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 B8CA4435A96; Tue, 21 Jul 2026 20:20:28 +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=1784665229; cv=none; b=frNCdkv3ULwyNYDpXy08eyOa03r+M/+sfvBOV9psluIyaYmlHMQtxaBywKI6mVjx1DKOgQAP+uOtFm/b2FJ/+eX7YZfd+20y1X6b4B5fRj66CQyDO68jKuIILRjhMx0iq0jkl19EOM3MTnkzy4z8K853ZmmLfYmxA4fPDYX6C9g= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784665229; c=relaxed/simple; bh=JIVpi8aKvn6LtWCdeobde7CmTwQKqAsYK/a7ULXwnok=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=FU7vx3CXwtCxM4hwYzbQLMrlh9cmGv8VYsrfvXwhgkRpNvSd0uuXgec5/ZG7zkfIGe7JwRSJbEr63OPPYpQIiu50poUblhWtn+ke3MgYXy+2nnAJHyWuh0brvTn/LM5KsGlg01QhePGMVbYDOup0Spn/rfhkM0ryOtKe8tL3/dI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=YS4k/xXg; 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="YS4k/xXg" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E77C51F000E9; Tue, 21 Jul 2026 20:20:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1784665228; bh=iYU5/FfVENadYBC47J7BjQXv7o+pX7REp4n8YYzziPk=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=YS4k/xXgXUaZGNRT87Rgv4yw4bggKHyKkcH+V0Hos6D1HBjYVSHD4HCl3gt329lL0 CKtEBd57nDgkZLeRIZ96AsNS331WaJt6ZxQLt0TkUW8SdW4wLHAGvjhuED4/TdHKu7 MNTvZ3xRQ9vc2BveIXH1JxfaLppsKMn0Uyv1uWog= 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 6.6 0223/1266] bpf: Restore sysctl new-value from 1 to 0 Date: Tue, 21 Jul 2026 17:11:00 +0200 Message-ID: <20260721152446.807593817@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260721152441.786066624@linuxfoundation.org> References: <20260721152441.786066624@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 6.6-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 @@ -1775,7 +1775,7 @@ 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;