Hello Eric W. Biederman,
This is a semi-automatic email about new static checker warnings.
The patch 4ce5d2b1a8fd: "vfs: Don't copy mount bind mounts of
/proc/<pid>/ns/mnt between namespaces" from Mar 30, 2013, leads to
the following Smatch complaint:
fs/namespace.c:2459 dup_mnt_ns()
warn: variable dereferenced before check 'p' (see line 2475)
fs/namespace.c
2441 new = copy_tree(old, old->mnt.mnt_root, copy_flags);
^^^^^^^^^^^^^^^^^
Old is dereferenced.
2442 if (IS_ERR(new)) {
2443 namespace_unlock();
2444 free_mnt_ns(new_ns);
2445 return ERR_CAST(new);
2446 }
2447 new_ns->root = new;
2448 br_write_lock(&vfsmount_lock);
2449 list_add_tail(&new_ns->list, &new->mnt_list);
2450 br_write_unlock(&vfsmount_lock);
2451
2452 /*
2453 * Second pass: switch the tsk->fs->* elements and mark new vfsmounts
2454 * as belonging to new namespace. We have already acquired a private
2455 * fs_struct, so tsk->fs->lock is not needed.
2456 */
2457 p = old;
^^^^^^^
P is a valid pointer.
2458 q = new;
2459 while (p) {
^^^
Existing check for "p".
2460 q->mnt_ns = new_ns;
2461 if (fs) {
2462 if (&p->mnt == fs->root.mnt) {
2463 fs->root.mnt = mntget(&q->mnt);
2464 rootmnt = &p->mnt;
2465 }
2466 if (&p->mnt == fs->pwd.mnt) {
2467 fs->pwd.mnt = mntget(&q->mnt);
2468 pwdmnt = &p->mnt;
2469 }
2470 }
2471 p = next_mnt(p, old);
2472 q = next_mnt(q, new);
2473 if (!q)
2474 break;
2475 while (p->mnt.mnt_root != q->mnt.mnt_root)
^^^^^^^^^^^^^^^
We dereference "p".
2476 p = next_mnt(p, old);
2477 }
regards,
dan carpenter
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