From: Dan Williams <dan.j.williams@intel.com>
To: "Rafael J. Wysocki" <rafael@kernel.org>,
Dan Williams <dan.j.williams@intel.com>
Cc: <gregkh@linuxfoundation.org>,
Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>,
Marc Herbert <marc.herbert@intel.com>,
"Rafael J. Wysocki" <rafael@kernel.org>,
<linux-kernel@vger.kernel.org>, <linux-pci@vger.kernel.org>,
<linux-coco@lists.linux.dev>, <alsa-devel@alsa-project.org>
Subject: Re: [PATCH 1/3] sysfs: Fix crash on empty group attributes array
Date: Thu, 22 Feb 2024 14:03:13 -0800 [thread overview]
Message-ID: <65d7c4a17f351_ca001294e8@dwillia2-xfh.jf.intel.com.notmuch> (raw)
In-Reply-To: <CAJZ5v0hmD+7iSKKexpUccvMUtjNpd9fHo3vRrshD_s=rb5Vq_w@mail.gmail.com>
Rafael J. Wysocki wrote:
> On Thu, Feb 22, 2024 at 9:40 PM Dan Williams <dan.j.williams@intel.com> wrote:
> >
> > It turns out that arch/x86/events/intel/core.c makes use of "empty"
> > attributes.
> >
> > static struct attribute *empty_attrs;
> >
> > __init int intel_pmu_init(void)
> > {
> > struct attribute **extra_skl_attr = &empty_attrs;
> > struct attribute **extra_attr = &empty_attrs;
> > struct attribute **td_attr = &empty_attrs;
> > struct attribute **mem_attr = &empty_attrs;
> > struct attribute **tsx_attr = &empty_attrs;
> > ...
> >
> > That breaks the assumption __first_visible() that expects that if
> > grp->attrs is set then grp->attrs[0] must also be set and results in
> > backtraces like:
> >
> > BUG: kernel NULL pointer dereference, address: 00rnel mode
> > #PF: error_code(0x0000) - not-present ] PREEMPT SMP NOPTI
> > CPU: 1 PID: 1 Comm: swapper/IP: 0010:exra_is_visible+0x14/0x20
> > ? exc_page_fault+0x68/0x190
> > internal_create_groups+0x42/0xa0
> > pmu_dev_alloc+0xc0/0xe0
> > perf_event_sysfs_init+0x580000000000 ]---
> > RIP: 0010:exra_is_visible+0x14/0
> >
> > Check for non-empty attributes array before calling is_visible().
> >
> > Reported-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
> > Closes: https://github.com/thesofproject/linux/pull/4799#issuecomment-1958537212
> > Fixes: 70317fd24b41 ("sysfs: Introduce a mechanism to hide static attribute_groups")
>
> This is not in the mainline, so linux-next I suppose?
...or at least it will be shortly. Greg notified that it is currently in
driver-core-next:
https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core.git/commit/?h=driver-core-next&id=70317fd24b41
next prev parent reply other threads:[~2024-02-22 22:03 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-02-22 20:40 [PATCH 0/3] sysfs: Group visibility fixups Dan Williams
2024-02-22 20:40 ` [PATCH 1/3] sysfs: Fix crash on empty group attributes array Dan Williams
2024-02-22 21:14 ` Rafael J. Wysocki
2024-02-22 22:03 ` Dan Williams [this message]
2024-02-22 23:15 ` Dan Williams
2024-04-22 9:20 ` Lukas Wunner
2024-04-26 17:59 ` Dan Williams
2024-04-26 19:18 ` Lukas Wunner
2024-04-27 11:05 ` Greg KH
2024-04-27 16:49 ` Dan Williams
2024-04-27 21:14 ` Lukas Wunner
2024-04-27 21:33 ` Dan Williams
2024-04-27 22:39 ` Dan Williams
2024-04-27 23:09 ` Dan Williams
2024-04-28 10:08 ` Lukas Wunner
2024-04-29 17:47 ` Dan Williams
2024-02-22 20:41 ` [PATCH 2/3] sysfs: Document new "group visible" helpers Dan Williams
2024-02-22 20:41 ` [PATCH 3/3] sysfs: Introduce DEFINE_SIMPLE_SYSFS_GROUP_VISIBLE() Dan Williams
2024-02-23 6:33 ` [PATCH 0/3] sysfs: Group visibility fixups Greg KH
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