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Configure: adjusted optimization level for Sun C.
With "-fast" (and with "-xbuiltin=%all -xO4"), Sun C miscompiles
ngx_http_script_add_copy_code(), which is inlined into
ngx_http_script_compile(). From the assembly code it looks like
the code uses uninitialized register when calculating new p value
after memcpy:
movq %r15,%rdi
call _memcpy
leaq (%r15,rbx),%rax
movq (%r12),%rbx
movb $0x0000000000000000,(%rax)
Note that %rax is set to (%r15 + %rbx), but %rbx is only set after
it is used. As such, "*p = '\0'" tries to modify an unrelated memory
address, leading to a segmentation fault.
The issue was seen in tests which use null-terminated complex values:
proxy_ssl_certificate_vars.t, uwsgi_ssl_certificate_vars.t,
stream_proxy_ssl_certificate_vars.t. Tested with Sun C compilers
from Sun Studio 12.3, 12.4, 12.5, and 12.6.
Restructuring code, such as splitting ngx_cpymem() with a separate
"p += value->len" increment, fixes things, but it is not clear if its
the only place where such miscompilation can happen.
Fix is to use "-fast -xO3". Since IPO requires "-xO5", it is commented
out.
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Wed, 07 Aug 2024 03:56:23 +0300 |
parents | 04ebf29eaf5b |
children |
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# Copyright (C) Nginx, Inc. if [ $USE_THREADS = YES ]; then if [ "$NGX_PLATFORM" = win32 ]; then cat << END $0: --with-threads is not supported on Windows END exit 1 fi have=NGX_THREADS . auto/have CORE_DEPS="$CORE_DEPS $THREAD_POOL_DEPS" CORE_SRCS="$CORE_SRCS $THREAD_POOL_SRCS" CORE_LIBS="$CORE_LIBS -lpthread" NGX_LIBPTHREAD="-lpthread" fi