[compiler-rt] r300889 - [asan] Optimize strchr for strict_string_checks=false
Diana Picus via llvm-commits
llvm-commits at lists.llvm.org
Fri Apr 21 01:20:46 PDT 2017
I don't think r300939 fixed everything:
http://lab.llvm.org:8011/builders/clang-cmake-armv7-a15-full/builds/6087
On 21 April 2017 at 03:30, Vitaly Buka via llvm-commits
<llvm-commits at lists.llvm.org> wrote:
> Thanks,
> Maybe r300939 would fix.
>
> On Thu, Apr 20, 2017 at 6:20 PM Ahmed Bougacha <ahmed.bougacha at gmail.com>
> wrote:
>>
>> Hey Vitaly,
>>
>> I saw your fixes in r300906 and r300935, but this fails differently
>> for me on Darwin:
>>
>>
>> ASAN:DEADLYSIGNAL
>> =================================================================
>> ==52312==ERROR: AddressSanitizer: BUS on unknown address
>> 0x00010affd000 (pc 0x7fff999a7168 bp 0x7fff57e31270 sp 0x7fff57e31270
>> T0)
>> #0 0x7fff999a7167 in strlen (libsystem_c.dylib:x86_64+0x1167)
>> #1 0x107dee5bb in wrap_strchr sanitizer_common_interceptors.inc:578
>> #2 0x107dceaa5 in main strchr.c:29
>> #3 0x7fff970345ac in start (libdyld.dylib:x86_64+0x35ac)
>>
>> ==52312==Register values:
>> ....
>> AddressSanitizer can not provide additional info.
>> SUMMARY: AddressSanitizer: BUS (libsystem_c.dylib:x86_64+0x1167) in strlen
>> ==52312==ABORTING
>>
>>
>> Does that ring a bell?
>>
>> Thanks!
>> -Ahmed
>>
>>
>> On Thu, Apr 20, 2017 at 1:59 PM, Vitaly Buka via llvm-commits
>> <llvm-commits at lists.llvm.org> wrote:
>> > Author: vitalybuka
>> > Date: Thu Apr 20 15:59:37 2017
>> > New Revision: 300889
>> >
>> > URL: http://llvm.org/viewvc/llvm-project?rev=300889&view=rev
>> > Log:
>> > [asan] Optimize strchr for strict_string_checks=false
>> >
>> > Summary:
>> > strchr interceptor does not need to call strlen if strict_string_checks
>> > is not
>> > enabled. Unnecessary strlen calls affect python parser performance.
>> >
>> > Reviewers: eugenis, kcc
>> >
>> > Subscribers: llvm-commits, kubamracek
>> >
>> > Differential Revision: https://reviews.llvm.org/D32264
>> >
>> > Added:
>> > compiler-rt/trunk/test/asan/TestCases/Posix/strchr.c
>> > Modified:
>> >
>> > compiler-rt/trunk/lib/sanitizer_common/sanitizer_common_interceptors.inc
>> >
>> > Modified:
>> > compiler-rt/trunk/lib/sanitizer_common/sanitizer_common_interceptors.inc
>> > URL:
>> > http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/sanitizer_common/sanitizer_common_interceptors.inc?rev=300889&r1=300888&r2=300889&view=diff
>> >
>> > ==============================================================================
>> > ---
>> > compiler-rt/trunk/lib/sanitizer_common/sanitizer_common_interceptors.inc
>> > (original)
>> > +++
>> > compiler-rt/trunk/lib/sanitizer_common/sanitizer_common_interceptors.inc Thu
>> > Apr 20 15:59:37 2017
>> > @@ -139,12 +139,9 @@ bool PlatformHasDifferentMemcpyAndMemmov
>> > #define COMMON_INTERCEPTOR_NOTHING_IS_INITIALIZED (0)
>> > #endif
>> >
>> > -#define COMMON_INTERCEPTOR_READ_STRING_OF_LEN(ctx, s, len, n) \
>> > - COMMON_INTERCEPTOR_READ_RANGE((ctx), (s), \
>> > - common_flags()->strict_string_checks ? (len) + 1 : (n) )
>> > -
>> > #define COMMON_INTERCEPTOR_READ_STRING(ctx, s, n) \
>> > - COMMON_INTERCEPTOR_READ_STRING_OF_LEN((ctx), (s), REAL(strlen)(s),
>> > (n))
>> > + COMMON_INTERCEPTOR_READ_RANGE((ctx), (s), \
>> > + common_flags()->strict_string_checks ? (REAL(strlen)(s)) + 1 :
>> > (n) )
>> >
>> > #ifndef COMMON_INTERCEPTOR_ON_DLOPEN
>> > #define COMMON_INTERCEPTOR_ON_DLOPEN(filename, flag) \
>> > @@ -450,8 +447,7 @@ static inline void StrstrCheck(void *ctx
>> > const char *s2) {
>> > uptr len1 = REAL(strlen)(s1);
>> > uptr len2 = REAL(strlen)(s2);
>> > - COMMON_INTERCEPTOR_READ_STRING_OF_LEN(ctx, s1, len1,
>> > - r ? r - s1 + len2 : len1 +
>> > 1);
>> > + COMMON_INTERCEPTOR_READ_STRING(ctx, s1, r ? r - s1 + len2 : len1 +
>> > 1);
>> > COMMON_INTERCEPTOR_READ_RANGE(ctx, s2, len2 + 1);
>> > }
>> > #endif
>> > @@ -577,10 +573,11 @@ INTERCEPTOR(char*, strchr, const char *s
>> > return internal_strchr(s, c);
>> > COMMON_INTERCEPTOR_ENTER(ctx, strchr, s, c);
>> > char *result = REAL(strchr)(s, c);
>> > - uptr len = internal_strlen(s);
>> > - uptr n = result ? result - s + 1 : len + 1;
>> > - if (common_flags()->intercept_strchr)
>> > - COMMON_INTERCEPTOR_READ_STRING_OF_LEN(ctx, s, len, n);
>> > + if (common_flags()->intercept_strchr) {
>> > + // Keep strlen as macro argument, as macro may ignore it.
