Messages in this thread | | | Date | Fri, 2 Oct 2015 14:21:39 +0300 | Subject | Re: [PATCH] fuse: break infinite loop in fuse_fill_write_pages() | From | Konstantin Khlebnikov <> |
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Bump. Add more peopple in CC.
On Mon, Sep 21, 2015 at 1:02 PM, Roman Gushchin <klamm@yandex-team.ru> wrote: > I got a report about unkillable task eating CPU. Thge further > investigation shows, that the problem is in the fuse_fill_write_pages() > function. If iov's first segment has zero length, we get an infinite > loop, because we never reach iov_iter_advance() call. > > Fix this by calling iov_iter_advance() before repeating an attempt to > copy data from userspace. > > A similar problem is described in 124d3b7041f ("fix writev regression: > pan hanging unkillable and un-straceable"). > > Signed-off-by: Roman Gushchin <klamm@yandex-team.ru> > Cc: Miklos Szeredi <miklos@szeredi.hu> > --- > fs/fuse/file.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/fs/fuse/file.c b/fs/fuse/file.c > index f523f2f..195476a 100644 > --- a/fs/fuse/file.c > +++ b/fs/fuse/file.c > @@ -1049,6 +1049,7 @@ static ssize_t fuse_fill_write_pages(struct fuse_req *req, > tmp = iov_iter_copy_from_user_atomic(page, ii, offset, bytes); > flush_dcache_page(page); > > + iov_iter_advance(ii, tmp); > if (!tmp) { > unlock_page(page); > page_cache_release(page); > @@ -1061,7 +1062,6 @@ static ssize_t fuse_fill_write_pages(struct fuse_req *req, > req->page_descs[req->num_pages].length = tmp; > req->num_pages++; > > - iov_iter_advance(ii, tmp); > count += tmp; > pos += tmp; > offset += tmp; > -- > 2.4.3 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/
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