Fix #152 crash on Apple M1 by casting 0 to (OBJECT *) explicitly. #214
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Currently, when the NULL-terminated variadic function call_rule() is invoked, the value "0" is passed as the last argument to act as a terminator. However, this is an integer value, which is incompatible with the pointer data type expected by call_rule(). This is undefined behavior in C, correct operation is not guaranteed. In fact, it causes b2 to crash on Apple M1 when GCC is used - the loop is not terminated when it should, instead, it keeps running, creating the following error: > lol_add failed due to reached limit of 19 elements In some cases, it can even corrupt the internal state of the program, creating an infinite loop. This commit fixes the problem by explicitly casting the value 0 to the correct pointer type (OBJECT *). Signed-off-by: Yifeng Li <[email protected]>
This was referenced Feb 20, 2023
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This is great. Thanks for finding this!
You should do it against the version/4.9.4 branch. I'll be releasing that one in the next couple of days. |
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I've changed the base branch to v4.9.4. Please take a look and let me know if it can be merged. |
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Thank you for this. Spent 48+ hours trying to build libbitcoin using gcc on a Mac until I found your patch |
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Currently, when the
NULL-terminated variadic functioncall_rule()is invoked, the value0is passed as the last argument to act as a terminator. However, this is an integer value, which is incompatible with the pointer data type expected bycall_rule().This is undefined behavior in C, correct operation is not guaranteed. In fact, it causes b2 to crash on Apple M1 when GCC is used - the loop is not terminated when it should, instead, it keeps running, creating the following error:
In some cases, it can even corrupt the internal state of the program, creating an infinite loop.
This commit fixes the problem (Issue #152) by explicitly casting the value
0to the correct pointer type(OBJECT *). According to Rich Felker, the primary author of musl libc, type casting from 0 is technically safer than using the valueNULL.P.S: I'm not sure which is the correct branch to merge, I selected 4.9.3 only as a placeholder.