Return-Path: Received: from mail-oi0-f43.google.com ([209.85.218.43]:34214 "EHLO mail-oi0-f43.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750763AbdHAFfr (ORCPT ); Tue, 1 Aug 2017 01:35:47 -0400 MIME-Version: 1.0 In-Reply-To: <20170731154322.tfzkukscda4fe7wm@codemonkey.org.uk> References: <20170714142543.k5xcbnb4mww3sxpy@codemonkey.org.uk> <20170716211530.sx7mn35f2mhmykug@codemonkey.org.uk> <1500245845.13893.3.camel@primarydata.com> <20170717030504.qca74wsswct26ytn@codemonkey.org.uk> <20170731154322.tfzkukscda4fe7wm@codemonkey.org.uk> From: Linus Torvalds Date: Mon, 31 Jul 2017 22:35:45 -0700 Message-ID: Subject: Re: [GIT PULL] Please pull NFS client changes for Linux 4.13 To: "davej@codemonkey.org.uk" , Linus Torvalds , Trond Myklebust , "linux-kernel@vger.kernel.org" , "bfields@fieldses.org" , "linux-nfs@vger.kernel.org" , "schumaker.anna@gmail.com" , "linux-fsdevel@vger.kernel.org" Content-Type: text/plain; charset="UTF-8" Sender: linux-nfs-owner@vger.kernel.org List-ID: On Mon, Jul 31, 2017 at 8:43 AM, davej@codemonkey.org.uk wrote: > Another NFSv4 KASAN splat, this time from rc3. > > BUG: KASAN: use-after-free in nfs4_exchange_id_done+0x3d7/0x8e0 [nfsv4] Ugh. It's really hard to tell what access that it - KASAN doesn't actually give enough information. There's lots of 8-byte accesses there in that function. Any chance of getting the output from ./scripts/faddr2line vmlinux nfs4_exchange_id_done+0x3d7/0x8e0 or something? That would be extremely useful in general for stacktraces, but it's doubly useful for KASAN because most *other* stacktraces tend to have a very limited number of things that can warn (ie there's one or two WARN_ON() calls in a function), but KASAN can have tens or hundreds.. Linus > Read of size 8 at addr ffff8804508af528 by task kworker/2:1/34 > > CPU: 2 PID: 34 Comm: kworker/2:1 Not tainted 4.13.0-rc3-think+ #1 > Workqueue: rpciod rpc_async_schedule [sunrpc] > Call Trace: > dump_stack+0x68/0xa1 > print_address_description+0xd9/0x270 > kasan_report+0x257/0x370 > ? nfs4_exchange_id_done+0x3d7/0x8e0 [nfsv4] > check_memory_region+0x13a/0x1a0 > __asan_loadN+0xf/0x20 > nfs4_exchange_id_done+0x3d7/0x8e0 [nfsv4] > ? nfs4_exchange_id_release+0xb0/0xb0 [nfsv4] > rpc_exit_task+0x69/0x110 [sunrpc] > ? rpc_destroy_wait_queue+0x20/0x20 [sunrpc] > ? rpc_destroy_wait_queue+0x20/0x20 [sunrpc] > __rpc_execute+0x1a0/0x840 [sunrpc] > ? rpc_wake_up_queued_task+0x50/0x50 [sunrpc] > ? __lock_is_held+0x9a/0x100 > ? debug_lockdep_rcu_enabled.part.16+0x1a/0x30 > rpc_async_schedule+0x12/0x20 [sunrpc] > process_one_work+0x4d5/0xa70 > ? flush_delayed_work+0x70/0x70 > ? lock_acquire+0xfc/0x220 > worker_thread+0x88/0x630 > ? pci_mmcfg_check_reserved+0xc0/0xc0 > kthread+0x1a6/0x1f0 > ? process_one_work+0xa70/0xa70 > ? kthread_create_on_node+0xc0/0xc0 > ret_from_fork+0x27/0x40 > > Allocated by task 1: > save_stack_trace+0x1b/0x20 > save_stack+0x46/0xd0 > kasan_kmalloc+0xad/0xe0 > kasan_slab_alloc+0x12/0x20 > kmem_cache_alloc+0xe0/0x2f0 > getname_flags+0x43/0x220 > getname+0x12/0x20 > do_sys_open+0x14c/0x2b0 > SyS_open+0x1e/0x20 > do_syscall_64+0xea/0x260 > return_from_SYSCALL_64+0x0/0x7a > > Freed by task 1: > save_stack_trace+0x1b/0x20 > save_stack+0x46/0xd0 > kasan_slab_free+0x72/0xc0 > kmem_cache_free+0xa8/0x300 > putname+0x80/0x90 > do_sys_open+0x22f/0x2b0 > SyS_open+0x1e/0x20 > do_syscall_64+0xea/0x260 > return_from_SYSCALL_64+0x0/0x7a > > The buggy address belongs to the object at ffff8804508aeac0\x0a which belongs to the cache names_cache of size 4096 > The buggy address is located 2664 bytes inside of\x0a 4096-byte region [ffff8804508aeac0, ffff8804508afac0) > The buggy address belongs to the page: > page:ffffea0011422a00 count:1 mapcount:0 mapping: (null) index:0x0 > [CONT START] compound_mapcount: 0 > flags: 0x8000000000008100(slab|head) > raw: 8000000000008100 0000000000000000 0000000000000000 0000000100070007 > raw: ffffea00113d6020 ffffea001136e220 ffff8804664f8040 0000000000000000 > page dumped because: kasan: bad access detected > > Memory state around the buggy address: > ffff8804508af400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ffff8804508af480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >>ffff8804508af500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ^ > ffff8804508af580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ffff8804508af600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ================================================================== >