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

[Vegard Nossum <vegard.nossum@xxxxxxxxxx>]

(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@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.
>
> 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@xxxxxxxxxxx

I've attached a properly formatted patch.

Thanks,


Vegard

>From a35302316c1c36e22b60d1644db0340558de695f Mon Sep 17 00:00:00 2001
From: Vegard Nossum <vegard.nossum@xxxxxxxxxx>
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@xxxxxxxxxx/
Link: https://lore.kernel.org/r/a1461e21-c744-767d-6dfc-6641fd3e3ce2@xxxxxxxxxxx
Debugged-by: Vlastimil Babka <vbabka@xxxxxxx>
Debugged-by: Kees Cook <keescook@xxxxxxxxxxxx>
Reported-by: Jan Kiszka <jan.kiszka@xxxxxxxxxxx>
Fixes: f79c8e4136eac37255ead8875593ae33a2c16d20 ("ACPICA: Namespace: simplify creation of the initial/default namespace")
Signed-off-by: Vegard Nossum <vegard.nossum@xxxxxxxxxx>
---
 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