Fix compilation error in UPROBE_setup caused by pointer type mismatch in ternary expression. The probed_uretprobe and probed_uprobe function pointers have different type attributes (__attribute__((nocf_check))), which causes the conditional operator to fail with:
seccomp_bpf.c:5175:74: error: pointer type mismatch in conditional expression [-Wincompatible-pointer-types]
Cast both function pointers to 'const void *' to match the expected parameter type of get_uprobe_offset(), resolving the type mismatch while preserving the function selection logic.
Signed-off-by: Nirbhay Sharma nirbhay.lkd@gmail.com --- tools/testing/selftests/seccomp/seccomp_bpf.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/tools/testing/selftests/seccomp/seccomp_bpf.c b/tools/testing/selftests/seccomp/seccomp_bpf.c index 874f17763536..e13ffe18ef95 100644 --- a/tools/testing/selftests/seccomp/seccomp_bpf.c +++ b/tools/testing/selftests/seccomp/seccomp_bpf.c @@ -5172,7 +5172,8 @@ FIXTURE_SETUP(UPROBE) ASSERT_GE(bit, 0); }
- offset = get_uprobe_offset(variant->uretprobe ? probed_uretprobe : probed_uprobe); + offset = get_uprobe_offset(variant->uretprobe ? + (const void *)probed_uretprobe : (const void *)probed_uprobe); ASSERT_GE(offset, 0);
if (variant->uretprobe)
On Sun, Oct 26, 2025 at 12:19:04AM +0530, Nirbhay Sharma wrote:
Fix compilation error in UPROBE_setup caused by pointer type mismatch in ternary expression. The probed_uretprobe and probed_uprobe function pointers have different type attributes (__attribute__((nocf_check))),
just probed_uprobe right?
which causes the conditional operator to fail with:
seccomp_bpf.c:5175:74: error: pointer type mismatch in conditional expression [-Wincompatible-pointer-types]
curious what compiler do you see that with? gcc-15 is silent, the change looks good to me
thanks, jirka
Cast both function pointers to 'const void *' to match the expected parameter type of get_uprobe_offset(), resolving the type mismatch while preserving the function selection logic.
Signed-off-by: Nirbhay Sharma nirbhay.lkd@gmail.com
tools/testing/selftests/seccomp/seccomp_bpf.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/tools/testing/selftests/seccomp/seccomp_bpf.c b/tools/testing/selftests/seccomp/seccomp_bpf.c index 874f17763536..e13ffe18ef95 100644 --- a/tools/testing/selftests/seccomp/seccomp_bpf.c +++ b/tools/testing/selftests/seccomp/seccomp_bpf.c @@ -5172,7 +5172,8 @@ FIXTURE_SETUP(UPROBE) ASSERT_GE(bit, 0); }
- offset = get_uprobe_offset(variant->uretprobe ? probed_uretprobe : probed_uprobe);
- offset = get_uprobe_offset(variant->uretprobe ?
(const void *)probed_uretprobe : (const void *)probed_uprobe);if (variant->uretprobe) -- 2.48.1
I tried to reproduce it with a small testcase and I could reproduce the error with -fcf-protection and not without (where I get a warning that the nocf_check attribute is ignored b/c of no flag).
Hi Jiri,
Thank you for the review and for catching that inaccuracy!
On 10/26/25 2:48 AM, Jiri Olsa wrote:
just probed_uprobe right?
Yes, you're absolutely correct. Only probed_uprobe has the __attribute__((nocf_check)) attribute. I apologize for the confusion in my original commit message. I'll fix this in v2.
curious what compiler do you see that with?
I am seeing this error with Clang 19.1.2 on Fedora, which enables -fcf-protection=full by default. As Sam confirmed, the error occurs specifically when CFI protection is enabled via -fcf-protection. GCC without this flag treats it as a warning or ignores the nocf_check attribute entirely.
I'll send v2 with the corrected commit message.
Thanks again for the review!
Best regards, Nirbhay
Fix compilation error in UPROBE_setup caused by pointer type mismatch in the ternary expression when compiled with -fcf-protection. The probed_uprobe function pointer has the __attribute__((nocf_check)) attribute, which causes the conditional operator to fail when combined with the regular probed_uretprobe function pointer:
seccomp_bpf.c:5175:74: error: pointer type mismatch in conditional expression [-Wincompatible-pointer-types]
Cast both function pointers to 'const void *' to match the expected parameter type of get_uprobe_offset(), resolving the type mismatch while preserving the function selection logic.
This error appears with compilers that enable Control Flow Integrity (CFI) protection via -fcf-protection, such as Clang 19.1.2 (default on Fedora).
Signed-off-by: Nirbhay Sharma nirbhay.lkd@gmail.com --- tools/testing/selftests/seccomp/seccomp_bpf.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/tools/testing/selftests/seccomp/seccomp_bpf.c b/tools/testing/selftests/seccomp/seccomp_bpf.c index 874f17763536..e13ffe18ef95 100644 --- a/tools/testing/selftests/seccomp/seccomp_bpf.c +++ b/tools/testing/selftests/seccomp/seccomp_bpf.c @@ -5172,7 +5172,8 @@ FIXTURE_SETUP(UPROBE) ASSERT_GE(bit, 0); }
- offset = get_uprobe_offset(variant->uretprobe ? probed_uretprobe : probed_uprobe); + offset = get_uprobe_offset(variant->uretprobe ? + (const void *)probed_uretprobe : (const void *)probed_uprobe); ASSERT_GE(offset, 0);
if (variant->uretprobe)
Nirbhay Sharma nirbhay.lkd@gmail.com writes:
Fix compilation error in UPROBE_setup caused by pointer type mismatch in the ternary expression when compiled with -fcf-protection. The probed_uprobe function pointer has the __attribute__((nocf_check)) attribute, which causes the conditional operator to fail when combined with the regular probed_uretprobe function pointer:
Just as a curiosity to share: I found a few tangential issues and reported them as https://gcc.gnu.org/PR122427.
seccomp_bpf.c:5175:74: error: pointer type mismatch in conditional expression [-Wincompatible-pointer-types]
Cast both function pointers to 'const void *' to match the expected parameter type of get_uprobe_offset(), resolving the type mismatch while preserving the function selection logic.
This error appears with compilers that enable Control Flow Integrity (CFI) protection via -fcf-protection, such as Clang 19.1.2 (default on Fedora).
Reviewed-by: Sam James sam@gentoo.org
Signed-off-by: Nirbhay Sharma nirbhay.lkd@gmail.com
tools/testing/selftests/seccomp/seccomp_bpf.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/tools/testing/selftests/seccomp/seccomp_bpf.c b/tools/testing/selftests/seccomp/seccomp_bpf.c index 874f17763536..e13ffe18ef95 100644 --- a/tools/testing/selftests/seccomp/seccomp_bpf.c +++ b/tools/testing/selftests/seccomp/seccomp_bpf.c @@ -5172,7 +5172,8 @@ FIXTURE_SETUP(UPROBE) ASSERT_GE(bit, 0); }
- offset = get_uprobe_offset(variant->uretprobe ? probed_uretprobe : probed_uprobe);
- offset = get_uprobe_offset(variant->uretprobe ?
(const void *)probed_uretprobe : (const void *)probed_uprobe);if (variant->uretprobe)
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Jiri Olsa -
Nirbhay Sharma -
Sam James