From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from m16.mail.163.com (m16.mail.163.com [117.135.210.5]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C94A2415B8E; Wed, 23 Sep 2026 09:07:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=117.135.210.5 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790154457; cv=none; b=m2dOcS1kDjXXIuWYxzWTnkISSfWz5mi8aEmEW64yKSxFNC3qqOvlsdbRyU0UCBCzr+SLNh8MiDMFuII4DYRzbq7pumf/zAXojXZpoAu1gy/GmdvH9a/5xOXki4uANSZriLLrQlPvAVLQ6d79+CDq6SUzEGRDmpKFB5WU8rT+oTY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790154457; c=relaxed/simple; bh=HGgYm9qGLtOperaISr/aJq9Y9j4XNTtLD47q3ReqFbE=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=D6wHy99V8Ejx8gsFmzFQOIr9WVjj/R+phzSDA7F7SeT7oUP8rbtU82cB5p7XkgQbRutiGRax4ZkXIAVevoXW7pRsAGobfLmD1DJwfyBtV7q0Sgm6DjiuSadBFd7KNaHUKJ2syFLbLuuemzMa/QhAiVnXP8URJSQs1iOimNjy8tA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=163.com; spf=pass smtp.mailfrom=163.com; dkim=pass (1024-bit key) header.d=163.com header.i=@163.com header.b=AI0UpREB; arc=none smtp.client-ip=117.135.210.5 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=163.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=163.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=163.com header.i=@163.com header.b="AI0UpREB" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=163.com; s=s110527; h=From:To:Subject:Date:Message-ID:MIME-Version; bh=ek /Rk6bCy5QsmhvpMdt5/FZmTHXY1qQDmWgitxSiKiA=; b=AI0UpREBGtv5v4KDX7 L21bVbFv3k2mRyValzxbO7faltC0Y6YgWBjfYw4SwPPZr2pfN4i9XlGvWw3E7t2Z DeCUFo1+p6Ttpsn89duTtRqeHxyeNQ4lXJS4fGGKApi9KuAzMPEScC+O+pOQOQBg o7e5Pol8Z6MKrMsxGvpbN7smU= Received: from nec8-i7 (unknown []) by gzsmtp3 (Coremail) with SMTP id PigvCgDXvIWmlrNqQZffAw--.40141S2; Wed, 23 Sep 2026 17:06:46 +0800 (CST) From: chenyuan_fl@163.com To: bpf@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Alexei Starovoitov , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Eduard Zingerman , Kumar Kartikeya Dwivedi , Martin KaFai Lau , Song Liu , Yonghong Song , Jiri Olsa , Ihor Solodrai , Yuan Chen Subject: [PATCH bpf-next 0/2] bpf: Keep target extended until its last freplace link detaches Date: Wed, 23 Sep 2026 17:06:33 +0800 Message-ID: <20260923090635.368488-1-chenyuan_fl@163.com> X-Mailer: git-send-email 2.54.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CM-TRANSID:PigvCgDXvIWmlrNqQZffAw--.40141S2 X-Coremail-Antispam: 1Uf129KBjvJXoW7AF4rCrW7CF17Gr43CF43trb_yoW8Jw18pF WkXw15Jr48JFZ2qayfCw4UX34fua1kG3y5GryfWryrAas5KrW0gFWIgw1ayF98trsaqw1Y vF1vgr1kGw4xCrJanT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDUYxBIdaVFxhVjvjDU0xZFpf9x07j0jgxUUUUU= X-CM-SenderInfo: xfkh05pxdqswro6rljoofrz/xtbC5gZWFGqzlqZc-wAA3o From: Yuan Chen is_extended is a plain boolean, but one target prog can carry several freplace links at the same time, one on its entry and one on a global subprogram. __bpf_trampoline_unlink_prog() cleared it whenever *any* of them detached, so with two links on one target, detaching one of them re-armed the unbounded tail call loop closed by commit d6083f040d5d ("bpf: Prevent tailcall infinite loop caused by freplace"): a single BPF_PROG_TEST_RUN on the tail-called target then panics the kernel, reproduced on both bpf-next and master. Patch 1 replaces the boolean with a count of the freplace links attached to each target prog, so the target stays extended until its last link detaches. Patch 2 adds a selftest covering the sequence. Yuan Chen (2): bpf: Keep target extended until its last freplace link detaches selftests/bpf: Verify is_extended with multiple freplace links include/linux/bpf.h | 4 +- kernel/bpf/arraymap.c | 2 +- kernel/bpf/trampoline.c | 10 ++- .../selftests/bpf/prog_tests/tailcalls.c | 74 +++++++++++++++++++ .../bpf/progs/tailcall_freplace_multi.c | 27 +++++++ 5 files changed, 110 insertions(+), 7 deletions(-) create mode 100644 tools/testing/selftests/bpf/progs/tailcall_freplace_multi.c -- 2.54.0