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| author | Dan Williams <dan.j.williams@intel.com> | 2024-02-22 12:40:54 -0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2024-02-23 07:34:26 +0100 |
| commit | cd69fedf58f8ab1ab511f7c6ac1969cebf1c935f (patch) | |
| tree | fbbf7b6eb9d3ed5c3ea7c20e17ec8f199ac41dbe /fs/sysfs/group.c | |
| parent | 01aacda0b10eca95444bf481ffdef858a0a883cc (diff) | |
| download | linux-cd69fedf58f8ab1ab511f7c6ac1969cebf1c935f.tar.gz linux-cd69fedf58f8ab1ab511f7c6ac1969cebf1c935f.tar.bz2 linux-cd69fedf58f8ab1ab511f7c6ac1969cebf1c935f.zip | |
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@linux.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@intel.com>
Cc: Rafael J. Wysocki <rafael@kernel.org>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Tested-by: Marc Herbert <marc.herbert@intel.com>
Link: https://lore.kernel.org/r/170863445442.1479840.1818801787239831650.stgit@dwillia2-xfh.jf.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs/sysfs/group.c')
| -rw-r--r-- | fs/sysfs/group.c | 4 |
1 files 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; |