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Message-ID: <536eca11-b4b9-c1a8-6e6b-fcd0c339a3ec@leemhuis.info>
Date:   Thu, 24 Mar 2022 12:49:07 +0100
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Subject: Re: PANIC: "Oops: 0000 [#1] PREEMPT SMP PTI" starting from 5.17 on
 dual socket Intel Xeon Gold servers
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To:     linux-kernel <linux-kernel@vger.kernel.org>,
        regressions@lists.linux.dev
References: <CAE4VaGDZr_4wzRn2___eDYRtmdPaGGJdzu_LCSkJYuY9BEO3cw@mail.gmail.com>
From:   Thorsten Leemhuis <regressions@leemhuis.info>
In-Reply-To: <CAE4VaGDZr_4wzRn2___eDYRtmdPaGGJdzu_LCSkJYuY9BEO3cw@mail.gmail.com>
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[TLDR: I'm adding the regression report below to regzbot, the Linux
kernel regression tracking bot; all text you find below is compiled from
a few templates paragraphs you might have encountered already already
from similar mails.]

Hi, this is your Linux kernel regression tracker. Top-posting for once,
to make this easily accessible to everyone.

To be sure below issue doesn't fall through the cracks unnoticed, I'm
adding it to regzbot, my Linux kernel regression tracking bot:

#regzbot ^introduced v5.16..v5.17
#regzbot ignore-activity

If it turns out this isn't a regression, free free to remove it from the
tracking by sending a reply to this thread containing a paragraph like
"#regzbot invalid: reason why this is invalid" (without the quotes).

Reminder for developers: when fixing the issue, please add a 'Link:'
tags pointing to the report (the mail quoted above) using
lore.kernel.org/r/, as explained in
'Documentation/process/submitting-patches.rst' and
'Documentation/process/5.Posting.rst'. Regzbot needs them to
automatically connect reports with fixes, but they are useful in
general, too.

I'm sending this to everyone that got the initial report, to make
everyone aware of the tracking. I also hope that messages like this
motivate people to directly get at least the regression mailing list and
ideally even regzbot involved when dealing with regressions, as messages
like this wouldn't be needed then. And don't worry, if I need to send
other mails regarding this regression only relevant for regzbot I'll
send them to the regressions lists only (with a tag in the subject so
people can filter them away). With a bit of luck no such messages will
be needed anyway.

Ciao, Thorsten (wearing his 'the Linux kernel's regression tracker' hat)

P.S.: As the Linux kernel's regression tracker I'm getting a lot of
reports on my table. I can only look briefly into most of them and lack
knowledge about most of the areas they concern. I thus unfortunately
will sometimes get things wrong or miss something important. I hope
that's not the case here; if you think it is, don't hesitate to tell me
in a public reply, it's in everyone's interest to set the public record
straight.


