On Mon, 21 Nov 2022 12:21:30 +0100 Alexander Potapenko <glider@xxxxxxxxxx> wrote: > When aops->write_begin() does not initialize fsdata, KMSAN reports > an error passing the latter to aops->write_end(). > > Fix this by unconditionally initializing fsdata. > > ... > I'm assuming that this is not-a-bug, and that these changes are purely workarounds for a KMSAN shortcoming? If true, this important info should be included in each changelog, please. If false, please provide a full description of the end-user visible effects of the bug. Also, it would be helpful to describe why it is not considered practical to teach KMSAN to handle this? > --- a/fs/ext4/verity.c > +++ b/fs/ext4/verity.c > @@ -79,7 +79,7 @@ static int pagecache_write(struct inode *inode, const void *buf, size_t count, > size_t n = min_t(size_t, count, > PAGE_SIZE - offset_in_page(pos)); > struct page *page; > - void *fsdata; > + void *fsdata = NULL; > int res; > > res = aops->write_begin(NULL, mapping, pos, n, &page, &fsdata);
