From patchwork Thu Feb 22 20:40:54 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dan Williams X-Patchwork-Id: 774926 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 alsa0.perex.cz (alsa0.perex.cz [77.48.224.243]) (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 E71B1C48BF8 for ; Thu, 22 Feb 2024 20:42:02 +0000 (UTC) Received: from alsa1.perex.cz (alsa1.perex.cz [207.180.221.201]) (using TLSv1.2 with cipher ADH-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by alsa0.perex.cz (Postfix) with ESMTPS id 099D01DF; Thu, 22 Feb 2024 21:41:51 +0100 (CET) DKIM-Filter: OpenDKIM Filter v2.11.0 alsa0.perex.cz 099D01DF DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=alsa-project.org; s=default; t=1708634521; bh=VU7eFjyMMwj2wha596144IVFoZku7WK0IDQNMvyYawg=; h=Subject:From:To:Cc:Date:In-Reply-To:References:List-Id: List-Archive:List-Help:List-Owner:List-Post:List-Subscribe: List-Unsubscribe:From; b=aFZAZRf7TR5pJ32m8m1cbT40VUcmwPBmR+5stsM/TUJk9tcYIxZSFQwOkJ5aMoBaZ gqT1PsNEmgJjJXZkaIfNxHa5mYIvr+OamBYE9oxTYrpJ88ipHttiC4Ve143EZ+IYlA Wu0SqI+/Ejnf/9sDcV7wyP6pE90mKNAOzkWAXuvU= Received: by alsa1.perex.cz (Postfix, from userid 50401) id 7A73AF805D3; Thu, 22 Feb 2024 21:41:12 +0100 (CET) Received: from mailman-core.alsa-project.org (mailman-core.alsa-project.org [10.254.200.10]) by alsa1.perex.cz (Postfix) with ESMTP id B3852F805D5; Thu, 22 Feb 2024 21:41:11 +0100 (CET) Received: by alsa1.perex.cz (Postfix, from userid 50401) id 2F7F4F804B0; Thu, 22 Feb 2024 21:41:06 +0100 (CET) Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.9]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by alsa1.perex.cz (Postfix) with ESMTPS id 5DDC8F8047D for ; Thu, 22 Feb 2024 21:40:56 +0100 (CET) DKIM-Filter: OpenDKIM Filter v2.11.0 alsa1.perex.cz 5DDC8F8047D Authentication-Results: alsa1.perex.cz; dkim=pass (2048-bit key, unprotected) header.d=intel.com header.i=@intel.com header.a=rsa-sha256 header.s=Intel header.b=PqBj5cdl DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1708634458; x=1740170458; h=subject:from:to:cc:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=VU7eFjyMMwj2wha596144IVFoZku7WK0IDQNMvyYawg=; b=PqBj5cdlp4lBm/3rp4dyDNdEV24xrC6pK4m2vp5pMsqkmHBzUOASMip0 mtK1k/4yYlUCGQ3nTCdN1qQyqhrIRekqBD4saPCroiciTDpQaQ8KN04Pe 79u3dSaYmUX0n55osg3Bmq8FrrT/3XUZ7KRo3tEA3jdiMV9uEp8NZKPfv UaA5c5tJDFlndpP+ztzfbOndG92gMYrsaOP4RnElaC33i3/OGH8RkSP52 YDPgmF96ZFat/GQTFbyurjr0D4ONGaJddtLVBlYSNEeFHCiXcrdAPPzxp dOgZn2QZMD+A/hx7oOQhgNsoRu5JVKC8iLkmR0dSUycPhavUjtTHMqSfN w==; X-IronPort-AV: E=McAfee;i="6600,9927,10992"; a="25358650" X-IronPort-AV: E=Sophos;i="6.06,179,1705392000"; d="scan'208";a="25358650" Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by orvoesa101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 22 Feb 2024 12:40:56 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10992"; a="913585389" X-IronPort-AV: E=Sophos;i="6.06,179,1705392000"; d="scan'208";a="913585389" Received: from wyeh-mobl.amr.corp.intel.com (HELO dwillia2-xfh.jf.intel.com) ([10.209.77.87]) by fmsmga002-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 22 Feb 2024 12:40:55 -0800 Subject: [PATCH 1/3] sysfs: Fix crash on empty group