diff mbox series

[seccomp] selftests/seccomp: Fix compile warning when CC=clang

Message ID 20220526223407.1686936-1-zhuyifei@google.com (mailing list archive)
State Not Applicable
Delegated to: BPF
Headers show
Series [seccomp] selftests/seccomp: Fix compile warning when CC=clang | expand

Checks

Context Check Description
bpf/vmtest-bpf-next-PR success PR summary
bpf/vmtest-bpf-next-VM_Test-1 success Logs for Kernel LATEST on ubuntu-latest with gcc
bpf/vmtest-bpf-next-VM_Test-2 success Logs for Kernel LATEST on ubuntu-latest with llvm-15
bpf/vmtest-bpf-next-VM_Test-3 success Logs for Kernel LATEST on z15 with gcc
netdev/tree_selection success Not a local patch

Commit Message

YiFei Zhu May 26, 2022, 10:34 p.m. UTC
clang has -Wconstant-conversion by default, and the constant 0xAAAAAAAAA
(9 As) being converted to an int, which is generally 32 bits, results
in the compile warning:

  clang -Wl,-no-as-needed -Wall -isystem ../../../../usr/include/  -lpthread  seccomp_bpf.c -lcap -o seccomp_bpf
  seccomp_bpf.c:812:67: warning: implicit conversion from 'long' to 'int' changes value from 45812984490 to -1431655766 [-Wconstant-conversion]
          int kill = kill_how == KILL_PROCESS ? SECCOMP_RET_KILL_PROCESS : 0xAAAAAAAAA;
              ~~~~                                                         ^~~~~~~~~~~
  1 warning generated.

-1431655766 is the expected truncation, 0xAAAAAAAA (8 As), so use
this directly in the code to avoid the warning.

Fixes: 3932fcecd962 ("selftests/seccomp: Add test for unknown SECCOMP_RET kill behavior")
Signed-off-by: YiFei Zhu <zhuyifei@google.com>
---
 tools/testing/selftests/seccomp/seccomp_bpf.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Kees Cook May 27, 2022, 8:34 p.m. UTC | #1
On Thu, 26 May 2022 22:34:07 +0000, YiFei Zhu wrote:
> clang has -Wconstant-conversion by default, and the constant 0xAAAAAAAAA
> (9 As) being converted to an int, which is generally 32 bits, results
> in the compile warning:
> 
>   clang -Wl,-no-as-needed -Wall -isystem ../../../../usr/include/  -lpthread  seccomp_bpf.c -lcap -o seccomp_bpf
>   seccomp_bpf.c:812:67: warning: implicit conversion from 'long' to 'int' changes value from 45812984490 to -1431655766 [-Wconstant-conversion]
>           int kill = kill_how == KILL_PROCESS ? SECCOMP_RET_KILL_PROCESS : 0xAAAAAAAAA;
>               ~~~~                                                         ^~~~~~~~~~~
>   1 warning generated.
> 
> [...]

Applied to for-next/seccomp, thanks!

[1/1] selftests/seccomp: Fix compile warning when CC=clang
      https://git.kernel.org/kees/c/73a8dbafd31a
diff mbox series

Patch

diff --git a/tools/testing/selftests/seccomp/seccomp_bpf.c b/tools/testing/selftests/seccomp/seccomp_bpf.c
index 136df5b76319..4ae6c8991307 100644
--- a/tools/testing/selftests/seccomp/seccomp_bpf.c
+++ b/tools/testing/selftests/seccomp/seccomp_bpf.c
@@ -809,7 +809,7 @@  void kill_thread_or_group(struct __test_metadata *_metadata,
 		.len = (unsigned short)ARRAY_SIZE(filter_thread),
 		.filter = filter_thread,
 	};
-	int kill = kill_how == KILL_PROCESS ? SECCOMP_RET_KILL_PROCESS : 0xAAAAAAAAA;
+	int kill = kill_how == KILL_PROCESS ? SECCOMP_RET_KILL_PROCESS : 0xAAAAAAAA;
 	struct sock_filter filter_process[] = {
 		BPF_STMT(BPF_LD|BPF_W|BPF_ABS,
 			offsetof(struct seccomp_data, nr)),