From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pg1-f193.google.com (mail-pg1-f193.google.com [209.85.215.193]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7D5FE226863 for ; Wed, 4 Mar 2026 07:09:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.215.193 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772608183; cv=none; b=jFEw+dbwZtIucB8f2i2lOBaYDFHwo3Q/hoYjy4t1EPSVeeET4L78fpOIQ/4ZbBwl3CckPmbQw5XzxmKtyE9lpGMAY26dup4yTtx/suPw2uTJN6P1uP/eYlrqXNInCwX83glEMjlx6dKuTsds+wuvjlOncnWBJJHFHHHNZWohbL8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772608183; c=relaxed/simple; bh=4d/pDtjsCeJbpYXYsN17tpsk+pR/bruOy5b6xlGmRdQ=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=bcw5b+1EH4OsmUr9ZD8Q2OqduNad09ke29ZktVMiwTEJ9ggKCsVjg8rDxK1DjAPkm/zx+xYFXuXo7N5ZdUWicyYTtkvBUOfsDOs0xQ9fdnhNjIwTmH3g7ZRuqEt3Y/yUIrt7Ko2gv5tBIz1v9bN8U5YTYpjlGLavnJNAcCE3REI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=gOonlHRw; arc=none smtp.client-ip=209.85.215.193 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="gOonlHRw" Received: by mail-pg1-f193.google.com with SMTP id 41be03b00d2f7-c648bc907ebso4107981a12.3 for ; Tue, 03 Mar 2026 23:09:41 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1772608181; x=1773212981; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=nQWG5MjkMMO6X/T7/5cytYtSTJXPfn5rr0LrLEyQ9mg=; b=gOonlHRwrIn5gvqocpEdfWpHl/04k8qEAuqw/klMPYhlaYghN1uqrhcWyWOKCavxPm 2FW4E4krr+gXnoka01bL/vGSOcrRK/t/PoQx4tats9Gt5GSLKg0GnuVe92ynsQy/GijF docCnkNxKBWRH5NyJqxx1MOeIJxjkUoHsOCvsehG4n04rfCirmqeMJEXAb2faqlRJ1u9 wK3Pxjy+bD9yCZGj7Z722ABQ6RECJ0Pvkkjml+MmFB0Thobr9L+9Smaf7QSqj7sSHO9C s09qP1unAzBxgxnBDYKVeCl8eJ4uL1ufX0eAdDt+v2C7zfr4xfCnLDYlwMWSo5u0livY V6YA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1772608181; x=1773212981; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-gg:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=nQWG5MjkMMO6X/T7/5cytYtSTJXPfn5rr0LrLEyQ9mg=; b=ulzK29wgdZ+/XXTwBFWNGwgPUkFNE4DLqSQMwmDuduo9AI+Xz57Bw4LZryDIuQcnL5 bfqDtXw3O/AIuTvDIChEt+CDrc1ObVTftUwo/S9Nr1OHptdedZ5ZRzKks3pAVcN/5iHM fJ7zkpqtWWYuJIkY/JH7Gn53TRoPROmvP2gK8+UJbgXBBoMsc+bgu94hSnQoXXLjULWl LYuI/5HfqEuEVGjsZrXbW6Lioy/dEI6klxjGZlOxhddr42qWCRnWZb4kcxdLwiovlof7 zgA7CCX4vUgNtItQneAnWpgbypswSRBsNJYHgFXMIzbcwFNhMO/yjKo0a+pqRSJhrhcj rhKw== X-Gm-Message-State: AOJu0Yyvnpmx1s9ncFqNv0f4wOvm+fE/cgfD+EqPY45/0cAY+xwCTGVY dWwYVuYwT4Zfa2qXBOgB2TOvdYtyW/Mmn+UHkzqNSTduZPzdi+W6xXG7 X-Gm-Gg: ATEYQzwkbymw6ZNi5b92Ul7zQRvSi2q0BspVwWbU87LkwHW+mFBa46xAfst1+qR9L6z evOtxVa7QVKaX8LHya/VD9fIUcb0TuIIfHrTilX/ESnSRB2EE9dJAjaDlu9b7ksqm3QQNNT73jU en8rwkVBsXgsWnBGnwZ6gQ7VvWZSlEkrv4F9UU73NRJIqUnjtYFcrsxjlIEqZbVBHN0zhC5+5oA E+xEcXeGZNxFM3+ww4xppu/gspL6FU5Ev95ddsjQSuaGy7t9C5JGKt8her2EFMiNwHyEEKHecF7 vXzQQLWv3E8lU4VksA85gm56zRVJNao+EJ1t8xJq1Rfl6qqr3+Gb3kvUV0VtUoLJmj0EhA87+TM /axl+oZq2XERsaB4mcgYKIdWBpmKwLdvjMAfy/sZ83vdOCZOa2fc324O2xD+49Aj5VwGAYJv4K5 zTuIt2nBfGXRVtvbD/hsGVBTUdRN1ZJ06q17RWs/1yIs4qsmOvmA== X-Received: