Re: Linux 2.4.33-rc1

Willy Tarreau
2006-06-19T04:04:57Z

On Mon, Jun 19, 2006 at 09:07:03AM +1000, Grant Coady wrote:
> On Mon, 19 Jun 2006 00:37:36 +0200, Willy Tarreau <w@1wt.eu> wrote:
>
> >Hi Grant,
> >
> >On Mon, Jun 19, 2006 at 08:25:06AM +1000, Grant Coady wrote:
> >> On Sun, 18 Jun 2006 10:37:18 -0300, Marcelo Tosatti <marcelo@kvack.org> wrote:
> >>
> >> >Can you please try the attached patch.
> >> >
> >> >Grab a reference to the victim inode before calling vfs_unlink() to avoid
> >> >it vanishing under us.
> >> >
> >> >diff --git a/fs/namei.c b/fs/namei.c
> >> >index 42cce98..7993283 100644
> >> >--- a/fs/namei.c
> >> >+++ b/fs/namei.c
> >> >@@ -1509,6 +1509,7 @@ asmlinkage long sys_unlink(const char *
> >> > char * name;
> >> > struct dentry *dentry;
> >> > struct nameidata nd;
> >> >+ struct inode *inode = NULL;
> >> >
> >> > name = getname(pathname);
> >> > if(IS_ERR(name))
> >> >@@ -1527,11 +1528,16 @@ asmlinkage long sys_unlink(const char *
> >> > /* Why not before? Because we want correct error value */
> >> > if (nd.last.name[nd.last.len])
> >> > goto slashes;
> >> >+ inode = dentry->d_inode;
> >> >+ if (inode)
> >> >+ atomic_inc(&inode->i_count);
> >> > error = vfs_unlink(nd.dentry->d_inode, dentry);
> >> > exit2:
> >> > dput(dentry);
> >> > }
> >
> >Could you add this line here, because your oops still looks like the NULL
> >is close to this area :
> >
> >+ printk(KERN_DEBUG "nd.dentry->d_inode = %p\n", nd.dentry->d_inode);
>
> It didn't get there for the segfault case, gets there for local file
> delete
>
> After:
> grant@sempro:~$ dmesg >dmesg
> grant@sempro:~$ rm dmesg
>
> Jun 19 08:49:17 sempro kernel: nd.dentry->d_inode = f73f4b80
>
> After:
> grant@sempro:~$ dmesg >/home/share/dmesg-test
> grant@sempro:~$ rm /home/share/dmesg-test
> Segmentation fault
>
> Nothing reported by debug or syslog, oops in messages.

Thanks. Then, could you send us your 'namei.o' file please ? Mine does
not produce the same content as yours and it makes it difficult to find
the exact position in the code.

Cheers,
Willy