linux-kernel - Re: [linus:master] [mm, slub] 0af8489b02: kernel_BUG_at

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Message-ID: <Y71t89JMgtRoNHM/@xsang-OptiPlex-9020>
Date:   Tue, 10 Jan 2023 21:53:55 +0800
From:   Oliver Sang <oliver.sang@...el.com>
To:     Vlastimil Babka <vbabka@...e.cz>
CC:     Hyeonggon Yoo <42.hyeyoo@...il.com>, <oe-lkp@...ts.linux.dev>,
        <lkp@...el.com>, Mike Rapoport <rppt@...ux.ibm.com>,
        Christoph Lameter <cl@...ux.com>,
        <linux-kernel@...r.kernel.org>, <linux-mm@...ck.org>,
        Matthew Wilcox <willy@...radead.org>
Subject: Re: [linus:master] [mm, slub] 0af8489b02:
 kernel_BUG_at_include/linux/mm.h

hi all,

On Mon, Jan 09, 2023 at 10:01:15PM +0800, Oliver Sang wrote:
> 
> On Fri, Jan 06, 2023 at 11:13:15AM +0100, Vlastimil Babka wrote:
> 
> > And if the rate at the parent (has it increased thanks to the
> > DEBUG_PAGEALLOC?) is sufficient to bisect to the truly first bad commit. Thanks!
> 
> got it. Thanks for suggestion!
> 
> since 0af8489b02 is based on v6.1-rc2, we will test (both rectorture and boot)
> with same config upon v6.1-rc2 to see if it's really clean there.
> if so we will use dmesg.invalid_opcode:#[##] to trigger new bisect.
> 
> will keep you updated. Thanks

by more tests, we cannot make sure the v6.1-rc2 is clean, so we also checked
v6.1-rc1 and v6.0. from results, we have low confidence that we can make a
successful bisection based on them [1][2]. could you suggest?

a further information not sure if it's helpful, [1][2] are both i386 based.
we also tried to run boot tests on x86_64 upon commit 0af8489b02, whatever
with or without CONFIG_DEBUG_PAGEALLOC/CONFIG_DEBUG_PAGEALLOC_ENABLE_DEFAULT,
we never obseve similar issues (also run 999 times).


[1]
boot results:
=========================================================================================
compiler/kconfig/rootfs/sleep/tbox_group/testcase:
  gcc-11/i386-randconfig-a012-20221226+CONFIG_DEBUG_PAGEALLOC+CONFIG_DEBUG_PAGEALLOC_ENABLE_DEFAULT/debian-11.1-i386-20220923.cgz/1/vm-snb/boot

            v6.0                    v6.1-rc1                    v6.1-rc2 56d5a2b9ba85a390473e86b4fe4 0af8489b0216fa1dd83e264bef8
---------------- --------------------------- --------------------------- --------------------------- ---------------------------
       fail:runs  %reproduction    fail:runs  %reproduction    fail:runs  %reproduction    fail:runs  %reproduction    fail:runs
           |             |             |             |             |             |             |             |             |
           :999          0%           2:999          0%           1:999          1%          11:999         21%         208:999   dmesg.invalid_opcode:#[##]
           :999          0%            :999          0%            :999          0%           2:999          5%          51:999   dmesg.kernel_BUG_at_include/linux/mm.h
           :999          0%           1:999          0%            :999          0%           4:999          4%          40:999   dmesg.kernel_BUG_at_include/linux/page-flags.h
           :999          0%           1:999          0%           1:999          0%           4:999         11%         111:999   dmesg.kernel_BUG_at_lib/list_debug.c
           :999          0%            :999          0%            :999          0%            :999          0%           2:999   dmesg.kernel_BUG_at_mm/page_alloc.c
           :999          0%            :999          0%            :999          0%           1:999          0%           3:999   dmesg.kernel_BUG_at_mm/usercopy.c

[2]
rcutorture results:
=========================================================================================
compiler/kconfig/rootfs/runtime/tbox_group/test/testcase/torture_type:
  gcc-11/i386-randconfig-a012-20221226+CONFIG_DEBUG_PAGEALLOC+CONFIG_DEBUG_PAGEALLOC_ENABLE_DEFAULT/debian-11.1-i386-20220923.cgz/300s/vm-snb/default/rcutorture/tasks-tracing

            v6.0                    v6.1-rc1                    v6.1-rc2 56d5a2b9ba85a390473e86b4fe4 0af8489b0216fa1dd83e264bef8
---------------- --------------------------- --------------------------- --------------------------- ---------------------------
       fail:runs  %reproduction    fail:runs  %reproduction    fail:runs  %reproduction    fail:runs  %reproduction    fail:runs
           |             |             |             |             |             |             |             |             |
           :999          0%           3:999          0%            :999          1%           8:998         20%         200:999   dmesg.invalid_opcode:#[##]
           :999          0%            :999          0%            :999          0%            :998          5%          51:999   dmesg.kernel_BUG_at_include/linux/mm.h
           :999          0%            :999          0%            :999          0%           3:998          4%          42:999   dmesg.kernel_BUG_at_include/linux/page-flags.h
           :999          0%           3:999          0%            :999          0%           4:998         10%         102:999   dmesg.kernel_BUG_at_lib/list_debug.c
           :999          0%            :999          0%            :999          0%            :998          0%           2:999   dmesg.kernel_BUG_at_mm/page_alloc.c
           :999          0%            :999          0%            :999          0%           1:998          0%           3:999   dmesg.kernel_BUG_at_mm/usercopy.c

> 
> > 
> >