From patchwork Thu Apr 28 22:10:37 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dan Williams X-Patchwork-Id: 12831291 Received: from mga05.intel.com (mga05.intel.com [192.55.52.43]) (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 58FAE3D8D for ; Thu, 28 Apr 2022 22:10:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1651183838; x=1682719838; h=subject:from:to:cc:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=szNK7NyLKQ9MBHYyKQS30kvZW9aBafZ+FwCwnr+bNSM=; b=fXSPAJuogO+FRQ2k1q9ZerizsTDheMFPbYhT0SfY953TeB4Styii4T8r HY/MtqpJBg3OR6/f9yu/USppsiK2qkkqG8Z3rgkIVJL6B+y9jSjmX4pH+ WY/W1GIsIpf53EjRV/QkELYWog3gUQdhBrt7Ykm0nKbX7QnfxSEyuQJuE t14yxcsTPbEpfkx04XrmTJnRcjLjzY0B5G+a/AfTSbogdUqbfp+Bg8bRT TrVjjgiiPd+6qh8mYz1v27H76gFuTq/iUz2KeNOvsobnCafffYey7oDhz 0BuTMW2Db19YkhqZxYExyYIc2gLIgXEVYlJLTrk/0/qmLsfZXRTG2O3iR Q==; X-IronPort-AV: E=McAfee;i="6400,9594,10331"; a="352871328" X-IronPort-AV: E=Sophos;i="5.91,296,1647327600"; d="scan'208";a="352871328" Received: from fmsmga006.fm.intel.com ([10.253.24.20]) by fmsmga105.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 28 Apr 2022 15:10:37 -0700 X-IronPort-AV: E=Sophos;i="5.91,296,1647327600"; d="scan'208";a="808817336" Received: from dwillia2-desk3.jf.intel.com (HELO dwillia2-desk3.amr.corp.intel.com) ([10.54.39.25]) by fmsmga006-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 28 Apr 2022 15:10:37 -0700 Subject: [ndctl PATCH 07/10] cxl/memdev: Fix bus_invalidate() crash From: Dan Williams To: vishal.l.verma@intel.com Cc: linux-cxl@vger.kernel.org, nvdimm@lists.linux.dev Date: Thu, 28 Apr 2022 15:10:37 -0700 Message-ID: <165118383756.1676208.5717187278816036969.stgit@dwillia2-desk3.amr.corp.intel.com> In-Reply-To: <165118380037.1676208.7644295506592461996.stgit@dwillia2-desk3.amr.corp.intel.com> References: <165118380037.1676208.7644295506592461996.stgit@dwillia2-desk3.amr.corp.intel.com> User-Agent: StGit/0.18-3-g996c Precedence: bulk X-Mailing-List: nvdimm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 bus_invalidate() attempts to limit the invalidation of memdevs to a single bus scope. However, the ordering of bus_invalidate() leads to a use after free. Unconditionally invalidate memdevs (disconnect memdevs from their endpoints) and resotre on next lookup. Otherwise the following command results in the following backtrace with cxl_test: cxl disable-memdev 5,1 --force #2 0x00007ffff7fb97d4 in snprintf (__fmt=0x7ffff7fbc3ed "%s/driver", __n=98, __s=0x574d545619f7bae2 ) at /usr/include/bits/stdio2.h:71 #3 cxl_port_is_enabled (port=port@entry=0x422eb0) at ../cxl/lib/libcxl.c:1379 #4 0x00007ffff7fb99a9 in cxl_port_get_bus (port=0x422eb0) at ../cxl/lib/libcxl.c:1339 #5 0x00007ffff7fba3d0 in bus_invalidate (bus=bus@entry=0x421740) at ../cxl/lib/libcxl.c:549 #6 0x00007ffff7fba4e7 in cxl_memdev_disable_invalidate (memdev=0x416fd0) at ../cxl/lib/libcxl.c:596 #7 0x000000000040624e in memdev_action (argc=, argv=, ctx=0x4152a0, action=action@entry=0x406b70 , options=options@entry=0x40fca0 , usage=usage@entry=0x40f4b0 "cxl disable-memdev [..] []") at ../cxl/memdev.c:506 #8 0x0000000000406d57 in cmd_disable_memdev (argc=, argv=, Signed-off-by: Dan Williams --- cxl/lib/libcxl.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/cxl/lib/libcxl.c b/cxl/lib/libcxl.c index 0e8dd20e3c47..374b0f13905a 100644 --- a/cxl/lib/libcxl.c +++ b/cxl/lib/libcxl.c @@ -546,8 +546,7 @@ static void bus_invalidate(struct cxl_bus *bus) * indeterminate, delete them all and start over. */ cxl_memdev_foreach(ctx, memdev) - if (cxl_memdev_get_bus(memdev) == bus) - memdev->endpoint = NULL; + memdev->endpoint = NULL; bus_port = cxl_bus_get_port(bus); list_for_each_safe(&bus_port->child_ports, port, _p, list)