diff -u --recursive --new-file -X /linux/dontdiff a/fs/fat/dir.c b/fs/fat/dir.c
--- a/fs/fat/dir.c Mon Sep 29 01:05:41 2003
+++ b/fs/fat/dir.c Mon Sep 29 01:11:39 2003
@@ -630,7 +630,7 @@
put_user(slen, &d1->d_reclen))
goto efault;
} else {
- if (put_user(0, d2->d_name) ||
+ if (put_user(0, d2->d_name+0) ||
put_user(0, &d2->d_reclen) ||
copy_to_user(d1->d_name, name, len) ||
put_user(0, d1->d_name+len) ||
@@ -663,7 +663,7 @@
return -EINVAL;
}
- d1 = (struct dirent *)arg;
+ d1 = (struct dirent __user *)arg;
if (!access_ok(VERIFY_WRITE, d1, sizeof(struct dirent[2])))
return -EFAULT;
/*
On Mon, 29 Sep 2003 [email protected] wrote:
>
> --- a/fs/fat/dir.c Mon Sep 29 01:05:41 2003
> +++ b/fs/fat/dir.c Mon Sep 29 01:11:39 2003
> @@ -630,7 +630,7 @@
> put_user(slen, &d1->d_reclen))
> goto efault;
> } else {
> - if (put_user(0, d2->d_name) ||
> + if (put_user(0, d2->d_name+0) ||
> put_user(0, &d2->d_reclen) ||
> copy_to_user(d1->d_name, name, len) ||
> put_user(0, d1->d_name+len) ||
The above seems to just work around a sparse bug. Please don't - I'd
rather have regular code and try to fix the sparse problem.
Hmm.. I wonder why sparse doesn't get the address space right on arrays.
It should see that "d2" is a user pointer , so d2->d_name is one too.
It gets it right if you add the "+0", or if you add a "&" in front. So
it looks like the sparse array->pointer degeneration misses something.
Linus
On Mon, Sep 29, 2003 at 09:50:54AM -0700, Linus Torvalds wrote:
>
> On Mon, 29 Sep 2003 [email protected] wrote:
> >
> > --- a/fs/fat/dir.c Mon Sep 29 01:05:41 2003
> > +++ b/fs/fat/dir.c Mon Sep 29 01:11:39 2003
> > @@ -630,7 +630,7 @@
> > put_user(slen, &d1->d_reclen))
> > goto efault;
> > } else {
> > - if (put_user(0, d2->d_name) ||
> > + if (put_user(0, d2->d_name+0) ||
> > put_user(0, &d2->d_reclen) ||
> > copy_to_user(d1->d_name, name, len) ||
> > put_user(0, d1->d_name+len) ||
>
> The above seems to just work around a sparse bug. Please don't - I'd
> rather have regular code and try to fix the sparse problem.
>
> Hmm.. I wonder why sparse doesn't get the address space right on arrays.
> It should see that "d2" is a user pointer , so d2->d_name is one too.
. The problem is in "*d2->d_name", the address space get
lost at evaluate_dereference of "*". It is a monster macro right
there. The simple version is:
struct dentry {
char d_name[256];
};
int foo (void) {
struct dentry __attribute__((noderef, address_space(1))) *d2;
__typeof__(*d2->d_name) *__pu_addr = d2->d_name;
^^^^^^^^^^^
}
> It gets it right if you add the "+0", or if you add a "&" in front. So
> it looks like the sparse array->pointer degeneration misses something.
Besids address sapce, it seems that the source and target base type
is pointer of char_ctype instead of pointer of void_ctype. I get lost
there.
Regards.
Chris
On Tue, 30 Sep 2003, Christopher Li wrote:
>
> The problem is in "*d2->d_name", the address space get
> lost at evaluate_dereference of "*"
Yes, but taking the address of it should still undo all the things.
"evaluate_addressof()" does the right (fairly complex) magic, but
apparently the "degenerate()" function does not.
Ho humm.. degenerate() really should be 100% the same as
"evaluate_addressof()", but I'm sure I had some reason for doing them
separately.
Probably a very bad reason, brought on by terminal mental illness. But a
reason none-the-less..
Linus