[LTP] [PATCH] cgroup_core02: Allocate child stack using mmap()

[LTP] [PATCH] cgroup_core02: Allocate child stack using mmap()

[Martin Doucha]

Some architectures like arm64 have strict requirements for stack alignment.
Statically allocated buffer may result in one of the test processes
getting killed by SIGBUS. Allocate child stack using mmap() to ensure
the requirements are met.

Signed-off-by: Martin Doucha <mdoucha@suse.cz>
---
 testcases/kernel/controllers/cgroup/cgroup_core02.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/testcases/kernel/controllers/cgroup/cgroup_core02.c b/testcases/kernel/controllers/cgroup/cgroup_core02.c
index 733e88ee7..e0b96ecf4 100644
--- a/testcases/kernel/controllers/cgroup/cgroup_core02.c
+++ b/testcases/kernel/controllers/cgroup/cgroup_core02.c
@@ -51,7 +51,7 @@ static int lesser_ns_open_thread_fn(void *arg)
 static void test_lesser_ns_open(void)
 {
 	int i;
-	static char stack[65536];
+	char *stack;
 	pid_t pid;
 	int status;
 	struct lesser_ns_open_thread_arg targ = { .fds = {0}, .loops = -1};
@@ -63,14 +63,19 @@ static void test_lesser_ns_open(void)
 		SAFE_CG_PRINT(cg_child_a, "cgroup.procs", "0");
 		SAFE_CG_FCHOWN(cg_child_a, "cgroup.procs",  nobody_uid, -1);
 		SAFE_CG_FCHOWN(cg_child_b, "cgroup.procs",  nobody_uid, -1);
+		stack = SAFE_MMAP(NULL, 65536, PROT_READ | PROT_WRITE,
+			MAP_PRIVATE | MAP_ANONYMOUS | MAP_STACK, -1, 0);
 		pid  = ltp_clone(CLONE_NEWCGROUP | CLONE_FILES | CLONE_VM | SIGCHLD,
 					lesser_ns_open_thread_fn, &targ, 65536, stack);
+
 		if (pid < 0)  {
 			tst_res(TFAIL, "unexpected negative pid %d", pid);
 			exit(1);
 		}
 
 		SAFE_WAITPID(pid, &status, 0);
+		SAFE_MUNMAP(stack, 65536);
+
 		for (i = 0; i < targ.loops; i++) {
 			if (targ.fds[i] < 1) {
 				tst_res(TFAIL, "unexpected negative fd %d", targ.fds[i]);
-- 
2.47.0


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Re: [LTP] [PATCH] cgroup_core02: Allocate child stack using mmap()

[Petr Vorel]

Hi Martin,

> Some architectures like arm64 have strict requirements for stack alignment.
> Statically allocated buffer may result in one of the test processes
> getting killed by SIGBUS. Allocate child stack using mmap() to ensure
> the requirements are met.

Acked-by: Petr Vorel <pvorel@suse.cz>

LGTM, thanks for fixing this.

Kind regards,
Petr

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Re: [LTP] [PATCH] cgroup_core02: Allocate child stack using mmap()

[Cyril Hrubis]

Hi!
Reviewed-by: Cyril Hrubis <chrubis@suse.cz>

-- 
Cyril Hrubis
chrubis@suse.cz

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