From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 2B5D345198D; Mon, 31 Aug 2026 13:34:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788183266; cv=none; b=Ug+8x9eS9R1am5cfkCMV4LU1/EzYHzm4+jMylnphi0VV9PKzJixQC+Toj+u+SkXIL+N6tQBywq9ld8K4+ZhrNs2sqbqlC9a+6IMleqCbgsN/m56/wLA3EsoAd96VaOtwlq0F0Wh3RmsRpFQXN8nxqlnjoooIq84FyRQdhym8JoQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788183266; c=relaxed/simple; bh=TLfYzGUIswu7v7i4IyLCKYCaudwZUkNJeYDprQrSV3I=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=bPC8O2/tS1V/5cg1eXFCw/HfhkuRuit8G5fjucagZlTjs3TW6oRP3HtcMA2mvuOv6vLj0eVmy38eoMYIPRgumIS3mlXDPNU/cOJP5dFiIy5DqjjMK8kJH5khQB/+Y+aixqNgyCruVCxgcCzO4XhrJijLe5jQUgvUIXIKAYhKaCI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=GEdX9lkb; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="GEdX9lkb" Received: by smtp.kernel.org (Postfix) with ESMTPSA id BBFED1F00A3D; Mon, 31 Aug 2026 13:34:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788183264; bh=XoRoi6gG2L4vd/lsErEQ4O/Q6peYNr+LJMWT8TDS2ks=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=GEdX9lkbk/1II8R6iEIsJbIgTgp/J5xXLedjM2cRo51i+5S7XdYsmYzIk8Ddkf863 EMo900ER4mOn4xZZMeFpkF4CoJzZL+w98BwzyhFW1Jze+3xk90xMggW5L6s29JzW9k RQmezr805+IV7OQ95dv04rnd25ozaMtpCPBhMMwvvPdJiVUcDNSnzFhnpeS4FfF6Sj WvMUhgk2nmDJe62YZxAI48Ghk+K6ABQnrXKRDyHn5Ck5y6uAJTRWbiMJguxAf36DFk nXsX8lNVZFMzF9pWKSLeI44ufY7Eg8AWUDlnUTIkYao0x6eCwfnoFMlsy0rUkyQdOv phEDsm4GXzJ8w== From: Sasha Levin To: patches@lists.linux.dev, stable@vger.kernel.org Cc: Daniel Borkmann , Alexei Starovoitov , Sasha Levin , andrii@kernel.org, eddyz87@gmail.com, memxor@gmail.com, bpf@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH AUTOSEL 6.18-5.15] libbpf: Also reset {insn,data}_cur on realloc failure Date: Mon, 31 Aug 2026 09:21:12 -0400 Message-ID: <20260831133314.4125787-44-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260831133314.4125787-1-sashal@kernel.org> References: <20260831133314.4125787-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 6.18.48 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Daniel Borkmann [ Upstream commit d2f7bd066ed492aeaf82864fbf1f06770f9d9f9d ] realloc_insn_buf() as well as realloc_data_buf() free and NULL gen->insn_start / gen->data_start on -ENOMEM but leave gen->insn_cur / gen->data_cur pointing into the old, freed buffer. Just reset the cursors to NULL alongside the base pointers so the freed state is coherent. Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/r/20260529094119.307264-3-daniel@iogearbox.net Signed-off-by: Alexei Starovoitov Signed-off-by: Sasha Levin --- LLM Generated explanations, may be completely bogus: The background search for the commit hash finished: `git log --grep` did not turn up **"libbpf: Also reset {insn,data}_cur on realloc failure"** in this 6.18.44 tree. The matches were unrelated "reset" commits in other subsystems, which fits — the fix is not applied here yet. The earlier analysis still holds: this is patch 3/3 of Daniel Borkmann’s gen_loader series; patches 2 (hash skip) and the endianness guard are already in this tree, but the root cursor-reset fix is missing. It’s a small, real userspace memory-safety fix on the OOM path and should be backported. **YES** tools/lib/bpf/gen_loader.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/tools/lib/bpf/gen_loader.c b/tools/lib/bpf/gen_loader.c index d41defa1936d3..4e2d25e024af4 100644 --- a/tools/lib/bpf/gen_loader.c +++ b/tools/lib/bpf/gen_loader.c @@ -63,6 +63,7 @@ static int realloc_insn_buf(struct bpf_gen *gen, __u32 size) gen->error = -ENOMEM; free(gen->insn_start); gen->insn_start = NULL; + gen->insn_cur = NULL; return -ENOMEM; } gen->insn_start = insn_start; @@ -86,6 +87,7 @@ static int realloc_data_buf(struct bpf_gen *gen, __u32 size) gen->error = -ENOMEM; free(gen->data_start); gen->data_start = NULL; + gen->data_cur = NULL; return -ENOMEM; } gen->data_start = data_start; -- 2.53.0