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linux-stable-mirror/tools/testing
Tengda Wu dcb5997ead selftests/bpf: Fix freplace_link segfault in tailcalls prog test
[ Upstream commit a63a631c9b ]

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: 021611d33e ("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.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-04-10 14:39:19 +02:00
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