From mboxrd@z Thu Jan 1 00:00:00 1970 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 smtp.subspace.kernel.org (Postfix) with ESMTPS id 1BCDE7175E; Thu, 22 Feb 2024 20:40:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.175.65.9 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708634458; cv=none; b=FTENMGEmwlL1rPIopQn1PTFUkd7sVmJVqILozSiqyWJ6TwKqEUQlb7enUmgK7LoyRtooMCCOIeeafIEmS6uksBowY3U2QRCAE98HgIBCGI87G5g/PuxzABCb0GlzcGwQNW4DZ6WdPvgT9jB8pTtNYe4S4ebSfIYbA2fpmMCDaAg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708634458; c=relaxed/simple; bh=VU7eFjyMMwj2wha596144IVFoZku7WK0IDQNMvyYawg=; h=Subject:From:To:Cc:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=T7J3tYZWs2uhYQutGox9N3DTt6ychvozblzWoQK//oDU3+deByrK8pZSSP6Dqxir+3NYyEvgA5C/D8gBlPWc5/FV2xnTLcC05CUlUc8qtd+LAoSro8P+9DFC/TlUURbR9E0/wzT3KVZ2CmAcpfqpZxeLZZiGcMKLiCeLl3ebwKg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com; spf=pass smtp.mailfrom=intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=BJDRr7Pc; arc=none smtp.client-ip=198.175.65.9 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="BJDRr7Pc" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1708634456; x=1740170456; h=subject:from:to:cc:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=VU7eFjyMMwj2wha596144IVFoZku7WK0IDQNMvyYawg=; b=BJDRr7Pcb6cEA+VTqFzLFNR7BdtA+P3xs4ApFPZwR/HKMCMFlY/urv+B yW6c+riVRoDZjr3O3rYKR0jZKBpBPALr4Ou191q4KZ8TzGj0CrXud4hQr ICEq/T5FFRQEWS4O3nt4xjEeJ3vV5436IIW3O7JcmSlQCZUAclUIn3zt+ IFVWX/u9tqzgGE2Xt2Ju+mhK9muEM4CGTQxx0wWZl8ElL/jJelBzzsltt 2AALjZm+rC2rruixOQ5ODzed8hE7Bh0VRphJhPp899wTVCenhx/rNRgIX oQdWa1FHH10owNU9/uLUSe/63u9U4W+XGyalNU5CzYhFIMdU1xg5jm09w Q==; X-IronPort-AV: E=McAfee;i="6600,9927,10992"; a="25358647" X-IronPort-AV: E=Sophos;i="6.06,179,1705392000"; d="scan'208";a="25358647" 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 Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit 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;