>> > + COMMON_INTERCEPTOR_READ_STRING(ctx, s,
>> > + (result ? result - s : REAL(strlen)(s)) + 1);
>> > + }
>> > return result;
>> > }
>> > #define INIT_STRCHR COMMON_INTERCEPT_FUNCTION(strchr)
>> > @@ -609,9 +606,8 @@ INTERCEPTOR(char*, strrchr, const char *
>> > if (COMMON_INTERCEPTOR_NOTHING_IS_INITIALIZED)
>> > return internal_strrchr(s, c);
>> > COMMON_INTERCEPTOR_ENTER(ctx, strrchr, s, c);
>> > - uptr len = internal_strlen(s);
>> > if (common_flags()->intercept_strchr)
>> > - COMMON_INTERCEPTOR_READ_STRING_OF_LEN(ctx, s, len, len + 1);
>> > + COMMON_INTERCEPTOR_READ_RANGE(ctx, s, REAL(strlen)(s) + 1);
>> > return REAL(strrchr)(s, c);
>> > }
>> > #define INIT_STRRCHR COMMON_INTERCEPT_FUNCTION(strrchr)
>> >
>> > Added: compiler-rt/trunk/test/asan/TestCases/Posix/strchr.c
>> > URL:
>> > http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/test/asan/TestCases/Posix/strchr.c?rev=300889&view=auto
>> >
>> > ==============================================================================
>> > --- compiler-rt/trunk/test/asan/TestCases/Posix/strchr.c (added)
>> > +++ compiler-rt/trunk/test/asan/TestCases/Posix/strchr.c Thu Apr 20
>> > 15:59:37 2017
>> > @@ -0,0 +1,36 @@
>> > +// Test strchr for strict_string_checks=false does not look beyond
>> > necessary
>> > +// char.
>> > +// RUN: %clang_asan %s -o %t
>> > +// RUN: %env_asan_opts=strict_string_checks=false %run %t 2>&1
>> > +// RUN: %env_asan_opts=strict_string_checks=true not %run %t 2>&1 |
>> > FileCheck %s
>> > +
>> > +#include <assert.h>
>> > +#include <stdint.h>
>> > +#include <stdlib.h>
>> > +#include <string.h>
>> > +#include <sys/mman.h>
>> > +#include <unistd.h>
>> > +
>> > +int main(int argc, char **argv) {
>> > + size_t page_size = sysconf(_SC_PAGE_SIZE);
>> > + size_t size = 2 * page_size;
>> > + char *s = (char *)mmap(0, size, PROT_READ | PROT_WRITE,
>> > + MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
>> > + assert(s);
>> > + assert(((uintptr_t)s & (page_size - 1)) == 0);
>> > + memset(s, 'o', size);
>> > + s[size - 1] = 0;
>> > +
>> > + char *p = s + page_size - 1;
>> > + *p = 'x';
>> > +
>> > + if (mprotect(p + 1, 1, PROT_NONE))
>> > + return 1;
>> > + char *r = strchr(s, 'x');
>> > + // CHECK: AddressSanitizer: SEGV on unknown address
>> > + // CHECK: The signal is caused by a READ memory access
>> > + // CHECK: strchr.c:[[@LINE-3]]
>> > + assert(r == p);
>> > +
>> > + return 0;
>> > +}
>> >
>> >
>> > _______________________________________________
>> > llvm-commits mailing list
>> > llvm-commits at lists.llvm.org
>> > http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-commits
>
>
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