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)
On Sun, Oct 26, 2025 at 02:42:33PM +0530, Nirbhay Sharma wrote:
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
Reviwed-by: Jiri Olsa jolsa@kernel.org
thanks, jirka
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
On 10/26/25 2:42 PM, Nirbhay Sharma wrote:
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);if (variant->uretprobe)
Hi all,
I'm following up on this patch that fixes the pointer type mismatch in UPROBE_setup when building with -fcf-protection. It resolves the incompatible-pointer-types error seen with Clang 19.
Please let me know if there are any comments or some changes needed.
Thanks, Nirbhay Sharma
On 11/25/25 04:20, Nirbhay Sharma wrote:
On 10/26/25 2:42 PM, Nirbhay Sharma wrote:
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)
Hi all,
I'm following up on this patch that fixes the pointer type mismatch in UPROBE_setup when building with -fcf-protection. It resolves the incompatible-pointer-types error seen with Clang 19.
Please let me know if there are any comments or some changes needed.
Hi Kees,
Is it okay to take this patch through my tree?
thanks, -- Shuah
linux-kselftest-mirror@lists.linaro.org
-
Jiri Olsa -
Nirbhay Sharma -
Sam James -
Shuah Khan