| Message ID | 20241101013741.295792-3-andrealmeid@igalia.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | tmpfs: Casefold fixes | expand |
On Thu, Oct 31, 2024 at 10:37:40PM -0300, André Almeida wrote: > DEVICE_STRING_ATTR_RO should be only used by device drivers since it > relies on `struct device` to use device_show_string() function. Using > this with non device code led to a kCFI violation: > > > cat /sys/fs/tmpfs/features/casefold > [ 70.558496] CFI failure at kobj_attr_show+0x2c/0x4c (target: device_show_string+0x0/0x38; expected type: 0xc527b809) > > Like the other filesystems, fix this by manually declaring the attribute > using kobj_attribute() and writing a proper show() function. > > Also, leave macros for anyone that need to expand tmpfs sysfs' with > more attributes (as seen in fs/btrfs/sysfs.c). > > Fixes: 5132f08bd332 ("tmpfs: Expose filesystem features via sysfs") > Reported-by: Nathan Chancellor <nathan@kernel.org> > Closes: https://lore.kernel.org/lkml/20241031051822.GA2947788@thelio-3990X/ > Signed-off-by: André Almeida <andrealmeid@igalia.com> Reviewed-by: Nathan Chancellor <nathan@kernel.org> Tested-by: Nathan Chancellor <nathan@kernel.org> > --- > mm/shmem.c | 29 +++++++++++++++++++++++++++-- > 1 file changed, 27 insertions(+), 2 deletions(-) > > diff --git a/mm/shmem.c b/mm/shmem.c > index b86f526a1cb1..6038e1d11987 100644 > --- a/mm/shmem.c > +++ b/mm/shmem.c > @@ -5548,13 +5548,38 @@ struct page *shmem_read_mapping_page_gfp(struct address_space *mapping, > EXPORT_SYMBOL_GPL(shmem_read_mapping_page_gfp); > > #if defined(CONFIG_SYSFS) && defined(CONFIG_TMPFS) > + > +#define __INIT_KOBJ_ATTR(_name, _mode, _show, _store) \ > +{ \ > + .attr = { .name = __stringify(_name), .mode = _mode }, \ > + .show = _show, \ > + .store = _store, \ > +} > + > +#define TMPFS_ATTR_W(_name, _store) \ > + static struct kobj_attribute tmpfs_attr_##_name = \ > + __INIT_KOBJ_ATTR(_name, 0200, NULL, _store) > + > +#define TMPFS_ATTR_RW(_name, _show, _store) \ > + static struct kobj_attribute tmpfs_attr_##_name = \ > + __INIT_KOBJ_ATTR(_name, 0644, _show, _store) > + > +#define TMPFS_ATTR_RO(_name, _show) \ > + static struct kobj_attribute tmpfs_attr_##_name = \ > + __INIT_KOBJ_ATTR(_name, 0444, _show, NULL) > + > #if IS_ENABLED(CONFIG_UNICODE) > -static DEVICE_STRING_ATTR_RO(casefold, 0444, "supported"); > +static ssize_t casefold_show(struct kobject *kobj, struct kobj_attribute *a, > + char *buf) > +{ > + return sysfs_emit(buf, "supported\n"); Small nit, I think this might be overindented? > +} > +TMPFS_ATTR_RO(casefold, casefold_show); > #endif > > static struct attribute *tmpfs_attributes[] = { > #if IS_ENABLED(CONFIG_UNICODE) > - &dev_attr_casefold.attr.attr, > + &tmpfs_attr_casefold.attr, > #endif > NULL > }; > -- > 2.47.0 >
diff --git a/mm/shmem.c b/mm/shmem.c index b86f526a1cb1..6038e1d11987 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -5548,13 +5548,38 @@ struct page *shmem_read_mapping_page_gfp(struct address_space *mapping, EXPORT_SYMBOL_GPL(shmem_read_mapping_page_gfp); #if defined(CONFIG_SYSFS) && defined(CONFIG_TMPFS) + +#define __INIT_KOBJ_ATTR(_name, _mode, _show, _store) \ +{ \ + .attr = { .name = __stringify(_name), .mode = _mode }, \ + .show = _show, \ + .store = _store, \ +} + +#define TMPFS_ATTR_W(_name, _store) \ + static struct kobj_attribute tmpfs_attr_##_name = \ + __INIT_KOBJ_ATTR(_name, 0200, NULL, _store) + +#define TMPFS_ATTR_RW(_name, _show, _store) \ + static struct kobj_attribute tmpfs_attr_##_name = \ + __INIT_KOBJ_ATTR(_name, 0644, _show, _store) + +#define TMPFS_ATTR_RO(_name, _show) \ + static struct kobj_attribute tmpfs_attr_##_name = \ + __INIT_KOBJ_ATTR(_name, 0444, _show, NULL) + #if IS_ENABLED(CONFIG_UNICODE) -static DEVICE_STRING_ATTR_RO(casefold, 0444, "supported"); +static ssize_t casefold_show(struct kobject *kobj, struct kobj_attribute *a, + char *buf) +{ + return sysfs_emit(buf, "supported\n"); +} +TMPFS_ATTR_RO(casefold, casefold_show); #endif static struct attribute *tmpfs_attributes[] = { #if IS_ENABLED(CONFIG_UNICODE) - &dev_attr_casefold.attr.attr, + &tmpfs_attr_casefold.attr, #endif NULL };