From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 3123115E8B; Mon, 30 Dec 2024 15:53:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1735574029; cv=none; b=cs7A/WGnt5V3xM6Ke14KkeftnK4dpz2qtCZEsDuSD2mzewJUGiY8MPirPLY3cQj5gupwX3Pr3hLZmeLFPk/35RbD/o8Yg57lgK5nSOKHvLLpfqDWh8nTXZ9oASvwKlAJyw1eg9Wk6NiMjCQU48Mw0d5q+vvBqutFn7aNoDmSW7E= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1735574029; c=relaxed/simple; bh=43P6t8il1B+TLzJCd4iD4h4wo5BE4FP3Uy6+PArnF40=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=o8SMADJjknPpWTB3G+OES+fLZIqq5xq5Bahx7WnI141p/ziXOgUsYRTbz8P4DFbFCII13jB0XBMx9pcOnQhJLc2ZvaIj5JBCmhyvgWlYXj0Zwh/PY9RS/LtnQlTDSRCHkT4x302WN5ghCrB9wLSEamXoY5sCVlHTkUFrvor3v48= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=VmzTPckY; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="VmzTPckY" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 921F8C4CED0; Mon, 30 Dec 2024 15:53:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1735574029; bh=43P6t8il1B+TLzJCd4iD4h4wo5BE4FP3Uy6+PArnF40=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=VmzTPckY2yMAC5jASQJ2+Bf7geiIcKpSVqg0SLKbfaL+VEFcQVBgV/DZjfHDgLrX6 vCVoXcjXbnjUR7eZOxodm8RHW0feTrrmK04Csr8MaGzYUA6mrVCh+rkSGgy3UyJzu2 rTmOj7FRn0+bzYrQyaTJuS6RwgExol+rdg4do+wM= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Andrea Righi , Andrii Nakryiko , Sasha Levin Subject: [PATCH 6.12 004/114] bpf: Fix bpf_get_smp_processor_id() on !CONFIG_SMP Date: Mon, 30 Dec 2024 16:42:01 +0100 Message-ID: <20241230154218.226125949@linuxfoundation.org> X-Mailer: git-send-email 2.47.1 In-Reply-To: <20241230154218.044787220@linuxfoundation.org> References: <20241230154218.044787220@linuxfoundation.org> User-Agent: quilt/0.68 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 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Andrea Righi [ Upstream commit 23579010cf0a12476e96a5f1acdf78a9c5843657 ] On x86-64 calling bpf_get_smp_processor_id() in a kernel with CONFIG_SMP disabled can trigger the following bug, as pcpu_hot is unavailable: [ 8.471774] BUG: unable to handle page fault for address: 00000000936a290c [ 8.471849] #PF: supervisor read access in kernel mode [ 8.471881] #PF: error_code(0x0000) - not-present page Fix by inlining a return 0 in the !CONFIG_SMP case. Fixes: 1ae6921009e5 ("bpf: inline bpf_get_smp_processor_id() helper") Signed-off-by: Andrea Righi Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20241217195813.622568-1-arighi@nvidia.com Signed-off-by: Sasha Levin --- kernel/bpf/verifier.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 4c486a0bfcc4..84d958f2c031 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -21085,11 +21085,15 @@ static int do_misc_fixups(struct bpf_verifier_env *env) * changed in some incompatible and hard to support * way, it's fine to back out this inlining logic */ +#ifdef CONFIG_SMP insn_buf[0] = BPF_MOV32_IMM(BPF_REG_0, (u32)(unsigned long)&pcpu_hot.cpu_number); insn_buf[1] = BPF_MOV64_PERCPU_REG(BPF_REG_0, BPF_REG_0); insn_buf[2] = BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_0, 0); cnt = 3; - +#else + insn_buf[0] = BPF_ALU32_REG(BPF_XOR, BPF_REG_0, BPF_REG_0); + cnt = 1; +#endif new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt); if (!new_prog) return -ENOMEM; -- 2.39.5