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 742643F9A13 for ; Wed, 5 Aug 2026 09:30:17 +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=1785922218; cv=none; b=D8aRVhc6vQ5aJzxm+e33e9VjcSLIELWDgMdtSeYlOPFpuXFNrFitqKwtTMvoiNVtel1EcVsWUPstpSr76ZygeNukyFyomhBO1uJ1dt4j/j9fra/uGvPAOj5eITwwuUnI45+msz/7BXdpkDSQaXPnf6p1zZfSB8mHfdxFH63e9GQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785922218; c=relaxed/simple; bh=ppb8jjpGhWwneikCpBymLQ15sTuC9ufsLQTe4BdfVAw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=qbaeOav0fjVJyoKe+CQTa5lAnXdcNTBtx+72/yRfn6YR+VBq1t2LUlzpFnmRH+jfWLdoR4PUhM2reSPVLZCbkaS1HQ2QQMfxlujMyVQdG9sSIK6N23eyHA52SuV/0A0wxxXdd2yTlM+qIcP50p0k9mOdauZlGDNmLfBs6gMUApQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=on7zVGaG; 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="on7zVGaG" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 315241F000E9; Wed, 5 Aug 2026 09:30:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1785922217; bh=KX5U7WvBdqmRrZENYfC1JP86DOg6FNWfh+tcB6gE36Y=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=on7zVGaG6wT/uQ1DaVzRKDNShchsXXJ5ARMxHqnX5VwvJ0s4aYs2pwrmZIWLNYOq3 hPljl4aznt3g2pJbQfaqo8HqDF5/Lx/X2dxDqzX8KLir7W5FbXW133JqtODZEamPmH Qwc6j90XzzCFPuHdcgiCQH3G+Ylg5wobbxKcAtBn5fwqoVuCMGeV0/9oh2nv40hB2Y 2EFzeDBDxXUuY4TWBDjMTKPqMVMC957FjCKRaOI6ycAH1QES/Pogl/VpTV7d3ReY3s xHop3acV4WstvlqJbkM11JaqaE+qEfjCbP1DAAoJX/zlStDCv3/w75QioPziDXb+ce hNgPVuxVFvUNA== From: Jiri Olsa To: Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko Cc: Sashiko , bpf@vger.kernel.org, Martin KaFai Lau , Eduard Zingerman , Song Liu , Yonghong Song , Quentin Monnet , Tao Chen , STAR Labs SG , Arnaud Lecomte Subject: [PATCHv4 bpf-next 09/12] bpf: Clear buf on error in __bpf_get_task_stack Date: Wed, 5 Aug 2026 11:28:40 +0200 Message-ID: <20260805092843.516315-10-jolsa@kernel.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260805092843.516315-1-jolsa@kernel.org> References: <20260805092843.516315-1-jolsa@kernel.org> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Both bpf_get_task_stack and bpf_get_task_stack_sleepable helpers that use __bpf_get_task_stack have buf defined as ARG_PTR_TO_UNINIT_MEM argument and we should initialize the buf on every return path. Adding missing buf memset for __bpf_get_task_stack fail paths. This provides deterministic buffer contents, which is useful when the buffer is used directly as a map key. Fixes: 06ab134ce8ec ("bpf: Refcount task stack in bpf_get_task_stack") Fixes: b992f01e6615 ("bpf: Guard against accessing NULL pt_regs in bpf_get_task_stack()") Reported-by: Sashiko Signed-off-by: Jiri Olsa --- kernel/bpf/stackmap.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/kernel/bpf/stackmap.c b/kernel/bpf/stackmap.c index b0e38e5b3738..eabeaef31b63 100644 --- a/kernel/bpf/stackmap.c +++ b/kernel/bpf/stackmap.c @@ -884,14 +884,17 @@ static long __bpf_get_task_stack(struct task_struct *task, void *buf, u32 size, struct pt_regs *regs; long res = -EINVAL; - if (!try_get_task_stack(task)) + if (!try_get_task_stack(task)) { + memset(buf, 0, size); return -EFAULT; + } regs = task_pt_regs(task); if (regs) res = __bpf_get_stack(regs, task, buf, size, flags, may_fault); + else + memset(buf, 0, size); put_task_stack(task); - return res; } -- 2.54.0