[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <170863445442.1479840.1818801787239831650.stgit@dwillia2-xfh.jf.intel.com>
Date: Thu, 22 Feb 2024 12:40:54 -0800
From: Dan Williams <dan.j.williams@...el.com>
To: gregkh@...uxfoundation.org
Cc: Pierre-Louis Bossart <pierre-louis.bossart@...ux.intel.com>,
Marc Herbert <marc.herbert@...el.com>, "Rafael J. Wysocki" <rafael@...nel.org>,
linux-kernel@...r.kernel.org, linux-pci@...r.kernel.org,
linux-coco@...ts.linux.dev, alsa-devel@...a-project.org
Subject: [PATCH 1/3] sysfs: Fix crash on empty group attributes array
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@...ux.intel.com>
Closes: https://github.com/thesofproject/linux/pull/4799#issuecomment-1958537212
Fixes: 70317fd24b41 ("sysfs: Introduce a mechanism to hide static attribute_groups")
Cc: Marc Herbert <marc.herbert@...el.com>
Cc: "Rafael J. Wysocki" <rafael@...nel.org>
Signed-off-by: Dan Williams <dan.j.williams@...el.com>
---
fs/sysfs/group.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/fs/sysfs/group.c b/fs/sysfs/group.c
index ccb275cdabcb..8c63ba3cfc47 100644
--- a/fs/sysfs/group.c
+++ b/fs/sysfs/group.c
@@ -33,10 +33,10 @@ static void remove_files(struct kernfs_node *parent,
static umode_t __first_visible(const struct attribute_group *grp, struct kobject *kobj)
{
- if (grp->attrs && grp->is_visible)
+ if (grp->attrs && grp->attrs[0] && grp->is_visible)
return grp->is_visible(kobj, grp->attrs[0], 0);
- if (grp->bin_attrs && grp->is_bin_visible)
+ if (grp->bin_attrs && grp->bin_attrs[0] && grp->is_bin_visible)
return grp->is_bin_visible(kobj, grp->bin_attrs[0], 0);
return 0;
Powered by blists - more mailing lists