kmemleak ignore debug objects 2017-08-14 16:51:01 +02:00
dec_and_lock.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
decompress_bunzip2.c
decompress_inflate.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
decompress_unlz4.c lib/decompress_unlz4: change module to work with new LZ4 module version 2017-02-24 17:46:57 -08:00
decompress_unlzma.c
decompress_unlzo.c
decompress_unxz.c
decompress.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
devres.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
digsig.c lib/digsig: fix dereference of NULL user_key_payload 2017-10-12 17:16:40 +01:00
div64.c A relatively calm cycle for the docs tree again. 2017-11-13 08:25:06 -08:00
dma-debug.c dma-debug: fix memory leak in debug_dma_alloc_coherent 2018-02-22 15:02:33 -08:00
dma-direct.c dma-direct: comment the dma_direct_free calling convention 2018-02-12 15:59:07 +00:00
dma-virt.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
dump_stack.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
dynamic_debug.c dynamic-debug-howto: fix optional/omitted ending line number to be LARGE instead of 0 2017-11-17 16:10:01 -08:00
dynamic_queue_limits.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2017-11-15 11:56:19 -08:00
earlycpio.c lib/cpio: Make find_cpio_data()'s offset arg optional 2016-06-08 11:04:19 +02:00
error-inject.c error-injection: Add injectable error types 2018-01-12 17:33:38 -08:00
errseq.c errseq: Add to documentation tree 2018-01-01 12:40:27 -07:00
extable.c lib/extable.c: use bsearch() library function in search_extable() 2017-07-10 16:32:35 -07:00
fault-inject.c fault-inject: fix wrong should_fail() decision in task context 2017-08-10 15:54:06 -07:00
fdt_empty_tree.c
fdt_ro.c
fdt_rw.c
fdt_strerror.c
fdt_sw.c
fdt_wip.c
fdt.c
find_bit_benchmark.c lib: optimize cpumask_next_and() 2018-02-06 18:32:44 -08:00
find_bit.c lib: optimize cpumask_next_and() 2018-02-06 18:32:44 -08:00
flex_array.c
flex_proportions.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
gcd.c lib/gcd: add kernel-doc notation 2017-10-07 10:45:14 -06:00
gen_crc32table.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
genalloc.c lib/genalloc.c: make the avail variable an atomic_long_t 2017-11-17 16:10:02 -08:00
glob.c lib: add module support to glob tests 2017-02-24 17:46:57 -08:00
globtest.c lib: add module support to glob tests 2017-02-24 17:46:57 -08:00
hexdump.c lib/hexdump.c: return -EINVAL in case of error in hex2bin() 2017-09-08 18:26:49 -07:00
hweight.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
idr.c idr: Fix handling of IDs above INT_MAX 2018-02-26 14:39:30 -05:00
inflate.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
int_sqrt.c lib/int_sqrt: adjust comments 2017-11-17 16:10:01 -08:00
interval_tree_test.c lib/rbtree-test: lower default params 2017-11-17 16:10:02 -08:00
interval_tree.c
iomap_copy.c
iomap.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
iommu-common.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
iommu-helper.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
ioremap.c License cleanup: add SPDX license identifiers to some files 2017-11-02 10:04:46 -07:00
iov_iter.c new primitive: iov_iter_for_each_range() 2017-10-11 22:36:54 -04:00
irq_poll.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
irq_regs.c
is_single_threaded.c sched/headers: Prepare to move 'init_task' and 'init_thread_union' from <linux/sched.h> to <linux/sched/task.h> 2017-03-02 08:42:38 +01:00
jedec_ddr_data.c
kasprintf.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
Kconfig dma mapping changes for Linux 4.16: 2018-01-31 11:32:27 -08:00
Kconfig.debug lib/Kconfig.debug: enable RUNTIME_TESTING_MENU 2018-02-21 15:35:43 -08:00
Kconfig.kasan kasan: rework Kconfig settings 2018-02-06 18:32:47 -08:00
Kconfig.kgdb lib: update location of kgdb documentation 2017-05-16 08:44:22 -03:00
Kconfig.ubsan Kconfig: lib/Kconfig.ubsan fix reference to ubsan documentation 2016-12-14 16:04:08 -08:00
kfifo.c
klist.c
kobject_uevent.c Merge 4.15-rc6 into driver-core-next 2018-01-02 14:56:51 +01:00
