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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 73106CA0EFA for ; Mon, 25 Aug 2025 09:01:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Type: Content-Transfer-Encoding:MIME-Version:References:In-Reply-To:Message-ID:Date :Subject:CC:To:From:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=Tj8a6GPuOmdWC97QKAJpys6LnXM9wpEnatX8NPRY2Qw=; b=lzrgRGLDko1K6Cso7oqXli0BYr Z57sTusZLGh6X+LaWSTtPjMxC/bwhbzawuYkPO6556XtiwNiu5AlxafCKGyVlT7BwdKRSpjPmU3r7 8ifho7MwwvVvc3GYR32zxFYlrxE6Gja+BPS30CnMExsVUGaMhmaSc3htdYQkGjeCMIGPyiUYmFg60 QFkA1UR6t3vPoSlXjmZkF4NjIM+6Hzj8tZGooB05mNu5mjH4MQoKZUFp4GGL1TM6w7sgW/085Agb0 wGYv6GoEiNjkQ06vfIwLeQGhh6+9OXv+sxib4q9ooIPzqI1rlowxqXKaJamjnawcq0bGettq2QcMc BPtZQblg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1uqT4f-00000007QeM-1etk; Mon, 25 Aug 2025 09:01:09 +0000 Received: from mailgw02.mediatek.com ([216.200.240.185]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1uqSlj-00000007MJy-2ZvD; Mon, 25 Aug 2025 08:41:36 +0000 X-UUID: 4ca7b49a818f11f09eb0dd999d3936bf-20250825 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=mediatek.com; s=dk; h=Content-Type:Content-Transfer-Encoding:MIME-Version:References:In-Reply-To:Message-ID:Date:Subject:CC:To:From; bh=Tj8a6GPuOmdWC97QKAJpys6LnXM9wpEnatX8NPRY2Qw=; b=aZ3knCbI68NQGGZOMKsi5/62yK9Gogkbn9hXqdtYGeWKSuFDuv0J/ULiNlbWlUjy+svS3umeQz5FrTB2BZlGIj1T+Y0khjouZJw7d6AGX9HdZQXuyYXtyVmEx+ijF5nuNDhCMDdpAMcgGtBUzYHNa+eRwmjywXoUkaRQVsL7MOM=; X-CID-P-RULE: Release_Ham X-CID-O-INFO: VERSION:1.3.3,REQID:ff0ddc88-bffa-49fa-b630-e7fc5b96822a,IP:0,UR L:0,TC:0,Content:0,EDM:0,RT:0,SF:0,FILE:0,BULK:0,RULE:Release_Ham,ACTION:r elease,TS:0 X-CID-META: VersionHash:f1326cf,CLOUDID:06e97e7a-966c-41bd-96b5-7d0b3c22e782,B ulkID:nil,BulkQuantity:0,Recheck:0,SF:81|82|102,TC:-5,Content:0|15|50,EDM: -3,IP:nil,URL:0,File:nil,RT:nil,Bulk:nil,QS:nil,BEC:nil,COL:0,OSI:0,OSA:0, AV:0,LES:1,SPR:NO,DKR:0,DKP:0,BRR:0,BRE:0,ARC:0 X-CID-BVR: 3,DMD|SSN|SDN X-CID-BAS: 3,DMD|SSN|SDN,0,_ X-CID-FACTOR: TF_CID_SPAM_SNR X-CID-RHF: D41D8CD98F00B204E9800998ECF8427E X-UUID: 4ca7b49a818f11f09eb0dd999d3936bf-20250825 Received: from mtkmbs11n2.mediatek.inc [(172.21.101.187)] by mailgw02.mediatek.com (envelope-from ) (musrelay.mediatek.com ESMTP with TLSv1.2 ECDHE-RSA-AES256-GCM-SHA384 256/256) with ESMTP id 1798410570; Mon, 25 Aug 2025 01:41:31 -0700 Received: from mtkmbs13n1.mediatek.inc (172.21.101.193) by MTKMBS09N2.mediatek.inc (172.21.101.94) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1258.39; Mon, 25 Aug 2025 16:41:28 +0800 Received: from mbjsdccf07.gcn.mediatek.inc (10.15.20.246) by mtkmbs13n1.mediatek.inc (172.21.101.73) with Microsoft SMTP Server id 15.2.1258.39 via Frontend Transport; Mon, 25 Aug 2025 16:41:27 +0800 From: To: Arnd Bergmann , Greg Kroah-Hartman , Matthias Brugger , AngeloGioacchino Del Regno CC: , , Xion Wang , , , Subject: [PATCH 1/1] misc: Prevent double registration and deregistration of miscdevice Date: Mon, 25 Aug 2025 16:45:47 +0800 Message-ID: <20250825084556.10358-2-xion.wang@mediatek.com> X-Mailer: git-send-email 2.45.2 In-Reply-To: <20250825084556.10358-1-xion.wang@mediatek.com> References: <20250825084556.10358-1-xion.wang@mediatek.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250825_014135_661689_509AC32C X-CRM114-Status: GOOD ( 14.01 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org From: Xion Wang When repeated calls to misc_register() or misc_deregister() on the same miscdevice could lead to kernel crashes or misc_list corruption due to multiple INIT_LIST_HEAD or list_del operations on the same list node. This patch improves the robustness of the misc device driver by preventing both double registration and double deregistration of miscdevice instances. Signed-off-by: Xion Wang --- drivers/char/misc.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/drivers/char/misc.c b/drivers/char/misc.c index 558302a64dd9..2f8666312966 100644 --- a/drivers/char/misc.c +++ b/drivers/char/misc.c @@ -210,6 +210,9 @@ int misc_register(struct miscdevice *misc) int err = 0; bool is_dynamic = (misc->minor == MISC_DYNAMIC_MINOR); + if (WARN_ON(misc->this_device)) + return -EEXIST; + INIT_LIST_HEAD(&misc->list); mutex_lock(&misc_mtx); @@ -251,6 +254,7 @@ int misc_register(struct miscdevice *misc) misc->minor = MISC_DYNAMIC_MINOR; } err = PTR_ERR(misc->this_device); + misc->this_device = NULL; goto out; } @@ -275,12 +279,13 @@ EXPORT_SYMBOL(misc_register); void misc_deregister(struct miscdevice *misc) { - if (WARN_ON(list_empty(&misc->list))) + if (WARN_ON(!misc->this_device)) return; mutex_lock(&misc_mtx); list_del(&misc->list); device_destroy(&misc_class, MKDEV(MISC_MAJOR, misc->minor)); + misc->this_device = NULL; misc_minor_free(misc->minor); mutex_unlock(&misc_mtx); } -- 2.45.2