From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=199.89.1.14 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1792432614; b=TY/TjmJy+Jk/bxDIv0j1PDOXAzT3EPC74WwlTdmlTN66Rog4UT048KFeXi0EI1CnTstG gCTO4AsSyLD7oUYJ4ZDvDYAAWwILu9+5DQ0Zp1wTtvTbZzfazXmEmi5ZprBUJoGNFr4KU lnh25lasEZKb0benfc3JR5f7OK0tA9f0/0ZbnDPCfkznAqx6aPJrruDgw4hNf7a8XEKxk fqKaIeGreCV5b5Zu0kNR4kvcc4zkMf6bVyqSvr3T4iI5CDskKo6kPS1nSltfv8T6Q9yrW gVcCINOeTdaCrzAXel/6zaJigPR5NK0EuGuCAhBYu3E2l/cpkU4Mmaxr4j9dwlTXwwA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1792432614; h=DMARC-Filter:Received:DKIM-Signature:X-Virus-Scanned:Received: Received:From:To:Cc:Subject:Date:Message-ID:X-Mailer:In-Reply-To: References:MIME-Version:Content-Transfer-Encoding; bh=TvtJs1ARGQT5I+pscgt24p7Y1pver8t2/3x3b7AFPJc=; b=xcEIl6TkR9tFhbTHd9zcLUBNj24jCjbZTkh4jwmD59rndmSY7mP7EZIRoDUF5x4Zdq8k ieVMhExVBwaLlSvgSyEVzvB2BlE0f0KJ47IdHpofz1O5M4ktAqY6bG4Cn8W+FdAaPXuYx 75n25ycgV/ROaxwbaZuNldL1s+JiLJcmLt5vhj8L4ues9iATDYKJjp1t9d3H7NMKyNa+0 PP6qsiteb/WvsbYUSA9SFXmU/pNKebvdAwYpjRA3cmcTBCP99mKZPnEp7SOyTwoN5ob8i YWXxw67YQCN44S0gYHt9qiHlnEI6+lfv0XR+cC4LTVaWPLky7uMpl7NwkzH0p2chzXQ== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=acm.org; spf=pass smtp.mailfrom=acm.org; dkim=pass header.d=acm.org header.i=@acm.org header.a=rsa-sha256 header.s=mr01 header.b=yoB+fPLp; arc=none smtp.remote-ip=199.89.1.14 Received: from 011.lax.mailroute.net (011.lax.mailroute.net [199.89.1.14]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5C73E606A31F for ; Mon, 19 Oct 2026 17:56:54 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 5C73E606A31F Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=acm.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=acm.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=acm.org header.i=@acm.org header.a=rsa-sha256 header.s=mr01 header.b=yoB+fPLp Received: from localhost (localhost [127.0.0.1]) by 011.lax.mailroute.net (Postfix) with ESMTP id 4j7jsq0lsVz1XM6J5; Mon, 19 Oct 2026 17:56:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=acm.org; h= content-transfer-encoding:mime-version:references:in-reply-to :x-mailer:message-id:date:date:subject:subject:from:from :received:received; s=mr01; t=1792432605; x=1795024606; bh=TvtJs 1ARGQT5I+pscgt24p7Y1pver8t2/3x3b7AFPJc=; b=yoB+fPLp08LFKuF/ABhQ6 PCc3rcHY4LZ5yxUK45UIOR2oEe2SO/V1M27Nk5FOrYM4M7xaHvyj+DU78W6iXZsW sipCq0/uM0bDpVGxHxwVrm9pt9kUKnjaNIKQWQrNNlMKgX83KWQj/GWrIucbJotJ vd0Lqlm/4AG9sSYOn39/t9ErtS8b5Q84oz2F5YDzPkYNMukOa8qNrYgYX2vpWKZ4 oeqeqQ/+NkW/Q58GwlmqlYf3g8bvmOQedJ6k8hnsw4eeAYtPzkAtF2ncdzmmqTSt nI1KPX8JxRXdX5cOnpx+fOKT06fWjoB3ytdWj/ABZb/NKvYFBClc3Ihb8awTm4qW w== X-Virus-Scanned: by MailRoute Received: from 011.lax.mailroute.net ([127.0.0.1]) by localhost (011.lax [127.0.0.1]) (mroute_mailscanner, port 10029) with LMTP id 7crdpGlrL-nh; Mon, 19 Oct 2026 17:56:45 +0000 (UTC) Received: from bvanassche.c.googlers.com.com (245.199.118.34.bc.googleusercontent.com [34.118.199.245]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: bvanassche@acm.org) by 011.lax.mailroute.net (Postfix) with ESMTPSA id 4j7jsl5Sy5z1XM4Tn; Mon, 19 Oct 2026 17:56:43 +0000 (UTC) From: Bart Van Assche To: linux-sparse@vger.kernel.org Cc: Bart Van Assche Subject: [PATCH 08/20] pre-process: Avoid zero-length VLAs for parameterless macros Date: Mon, 19 Oct 2026 10:56:21 -0700 Message-ID: <20261019175633.415493-9-bvanassche@acm.org> X-Mailer: git-send-email 2.56.0.212.g129ede20d9-goog In-Reply-To: <20261019175633.415493-1-bvanassche@acm.org> References: <20261019175633.415493-1-bvanassche@acm.org> X-Mailing-List: linux-sparse@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Ensure at least one element when declaring the variable-length args[] arrays in expand() and dump_macro() by using nargs ? nargs : 1 instead of nargs. Avoid undefined behavior in C from declaring zero-length variable-length arrays on the stack when expanding or dumping function-like macros define= d with an empty parameter list (nargs =3D=3D 0). Fixes: 669244d22464 ("[PATCH] lazy-copy macro expansion in pre-processing= ") Fixes: 9b4e30eb0baf ("teach sparse how to dump macro definitions") Signed-off-by: Bart Van Assche --- pre-process.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/pre-process.c b/pre-process.c index 4e322855d600..038e019b11c9 100644 --- a/pre-process.c +++ b/pre-process.c @@ -745,7 +745,7 @@ static int expand(struct token **list, struct symbol = *sym) struct token **tail; struct token *expansion =3D sym->expansion; int nargs =3D sym->arglist ? sym->arglist->count.normal : 0; - struct arg args[nargs]; + struct arg args[nargs ? nargs : 1]; =20 if (expanding->tainted) { token->pos.noexpand =3D 1; @@ -2285,7 +2285,7 @@ static int is_VA_ARGS_token(struct token *token) static void dump_macro(struct symbol *sym) { int nargs =3D sym->arglist ? sym->arglist->count.normal : 0; - struct token *args[nargs]; + struct token *args[nargs ? nargs : 1]; struct token *token; =20 printf("#define %s", show_ident(sym->ident));