From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 34140C43334 for ; Mon, 11 Jul 2022 09:12:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231340AbiGKJMk (ORCPT ); Mon, 11 Jul 2022 05:12:40 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46774 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231236AbiGKJLx (ORCPT ); Mon, 11 Jul 2022 05:11:53 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F188D252B6; Mon, 11 Jul 2022 02:09:16 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 0E5196118F; Mon, 11 Jul 2022 09:09:16 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 21033C36AE2; Mon, 11 Jul 2022 09:09:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1657530555; bh=p7Eab160yQGOQfojhbMWmzyaYKJ94lupJbD+g6sDDAk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ycWu1bgbpy4zfg6XvKumelQJpljnG6bcFLlYp9E67NNhpjpuAJ2eoLPjLLhGQXrJS lNXTISpYjA7KtRu1roMAKVdJxNj5w6t8zhR5qat/7PThTGsCivWD056MzIJ2SENRqg by0VDxR8B60dL4AZS0G+5x+bQkzmvenXs2KcAB/s= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Itay Iellin , Matthew Wilcox , Linus Torvalds Subject: [PATCH 4.19 27/31] ida: dont use BUG_ON() for debugging Date: Mon, 11 Jul 2022 11:07:06 +0200 Message-Id: <20220711090538.648147293@linuxfoundation.org> X-Mailer: git-send-email 2.37.0 In-Reply-To: <20220711090537.841305347@linuxfoundation.org> References: <20220711090537.841305347@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Linus Torvalds commit fc82bbf4dede758007763867d0282353c06d1121 upstream. This is another old BUG_ON() that just shouldn't exist (see also commit a382f8fee42c: "signal handling: don't use BUG_ON() for debugging"). In fact, as Matthew Wilcox points out, this condition shouldn't really even result in a warning, since a negative id allocation result is just a normal allocation failure: "I wonder if we should even warn here -- sure, the caller is trying to free something that wasn't allocated, but we don't warn for kfree(NULL)" and goes on to point out how that current error check is only causing people to unnecessarily do their own index range checking before freeing it. This was noted by Itay Iellin, because the bluetooth HCI socket cookie code does *not* do that range checking, and ends up just freeing the error case too, triggering the BUG_ON(). The HCI code requires CAP_NET_RAW, and seems to just result in an ugly splat, but there really is no reason to BUG_ON() here, and we have generally striven for allocation models where it's always ok to just do free(alloc()); even if the allocation were to fail for some random reason (usually obviously that "random" reason being some resource limit). Fixes: 88eca0207cf1 ("ida: simplified functions for id allocation") Reported-by: Itay Iellin Suggested-by: Matthew Wilcox Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- lib/idr.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) --- a/lib/idr.c +++ b/lib/idr.c @@ -573,7 +573,9 @@ void ida_free(struct ida *ida, unsigned { unsigned long flags; - BUG_ON((int)id < 0); + if ((int)id < 0) + return; + xa_lock_irqsave(&ida->ida_rt, flags); ida_remove(ida, id); xa_unlock_irqrestore(&ida->ida_rt, flags);