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From:   Jirka Hladky <jhladky@redhat.com>
Date:   Thu, 31 Mar 2022 00:16:23 +0200
Message-ID: <CAE4VaGBZk2NL6Tn2fGxmGMR-n8KFNqgPOktY_sQ1vjViLDNhhg@mail.gmail.com>
Subject: Re: PANIC: "Oops: 0000 [#1] PREEMPT SMP PTI" starting from 5.17 on
 dual socket Intel Xeon Gold servers
To:     Thorsten Leemhuis <regressions@leemhuis.info>
Cc:     linux-kernel <linux-kernel@vger.kernel.org>,
        regressions@lists.linux.dev
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

Hi Thorsten,

thanks for adding this to the regzbot bot.

Hi Greg and all,

I did bisecting and I have found the commit causing this issue [1].
Could you please have a look at the code how to fix it?

Thanks a lot
Jirka

[1]
=========================================================
$ git bisect visualize
commit 393c3714081a53795bbff0e985d24146def6f57f (refs/bisect/bad)
Author: Minchan Kim <minchan@kernel.org>
Date:   Thu Nov 18 15:00:08 2021 -0800

   kernfs: switch global kernfs_rwsem lock to per-fs lock

   The kernfs implementation has big lock granularity(kernfs_rwsem) so
   every kernfs-based(e.g., sysfs, cgroup) fs are able to compete the
   lock. It makes trouble for some cases to wait the global lock
   for a long time even though they are totally independent contexts
   each other.

   A general example is process A goes under direct reclaim with holding
   the lock when it accessed the file in sysfs and process B is waiting
   the lock with exclusive mode and then process C is waiting the lock
   until process B could finish the job after it gets the lock from
   process A.

   This patch switches the global kernfs_rwsem to per-fs lock, which
   put the rwsem into kernfs_root.

   Suggested-by: Tejun Heo <tj@kernel.org>
   Acked-by: Tejun Heo <tj@kernel.org>
   Signed-off-by: Minchan Kim <minchan@kernel.org>
   Link: https://lore.kernel.org/r/20211118230008.2679780-1-minchan@kernel.org
   Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
=========================================================

The bug is triggered by running NAS Parallel benchmark suite on
SuperMicro servers with 2x Xeon(R) Gold 6126 CPU. Here is the error
log:

[  247.035564] BUG: kernel NULL pointer dereference, address: 0000000000000008
[  247.036009] #PF: supervisor read access in kernel mode
[  247.036009] #PF: error_code(0x0000) - not-present page
[  247.036009] PGD 0 P4D 0
[  247.036009] Oops: 0000 [#1] PREEMPT SMP PTI
[  247.058060] CPU: 1 PID: 6546 Comm: umount Not tainted
5.16.0393c3714081a53795bbff0e985d24146def6f57f+ #16
[  247.058060] Hardware name: Supermicro Super Server/X11DDW-L, BIOS
2.0b 03/07/2018
[  247.058060] RIP: 0010:kernfs_remove+0x8/0x50
[  247.058060] Code: 4c 89 e0 5b 5d 41 5c 41 5d 41 5e c3 49 c7 c4 f4
ff ff ff eb b2 66 66 2e 0f 1f 84 00 00 00 00 00 66 90 0f 1f 44 00 00
41 54 55 <48> 8b 47 08 48 89 fd 48 85 c0 48 0f 44 c7 4c 8b 60 50 49 83
c4 60
[  247.058060] RSP: 0018:ffffbbfa48a27e48 EFLAGS: 00010246
[  247.058060] RAX: 0000000000000001 RBX: ffffffff89e31f98 RCX: 0000000080200018
[  247.058060] RDX: 0000000080200019 RSI: fffff6760786c900 RDI: 0000000000000000
[  247.058060] RBP: ffffffff89e31f98 R08: ffff926b61b24d00 R09: 0000000080200018
[  247.122048] R10: ffff926b61b24d00 R11: ffff926a8040c000 R12: ffff927bd09a2000
[  247.122048] R13: ffffffff89e31fa0 R14: dead000000000122 R15: dead000000000100
[  247.122048] FS:  00007f01be0a8c40(0000) GS:ffff926fa8e40000(0000)
knlGS:0000000000000000
[  247.122048] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  247.122048] CR2: 0000000000000008 CR3: 00000001145c6003 CR4: 00000000007706e0
[  247.122048] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[  247.122048] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[  247.122048] PKRU: 55555554
[  247.122048] Call Trace:
[  247.122048]  <TASK>
[  247.122048]  rdt_kill_sb+0x29d/0x350
[  247.122048]  deactivate_locked_super+0x36/0xa0
[  247.122048]  cleanup_mnt+0x131/0x190
[  247.122048]  task_work_run+0x5c/0x90
[  247.122048]  exit_to_user_mode_prepare+0x229/0x230
[  247.122048]  syscall_exit_to_user_mode+0x18/0x40
[  247.122048]  do_syscall_64+0x48/0x90
[  247.122048]  entry_SYSCALL_64_after_hwframe+0x44/0xae
[  247.122048] RIP: 0033:0x7f01be2d735b
[  247.122048] Code: 2b 0c 00 f7 d8 64 89 01 48 83 c8 ff c3 66 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 e9 2a 0c 00
f7 d8
[  247.122048] RSP: 002b:00007ffde1021e08 EFLAGS: 00000202 ORIG_RAX:
00000000000000a6
[  247.122048] RAX: 0000000000000000 RBX: 0000560c012bf5a0 RCX: 00007f01be2d735b
[  247.122048] RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000560c012c33a0
[  247.259079] RBP: 0000560c012bf370 R08: 0000000000000001 R09: 00007ffde1020b90
[  247.267058] R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000001
[  247.271055] R13: 0000560c012c33a0 R14: 0000560c012bf480 R15: 0000560c012bf370
[  247.279066]  </TASK>
[  247.283054] Modules linked in: rfkill sunrpc intel_rapl_msr
intel_rapl_common isst_if_common skx_edac nfit libnvdimm
x86_pkg_temp_thermal intel_powerclamp coretemp kvm_intel irdma kvm ice
iTCO_wdt intel_pmc_bxt iTCO_vendor_support i
rqbypass ib_uverbs ipmi_ssif rapl intel_cstate ib_core mei_me joydev
intel_uncore i2c_i801 ioatdma acpi_ipmi lpc_ich mei pcspkr i2c_smbus
intel_pch_thermal dca ipmi_si acpi_power_meter acpi_pad zram ip_tables
xfs ast i2c_algo_bit drm_v
ram_helper drm_kms_helper cec drm_ttm_helper ttm drm i40e
crct10dif_pclmul crc32_pclmul crc32c_intel ghash_clmulni_intel wmi
fuse ipmi_devintf ipmi_msghandler
[  247.335054] CR2: 0000000000000008
[  247.339041] ---[ end trace d8ccdb6c2d272688 ]---
[  247.355057] RIP: 0010:kernfs_remove+0x8/0x50
[  247.359059] Code: 4c 89 e0 5b 5d 41 5c 41 5d 41 5e c3 49 c7 c4 f4
ff ff ff eb b2 66 66 2e 0f 1f 84 00 00 00 00 00 66 90 0f 1f 44 00 00
41 54 55 <48> 8b 47 08 48 89 fd 48 85 c0 48 0f 44 c7 4c 8b 60 50 49 83
c4 60
[  247.379054] RSP: 0018:ffffbbfa48a27e48 EFLAGS: 00010246
[  247.383056] RAX: 0000000000000001 RBX: ffffffff89e31f98 RCX: 0000000080200018
[  247.391053] RDX: 0000000080200019 RSI: fffff6760786c900 RDI: 0000000000000000
[  247.395047] RBP: ffffffff89e31f98 R08: ffff926b61b24d00 R09: 0000000080200018
[  247.403055] R10: ffff926b61b24d00 R11: ffff926a8040c000 R12: ffff927bd09a2000
[  247.411046] R13: ffffffff89e31fa0 R14: dead000000000122 R15: dead000000000100
[  247.419055] FS:  00007f01be0a8c40(0000) GS:ffff926fa8e40000(0000)
knlGS:0000000000000000
[  247.427055] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  247.431055] CR2: 0000000000000008 CR3: 00000001145c6003 CR4: 00000000007706e0
[  247.439055] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[  247.443055] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[  247.455060] PKRU: 55555554

On Thu, Mar 24, 2022 at 12:49 PM Thorsten Leemhuis
<regressions@leemhuis.info> wrote:
>
> [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
> >
>
> --
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> 'Documentation/process/5.Posting.rst'.
>


-- 
-Jirka