by 2002:a17:902:d60f:b0:2ae:4bd5:a7f5 with SMTP id d9443c01a7336-2ae6ab6a1b3mr12636425ad.56.1772608180842; Tue, 03 Mar 2026 23:09:40 -0800 (PST) Received: from lima-ubuntu.hz.ali.com ([47.246.98.208]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-2adfb6b416bsm190980875ad.61.2026.03.03.23.09.35 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 03 Mar 2026 23:09:40 -0800 (PST) From: Qing Wang To: Alexei Starovoitov , Daniel Borkmann , John Fastabend , Andrii Nakryiko , Martin KaFai Lau , Eduard Zingerman , Song Liu , Yonghong Song , KP Singh , Stanislav Fomichev , Hao Luo , Jiri Olsa Cc: bpf@vger.kernel.org, linux-kernel@vger.kernel.org, Qing Wang , syzbot+b4c5ad098c821bf8d8bc@syzkaller.appspotmail.com Subject: [PATCH] bpf: Fix use-after-free in __bpf_trace_run() Date: Wed, 4 Mar 2026 15:09:27 +0800 Message-Id: <20260304070927.178464-1-wangqing7171@gmail.com> X-Mailer: git-send-email 2.34.1 Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit A use-after-free issue reported from syzbot exists in __bpf_trace_run(O). BUG: KASAN: slab-use-after-free in __bpf_trace_run kernel/trace/bpf_trace.c:2075 [inline] -> struct bpf_prog *prog = link->link.prog; The link(struct bpf_raw_tp_link) was freed when link->link.prog. The root cause is that: both bpf_raw_tp_link and tp_probes are RCU-managed, but there is no synchronization between their lifecycles. The link can be freed via call_rcu() before tp_probes is freed via call_srcu()/call_rcu_tasks_trace(), causing the link's lifetime to be shorter than tp_probes. This allows __bpf_trace_run() to access the freed link when a tracepoint fires. Fix by calling tracepoint_synchronize_unregister() to ensure tp_probes is freed before allowing the link to be freed. The issue was introduced by commit d4dfc5700e86 ("bpf: pass whole link instead of prog when triggering raw tracepoint"), which changed tracepoint callbacks to receive bpf_raw_tp_link pointers instead of bpf_prog pointers. Prior to this commit, this issue did not occur because the bpf_prog was directly used and protected by reference counting. Fixes: d4dfc5700e86 ("bpf: pass whole link instead of prog when triggering raw tracepoint") Reported-by: syzbot+b4c5ad098c821bf8d8bc@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=b4c5ad098c821bf8d8bc Tested-by: syzbot+b4c5ad098c821bf8d8bc@syzkaller.appspotmail.com Signed-off-by: Qing Wang --- kernel/bpf/syscall.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 0378e83b4099..fc93dd544162 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -3783,6 +3783,12 @@ static void bpf_raw_tp_link_release(struct bpf_link *link) bpf_probe_unregister(raw_tp->btp, raw_tp); bpf_put_raw_tracepoint(raw_tp->btp); + + /* + * Ensure tp_probes is freed before the link. This prevents + * use-after-free in __bpf_trace_run() when a tracepoint fires. + */ + tracepoint_synchronize_unregister(); } static void bpf_raw_tp_link_dealloc(struct bpf_link *link) -- 2.34.1