kobject.c Driver Core updates for 4.16-rc1 2018-02-01 10:00:28 -08:00
kstrtox.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
kstrtox.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
lcm.c
libcrc32c.c crypto: Work around deallocated stack frame reference gcc bug on sparc. 2017-06-08 17:36:03 +08:00
list_debug.c bug: switch data corruption check to __must_check 2017-02-24 17:46:56 -08:00
list_sort.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
llist.c locking/atomics: COCCINELLE/treewide: Convert trivial ACCESS_ONCE() patterns to READ_ONCE()/WRITE_ONCE() 2017-10-25 11:01:08 +02:00
locking-selftest-hardirq.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
locking-selftest-mutex.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
locking-selftest-rlock-hardirq.h
locking-selftest-rlock-softirq.h
locking-selftest-rlock.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
locking-selftest-rsem.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
locking-selftest-rtmutex.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
locking-selftest-softirq.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
locking-selftest-spin-hardirq.h
locking-selftest-spin-softirq.h
locking-selftest-spin.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
locking-selftest-wlock-hardirq.h
locking-selftest-wlock-softirq.h
locking-selftest-wlock.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
locking-selftest-wsem.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
locking-selftest.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
lockref.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
lru_cache.c
lshrdi3.c move libgcc.h to include/linux 2017-12-01 13:09:40 -08:00
Makefile lib/test_find_bit.c: rename to find_bit_benchmark.c 2018-02-06 18:32:44 -08:00
memory-notifier-error-inject.c
memweight.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
muldi3.c move libgcc.h to include/linux 2017-12-01 13:09:40 -08:00
net_utils.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
netdev-notifier-error-inject.c
nlattr.c netlink: Relax attr validation for fixed length types 2017-12-07 14:00:57 -05:00
nmi_backtrace.c lib/nmi_backtrace.c: fix kernel text address leak 2017-11-17 16:10:02 -08:00
nodemask.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
notifier-error-inject.c
notifier-error-inject.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
of-reconfig-notifier-error-inject.c
oid_registry.c 509: fix printing uninitialized stack memory when OID is empty 2017-12-08 15:13:28 +00:00
once.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-11-04 09:26:51 +09:00
parman.c lib: Introduce priority array area manager 2017-02-03 16:35:42 -05:00
parser.c parser: add u64 number parser 2016-12-06 10:17:03 +02:00
pci_iomap.c PCI: Add SPDX GPL-2.0 when no license was specified 2018-01-26 11:45:16 -06:00
percpu_counter.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
percpu_ida.c sched/headers: Prepare to remove the <linux/gfp.h> include from <linux/sched.h> 2017-03-02 08:42:34 +01:00
percpu_test.c
percpu-refcount.c percpu: READ_ONCE() now implies smp_read_barrier_depends() 2017-12-04 10:52:53 -08:00
plist.c sched/headers: Prepare for new header dependencies before moving code to <linux/sched/clock.h> 2017-03-02 08:42:27 +01:00
pm-notifier-error-inject.c
prime_numbers.c lib/prime_numbers: Suppress warn on kmalloc failure 2017-01-23 09:17:12 +01:00
radix-tree.c ida: do zeroing in ida_pre_get() 2018-02-21 15:35:43 -08:00
random32.c treewide: Switch DEFINE_TIMER callbacks to struct timer_list * 2017-11-21 15:57:05 -08:00
ratelimit.c lib/ratelimit.c: use deferred printk() version 2017-10-03 17:54:26 -07:00
rational.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
rbtree_test.c lib/rbtree-test: lower default params 2017-11-17 16:10:02 -08:00
rbtree.c lib/rbtree,drm/mm: add rbtree_replace_node_cached() 2017-12-14 16:00:48 -08:00
reciprocal_div.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
refcount.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
