When accessing one of the files under /sys/fs/nilfs2/features when CONFIG_CFI_CLANG is enabled, there is a CFI violation:
CFI failure at kobj_attr_show+0x59/0x80 (target: nilfs_feature_revision_show+0x0/0x30; expected type: 0xfc392c4d) ... Call Trace: <TASK> sysfs_kf_seq_show+0x2a6/0x390 ? __cfi_kobj_attr_show+0x10/0x10 kernfs_seq_show+0x104/0x15b seq_read_iter+0x580/0xe2b ...
When the kobject of the kset for /sys/fs/nilfs2 is initialized, its ktype is set to kset_ktype, which has a ->sysfs_ops of kobj_sysfs_ops. When nilfs_feature_attr_group is added to that kobject via sysfs_create_group(), the kernfs_ops of each files is sysfs_file_kfops_rw, which will call sysfs_kf_seq_show() when ->seq_show() is called. sysfs_kf_seq_show() in turn calls kobj_attr_show() through ->sysfs_ops->show(). kobj_attr_show() casts the provided attribute out to a 'struct kobj_attribute' via container_of() and calls ->show(), resulting in the CFI violation since neither nilfs_feature_revision_show() nor nilfs_feature_README_show() match the prototype of ->show() in 'struct kobj_attribute'.
Resolve the CFI violation by adjusting the second parameter in nilfs_feature_{revision,README}_show() from 'struct attribute' to 'struct kobj_attribute' to match the expected prototype.
Cc: stable@vger.kernel.org Fixes: aebe17f68444 ("nilfs2: add /sys/fs/nilfs2/features group") Reported-by: kernel test robot oliver.sang@intel.com Closes: https://lore.kernel.org/oe-lkp/202509021646.bc78d9ef-lkp@intel.com/ Signed-off-by: Nathan Chancellor nathan@kernel.org --- fs/nilfs2/sysfs.c | 4 ++-- fs/nilfs2/sysfs.h | 8 ++++---- 2 files changed, 6 insertions(+), 6 deletions(-)
diff --git a/fs/nilfs2/sysfs.c b/fs/nilfs2/sysfs.c index 14868a3dd592..bc52afbfc5c7 100644 --- a/fs/nilfs2/sysfs.c +++ b/fs/nilfs2/sysfs.c @@ -1075,7 +1075,7 @@ void nilfs_sysfs_delete_device_group(struct the_nilfs *nilfs) ************************************************************************/
static ssize_t nilfs_feature_revision_show(struct kobject *kobj, - struct attribute *attr, char *buf) + struct kobj_attribute *attr, char *buf) { return sysfs_emit(buf, "%d.%d\n", NILFS_CURRENT_REV, NILFS_MINOR_REV); @@ -1087,7 +1087,7 @@ static const char features_readme_str[] = "(1) revision\n\tshow current revision of NILFS file system driver.\n";
static ssize_t nilfs_feature_README_show(struct kobject *kobj, - struct attribute *attr, + struct kobj_attribute *attr, char *buf) { return sysfs_emit(buf, features_readme_str); diff --git a/fs/nilfs2/sysfs.h b/fs/nilfs2/sysfs.h index 78a87a016928..d370cd5cce3f 100644 --- a/fs/nilfs2/sysfs.h +++ b/fs/nilfs2/sysfs.h @@ -50,16 +50,16 @@ struct nilfs_sysfs_dev_subgroups { struct completion sg_segments_kobj_unregister; };
-#define NILFS_COMMON_ATTR_STRUCT(name) \ +#define NILFS_KOBJ_ATTR_STRUCT(name) \ struct nilfs_##name##_attr { \ struct attribute attr; \ - ssize_t (*show)(struct kobject *, struct attribute *, \ + ssize_t (*show)(struct kobject *, struct kobj_attribute *, \ char *); \ - ssize_t (*store)(struct kobject *, struct attribute *, \ + ssize_t (*store)(struct kobject *, struct kobj_attribute *, \ const char *, size_t); \ }
-NILFS_COMMON_ATTR_STRUCT(feature); +NILFS_KOBJ_ATTR_STRUCT(feature);
#define NILFS_DEV_ATTR_STRUCT(name) \ struct nilfs_##name##_attr { \
--- base-commit: b320789d6883cc00ac78ce83bccbfe7ed58afcf0 change-id: 20250905-nilfs2-fix-features-cfi-violation-3a53eb52a700
Best regards, -- Nathan Chancellor nathan@kernel.org