Re: [PATCH v1] perf cap: Add __NR_capget to arch/x86 unistd

[Ian Rogers]

On Fri, Oct 25, 2024 at 10:54 PM Ian Rogers <irogers@xxxxxxxxxx> wrote:
>
> As there are duplicated kernel headers in tools/include libc can pick
> up the wrong definitions. This was causing the wrong system call for
> capget in perf.
>
> Closes: https://lore.kernel.org/lkml/cc7d6bdf-1aeb-4179-9029-4baf50b59342@xxxxxxxxx/
> Signed-off-by: Ian Rogers <irogers@xxxxxxxxxx>

Forgot:
Fixes: e25ebda78e23 ("perf cap: Tidy up and improve capability testing")

Thanks,
Ian

> ---
>  tools/arch/x86/include/uapi/asm/unistd_32.h |  3 +++
>  tools/arch/x86/include/uapi/asm/unistd_64.h |  3 +++
>  tools/perf/util/cap.c                       | 10 +++-------
>  3 files changed, 9 insertions(+), 7 deletions(-)
>
> diff --git a/tools/arch/x86/include/uapi/asm/unistd_32.h b/tools/arch/x86/include/uapi/asm/unistd_32.h
> index 9de35df1afc3..63182a023e9d 100644
> --- a/tools/arch/x86/include/uapi/asm/unistd_32.h
> +++ b/tools/arch/x86/include/uapi/asm/unistd_32.h
> @@ -11,6 +11,9 @@
>  #ifndef __NR_getpgid
>  #define __NR_getpgid 132
>  #endif
> +#ifndef __NR_capget
> +#define __NR_capget 184
> +#endif
>  #ifndef __NR_gettid
>  #define __NR_gettid 224
>  #endif
> diff --git a/tools/arch/x86/include/uapi/asm/unistd_64.h b/tools/arch/x86/include/uapi/asm/unistd_64.h
> index d0f2043d7132..77311e8d1b5d 100644
> --- a/tools/arch/x86/include/uapi/asm/unistd_64.h
> +++ b/tools/arch/x86/include/uapi/asm/unistd_64.h
> @@ -11,6 +11,9 @@
>  #ifndef __NR_getpgid
>  #define __NR_getpgid 121
>  #endif
> +#ifndef __NR_capget
> +#define __NR_capget 125
> +#endif
>  #ifndef __NR_gettid
>  #define __NR_gettid 186
>  #endif
> diff --git a/tools/perf/util/cap.c b/tools/perf/util/cap.c
> index 7574a67651bc..69d9a2bcd40b 100644
> --- a/tools/perf/util/cap.c
> +++ b/tools/perf/util/cap.c
> @@ -7,13 +7,9 @@
>  #include "debug.h"
>  #include <errno.h>
>  #include <string.h>
> -#include <unistd.h>
>  #include <linux/capability.h>
>  #include <sys/syscall.h>
> -
> -#ifndef SYS_capget
> -#define SYS_capget 90
> -#endif
> +#include <unistd.h>
>
>  #define MAX_LINUX_CAPABILITY_U32S _LINUX_CAPABILITY_U32S_3
>
> @@ -21,9 +17,9 @@ bool perf_cap__capable(int cap, bool *used_root)
>  {
>         struct __user_cap_header_struct header = {
>                 .version = _LINUX_CAPABILITY_VERSION_3,
> -               .pid = getpid(),
> +               .pid = 0,
>         };
> -       struct __user_cap_data_struct data[MAX_LINUX_CAPABILITY_U32S];
> +       struct __user_cap_data_struct data[MAX_LINUX_CAPABILITY_U32S] = {};
>         __u32 cap_val;
>
>         *used_root = false;
> --
> 2.47.0.163.g1226f6d8fa-goog
>