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 296682FDC53; Thu, 16 Jul 2026 14:12:47 +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=1784211168; cv=none; b=dSSIT6Uf9jB/WYM40jjg7J1jFLWeFs5iGt0hCU4WlNEZ1Ph4tYD+eha/j9B5dbLD6FyrKmZTz6kLcljwEO7TN8ahX9G4OXwEd5WaZRVOahKp0ml7ATJzD2g6PBwLgFIaZVQUJzxJkvPa6/CNIm9v0zYmBevEyIji+5BR/JTZwAQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784211168; c=relaxed/simple; bh=pwZOQuhm8O7q1ap6HGPufeBCm/yg7zw9uTw3wSlTt2c=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=PJ+00SBcMRRxBnmFvEvn3FYQu8meL3Xha1T1K4Vd68TFm+bQwO92rTRG2D1azq0jTXoA4EIOdsDEcMmBBIc4C+H6V04s9OqWKPxfIRMyIu+Cra6jLgzgtqHNCCvXDaKBhoVzA7CD54pD/ko0lh7E3qenvVg3uqXQNUlmEEcQUeE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=HSboaBvD; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="HSboaBvD" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 97D321F000E9; Thu, 16 Jul 2026 14:12:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1784211167; bh=NuXPhibCv26cAorhqDNiewX79jC+rMJpKZjIRnIK1y4=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=HSboaBvDZldkL691xw+kv9zecPkYwEZJesAfSMzetV8EOPNafDmCVZawgqRnabJ7D rAxuPIGyTrKhdTKRQzEKIenALfRu6MkE30btrRYa9wmZ2fcsS20U9e0o6dtzYW8g36 NdNl0AUDJorvO69DMLK/9TrIZbE29K19VCukyU9s= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Yonghong Song , Zilin Guan , Dawei Feng , Jiayuan Chen , Xu Kuohai , Alexei Starovoitov Subject: [PATCH 6.18 281/480] bpf: Restore sysctl new-value from 1 to 0 Date: Thu, 16 Jul 2026 15:30:28 +0200 Message-ID: <20260716133050.906767479@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260716133044.672218725@linuxfoundation.org> References: <20260716133044.672218725@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Dawei Feng commit 2566c3b24219c5b30e35205cba029ff34ff7c78b upstream. Commit 4e63acdff864 ("bpf: Introduce bpf_sysctl_{get,set}_new_value helpers") changed the success return value to 0, but failed to update the corresponding check in __cgroup_bpf_run_filter_sysctl(). Since bpf_prog_run_array_cg() now returns 0 on success, the legacy ret == 1 condition is never satisfied. As a result, the modified value is ignored, and bpf_sysctl_set_new_value() fails to replace the write buffer. Fix this by checking for a return value of 0 instead, so cgroup/sysctl programs can correctly replace the pending sysctl buffer. This bug was discovered during a manual code review. Tested via a cgroup/sysctl BPF reproducer overriding writes to a target sysctl. Pre-fix, bpf_sysctl_set_new_value("foo") was silently ignored: the write returned 8192 and the value remained "600". Post-fix, the BPF replacement buffer properly propagates: the write returns 3 and the value updates to "foo". Fixes: f10d05966196 ("bpf: Make BPF_PROG_RUN_ARRAY return -err instead of allow boolean") Cc: stable@vger.kernel.org Acked-by: Yonghong Song Signed-off-by: Zilin Guan Signed-off-by: Dawei Feng Reviewed-by: Jiayuan Chen Acked-by: Xu Kuohai Link: https://lore.kernel.org/r/20260603105317.944304-4-dawei.feng@seu.edu.cn Signed-off-by: Alexei Starovoitov Signed-off-by: Greg Kroah-Hartman --- kernel/bpf/cgroup.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/kernel/bpf/cgroup.c +++ b/kernel/bpf/cgroup.c @@ -1939,7 +1939,7 @@ int __cgroup_bpf_run_filter_sysctl(struc kfree(ctx.cur_val); - if (ret == 1 && ctx.new_updated) { + if (!ret && ctx.new_updated) { kvfree(*buf); *buf = ctx.new_val; *pcount = ctx.new_len;