From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757004AbcEaJ2N (ORCPT ); Tue, 31 May 2016 05:28:13 -0400 Received: from mail-it0-f66.google.com ([209.85.214.66]:35679 "EHLO mail-it0-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756759AbcEaJ2H (ORCPT ); Tue, 31 May 2016 05:28:07 -0400 MIME-Version: 1.0 In-Reply-To: <20160530185616.GQ2527@techsingularity.net> References: <20160530155644.GP2527@techsingularity.net> <20160530185616.GQ2527@techsingularity.net> Date: Tue, 31 May 2016 11:28:05 +0200 X-Google-Sender-Auth: 6oXI9c4br3LvNfQpXxsMEUTrPPA Message-ID: Subject: Re: BUG: scheduling while atomic: cron/668/0x10c9a0c0 (was: Re: mm, page_alloc: avoid looking up the first zone in a zonelist twice) From: Geert Uytterhoeven To: Mel Gorman Cc: Andrew Morton , Linux Kernel Mailing List , Linux MM , linux-m68k Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Mel, On Mon, May 30, 2016 at 8:56 PM, Mel Gorman wrote: > Thanks. Please try the following instead > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > index bb320cde4d6d..557549c81083 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -3024,6 +3024,7 @@ get_page_from_freelist(gfp_t gfp_mask, unsigned int order, int alloc_flags, > apply_fair = false; > fair_skipped = false; > reset_alloc_batches(ac->preferred_zoneref->zone); > + z = ac->preferred_zoneref; > goto zonelist_scan; > } Thanks a lot, that seems to fix the issue!. Tested-by: Geert Uytterhoeven JFTR, without the fix, sometimes I get a different, but equally obscure, crash than the one I posted before: Kernel panic - not syncing: Aiee, killing interrupt handler! CPU: 0 PID: 668 Comm: cron Not tainted 4.7.0-rc1-atari-01184-g21f2f74eaf41989e #370 Stack from 00bf9be0: 00bf9be0 0031a075 000236d0 0000000f 007e9060 efcc5cd0 00bf800c 00bf9fcc 00000000 00000000 ffffffff 00bf9c18 00024cbe 00303d7f 0000000f 007e9060 efcc5cd0 007e9104 00bf9fcc 00bf9ea0 000061b2 00bf9cf8 efcc5d54 00bf9cf8 00000007 00000000 00000000 efcc5d50 00000000 00000000 00000000 00000000 00000000 00029efe 008fe870 008fe858 efcc5d50 008fe5d0 00029ee4 00bf9eb4 00000009 008fe858 008fe5d0 00355490 008fe5d0 0002a880 efcc5d50 007e9060 Call Trace: [<000236d0>] panic+0xae/0x23e [<00024cbe>] do_exit+0x8e/0x6e4 [<000061b2>] send_fault_sig+0x5a/0xb8 [<00029efe>] __dequeue_signal+0x1a/0xb2 [<00029ee4>] __dequeue_signal+0x0/0xb2 [<0002a880>] dequeue_signal+0xec/0xf6 [<0002538e>] do_group_exit+0x7a/0xa2 [<0002c084>] get_signal+0x19c/0x3d2 [<0002c280>] get_signal+0x398/0x3d2 [<00003648>] do_notify_resume+0x2e/0x786 [<00005654>] buserr_c+0x2d4/0x610 [<00034212>] search_exception_tables+0x1a/0x34 [<00005654>] buserr_c+0x2d4/0x610 [<00003db0>] handle_kernel_fault+0x10/0x58 [<00005654>] buserr_c+0x2d4/0x610 [<000061b2>] send_fault_sig+0x5a/0xb8 [<00046e3e>] update_rmtp+0x4e/0x68 [<00034212>] search_exception_tables+0x1a/0x34 [<00046e3e>] update_rmtp+0x4e/0x68 [<00003db0>] handle_kernel_fault+0x10/0x58 [<00046e3e>] update_rmtp+0x4e/0x68 [<000061b2>] send_fault_sig+0x5a/0xb8 [<000056b2>] buserr_c+0x332/0x610 [<0000c350>] dnrm_lp+0x162/0x17e [<00047276>] hrtimer_nanosleep+0xdc/0x128 [<00046e58>] hrtimer_wakeup+0x0/0x1e [<00010000>] stanh+0xd8/0x140 [<000029a0>] do_signal_return+0x10/0x1a [<00002924>] syscall+0x8/0xc [<0008c00b>] ___cache_free+0xcd/0x13e ---[ end Kernel panic - not syncing: Aiee, killing interrupt handler! Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds