6.12-stable review patch. If anyone has any objections, please let me know.
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From: Tengda Wu wutengda@huaweicloud.com
[ Upstream commit a63a631c9b5cb25a1c17dd2cb18c63df91e978b1 ]
There are two bpf_link__destroy(freplace_link) calls in test_tailcall_bpf2bpf_freplace(). After the first bpf_link__destroy() is called, if the following bpf_map_{update,delete}_elem() throws an exception, it will jump to the "out" label and call bpf_link__destroy() again, causing double free and eventually leading to a segfault.
Fix it by directly resetting freplace_link to NULL after the first bpf_link__destroy() call.
Fixes: 021611d33e78 ("selftests/bpf: Add test to verify tailcall and freplace restrictions") Signed-off-by: Tengda Wu wutengda@huaweicloud.com Signed-off-by: Andrii Nakryiko andrii@kernel.org Reviewed-by: Leon Hwang leon.hwang@linux.dev Link: https://lore.kernel.org/bpf/20250122022838.1079157-1-wutengda@huaweicloud.co... Signed-off-by: Alexei Starovoitov ast@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- tools/testing/selftests/bpf/prog_tests/tailcalls.c | 1 + 1 file changed, 1 insertion(+)
diff --git a/tools/testing/selftests/bpf/prog_tests/tailcalls.c b/tools/testing/selftests/bpf/prog_tests/tailcalls.c index 40f22454cf05b..1f0977742741f 100644 --- a/tools/testing/selftests/bpf/prog_tests/tailcalls.c +++ b/tools/testing/selftests/bpf/prog_tests/tailcalls.c @@ -1599,6 +1599,7 @@ static void test_tailcall_bpf2bpf_freplace(void) goto out;
err = bpf_link__destroy(freplace_link); + freplace_link = NULL; if (!ASSERT_OK(err, "destroy link")) goto out;