Fix compilation errors in pid_max.c by including <sys/mount.h>, which provides definitions for mount(), umount2(), MS_PRIVATE, MS_REC, and MNT_DETACH.

Without this header, the build fails with implicit declarations and undefined constants during selftest compilation.

Changes since v1: - Included example build errors below for clarity

Compile error: pid_max.c: In function ‘pid_max_cb’: pid_max.c:42:15: warning: implicit declaration of function ‘mount’ [-Wimplicit-function-declaration] 42 | ret = mount("", "/", NULL, MS_PRIVATE | MS_REC, 0); | ^~~~~ pid_max.c:42:36: error: ‘MS_PRIVATE’ undeclared; did you mean ‘MAP_PRIVATE’? pid_max.c:42:49: error: ‘MS_REC’ undeclared pid_max.c:48:9: warning: implicit declaration of function ‘umount2’ pid_max.c:48:26: error: ‘MNT_DETACH’ undeclared

[...output trimmed for brevity...]

make: *** [../lib.mk:222: /linux_mainline/tools/testing/selftests/pid_namespace/pid_max] Error 1

Signed-off-by: Moon Hee Lee moonhee.lee.ca@gmail.com --- tools/testing/selftests/pid_namespace/pid_max.c | 1 + 1 file changed, 1 insertion(+)

diff --git a/tools/testing/selftests/pid_namespace/pid_max.c b/tools/testing/selftests/pid_namespace/pid_max.c index 51c414faabb0..972bedc475f1 100644 --- a/tools/testing/selftests/pid_namespace/pid_max.c +++ b/tools/testing/selftests/pid_namespace/pid_max.c @@ -11,6 +11,7 @@ #include <string.h> #include <syscall.h> #include <sys/wait.h> +#include <sys/mount.h>

#include "../kselftest_harness.h" #include "../pidfd/pidfd.h"