Re: [PATCH] selftest: Fix UB of getline due to missing var init

["David Hildenbrand (Arm)" <david@kernel.org>]

On 5/26/26 13:38, Chris Gellermann wrote:
> Clone3_set_tid uses getline(&line, &len, f) in a loop to read the
> child's process status. The code expects that getline allocates the
> buffer for the line on the first loop iteration. For this, glibc[1]
> requires char *line to be set to NULL:
> 
>> ssize_t getline(char **restrict lineptr, ...)
>> If *lineptr is set to NULL before the call, then getline() will
>> allocate a buffer for storing the line.
> 
> However, char *line is only declared, leading to an undefined
> initialization value. Fix this by properly initializing it to NULL.
> 
> Same issue fixed in mlock-random-test.
> 
> [1] https://man7.org/linux/man-pages/man3/getline.3.html
> 
> Fixes: 41585bbeeef9 ("selftests: add tests for clone3() with *set_tid")
> Fixes: 26b4224d9961 ("selftests: expanding more mlock selftest")
> Signed-off-by: Chris Gellermann <christian.gellermann@codasip.com>
> ---

Acked-by: David Hildenbrand (arm) <david@kernel.org>

-- 
Cheers,

David