Bug #77447 [Ver]: PHP 7.3 built with ASAN crashes in zend_cpu_supports_avx2

Edit report at https://bugs.php.net/bug.php?id=77447&edit=1 ID: 77447 Updated by: nikic@php.net Reported by: hanno at hboeck dot de Summary: PHP 7.3 built with ASAN crashes in zend_cpu_supports_avx2 Status: Verified Type: Bug Package: Reproducible crash Operating System: Linux PHP Version: 7.3.1 Block user comment: N Private report: N New Comment: Looks like asan being incompatible with ifunc resolvers is a longstanding problem: https://github.com/google/sanitizers/issues/342 We might be able to work around it with some __attribute__((no_sanitize_address)) attributes. Previous Comments: ------------------------------------------------------------------------ [2019-01-14 10:24:35] nikic@php.net 0x555555c21f56 <zend_cpu_supports_sse42+4> callq 0x555555832560 <__cpu_indicator_init> 0x555555c21f5b <zend_cpu_supports_sse42+9> lea 0xb6971e(%rip),%rax 0x555555c21f62 <zend_cpu_supports_sse42+16> lea 0xc(%rax),%rax 0x555555c21f66 <zend_cpu_supports_sse42+20> mov %rax,%rdx 0x555555c21f69 <zend_cpu_supports_sse42+23> shr $0x3,%rdx 0x555555c21f6d <zend_cpu_supports_sse42+27> add $0x7fff8000,%rdx > 0x555555c21f74 <zend_cpu_supports_sse42+34> movzbl (%rdx),%edx (gdb) p &__cpu_model $8 = (<data variable, no debug info> *) 0x55555678b680 <__cpu_model> (gdb) p/x $rax $9 = 0x55555678b68c (gdb) p/x $rdx $10 = 0xaab2ace96d1 From what I gathered (addr>>3)+0x7fff8000 is the shadow address used by asan, and apparently it is not mapped. ------------------------------------------------------------------------ [2019-01-14 09:56:19] nikic@php.net Confirming the segfault. Had to add LIBS="-ldl" to avoid linker errors. ------------------------------------------------------------------------ [2019-01-11 14:59:05] hanno at hboeck dot de Description: ------------ I'm unable to get PHP 7.3 to run with address sanitizer. Reproduce: ./configure CFLAGS="-fsanitize=address -g" CXXFLAGS="-fsanitize=address -g" LDFLAGS="-fsanitize=address" --enable-debug make ./sapi/cli/php leads to a segfault. This problem does not happen with 7.2.x. Address Sanitizer has been an extremely helpful tool to identify memory corruption bugs and security issues in PHP, therefore this is concerning, as it might hamper the ability of security researchers to find bugs in PHP. A stack trace from GDB shows this happens in the function zend_cpu_supports_avx2(). AVX2 support is not available in PHP 7.2, therefore I believe this explains the difference between 7.2 and 7.3. Expected result: ---------------- No segfault with ASAN. Actual result: -------------- Segfault with ASAN. ------------------------------------------------------------------------ -- Edit this bug report at https://bugs.php.net/bug.php?id=77447&edit=1