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 9AAEB3A9630 for ; Mon, 3 Aug 2026 21:03:26 +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=1785791007; cv=none; b=IdYXryxZyeLbWCyWoR9LBIhtJa/kXQDf+HHtep7UuZ0tCJUlIGRlyz4ERYh7flMfd8ZisZQsUd8KfNvmrRhtkB1R2lBCmZqgVmOuMGtOn22JXyEJCIKH+1QoJojOAJauzVLMxLHW6MHv8M2okkWnnTR6zPltSuyt0drMyBdN0Uw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785791007; c=relaxed/simple; bh=3/HXEW5FfBFOU0CwB6FI3HNf11roMOF05omVYMpQJRo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=ezJwMYb4lnUV9I2IpdAt0tMbIaZN+KU9/j0o5EnLihQPa/ZKHQKN6SajbKUFC2lgWZdlaymMMfc8/BU+WVo+0y67IfpjqHD6d9BT5TKek0F3XT3sG5aby6yeNcSW/JL+3AsrCKIKoG74zWVqDom1JEK225qFhRlqWM4KtTaYS5s= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Ki+RjhBD; 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="Ki+RjhBD" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 197731F000E9; Mon, 3 Aug 2026 21:03:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1785791006; bh=vwFteO0bAzPzPTUgHsGK+W5DSjT2vxaLnUi3yNa3j7w=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=Ki+RjhBDQ4t64iyKcffiL40WvljYivrsU+8ILNaoDY9IqSMu2DwkaZBbTOuZZo7vm pbDpI5xX1Rq7fkLKecXBunZaDUZui0442uDZRKuJEsPVCX/XmxjX0vo1DNgsfpvqi3 3JWB8O+UwudG+5pk4Uwp8uIz/GXPCxyMDA6gxWVE/MZKUCeLtzIga80HVg70GOj1Ww 6t2Iy6OUhgHUYQCxHTB602PGOgfrNQsbM0SluG5uRKq4hEVWWknA9O5tUeEkvsoFos d6wKn7ag/tkrNXEqTr/ZvP2DOlV7t+I9S2udePIm3tqM3nzMGO2hItTzSG6gzy09rZ rI92kJ6anNagQ== 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: [PATCHv3 bpf-next 09/12] bpf: Clear buf on error in __bpf_get_task_stack Date: Mon, 3 Aug 2026 23:01:46 +0200 Message-ID: <20260803210149.296496-10-jolsa@kernel.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260803210149.296496-1-jolsa@kernel.org> References: <20260803210149.296496-1-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 976c4e4c1af6..7f728d319a65 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