2020-08-14 15:41:13

by kernel test robot

[permalink] [raw]
Subject: [mm] 3e38e0aaca: WARNING:at_mm/memcontrol.c:#mem_cgroup_alloc

Greeting,

FYI, we noticed the following commit (built with gcc-9):

commit: 3e38e0aaca9eafb12b1c4b731d1c10975cbe7974 ("mm: memcg: charge memcg percpu memory to the parent cgroup")
https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git master


in testcase: boot

on test machine: qemu-system-x86_64 -enable-kvm -cpu SandyBridge -smp 2 -m 8G

caused below changes (please refer to attached dmesg/kmsg for entire log/backtrace):


+----------------------------------------------+------------+------------+
| | 772616b031 | 3e38e0aaca |
+----------------------------------------------+------------+------------+
| boot_successes | 8 | 0 |
| boot_failures | 0 | 8 |
| WARNING:at_mm/memcontrol.c:#mem_cgroup_alloc | 0 | 8 |
| RIP:mem_cgroup_alloc | 0 | 8 |
+----------------------------------------------+------------+------------+


If you fix the issue, kindly add following tag
Reported-by: kernel test robot <[email protected]>


[ 0.909061] WARNING: CPU: 0 PID: 0 at mm/memcontrol.c:5220 mem_cgroup_alloc+0x7b/0x3ab
[ 0.910723] Modules linked in:
[ 0.912248] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.8.0-12303-g3e38e0aaca9eaf #1
[ 0.914712] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014
[ 0.918717] RIP: 0010:mem_cgroup_alloc+0x7b/0x3ab
[ 0.922712] Code: 45 da 21 00 41 89 84 24 f0 00 00 00 48 63 e8 85 c0 0f 88 1f 03 00 00 65 48 8b 04 25 00 6d 01 00 48 83 b8 50 09 00 00 00 75 02 <0f> 0b ba c0 0c 40 00 be 08 00 00 00 bf d0 03 00 00 e8 5d 56 fb ff
[ 0.926712] RSP: 0000:ffffffff82603e70 EFLAGS: 00010246
[ 0.930710] RAX: ffffffff8261a840 RBX: 0000000000000000 RCX: 0000000000000001
[ 0.933118] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
[ 0.934718] RBP: 0000000000000001 R08: ffff88822a003240 R09: ffffffff82680fd0
[ 0.937040] R10: 0000000000000044 R11: 0000000000000228 R12: ffff88822a591000
[ 0.938715] R13: ffffffff8265f050 R14: 0000000000000003 R15: ffffffff82c7bf80
[ 0.942710] FS: 0000000000000000(0000) GS:ffff88823fc00000(0000) knlGS:0000000000000000
[ 0.946086] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 0.946712] CR2: ffff88823ffff000 CR3: 0000000002612000 CR4: 00000000000006b0
[ 0.950712] Call Trace:
[ 0.952116] mem_cgroup_css_alloc+0x38/0x3f1
[ 0.953761] cgroup_init_subsys+0x85/0x16e
[ 0.954741] cgroup_init+0x129/0x35e
[ 0.956370] start_kernel+0x4df/0x524
[ 0.959277] secondary_startup_64+0xb6/0xc0
[ 0.961087] ---[ end trace a57ed6e4912a6aef ]---


To reproduce:

# build kernel
cd linux
cp config-5.8.0-12303-g3e38e0aaca9eaf .config
make HOSTCC=gcc-9 CC=gcc-9 ARCH=x86_64 olddefconfig prepare modules_prepare bzImage

git clone https://github.com/intel/lkp-tests.git
cd lkp-tests
bin/lkp qemu -k <bzImage> job-script # job-script is attached in this email



Thanks,
lkp


Attachments:
(No filename) (3.07 kB)
config-5.8.0-12303-g3e38e0aaca9eaf (118.87 kB)
job-script (4.55 kB)
dmesg.xz (13.31 kB)
Download all attachments

2020-08-14 18:15:54

by Linus Torvalds

[permalink] [raw]
Subject: Re: [mm] 3e38e0aaca: WARNING:at_mm/memcontrol.c:#mem_cgroup_alloc

On Fri, Aug 14, 2020 at 7:14 AM kernel test robot <[email protected]> wrote:
>
> FYI, we noticed the following commit (built with gcc-9):
>
> commit: 3e38e0aaca9eafb12b1c4b731d1c10975cbe7974 ("mm: memcg: charge memcg percpu memory to the parent cgroup")
> https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git master
>
>
> in testcase: boot
>
> on test machine: qemu-system-x86_64 -enable-kvm -cpu SandyBridge -smp 2 -m 8G
>
> caused below changes (please refer to attached dmesg/kmsg for entire log/backtrace):

This should have already been fixed by commit 9f457179244a ("mm:
memcontrol: fix warning when allocating the root cgroup").

But I forget what the syntax is to report that to the kernel test
robot. Would it be possible for lkp automatically look for "Fixes:"
tags, perhaps?

Linus

2020-08-15 22:11:06

by Philip Li

[permalink] [raw]
Subject: Re: [LKP] Re: [mm] 3e38e0aaca: WARNING:at_mm/memcontrol.c:#mem_cgroup_alloc

On Fri, Aug 14, 2020 at 10:00:44AM -0700, Linus Torvalds wrote:
> On Fri, Aug 14, 2020 at 7:14 AM kernel test robot <[email protected]> wrote:
> >
> > FYI, we noticed the following commit (built with gcc-9):
> >
> > commit: 3e38e0aaca9eafb12b1c4b731d1c10975cbe7974 ("mm: memcg: charge memcg percpu memory to the parent cgroup")
> > https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git master
> >
> >
> > in testcase: boot
> >
> > on test machine: qemu-system-x86_64 -enable-kvm -cpu SandyBridge -smp 2 -m 8G
> >
> > caused below changes (please refer to attached dmesg/kmsg for entire log/backtrace):
>
> This should have already been fixed by commit 9f457179244a ("mm:
> memcontrol: fix warning when allocating the root cgroup").
Thanks Linus for this info, usually the test bot checks the head
of fbc's branch to validate the bisection. If the head fixes
the issue, the bot shall not send out such fbc report. We will
double check this bisection process to resolve any logical issue.

>
> But I forget what the syntax is to report that to the kernel test
> robot. Would it be possible for lkp automatically look for "Fixes:"
> tags, perhaps?
Got it, we will investigate this which should be quite helpful, e.g. if
we want to check whether an upstream commit had fixes in other
repo like linux-next.

Thanks

>
> Linus
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