Re: slub freelist issue / BUG: unable to handle page fault for address: 000000003ffe0018

Vegard Nossum
2021-03-23T18:59:47Z

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(trimmed CCs)

On 2021-03-23 19:32, Kirill A. Shutemov wrote:
> On Fri, Jun 12, 2020 at 02:26:58PM +0200, Rafael J. Wysocki wrote:
>> On 6/11/2020 3:40 AM, Kaneda, Erik wrote:
>>>
>>>> -----Original Message-----
>>>> From: Vegard Nossum <vegard.nossum@oracle.com>
>>>> Sent: Friday, June 5, 2020 7:45 AM
>>>> To: Vlastimil Babka <vbabka@suse.cz>; Rafael J. Wysocki
>>>> <rafael@kernel.org>; Moore, Robert <robert.moore@intel.com>; Kaneda,
>>>> Erik <erik.kaneda@intel.com>
>>>> Cc: Kees Cook <keescook@chromium.org>; Wysocki, Rafael J
>>>> <rafael.j.wysocki@intel.com>; Christoph Lameter <cl@linux.com>; Andrew
>>>> Morton <akpm@linux-foundation.org>; Marco Elver <elver@google.com>;
>>>> Waiman Long <longman@redhat.com>; LKML <linux-
>>>> kernel@vger.kernel.org>; Linux MM <linux-mm@kvack.org>; ACPI Devel
>>>> Maling List <linux-acpi@vger.kernel.org>; Len Brown <lenb@kernel.org>;
>>>> Steven Rostedt <rostedt@goodmis.org>
>>>> Subject: Re: slub freelist issue / BUG: unable to handle page fault for
>>>> address: 000000003ffe0018
>>>>
>>>> On 2020-06-05 16:08, Vlastimil Babka wrote:
>>>>> On 6/5/20 3:12 PM, Rafael J. Wysocki wrote:
>>>>>> On Fri, Jun 5, 2020 at 2:48 PM Vegard Nossum
>>>> <vegard.nossum@oracle.com> wrote:
>>>>>>> On 2020-06-05 11:36, Vegard Nossum wrote:
>>>>>>>> On 2020-06-05 11:11, Vlastimil Babka wrote:
>>>>>>>>> On 6/4/20 8:46 PM, Vlastimil Babka wrote:
>>>>>>>>>> On 6/4/20 7:57 PM, Kees Cook wrote:
>>>>>>>>>>> On Thu, Jun 04, 2020 at 07:20:18PM +0200, Vegard Nossum wrote:
>>>>>>>>>>>> On 2020-06-04 19:18, Vlastimil Babka wrote:
>>>>>>>>>>>>> On 6/4/20 7:14 PM, Vegard Nossum wrote:
>>>>>>>>>>>>>> Hi all,
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> I ran into a boot problem with latest linus/master
>>>>>>>>>>>>>> (6929f71e46bdddbf1c4d67c2728648176c67c555) that manifests
>>>> like this:
>>>>>>>>>>>>> Hi, what's the .config you use?
>>>>>>>>>>>> Pretty much x86_64 defconfig minus a few options (PCI, USB,
>>>>>>>>>>>> ...)
>>>>>>>>>>> Oh yes indeed. I immediately crash in the same way with this config.
>>>>>>>>>>> I'll
>>>>>>>>>>> start digging...
>>>>>>>>>>>
>>>>>>>>>>> (defconfig finishes boot)
>>>>>>>>>> This is funny, booting with slub_debug=F results in:
>>>>>>>>>> I'm not sure if it's ACPI or ftrace wrong here, but looks like
>>>>>>>>>> the changed free pointer offset merely exposes a bug in something
>>>>>>>>>> else.
>>>>>>>>> So, with Kees' patch reverted, booting with slub_debug=F (or even
