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author | Daniel De Graaf <dgdegra@tycho.nsa.gov> | 2011-01-07 11:51:47 +0000 |
---|---|---|
committer | Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> | 2011-01-11 14:31:47 -0500 |
commit | f0a70c882ea546bbd802643990ceded32c39facc (patch) | |
tree | 3544db8b681c4bd513758579afc4847e2e87ecbf /drivers/xen | |
parent | ba5d1012292403c8037adf4a54c4ec50dfe846c4 (diff) | |
download | kernel_samsung_tuna-f0a70c882ea546bbd802643990ceded32c39facc.zip kernel_samsung_tuna-f0a70c882ea546bbd802643990ceded32c39facc.tar.gz kernel_samsung_tuna-f0a70c882ea546bbd802643990ceded32c39facc.tar.bz2 |
xen/gntdev: Fix circular locking dependency
apply_to_page_range will acquire PTE lock while priv->lock is held,
and mn_invl_range_start tries to acquire priv->lock with PTE already
held. Fix by not holding priv->lock during the entire map operation.
This is safe because map->vma is set nonzero while the lock is held,
which will cause subsequent maps to fail and will cause the unmap
ioctl (and other users of gntdev_del_map) to return -EBUSY until the
area is unmapped. It is similarly impossible for gntdev_vma_close to
be called while the vma is still being created.
Signed-off-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Diffstat (limited to 'drivers/xen')
-rw-r--r-- | drivers/xen/gntdev.c | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/drivers/xen/gntdev.c b/drivers/xen/gntdev.c index a2ea533..aba76d4 100644 --- a/drivers/xen/gntdev.c +++ b/drivers/xen/gntdev.c @@ -575,21 +575,26 @@ static int gntdev_mmap(struct file *flip, struct vm_area_struct *vma) if (!(vma->vm_flags & VM_WRITE)) map->flags |= GNTMAP_readonly; + spin_unlock(&priv->lock); + err = apply_to_page_range(vma->vm_mm, vma->vm_start, vma->vm_end - vma->vm_start, find_grant_ptes, map); if (err) { printk(KERN_WARNING "find_grant_ptes() failure.\n"); - goto unlock_out; + return err; } err = map_grant_pages(map); if (err) { printk(KERN_WARNING "map_grant_pages() failure.\n"); - goto unlock_out; + return err; } + map->is_mapped = 1; + return 0; + unlock_out: spin_unlock(&priv->lock); return err; |