rhashtable.c rhashtable: Call library function alloc_bucket_locks 2017-12-11 09:58:39 -05:00
sbitmap.c blk-mq: improve heavily contended tag case 2017-12-22 11:09:37 -07:00
scatterlist.c lib/scatterlist: Fix chaining support in sgl_alloc_order() 2018-01-19 12:31:03 -07:00
seq_buf.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
sg_pool.c lib: scatterlist: move SG pool code from SCSI driver to lib/sg_pool.c 2016-04-15 16:53:14 -04:00
sg_split.c
sha1.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
show_mem.c lib/show_mem.c: teach show_mem to work with the given nodemask 2017-02-22 16:41:30 -08:00
siphash.c siphash: implement HalfSipHash1-3 for hash tables 2017-01-09 13:58:57 -05:00
smp_processor_id.c lib: do not use print_symbol() 2018-01-05 15:24:00 +01:00
sort.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
stackdepot.c lib/stackdepot.c: use a non-instrumented version of memcmp() 2018-02-06 18:32:44 -08:00
stmp_device.c
string_helpers.c mm: treewide: remove GFP_TEMPORARY allocation flag 2017-09-13 18:53:16 -07:00
string.c lib/strscpy: Shut up KASAN false-positives in strscpy() 2018-02-01 12:20:21 -08:00
strncpy_from_user.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
strnlen_user.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
swiotlb.c swiotlb: remove various exports 2018-01-15 09:35:50 +01:00
syscall.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
test_bitmap.c lib/test_bitmap.c: clean up test_zero_fill_copy() test case and rename 2018-02-06 18:32:44 -08:00
test_bpf.c test_bpf: reduce MAX_TESTRUNS 2018-02-28 17:49:18 +01:00
test_debug_virtual.c lib: add test module for CONFIG_DEBUG_VIRTUAL 2017-09-08 18:26:49 -07:00
test_firmware.c test_firmware: fix missing unlock on error in config_num_requests_store() 2018-01-22 16:55:38 +01:00
test_hash.c lib/test_hash.c: fix warning in preprocessor symbol evaluation 2016-09-01 17:52:01 -07:00
test_hexdump.c
test_kasan.c kasan: remove redundant initialization of variable 'real_size' 2018-02-06 18:32:43 -08:00
test_kmod.c treewide: Use DEVICE_ATTR_RW 2018-01-09 16:33:31 +01:00
test_list_sort.c lib/test: delete five error messages for failed memory allocations 2017-11-17 16:10:01 -08:00
test_module.c
test_parman.c lib: fix spelling mistake: "actualy" -> "actually" 2017-02-26 11:03:38 -05:00
test_printf.c printk: hash addresses printed with %p 2017-11-29 12:09:02 +11:00
test_rhashtable.c rhashtable: Change rhashtable_walk_start to return void 2017-12-11 09:58:38 -05:00
test_siphash.c siphash: implement HalfSipHash1-3 for hash tables 2017-01-09 13:58:57 -05:00
test_sort.c lib/test_sort.c: add module unload support 2018-02-06 18:32:45 -08:00
test_static_key_base.c
test_static_keys.c
test_string.c lib: add module support to string tests 2017-11-17 16:10:01 -08:00
test_sysctl.c test_sysctl: test against int proc_dointvec() array support 2017-07-12 16:26:00 -07:00
test_user_copy.c lib: remove check for AVR32 arch in test_user_copy 2017-05-01 09:36:30 +02:00
test_uuid.c uuid: fix incorrect uuid_equal conversion in test_uuid_test 2017-07-21 09:38:30 +02:00
test-kstrtox.c
test-string_helpers.c
textsearch.c
timerqueue.c timerqueue: Document return values of timerqueue_add/del() 2017-12-29 23:13:10 +01:00
ts_bm.c
ts_fsm.c textsearch: fix typos in library helpers 2017-10-22 03:14:07 +01:00
ts_kmp.c textsearch: fix typos in library helpers 2017-10-22 03:14:07 +01:00
ubsan.c lib/ubsan: remove returns-nonnull-attribute checks 2018-02-06 18:32:46 -08:00
ubsan.h lib/ubsan: remove returns-nonnull-attribute checks 2018-02-06 18:32:46 -08:00
ucmpdi2.c move libgcc.h to include/linux 2017-12-01 13:09:40 -08:00
ucs2_string.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
usercopy.c Fix misannotated out-of-line _copy_to_user() 2017-12-11 09:35:11 -05:00
uuid.c Documentation: add UUID/GUID to kernel-api 2017-12-11 15:03:08 -07:00
vsprintf.c vsprintf: avoid misleading "(null)" for %px 2018-02-08 14:21:41 +01:00
win_minmax.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
xxhash.c lib: Add xxhash module 2017-08-15 09:02:07 -07:00