linux-kernel - Re: [PATCH] selftests/nolibc: disable brk()/sbrk() tests on musl

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Message-ID: <20240424220237.GA10281@1wt.eu>
Date: Thu, 25 Apr 2024 00:02:37 +0200
From: Willy Tarreau <w@....eu>
To: Thomas Weißschuh <linux@...ssschuh.net>
Cc: Shuah Khan <shuah@...nel.org>, linux-kselftest@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] selftests/nolibc: disable brk()/sbrk() tests on musl

On Wed, Apr 24, 2024 at 04:13:13AM +0200, Willy Tarreau wrote:
> On Wed, Apr 24, 2024 at 12:15:33AM +0200, Thomas Weißschuh wrote:
> > On musl calls to brk() and sbrk() always fail with ENOMEM.
> > Detect this and skip the tests on musl.
> > 
> > Tested on glibc 2.39 and musl 1.2.5 in addition to nolibc.
> > 
> > Signed-off-by: Thomas Weißschuh <linux@...ssschuh.net>
> > ---
> >  tools/testing/selftests/nolibc/nolibc-test.c | 10 +++++++---
> >  1 file changed, 7 insertions(+), 3 deletions(-)
> > 
> > diff --git a/tools/testing/selftests/nolibc/nolibc-test.c b/tools/testing/selftests/nolibc/nolibc-test.c
> > index 94bb6e11c16f..89be9ba95179 100644
> > --- a/tools/testing/selftests/nolibc/nolibc-test.c
> > +++ b/tools/testing/selftests/nolibc/nolibc-test.c
> > @@ -942,6 +942,7 @@ int run_syscall(int min, int max)
> >  	int ret = 0;
> >  	void *p1, *p2;
> >  	int has_gettid = 1;
> > +	int has_brk;
> >  
> >  	/* <proc> indicates whether or not /proc is mounted */
> >  	proc = stat("/proc", &stat_buf) == 0;
> > @@ -954,6 +955,9 @@ int run_syscall(int min, int max)
> >  	has_gettid = __GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 30);
> >  #endif
> >  
> > +	/* on musl setting brk()/sbrk() always fails */
> > +	has_brk = brk(0) == 0;
> > +
> >  	for (test = min; test >= 0 && test <= max; test++) {
> >  		int llen = 0; /* line length */
> >  
> > @@ -969,9 +973,9 @@ int run_syscall(int min, int max)
> >  		CASE_TEST(kill_0);            EXPECT_SYSZR(1, kill(getpid(), 0)); break;
> >  		CASE_TEST(kill_CONT);         EXPECT_SYSZR(1, kill(getpid(), 0)); break;
> >  		CASE_TEST(kill_BADPID);       EXPECT_SYSER(1, kill(INT_MAX, 0), -1, ESRCH); break;
> > -		CASE_TEST(sbrk_0);            EXPECT_PTRNE(1, sbrk(0), (void *)-1); break;
> > -		CASE_TEST(sbrk);              if ((p1 = p2 = sbrk(4096)) != (void *)-1) p2 = sbrk(-4096); EXPECT_SYSZR(1, (p2 == (void *)-1) || p2 == p1); break;
> > -		CASE_TEST(brk);               EXPECT_SYSZR(1, brk(sbrk(0))); break;
> > +		CASE_TEST(sbrk_0);            EXPECT_PTRNE(has_brk, sbrk(0), (void *)-1); break;
> > +		CASE_TEST(sbrk);              if ((p1 = p2 = sbrk(4096)) != (void *)-1) p2 = sbrk(-4096); EXPECT_SYSZR(has_brk, (p2 == (void *)-1) || p2 == p1); break;
> > +		CASE_TEST(brk);               EXPECT_SYSZR(has_brk, brk(sbrk(0))); break;
> >  		CASE_TEST(chdir_root);        EXPECT_SYSZR(1, chdir("/")); chdir(getenv("PWD")); break;
> >  		CASE_TEST(chdir_dot);         EXPECT_SYSZR(1, chdir(".")); break;
> >  		CASE_TEST(chdir_blah);        EXPECT_SYSER(1, chdir("/blah"), -1, ENOENT); break;
> 
> Looks good, thank you Thomas!

BTW, Acked-by: Willy Tarreau <w@....eu>

Willy