From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Subject: Re: Kernel panic with 4.16-rc1 (and 4.16-rc2) running selftest To: Cong Wang Cc: Khalid Aziz , LKML , "netdev@vger.kernel.org" , Matthew Wilcox References: <7995f335-ccac-bfdc-bb37-46d0f887c647@oracle.com> From: Randy Dunlap Message-ID: <96bf4941-17c0-0796-292c-b66087f5f52e@infradead.org> Date: Fri, 23 Feb 2018 16:27:01 -0800 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: [add Matthew Wilcox; hopefully he can look/see] On 02/23/2018 04:13 PM, Cong Wang wrote: > On Fri, Feb 23, 2018 at 3:27 PM, Cong Wang wrote: >> On Fri, Feb 23, 2018 at 11:00 AM, Randy Dunlap wrote: >>> [adding netdev] >>> >>> On 02/23/2018 08:05 AM, Khalid Aziz wrote: >>>> I am seeing a kernel panic with 4.16-rc1 and 4.16-rc2 kernels when running selftests >>>> from tools/testing/selftests. Last messages from selftest before kernel panic are: >>>> >> ... >>>> Same selftest does not cause panic on 4.15. git bisect pointed to commit 6ce711f2750031d12cec91384ac5cfa0a485b60a ("idr: Make 1-based IDRs more efficient"). >>>> Kernel config is attached. >> >> Looks like something horribly wrong with u32 key id idr... > > Adding a few printk's, I got: > > [ 31.231560] requested handle = ffe00000 > [ 31.232426] allocated handle = 0 > ... > [ 31.246475] requested handle = ffd00000 > [ 31.247555] allocated handle = 1 > > > So the bug is here where we can't allocate a specific handle: > > err = idr_alloc_u32(&tp_c->handle_idr, ht, &handle, > handle, GFP_KERNEL); > if (err) { > kfree(ht); > return err; > } > -- ~Randy