Messages in this thread | | | Date | Mon, 21 Nov 2022 11:48:40 -0800 | From | Andrew Morton <> | Subject | Re: [PATCH 1/5] fs: ext4: initialize fsdata in pagecache_write() |
| |
On Mon, 21 Nov 2022 12:21:30 +0100 Alexander Potapenko <glider@google.com> 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);
| |