Hi, On 5/19/26 3:14 PM, Sascha Hauer wrote: > On 2026-05-19 15:03, Ahmad Fatoum wrote: >> Hi, >> >> On 5/19/26 2:44 PM, Sascha Hauer wrote: >>> UBIFS uses kmem_cache_alloc() to allocate an ubifs_inode. The memory >>> returned from kmem_cache_alloc() is not zeroed. ubifs_alloc_inode() >>> zeroes all fields in the ubifs_inode except the embedded struct inode. >>> In Linux this is done in the kmem_cache constructor function which calls >>> inode_init_once(). In barebox we have the constructor function as well, >>> but we don't have an equivalent of inode_init_once(), so the constructor >>> is empty. zero the inode in the constructor instead so that barebox >>> gets a zeroed inode. >>> >>> Signed-off-by: Sascha Hauer <[email protected]> >>> --- >>> fs/ubifs/super.c | 1 + >>> 1 file changed, 1 insertion(+) >>> >>> diff --git a/fs/ubifs/super.c b/fs/ubifs/super.c >>> index 45037b42ea..4022270d4c 100644 >>> --- a/fs/ubifs/super.c >>> +++ b/fs/ubifs/super.c >>> @@ -1128,6 +1128,7 @@ static void kill_ubifs_super(struct super_block *s) >>> */ >>> static void inode_slab_ctor(void *obj) >>> { >>> + memset(obj, 0, sizeof(struct inode)); >> >> This works because inode is the first member of struct ubifs_inode, but >> I would prefer to avoid depending on that as it might change with a >> future update. >> >> Can't we just zero all of struct ubifs_inode here to be on the safe side? > > That was my first approach as well, but I was afraid this could be lost > on an UBIFS update. > > I could treat obj as a struct ubifs_inode and zero the inode member > instead.
Yes, that would work too. > > That would have prevented the bug I introduced with the JFFS2 patch as > well. > > Sascha > > -- > Pengutronix e.K. | | > Steuerwalder Str. 21 | http://www.pengutronix.de/ | > 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | > Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | > -- Pengutronix e.K. | | Steuerwalder Str. 21 | http://www.pengutronix.de/ | 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
