commit 025e87f8ea upstream.
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.
Link: https://lkml.kernel.org/r/20250906144410.22511-1-konishi.ryusuke@gmail.com
Fixes: aebe17f684 ("nilfs2: add /sys/fs/nilfs2/features group")
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Reported-by: kernel test robot <oliver.sang@intel.com>
Closes: https://lore.kernel.org/oe-lkp/202509021646.bc78d9ef-lkp@intel.com/
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
4c9b507880