>>>>>>>>> more specific slub_debug=F,ftrace_event_field) also hits this bug
>>>>>>>>> below. I wanted to bisect it, but v5.7 was also bad, and also
>>>>>>>>> v5.6. Didn't try further in history. So it's not new at all, and
>>>>>>>>> likely very specific to your config+QEMU? (and related to the ACPI
>>>>>>>>> error messages that precede it?).
>>>>>>>> I see it too, but not on v5.0. I can bisect it.
>>>>>>> commit 67a72420a326b45514deb3f212085fb2cd1595b5
>>>>>>> Author: Bob Moore <robert.moore@intel.com>
>>>>>>> Date: Fri Aug 16 14:43:21 2019 -0700
>>>>>>>
>>>>>>> ACPICA: Increase total number of possible Owner IDs
>>>>>>>
>>>>>>> ACPICA commit 1f1652dad88b9d767767bc1f7eb4f7d99e6b5324
>>>>>>>
>>>>>>> From 255 to 4095 possible IDs.
>>>>>>>
>>>>>>> Link: https://github.com/acpica/acpica/commit/1f1652da
>>>>>>> Reported-by: Hedi Berriche <hedi.berriche @hpe.com>
>>>>>>> Signed-off-by: Bob Moore <robert.moore@intel.com>
>>>>>>> Signed-off-by: Erik Schmauss <erik.schmauss@intel.com>
>>>>>>> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
>>>>>> Bob, Erik, did we miss something in that patch?
>>>>> Maybe the patch just changes layout in a way that exposes the bug.
>>>>>
>>>>> Anyway the "ftrace_event_field" cache is not really involved, this is
>>>>> just because of slab merging. After adding "slub_nomerge" to
>>>>> "slub_debug=F", it starts making more sense, as the cache becomes
>>>>> Acpi-Namespace
>>>>>
>>>>> [ 0.140408] ------------[ cut here ]------------
>>>>> [ 0.140837] cache_from_obj: Wrong slab cache. Acpi-Namespace but
>>>> object is from kmalloc-64
>>>>> [ 0.141406] WARNING: CPU: 0 PID: 1 at mm/slab.h:524
>>>> kmem_cache_free+0x1d3/0x250
>>>>> [ 0.142105] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.7.0+ #45
>>>>> [ 0.142393] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),
>>>> BIOS rel-1.13.0-0-gf21b5a4-rebuilt.opensuse.org 04/01/2014
>>>>> [ 0.142393] RIP: 0010:kmem_cache_free+0x1d3/0x250
>>>>> [ 0.142393] Code: 18 4d 85 ed 0f 84 10 ff ff ff 4c 39 ed 74 2f 49 8b 4d 58 48
>>>> 8b 55 58 48 c7 c6 10 47 a1 ac 48 c7 c7 00 c2 b0 ac e8 b1 cc eb ff <0f> 0b 48 89 de
>>>> 4c 89 ef e8 10 d7 ff ff 48 8b 15 59 36 9b 00 4c 89
>>>>> [ 0.142393] RSP: 0018:ffffb39cc0013dc0 EFLAGS: 00010282
>>>>> [ 0.142393] RAX: 0000000000000000 RBX: ffff937287409e00 RCX:
>>>> 0000000000000000
>>>>> [ 0.142393] RDX: 0000000000000001 RSI: 0000000000000092 RDI:
>>>> ffffffffacfdd32c
>>>>> [ 0.142393] RBP: ffff93728742ef00 R08: ffffb39cc0013c7d R09:
>>>> 00000000000000fc
>>>>> [ 0.142393] R10: ffffb39cc0013c78 R11: ffffb39cc0013c7d R12:
>>>> ffff937307409e00
>>>>> [ 0.142393] R13: ffff937287401d00 R14: 0000000000000000 R15:
>>>> 0000000000000000
>>>>> [ 0.142393] FS: 0000000000000000(0000) GS:ffff937287a00000(0000)
>>>> knlGS:0000000000000000
>>>>> [ 0.142393] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>>>>> [ 0.142393] CR2: 0000000000000000 CR3: 0000000003a0a000 CR4:
>>>> 00000000003406f0
>>>>> [ 0.142393] Call Trace:
>>>>> [ 0.142393] acpi_os_release_object+0x5/0x10
>>>>> [ 0.142393] acpi_ns_delete_children+0x46/0x59
>>>>> [ 0.142393] acpi_ns_delete_namespace_subtree+0x5c/0x79
>>>>> [ 0.142393] ? acpi_sleep_proc_init+0x1f/0x1f
>>>>> [ 0.142393] acpi_ns_terminate+0xc/0x31
>>>>> [ 0.142393] acpi_ut_subsystem_shutdown+0x45/0xa3
>>>>> [ 0.142393] ? acpi_sleep_proc_init+0x1f/0x1f
>>>>> [ 0.142393] acpi_terminate+0x5/0xf
>>>>> [ 0.142393] acpi_init+0x27b/0x308
>>>>> [ 0.142393] ? video_setup+0x79/0x79
>>>>> [ 0.142393] do_one_initcall+0x7b/0x160
>>>>> [ 0.142393] kernel_init_freeable+0x190/0x1f2
>>>>> [ 0.142393] ? rest_init+0x9a/0x9a
>>>>> [ 0.142393] kernel_init+0x5/0xf6
>>>>> [ 0.142393] ret_from_fork+0x22/0x30
>>>>> [ 0.142393] ---[ end trace 3539f236ef812ba1 ]---
>>>>> [ 0.142396] ------------[ cut here ]------------
>>>>>
>>>>> I've also changed the warning so it's not printed just once, and also
>>>>> prints tracking info (see the hunk at the end of my mail, I'll turn this to a
>>>> proper patch later).
>>>>> With "slub_debug=FU slub_nomerge" there are now multiple warnings,
>>>> but they all look the same:
>>>>> [ 0.143815] ------------[ cut here ]------------
>>>>> [ 0.144131] cache_from_obj: Wrong slab cache. Acpi-Namespace but
>>>> object is from kmalloc-64
>>>>> [ 0.144929] WARNING: CPU: 0 PID: 1 at mm/slab.h:524
>>>> kmem_cache_free+0x1d3/0x250
>>>>> [ 0.145129] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.7.0+ #45
>>>>> [ 0.145129] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),
>>>> BIOS rel-1.13.0-0-gf21b5a4-rebuilt.opensuse.org 04/01/2014
>>>>> [ 0.145129] RIP: 0010:kmem_cache_free+0x1d3/0x250
>>>>> [ 0.145129] Code: 18 4d 85 ed 0f 84 10 ff ff ff 4c 39 ed 74 2f 49 8b 4d 58 48
>>>> 8b 55 58 48 c7 c6 10 47 c1 8d 48 c7 c7 00 c2 d0 8d e8 b1 cc eb ff <0f> 0b 48 89 de
>>>> 4c 89 ef e8 10 d7 ff ff 48 8b 15 59 36 9b 00 4c 89
>>>>> [ 0.145129] RSP: 0018:ffff990b80013dc0 EFLAGS: 00010282
>>>>> [ 0.145129] RAX: 0000000000000000 RBX: ffff972d474ada80 RCX:
>>>> 0000000000000000
>>>>> [ 0.145129] RDX: 0000000000000001 RSI: 0000000000000092 RDI:
>>>> ffffffff8e1dd32c
>>>>> [ 0.145129] RBP: ffff972d47425680 R08: ffff990b80013c7d R09:
>>>> 00000000000000fc