attributes array From: Dan Williams To: gregkh@linuxfoundation.org Cc: Pierre-Louis Bossart , Marc Herbert , "Rafael J. Wysocki" , linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, linux-coco@lists.linux.dev, alsa-devel@alsa-project.org Date: Thu, 22 Feb 2024 12:40:54 -0800 Message-ID: <170863445442.1479840.1818801787239831650.stgit@dwillia2-xfh.jf.intel.com> In-Reply-To: <170863444851.1479840.10249410842428140526.stgit@dwillia2-xfh.jf.intel.com> References: <170863444851.1479840.10249410842428140526.stgit@dwillia2-xfh.jf.intel.com> User-Agent: StGit/0.18-3-g996c MIME-Version: 1.0 Message-ID-Hash: RVRBVNKKO2XANNJLF3XFOIN3J6VZFEUL X-Message-ID-Hash: RVRBVNKKO2XANNJLF3XFOIN3J6VZFEUL X-MailFrom: dan.j.williams@intel.com X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; emergency; loop; banned-address; member-moderation; header-match-alsa-devel.alsa-project.org-0; header-match-alsa-devel.alsa-project.org-1; nonmember-moderation; administrivia; implicit-dest; max-recipients; max-size; news-moderation; no-subject; digests; suspicious-header X-Mailman-Version: 3.3.9 Precedence: list List-Id: "Alsa-devel mailing list for ALSA developers - http://www.alsa-project.org" Archived-At: List-Archive: List-Help: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: It turns out that arch/x86/events/intel/core.c makes use of "empty" attributes. static struct attribute *empty_attrs; __init int intel_pmu_init(void) { struct attribute **extra_skl_attr = &empty_attrs; struct attribute **extra_attr = &empty_attrs; struct attribute **td_attr = &empty_attrs; struct attribute **mem_attr = &empty_attrs; struct attribute **tsx_attr = &empty_attrs; ... That breaks the assumption __first_visible() that expects that if grp->attrs is set then grp->attrs[0] must also be set and results in backtraces like: BUG: kernel NULL pointer dereference, address: 00rnel mode #PF: error_code(0x0000) - not-present ] PREEMPT SMP NOPTI CPU: 1 PID: 1 Comm: swapper/IP: 0010:exra_is_visible+0x14/0x20 ? exc_page_fault+0x68/0x190 internal_create_groups+0x42/0xa0 pmu_dev_alloc+0xc0/0xe0 perf_event_sysfs_init+0x580000000000 ]--- RIP: 0010:exra_is_visible+0x14/0 Check for non-empty attributes array before calling is_visible(). Reported-by: Pierre-Louis Bossart Closes: https://github.com/thesofproject/linux/pull/4799#issuecomment-1958537212 Fixes: 70317fd24b41 ("sysfs: Introduce a mechanism to hide static attribute_groups") Cc: Marc Herbert Cc: "Rafael J. Wysocki" Signed-off-by: Dan Williams --- fs/sysfs/group.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/fs/sysfs/group.c b/fs/sysfs/group.c index ccb275cdabcb..8c63ba3cfc47 100644 --- a/fs/sysfs/group.c +++ b/fs/sysfs/group.c @@ -33,10 +33,10 @@ static void remove_files(struct kernfs_node *parent, static umode_t __first_visible(const struct attribute_group *grp, struct kobject *kobj) { - if (grp->attrs && grp->is_visible) + if (grp->attrs && grp->attrs[0] && grp->is_visible) return grp->is_visible(kobj, grp->attrs[0], 0); - if (grp->bin_attrs && grp->is_bin_visible) + if (grp->bin_attrs && grp->bin_attrs[0] && grp->is_bin_visible) return grp->is_bin_visible(kobj, grp->bin_attrs[0], 0); return 0;