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Date: Wed, 28 Oct 2020 16:11:05 -0400
From: Rich Felker <dalias@libc.org>
To: musl@lists.openwall.com
Message-ID: <20201028201104.GH534@brightrain.aerifal.cx>
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Subject: [musl] bug: sem_close always unmaps semaphore regardless of ref count


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I found this while reading the code during review of lock usage for
MT-fork. Test case attached (can be adapted for libc-test regression
tests, I think, or improved to be a conformance test).

Rich

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#include <semaphore.h>

int main()
{
	char buf[] = "mysemXXXXXX";
	if (!mktemp(buf)) return 1;
	sem_t *sem = sem_open(buf, O_CREAT|O_EXCL, 0600);
	sem_open(buf, 0);
	sem_unlink(buf);
	sem_close(sem);
	sem_post(sem);
}

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