>>>>> [ 0.145129] R10: ffff990b80013c78 R11: ffff990b80013c7d R12:
>>>> ffff972dc74ada80
>>>>> [ 0.145129] R13: ffff972d474038c0 R14: 0000000000000000 R15:
>>>> 0000000000000000
>>>>> [ 0.145129] FS: 0000000000000000(0000) GS:ffff972d47a00000(0000)
>>>> knlGS:0000000000000000
>>>>> [ 0.145129] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>>>>> [ 0.145129] CR2: 0000000000000000 CR3: 000000000660a000 CR4:
>>>> 00000000003406f0
>>>>> [ 0.145129] Call Trace:
>>>>> [ 0.145129] acpi_os_release_object+0x5/0x10
>>>>> [ 0.145129] acpi_ns_delete_children+0x46/0x59
>>>>> [ 0.145129] acpi_ns_delete_namespace_subtree+0x5c/0x79
>>>>> [ 0.145129] ? acpi_sleep_proc_init+0x1f/0x1f
>>>>> [ 0.145129] acpi_ns_terminate+0xc/0x31
>>>>> [ 0.145129] acpi_ut_subsystem_shutdown+0x45/0xa3
>>>>> [ 0.145129] ? acpi_sleep_proc_init+0x1f/0x1f
>>>>> [ 0.145129] acpi_terminate+0x5/0xf
>>>>> [ 0.145129] acpi_init+0x27b/0x308
>>>>> [ 0.145129] ? video_setup+0x79/0x79
>>>>> [ 0.145129] do_one_initcall+0x7b/0x160
>>>>> [ 0.145129] kernel_init_freeable+0x190/0x1f2
>>>>> [ 0.145129] ? rest_init+0x9a/0x9a
>>>>> [ 0.145129] kernel_init+0x5/0xf6
>>>>> [ 0.145129] ret_from_fork+0x22/0x30
>>>>> [ 0.145129] ---[ end trace 574554fca7bd06bb ]---
>>>>> [ 0.145133] INFO: Allocated in acpi_ns_root_initialize+0xb6/0x2d1 age=58
>>>> cpu=0 pid=0
>>>>> [ 0.145881] kmem_cache_alloc_trace+0x1a9/0x1c0
>>>>> [ 0.146132] acpi_ns_root_initialize+0xb6/0x2d1
>>>>> [ 0.146578] acpi_initialize_subsystem+0x65/0xa8
>>>>> [ 0.147024] acpi_early_init+0x5d/0xd1
>>>>> [ 0.147132] start_kernel+0x45b/0x518
>>>>> [ 0.147491] secondary_startup_64+0xb6/0xc0
>>>>> [ 0.147897] ------------[ cut here ]------------
>>>>>
>>>>> And it seems ACPI is allocating an object via kmalloc() and then
>>>>> freeing it via kmem_cache_free(<"Acpi-Namespace" kmem_cache>) which
>>>> is wrong.
>>>>>> ./scripts/faddr2line vmlinux 'acpi_ns_root_initialize+0xb6'
>>>>> acpi_ns_root_initialize+0xb6/0x2d1:
>>>>> kmalloc at include/linux/slab.h:555
>>>>> (inlined by) kzalloc at include/linux/slab.h:669 (inlined by)
>>>>> acpi_os_allocate_zeroed at include/acpi/platform/aclinuxex.h:57
>>>>> (inlined by) acpi_ns_root_initialize at
>>>>> drivers/acpi/acpica/nsaccess.c:102
>>>>>
>>> Hi Vegard,
>>>
>>>> That's it :-) This fixes it for me:
>>> We'll take this patch for ACPICA and it will be in the next release.
>>>
>>> Rafael, do you want to take this as a part of the next rc?
>>
>> Yes, I do.
>
> Folks, what happened to the patch? I don't see it in current upstream.
>
> Looks like it got reported again:
>
> https://lore.kernel.org/r/a1461e21-c744-767d-6dfc-6641fd3e3ce2@siemens.com
>

