Re: strerror() sets errno to ENOMEM unexpectedly on cross builds with glibc 2.28

[Tim Rühsen]

On 12/18/18 1:30 PM, Tim Rühsen wrote:
> Hi,
> 
> at GnuTLS we recently see Debian cross builds failing due to the issue
> described in the email subject.
> 
> I can't find code in gnulib's strerror.c or strerror-override.c.
> 
> But a stand-alone test calling libc's strerror(-3) without gnulib leaves
> errno at 0.
> 
> $ cat gl/tests/test-strerror.log
> ../../../gl/tests/test-strerror.c:72: assertion 'errno == 0 || errno ==
> EINVAL' failed
> qemu: uncaught target signal 6 (Aborted) - core dumped
> FAIL test-strerror (exit status: 134)
> 
> 
> Maybe someone has an idea what is going on ?

After some more testing, I can reproduce with the following

$ arm-linux-gnueabihf-gcc -Wall -Wextra x.c -o x
$ ./x

errno=12, msg=Unknown error -3

$ cat x.c
#include <stdio.h>
#include <string.h>
#include <errno.h>

int main(void)
{
        errno=0;
        char *msg=strerror(-3);
        printf("errno=%d, msg=%s\n",errno,msg);

        return 0;
}

I will file a bug on the Debian bugtracker.

Regards, Tim

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