From: Reinette Chatre <reinette.chatre@intel.com>
To: "Moger, Babu" <bmoger@amd.com>, <babu.moger@amd.com>,
<tony.luck@intel.com>, <Dave.Martin@arm.com>,
<james.morse@arm.com>, <dave.hansen@linux.intel.com>,
<bp@alien8.de>
Cc: <kas@kernel.org>, <rick.p.edgecombe@intel.com>,
<linux-kernel@vger.kernel.org>, <x86@kernel.org>,
<linux-coco@lists.linux.dev>, <kvm@vger.kernel.org>
Subject: Re: [PATCH] fs/resctrl: Fix MBM events being unconditionally enabled in mbm_event mode
Date: Tue, 14 Oct 2025 16:09:43 -0700 [thread overview]
Message-ID: <5163ce35-f843-41a3-abfc-5af91b7c68bc@intel.com> (raw)
In-Reply-To: <a75b2fa6-409c-4b33-9142-7be02bf6d217@amd.com>
Hi Babu,
On 10/14/25 3:45 PM, Moger, Babu wrote:
> On 10/14/2025 3:57 PM, Reinette Chatre wrote:
>> On 10/14/25 10:43 AM, Babu Moger wrote:
>>>> Yes. I saw the issues. It fails to mount in my case with panic trace.
>>
>> (Just to ensure that there is not anything else going on) Could you please confirm if the panic is from
>> mon_add_all_files()->mon_event_read()->mon_event_count()->__mon_event_count()->resctrl_arch_reset_rmid()
>> that creates the MBM event files during mount and then does the initial read of RMID to determine the
>> starting count?
>
> It happens just before that (at mbm_cntr_get). We have not allocated d->cntr_cfg for the counters.
> ===================Panic trace =================================
>
> 349.330416] BUG: kernel NULL pointer dereference, address: 0000000000000008
> [ 349.338187] #PF: supervisor read access in kernel mode
> [ 349.343914] #PF: error_code(0x0000) - not-present page
> [ 349.349644] PGD 10419f067 P4D 0
> [ 349.353241] Oops: Oops: 0000 [#1] SMP NOPTI
> [ 349.357905] CPU: 45 UID: 0 PID: 3449 Comm: mount Not tainted 6.18.0-rc1+ #120 PREEMPT(voluntary)
> [ 349.367803] Hardware name: AMD Corporation PURICO/PURICO, BIOS RPUT1003E 12/11/2024
> [ 349.376334] RIP: 0010:mbm_cntr_get+0x56/0x90
> [ 349.381096] Code: 45 8d 41 fe 83 f8 01 77 3d 8b 7b 50 85 ff 7e 36 49 8b 84 24 f0 04 00 00 45 31 c0 eb 0d 41 83 c0 01 48 83 c0 10 44 39 c7 74 1c <48> 3b 50 08 75 ed 3b 08 75 e9 48 83 c4 10 44 89 c0 5b 41 5c 41 5d
> [ 349.402037] RSP: 0018:ff56bba58655f958 EFLAGS: 00010246
> [ 349.407861] RAX: 0000000000000000 RBX: ffffffff9525b900 RCX: 0000000000000002
> [ 349.415818] RDX: ffffffff95d526a0 RSI: ff1f5d52517c1800 RDI: 0000000000000020
> [ 349.423774] RBP: ff56bba58655f980 R08: 0000000000000000 R09: 0000000000000001
> [ 349.431730] R10: ff1f5d52c616a6f0 R11: fffc6a2f046c3980 R12: ff1f5d52517c1800
> [ 349.439687] R13: 0000000000000001 R14: ffffffff95d526a0 R15: ffffffff9525b968
> [ 349.447635] FS: 00007f17926b7800(0000) GS:ff1f5d59d45ff000(0000) knlGS:0000000000000000
> [ 349.456659] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [ 349.463064] CR2: 0000000000000008 CR3: 0000000147afe002 CR4: 0000000000771ef0
> [ 349.471022] PKRU: 55555554
> [ 349.474033] Call Trace:
> [ 349.476755] <TASK>
> [ 349.479091] ? kernfs_add_one+0x114/0x170
> [ 349.483560] rdtgroup_assign_cntr_event+0x9b/0xd0
> [ 349.488795] rdtgroup_assign_cntrs+0xab/0xb0
> [ 349.493553] rdt_get_tree+0x4be/0x770
> [ 349.497623] vfs_get_tree+0x2e/0xf0
> [ 349.501508] fc_mount+0x18/0x90
> [ 349.505007] path_mount+0x360/0xc50
> [ 349.508884] ? putname+0x68/0x80
> [ 349.512479] __x64_sys_mount+0x124/0x150
> [ 349.516848] x64_sys_call+0x2133/0x2190
> [ 349.521123] do_syscall_64+0x74/0x970
>
> ==================================================================
Thank you for capturing this. This is a different trace but it confirms that it is the
same root cause. Specifically, event is enabled after the state it depends on is (not) allocated
during domain online.
Reinette
next prev parent reply other threads:[~2025-10-14 23:10 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-09-30 20:26 [PATCH] fs/resctrl: Fix MBM events being unconditionally enabled in mbm_event mode Babu Moger
2025-10-06 17:56 ` Reinette Chatre
2025-10-06 20:38 ` Moger, Babu
2025-10-07 1:23 ` Reinette Chatre
2025-10-07 17:36 ` Babu Moger
2025-10-08 2:38 ` Reinette Chatre
2025-10-14 16:24 ` Reinette Chatre
2025-10-14 17:38 ` Babu Moger
2025-10-14 17:43 ` Babu Moger
2025-10-14 20:57 ` Reinette Chatre
2025-10-14 22:45 ` Moger, Babu
2025-10-14 23:09 ` Reinette Chatre [this message]
2025-10-15 14:55 ` Moger, Babu
2025-10-15 19:56 ` Reinette Chatre
2025-10-15 20:37 ` Moger, Babu
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=5163ce35-f843-41a3-abfc-5af91b7c68bc@intel.com \
--to=reinette.chatre@intel.com \
--cc=Dave.Martin@arm.com \
--cc=babu.moger@amd.com \
--cc=bmoger@amd.com \
--cc=bp@alien8.de \
--cc=dave.hansen@linux.intel.com \
--cc=james.morse@arm.com \
--cc=kas@kernel.org \
--cc=kvm@vger.kernel.org \
--cc=linux-coco@lists.linux.dev \
--cc=linux-kernel@vger.kernel.org \
--cc=rick.p.edgecombe@intel.com \
--cc=tony.luck@intel.com \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).