On Thu, Apr 21, 2022 at 9:53 AM Daniel Borkmann daniel@iogearbox.net wrote:
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.
Great, thanks Daniel!
https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git/commit/?id=...
Thanks, Daniel
Fixes: 1717e248014c ("selftests/bpf: Uprobe tests should verify param/return values") Signed-off-by: Artem Savkov asavkov@redhat.com
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);