From: Petr Vorel <pvorel@suse.cz>
To: Teo Couprie Diaz <teo.coupriediaz@arm.com>
Cc: ltp@lists.linux.it
Subject: Re: [LTP] [PATCH] syscalls/brk: add direct syscall tst_variant
Date: Tue, 6 Dec 2022 15:04:21 +0100 [thread overview]
Message-ID: <20221206140421.GB21839@pevik> (raw)
In-Reply-To: <20221206122604.212528-1-teo.coupriediaz@arm.com>
Hi Teo,
> Direct usage of brk is discouraged in favor of using malloc. Also, brk was
> removed from POSIX in POSIX.1-2001.
> In particular, the Musl libc's brk always returns -ENOMEM which causes
> the LTP tests to exit prematurely. Invoking the syscall directly allows
> them to properly validate brk behavior. Add a new test variant handling if
> the libc wrappers are not implemented and testing the direct syscall.
> Use tst_syscall() and handle the failure cases ourselves, as
> we don't depend on the libc to do it anymore.
> The patch also works around the dependency on sbrk to get the current break
> as it has the same issues. Instead, call tst_syscall(__NR_brk, 0) which
> always returns the current break.
> Update brk01 to use void* to unify it with brk02.
That brought warnings, see below.
...
> +++ b/testcases/kernel/syscalls/brk/brk02.c
> @@ -14,24 +14,51 @@
> #include <unistd.h>
> #include <sys/mman.h>
> #include "tst_test.h"
> +#include "lapi/syscalls.h"
> +
> +inline void *brk_variants(void *addr)
> +{
> + void *brk_addr;
> + if (tst_variant) {
> + brk_addr = (void *)tst_syscall(__NR_brk, addr);
> + } else {
> + brk_addr = (void *)brk(addr);
NOTE using pointer for brk() is problematic, there are complains:
brk02.c: In function ‘brk_variants’:
brk02.c:26:28: warning: cast to pointer from integer of different size
[-Wint-to-pointer-cast]
26 | brk_addr = (void *)brk(addr);
| ^
Not sure how to fix this. Problem is in both C files, on several places.
There are also code style problems (you can see it when running make check in
testcases/kernel/syscalls/brk/), but that's a minor detail.
Kind regards,
Petr
--
Mailing list info: https://lists.linux.it/listinfo/ltp
next prev parent reply other threads:[~2022-12-06 14:04 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-12-06 12:26 [LTP] [PATCH] syscalls/brk: add direct syscall tst_variant Teo Couprie Diaz
2022-12-06 14:04 ` Petr Vorel [this message]
2022-12-06 14:45 ` Teo Couprie Diaz
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