On 22.03.22 00:29, Jirka Hladky wrote:
> Starting from kernel 5.17 (tested with rc2, rc4, rc7, rc8) we
> experience kernel oops on Intel Xeon Gold dual-socket servers (2x Xeon
> Gold 6126 CPU)
> 
> Bellow is a backtrace and the dmesg log.
> 
> I have trouble creating a simple reproducer - it happens at random
> places when preparing the NAS benchmark to be run. The script creates
> a bunch of directories, compiles the benchmark a start trial runs.
> 
> Could you please help to narrow down the problem?
> 
> Reports bellow were created with kernel 5.17 rc8 and with
> echo 1 > /proc/sys/kernel/panic_on_oops
> setting.
> 
> crash> sys
>       KERNEL: /usr/lib/debug/lib/modules/5.17.0-0.rc8.123.fc37.x86_64/vmlinux
>     DUMPFILE: vmcore  [PARTIAL DUMP]
>         CPUS: 48
>         DATE: Thu Mar 17 02:49:40 CET 2022
>       UPTIME: 00:02:50
> LOAD AVERAGE: 0.32, 0.10, 0.03
>        TASKS: 608
>     NODENAME: gold-2s-c
>      RELEASE: 5.17.0-0.rc8.123.fc37.x86_64
>      VERSION: #1 SMP PREEMPT Mon Mar 14 18:11:49 UTC 2022
>      MACHINE: x86_64  (2600 Mhz)
>       MEMORY: 94.7 GB
>        PANIC: "Oops: 0000 [#1] PREEMPT SMP PTI" (check log for details)
> 
> 
> crash> bt
> PID: 2480   TASK: ffff9e8f76cb8000  CPU: 26  COMMAND: "umount"
> #0 [ffffae00cacbfbb8] machine_kexec at ffffffffbb068980
> #1 [ffffae00cacbfc08] __crash_kexec at ffffffffbb1a300a
> #2 [ffffae00cacbfcc8] crash_kexec at ffffffffbb1a4045
> #3 [ffffae00cacbfcd0] oops_end at ffffffffbb02c410
> #4 [ffffae00cacbfcf0] page_fault_oops at ffffffffbb076a38
> #5 [ffffae00cacbfd68] exc_page_fault at ffffffffbbd0b7c1
> #6 [ffffae00cacbfd90] asm_exc_page_fault at ffffffffbbe00ace
>    [exception RIP: kernfs_remove+7]
>    RIP: ffffffffbb421f67  RSP: ffffae00cacbfe48  RFLAGS: 00010246
>    RAX: 0000000000000001  RBX: ffffffffbce31e58  RCX: 0000000080200018
>    RDX: 0000000080200019  RSI: ffffdfbd44161640  RDI: 0000000000000000
>    RBP: ffffffffbce31e58   R8: 0000000000000000   R9: 0000000080200018
>    R10: ffff9e8f05859e80  R11: ffff9e9443b1bd98  R12: ffff9ea057f1d000
>    R13: ffffffffbce31e60  R14: dead000000000122  R15: dead000000000100
>    ORIG_RAX: ffffffffffffffff  CS: 0010  SS: 0018
> #7 [ffffae00cacbfe58] rdt_kill_sb at ffffffffbb05074b
> #8 [ffffae00cacbfea8] deactivate_locked_super at ffffffffbb36ce1f
> #9 [ffffae00cacbfec0] cleanup_mnt at ffffffffbb39176e
> #10 [ffffae00cacbfee8] task_work_run at ffffffffbb10703c
> #11 [ffffae00cacbff08] exit_to_user_mode_prepare at ffffffffbb17a399
> #12 [ffffae00cacbff28] syscall_exit_to_user_mode at ffffffffbbd0bde8
> #13 [ffffae00cacbff38] do_syscall_64 at ffffffffbbd071a6
> #14 [ffffae00cacbff50] entry_SYSCALL_64_after_hwframe at ffffffffbbe0007c
>    RIP: 00007f442c75126b  RSP: 00007ffc82d66fe8  RFLAGS: 00000202
>    RAX: 0000000000000000  RBX: 000055bd4cc37090  RCX: 00007f442c75126b
>    RDX: 0000000000000001  RSI: 0000000000000001  RDI: 000055bd4cc3b950
>    RBP: 000055bd4cc371a8   R8: 0000000000000000   R9: 0000000000000073
>    R10: 0000000000000000  R11: 0000000000000202  R12: 0000000000000001
>    R13: 000055bd4cc3b950  R14: 000055bd4cc372c0  R15: 000055bd4cc37090
>    ORIG_RAX: 00000000000000a6  CS: 0033  SS: 002b
> 
> [2] dmesg
> [  172.776553] BUG: kernel NULL pointer dereference, address: 0000000000000008
> [  172.783513] #PF: supervisor read access in kernel mode
> [  172.788652] #PF: error_code(0x0000) - not-present page
> [  172.793793] PGD 0 P4D 0
> [  172.796330] Oops: 0000 [#1] PREEMPT SMP PTI
> [  172.800519] CPU: 26 PID: 2480 Comm: umount Kdump: loaded Not
> tainted 5.17.0-0.rc8.123.fc37.x86_64 #1
> [  172.809645] Hardware name: Supermicro Super Server/X11DDW-L, BIOS
> 2.0b 03/07/2018
> [  172.817123] RIP: 0010:kernfs_remove+0x7/0x50
> [  172.821397] Code: e8 be e7 2c 00 48 89 df e8 b6 8c f0 ff 48 c7 c3
> f4 ff ff ff 48 89 d8 5b 5d 41 5c 41 5d 41 5e c3 cc 66 90 0f 1f 44 00
> 00 55 53 <48> 8b 47 08 48 89 fb 48 85 c0 48 0f 44 c7 48 8b 68 50 48 83
> c5 60
