On Wed, May 11, 2011 at 5:08 PM, Trond Myklebust <Trond.Myklebust@xxxxxxxxxx> wrote: > On Wed, 2011-05-11 at 17:03 -0400, Peng Huang wrote: >> lookup_one_len() may call nfs_loopup_revalidate() with nd == NULL >> indirectly, that causes the kernel crash. >> >> RIP: 0010:[<ffffffffa0ba3b41>] Â[<ffffffffa0ba3b41>] >> nfs_lookup_revalidate+0x21/0x4a0 [nfs] >> RSP: 0018:ffff88018f00fae8 ÂEFLAGS: 00010286 >> >> Call Trace: >> Â[<ffffffff81164a17>] do_revalidate+0x17/0x60 >> Â[<ffffffff81164e9b>] __lookup_hash+0xcb/0x140 >> Â[<ffffffff811653c4>] lookup_one_len+0x94/0xe0 >> Â[<ffffffff81241ef1>] ecryptfs_lookup+0x91/0x1d0 >> Â[<ffffffff81164d85>] d_alloc_and_lookup+0x45/0x90 >> Â[<ffffffff8116f7b5>] ? d_lookup+0x35/0x60 >> Â[<ffffffff811669b2>] do_lookup+0x192/0x2d0 >> Â[<ffffffff811763be>] ? vfsmount_lock_local_unlock+0x1e/0x30 >> Â[<ffffffff8126d09c>] ? security_inode_permission+0x1c/0x30 >> Â[<ffffffff81167d67>] link_path_walk+0x597/0xae0 >> Â[<ffffffff8117638e>] ? vfsmount_lock_local_lock+0x1e/0x30 >> Â[<ffffffff81165905>] ? path_init_rcu+0xa5/0x210 >> Â[<ffffffff8116858b>] do_path_lookup+0x5b/0x140 >> Â[<ffffffff811692f7>] user_path_at+0x57/0xa0 >> Â[<ffffffff8159fd08>] ? do_page_fault+0x1e8/0x4e0 >> Â[<ffffffff8115eb86>] vfs_fstatat+0x46/0x80 >> Â[<ffffffff8116b990>] ? filldir+0x0/0xe0 >> Â[<ffffffff8115ec2e>] vfs_lstat+0x1e/0x20 >> Â[<ffffffff8115ec54>] sys_newlstat+0x24/0x50 >> Â[<ffffffff8159c995>] ? page_fault+0x25/0x30 >> Â[<ffffffff8100bfc2>] system_call_fastpath+0x16/0x1b >> >> Signed-off-by: Peng Huang <shawn.p.huang@xxxxxxxxx> >> --- >> Âfs/nfs/dir.c | Â Â2 +- >> Â1 files changed, 1 insertions(+), 1 deletions(-) >> >> diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c >> index 2c3eb33..9452aa5 100644 >> --- a/fs/nfs/dir.c >> +++ b/fs/nfs/dir.c >> @@ -1028,7 +1028,7 @@ static int nfs_lookup_revalidate(struct dentry *dentry, struct nameidata *nd) >> Â Â Â struct nfs_fattr *fattr = NULL; >> Â Â Â int error; >> >> - Â Â if (nd->flags & LOOKUP_RCU) >> + Â Â if (nd != NULL && nd->flags & LOOKUP_RCU) >> Â Â Â Â Â Â Â return -ECHILD; >> >> Â Â Â parent = dget_parent(dentry); > > That's exactly what Tyler Hicks proposed last week and which was NACKed. > We simply won't support layered filesystems that don't do intents. > > IOW: Feel free to change the above to. > > if (nd == NULL) > Â Â return -EIO; > I tested returning -EIO when nd is NULL. Kernel does not crash, but ecryptfs can not work on nfs anymore. Peng Huang > > > > -- > Trond Myklebust > Linux NFS client maintainer > > NetApp > Trond.Myklebust@xxxxxxxxxx > www.netapp.com > > -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
