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(-)
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)),
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
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