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Since the new stack overflow detection system (ocaml#8670), ASAN was confused. We fix the issue by resetting the 'use_sigaltstack' flag and by disabling ASAN on functions used by the stack overflow handler.
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Could someone add the "no change entry required" tag on this PR? |
xavierleroy
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Oct 19, 2019
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Thanks for your expertise with the sanitizers, much appreciated.
If I understand correctly:
use_sigaltstack=0instructs the sanitizer that we are using sigaltstack for our own purposes.- The
CAMLno_asanannotations are put on functions that run on the alternate stack. Without this annotation, ASAN sees code that accesses a global variable as if it were the call stack and complains about it.
Looks good to me! Merging.
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| #define CAMLno_tsan | ||
| #define CAMLno_asan | ||
| #if defined(__has_feature) | ||
| # if __has_feature(thread_sanitizer) | ||
| # undef CAMLno_tsan | ||
| # define CAMLno_tsan __attribute__((no_sanitize("thread"))) | ||
| # endif | ||
| # if __has_feature(address_sanitizer) | ||
| # undef CAMLno_asan | ||
| # define CAMLno_asan __attribute__((no_sanitize("address"))) | ||
| # endif | ||
| #endif |
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For other readers who might wonder about it:
#if defined(__has_feature) && __has_feature(thread_sanitizer)
wouldn't work with GCC (and perhaps other non-Clang compilers) because it would try to expand __has_feature(thread_sanitizer) even though the left part of && is false.
This justifies the #define / #undef / #define dance.
xavierleroy
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Oct 19, 2019
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"Extra-check" CI is happy. Cherry-picked to 4.10 as commit 0ba3ab1. |
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Since the new stack overflow detection system (#8670), ASAN was confused.
We fix the issue by resetting the 'use_sigaltstack' flag and by disabling
ASAN on functions used by the stack overflow handler.