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

[Rafael J. Wysocki]

On 6/11/2020 3:40 AM, Kaneda, Erik wrote:
> > -----Original Message-----
> > From: Vegard Nossum <vegard.nossum@xxxxxxxxxx>
> > Sent: Friday, June 5, 2020 7:45 AM
> > To: Vlastimil Babka <vbabka@xxxxxxx>; Rafael J. Wysocki
> > <rafael@xxxxxxxxxx>; Moore, Robert <robert.moore@xxxxxxxxx>; Kaneda,
> > Erik <erik.kaneda@xxxxxxxxx>
> > Cc: Kees Cook <keescook@xxxxxxxxxxxx>; Wysocki, Rafael J
> > <rafael.j.wysocki@xxxxxxxxx>; Christoph Lameter <cl@xxxxxxxxx>; Andrew
> > Morton <akpm@xxxxxxxxxxxxxxxxxxxx>; Marco Elver <elver@xxxxxxxxxx>;
> > Waiman Long <longman@xxxxxxxxxx>; LKML <linux-
> > kernel@xxxxxxxxxxxxxxx>; Linux MM <linux-mm@xxxxxxxxx>; ACPI Devel
> > Maling List <linux-acpi@xxxxxxxxxxxxxxx>; Len Brown <lenb@xxxxxxxxxx>;
> > Steven Rostedt <rostedt@xxxxxxxxxxx>
> > 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@xxxxxxxxxx> 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@xxxxxxxxx>
> > > > > 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@xxxxxxxxx>
> > > > >        Signed-off-by: Erik Schmauss <erik.schmauss@xxxxxxxxx>
> > > > >        Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
> > > > 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.

Cheers!