On 4/21/22 3:23 PM, Artem Savkov wrote:
I am getting the following compilation error for prog_tests/uprobe_autoattach.c
tools/testing/selftests/bpf/prog_tests/uprobe_autoattach.c: In function ‘test_uprobe_autoattach’:
./test_progs.h:209:26: error: pointer ‘mem’ may be used after ‘free’ [-Werror=use-after-free]
mem variable is now used in one of the asserts so it shouldn't be freed right
away. Move free(mem) after the assert block.
Looks good, but I rephrased this a bit to avoid confusion. It's false positive given we
only compare the addresses but don't deref mem, which the compiler might not be able to
follow in this case.
https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git/commit/?id=6a12b8e20d7e72386594a9dbe7bf2d7fae3b3aa6
Thanks,
Daniel
Fixes: 1717e248014c ("selftests/bpf: Uprobe tests should verify param/return values")
Signed-off-by: Artem Savkov <asavkov@xxxxxxxxxx>
---
tools/testing/selftests/bpf/prog_tests/uprobe_autoattach.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/tools/testing/selftests/bpf/prog_tests/uprobe_autoattach.c b/tools/testing/selftests/bpf/prog_tests/uprobe_autoattach.c
index d6003dc8cc99..35b87c7ba5be 100644
--- a/tools/testing/selftests/bpf/prog_tests/uprobe_autoattach.c
+++ b/tools/testing/selftests/bpf/prog_tests/uprobe_autoattach.c
@@ -34,7 +34,6 @@ void test_uprobe_autoattach(void)
/* trigger & validate shared library u[ret]probes attached by name */
mem = malloc(malloc_sz);
- free(mem);
ASSERT_EQ(skel->bss->uprobe_byname_parm1, trigger_val, "check_uprobe_byname_parm1");
ASSERT_EQ(skel->bss->uprobe_byname_ran, 1, "check_uprobe_byname_ran");
@@ -44,6 +43,8 @@ void test_uprobe_autoattach(void)
ASSERT_EQ(skel->bss->uprobe_byname2_ran, 3, "check_uprobe_byname2_ran");
ASSERT_EQ(skel->bss->uretprobe_byname2_rc, mem, "check_uretprobe_byname2_rc");
ASSERT_EQ(skel->bss->uretprobe_byname2_ran, 4, "check_uretprobe_byname2_ran");
+
+ free(mem);
cleanup:
test_uprobe_autoattach__destroy(skel);
}