I've attached a properly formatted patch.

Thanks,

Vegard

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From a35302316c1c36e22b60d1644db0340558de695f Mon Sep 17 00:00:00 2001
From: Vegard Nossum <vegard.nossum@oracle.com>
Date: Mon, 8 Jun 2020 09:57:51 +0200
Subject: [PATCH] ACPICA: Always create namespace nodes using
acpi_ns_create_node()

ACPI is allocating an object using kmalloc(), but then frees it
using kmem_cache_free(<"Acpi-Namespace" kmem_cache>).

This is wrong and can lead to boot failures manifesting like this:

hpet0: 3 comparators, 64-bit 100.000000 MHz counter
clocksource: Switched to clocksource tsc-early
BUG: unable to handle page fault for address: 000000003ffe0018
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 0 P4D 0
Oops: 0000 [#1] SMP PTI
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.6.0+ #211
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014
RIP: 0010:kmem_cache_alloc+0x70/0x1d0
Code: 00 00 4c 8b 45 00 65 49 8b 50 08 65 4c 03 05 6f cc e7 7e 4d 8b 20 4d 85 e4 0f 84 3d 01 00 00 8b 45 20 48 8b 7d 00 48 8d 4a 01 <49> 8b 1c 04 4c 89 e0 65 48 0f c7 0f 0f 94 c0 84 c0 74 c5 8b 45 20
RSP: 0000:ffffc90000013df8 EFLAGS: 00010206
RAX: 0000000000000018 RBX: ffffffff81c49200 RCX: 0000000000000002
RDX: 0000000000000001 RSI: 0000000000000dc0 RDI: 000000000002b300
RBP: ffff88803e403d00 R08: ffff88803ec2b300 R09: 0000000000000001
R10: 0000000000000dc0 R11: 0000000000000006 R12: 000000003ffe0000
R13: ffffffff8110a583 R14: 0000000000000dc0 R15: ffffffff81c49a80
FS: 0000000000000000(0000) GS:ffff88803ec00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000003ffe0018 CR3: 0000000001c0a001 CR4: 00000000003606f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
__trace_define_field+0x33/0xa0
event_trace_init+0xeb/0x2b4
tracer_init_tracefs+0x60/0x195
? register_tracer+0x1e7/0x1e7
do_one_initcall+0x74/0x160
kernel_init_freeable+0x190/0x1f0
? rest_init+0x9a/0x9a
kernel_init+0x5/0xf6
ret_from_fork+0x35/0x40
CR2: 000000003ffe0018
---[ end trace 707efa023f2ee960 ]---
RIP: 0010:kmem_cache_alloc+0x70/0x1d0

Bisection leads to unrelated changes in slab; Vlastimil Babka
suggests an unrelated layout or slab merge change merely exposed
the underlying bug.

Link: https://lore.kernel.org/lkml/4dc93ff8-f86e-f4c9-ebeb-6d3153a78d03@oracle.com/
Link: https://lore.kernel.org/r/a1461e21-c744-767d-6dfc-6641fd3e3ce2@siemens.com
Debugged-by: Vlastimil Babka <vbabka@suse.cz>
Debugged-by: Kees Cook <keescook@chromium.org>
Reported-by: Jan Kiszka <jan.kiszka@siemens.com>
Fixes: f79c8e4136eac37255ead8875593ae33a2c16d20 ("ACPICA: Namespace: simplify creation of the initial/default namespace")
Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
---
drivers/acpi/acpica/nsaccess.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/drivers/acpi/acpica/nsaccess.c b/drivers/acpi/acpica/nsaccess.c
index 3f045b5953b2e..1be9b34732ab8 100644
--- a/drivers/acpi/acpica/nsaccess.c
+++ b/drivers/acpi/acpica/nsaccess.c
@@ -98,14 +98,12 @@ acpi_status acpi_ns_root_initialize(void)
* predefined names are at the root level. It is much easier to
* just create and link the new node(s) here.
*/
- new_node =
- ACPI_ALLOCATE_ZEROED(sizeof(struct acpi_namespace_node));
+ new_node = acpi_ns_create_node(*ACPI_CAST_PTR (u32, init_val->name));
if (!new_node) {
status = AE_NO_MEMORY;
goto unlock_and_exit;
}

- ACPI_COPY_NAMESEG(new_node->name.ascii, init_val->name);
new_node->descriptor_type = ACPI_DESC_TYPE_NAMED;
new_node->type = init_val->type;

--
2.16.1.72.g5be1f00a9.dirty