Messages in this thread | | | Date | Tue, 11 Oct 2005 21:00:06 -0700 | From | Andy Isaacson <> | Subject | Re: sys_sendfile oops in 2.6.13? |
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On Tue, Oct 11, 2005 at 10:56:43AM +0200, Grzegorz Nosek wrote: > I found an (IMHO) silly bug in do_sendfile in 2.6.13.x kernels (at > least in 2.6.13.3 and .4, didn't backtrack to find where it > originated). Without the patch all I apparently get from sys_sendfile > is an oops due to a call in sys_sendfile with ppos being NULL. With the > patch it works OK. Noticed in vsftpd. > > @@ -719,7 +719,7 @@ > current->syscr++; > current->syscw++; > > - if (*ppos > max) > + if (ppos && *ppos > max)
That change can't fix a bug in 2.6.13, because ppos is forced to be non-null further up the file:
622 static ssize_t do_sendfile(int out_fd, int in_fd, loff_t *ppos, ... 647 if (!ppos) 648 ppos = &in_file->f_pos; ... 684 pos = *ppos; ... 701 current->syscr++; 702 current->syscw++; 703 704 if (*ppos > max) 705 retval = -EOVERFLOW;
(line numbers from 2.6.13.)
So there must be something else at work. Perhaps your patches?
On Tue, Oct 11, 2005 at 04:53:47PM +0200, Jiri Slaby wrote: > I don't know the code surrounding this, but shouldn't be this > (!ppos || *ppos > max)?
That would be wrong, too; if it were valid to call in with ppos==0, you wouldn't want to return EOVERFLOW; and if ppos==0 were not valid and you wanted to return an error, EOVERFLOW would be the wrong error to return.
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