> [  172.840141] RSP: 0018:ffffae00cacbfe48 EFLAGS: 00010246
> [  172.845367] RAX: 0000000000000001 RBX: ffffffffbce31e58 RCX: 0000000080200018
> [  172.852501] RDX: 0000000080200019 RSI: ffffdfbd44161640 RDI: 0000000000000000
> [  172.859632] RBP: ffffffffbce31e58 R08: 0000000000000000 R09: 0000000080200018
> [  172.866764] R10: ffff9e8f05859e80 R11: ffff9e9443b1bd98 R12: ffff9ea057f1d000
> [  172.873899] R13: ffffffffbce31e60 R14: dead000000000122 R15: dead000000000100
> [  172.881033] FS:  00007f442c53c800(0000) GS:ffff9e9429000000(0000)
> knlGS:0000000000000000
> [  172.889117] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [  172.894861] CR2: 0000000000000008 CR3: 000000010ba96006 CR4: 00000000007706e0
> [  172.901997] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> [  172.909127] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> [  172.916261] PKRU: 55555554
> [  172.918974] Call Trace:
> [  172.921427]  <TASK>
> [  172.923533]  rdt_kill_sb+0x29b/0x350
> [  172.927112]  deactivate_locked_super+0x2f/0xa0
> [  172.931559]  cleanup_mnt+0xee/0x180
> [  172.935051]  task_work_run+0x5c/0x90
> [  172.938629]  exit_to_user_mode_prepare+0x229/0x230
> [  172.943424]  syscall_exit_to_user_mode+0x18/0x40
> [  172.948043]  do_syscall_64+0x46/0x80
> [  172.951623]  entry_SYSCALL_64_after_hwframe+0x44/0xae
> [  172.956675] RIP: 0033:0x7f442c75126b
> [  172.960271] Code: cb 1b 0e 00 f7 d8 64 89 01 48 83 c8 ff c3 90 f3
> 0f 1e fa 31 f6 e9 05 00 00 00 0f 1f 44 00 00 f3 0f 1e fa b8 a6 00 00
> 00 0f 05 <48> 3d 00 f0 ff ff 77 05 c3 0f 1f 40 00 48 8b 15 91 1b 0e 00
> f7 d8
> [  172.979017] RSP: 002b:00007ffc82d66fe8 EFLAGS: 00000202 ORIG_RAX:
> 00000000000000a6
> [  172.986584] RAX: 0000000000000000 RBX: 000055bd4cc37090 RCX: 00007f442c75126b
> [  172.993715] RDX: 0000000000000001 RSI: 0000000000000001 RDI: 000055bd4cc3b950
> [  173.000849] RBP: 000055bd4cc371a8 R08: 0000000000000000 R09: 0000000000000073
> [  173.007980] R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000001
> [  173.015115] R13: 000055bd4cc3b950 R14: 000055bd4cc372c0 R15: 000055bd4cc37090
> [  173.022249]  </TASK>
> [  173.024440] Modules linked in: rfkill intel_rapl_msr
> intel_rapl_common isst_if_common irdma skx_edac nfit libnvdimm ice
> x86_pkg_temp_thermal intel_powerclamp coretemp ib_uverbs iTCO_wdt
> intel_pmc_bxt ib_core iTCO_vendor_support kvm_
> intel ipmi_ssif kvm irqbypass rapl acpi_ipmi intel_cstate i40e joydev
> mei_me ioatdma i2c_i801 intel_uncore lpc_ich i2c_smbus mei
> intel_pch_thermal dca ipmi_si ipmi_devintf ipmi_msghandler acpi_pad
> acpi_power_meter fuse zram xfs crct10d
> if_pclmul ast crc32_pclmul crc32c_intel drm_vram_helper drm_ttm_helper
> ttm wmi ghash_clmulni_intel
> [  173.073900] CR2: 0000000000000008
> 

-- 
Additional information about regzbot:

If you want to know more about regzbot, check out its web-interface, the
getting start guide, and the references documentation:

https://linux-regtracking.leemhuis.info/regzbot/
https://gitlab.com/knurd42/regzbot/-/blob/main/docs/getting_started.md
https://gitlab.com/knurd42/regzbot/-/blob/main/docs/reference.md

The last two documents will explain how you can interact with regzbot
yourself if your want to.

Hint for reporters: when reporting a regression it's in your interest to
CC the regression list and tell regzbot about the issue, as that ensures
the regression makes it onto the radar of the Linux kernel's regression
tracker -- that's in your interest, as it ensures your report won't fall
through the cracks unnoticed.

Hint for developers: you normally don't need to care about regzbot once
it's involved. Fix the issue as you normally would, just remember to
include 'Link:' tag in the patch descriptions pointing to all reports
about the issue. This has been expected from developers even before
regzbot showed up for reasons explained in
'Documentation/process/submitting-patches.rst' and
'Documentation/process/5.Posting.rst'.