__wait.c: fix a timeout (WebAssembly#361)

yamt · john-sharratt · commit 1055f0192e00 · 2023-03-06T10:05:09.000+11:00
Note: The typical symptom of this bug is a busy waiting on a lock.

Note: 0 means immediate timeout. a negative value means no timeout.
diff --git a/libc-top-half/musl/src/thread/__wait.c b/libc-top-half/musl/src/thread/__wait.c
@@ -48,7 +48,7 @@ void __wait(volatile int *addr, volatile int *waiters, int val, int priv)
 		__syscall(SYS_futex, addr, FUTEX_WAIT|priv, val, 0) != -ENOSYS
 		|| __syscall(SYS_futex, addr, FUTEX_WAIT, val, 0);
 #else
-		__wasilibc_futex_wait_wasix(addr, FUTEX_WAIT, val, 0);
+		__wasilibc_futex_wait_wasix(addr, FUTEX_WAIT, val, -1);
 #endif
 	}
 	if (waiters) a_dec(waiters);

Original file line number	Diff line number	Diff line change
`@@ -48,7 +48,7 @@ void __wait(volatile int addr, volatile int waiters, int val, int priv)`
`48`	`48`	`__syscall(SYS_futex, addr, FUTEX_WAIT\|priv, val, 0) != -ENOSYS`
`49`	`49`	`\|\| __syscall(SYS_futex, addr, FUTEX_WAIT, val, 0);`
`50`	`50`	`#else`
`51`		`- __wasilibc_futex_wait_wasix(addr, FUTEX_WAIT, val, 0);`
	`51`	`+ __wasilibc_futex_wait_wasix(addr, FUTEX_WAIT, val, -1);`
`52`	`52`	`#endif`
`53`	`53`	`}`
`54`	`54`	`if (waiters) a_dec(waiters);`