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authorDaniel De Graaf <dgdegra@tycho.nsa.gov>2011-10-11 23:16:06 +0400
committerKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>2011-10-14 18:02:10 +0400
commit1f1503ba096d3a394d1454dac77467092ca996e6 (patch)
tree82b0a522dab0bf6c8ec8fd5b970d7027adfe3ebf /drivers/xen
parent0930bba674e248b921ea659b036ff02564e5a5f4 (diff)
downloadlinux-1f1503ba096d3a394d1454dac77467092ca996e6.tar.xz
xen/gntdev: Fix sleep-inside-spinlock
BUG: sleeping function called from invalid context at /local/scratch/dariof/linux/kernel/mutex.c:271 in_atomic(): 1, irqs_disabled(): 0, pid: 3256, name: qemu-dm 1 lock held by qemu-dm/3256: #0: (&(&priv->lock)->rlock){......}, at: [<ffffffff813223da>] gntdev_ioctl+0x2bd/0x4d5 Pid: 3256, comm: qemu-dm Tainted: G W 3.1.0-rc8+ #5 Call Trace: [<ffffffff81054594>] __might_sleep+0x131/0x135 [<ffffffff816bd64f>] mutex_lock_nested+0x25/0x45 [<ffffffff8131c7c8>] free_xenballooned_pages+0x20/0xb1 [<ffffffff8132194d>] gntdev_put_map+0xa8/0xdb [<ffffffff816be546>] ? _raw_spin_lock+0x71/0x7a [<ffffffff813223da>] ? gntdev_ioctl+0x2bd/0x4d5 [<ffffffff8132243c>] gntdev_ioctl+0x31f/0x4d5 [<ffffffff81007d62>] ? check_events+0x12/0x20 [<ffffffff811433bc>] do_vfs_ioctl+0x488/0x4d7 [<ffffffff81007d4f>] ? xen_restore_fl_direct_reloc+0x4/0x4 [<ffffffff8109168b>] ? lock_release+0x21c/0x229 [<ffffffff81135cdd>] ? rcu_read_unlock+0x21/0x32 [<ffffffff81143452>] sys_ioctl+0x47/0x6a [<ffffffff816bfd82>] system_call_fastpath+0x16/0x1b gntdev_put_map tries to acquire a mutex when freeing pages back to the xenballoon pool, so it cannot be called with a spinlock held. In gntdev_release, the spinlock is not needed as we are freeing the structure later; in the ioctl, only the list manipulation needs to be under the lock. Reported-and-Tested-By: Dario Faggioli <dario.faggioli@citrix.com> 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.c5
1 files changed, 2 insertions, 3 deletions
diff --git a/drivers/xen/gntdev.c b/drivers/xen/gntdev.c
index 3e3603f35242..880798aae2f2 100644
--- a/drivers/xen/gntdev.c
+++ b/drivers/xen/gntdev.c
@@ -492,13 +492,11 @@ static int gntdev_release(struct inode *inode, struct file *flip)
pr_debug("priv %p\n", priv);
- spin_lock(&priv->lock);
while (!list_empty(&priv->maps)) {
map = list_entry(priv->maps.next, struct grant_map, next);
list_del(&map->next);
gntdev_put_map(map);
}
- spin_unlock(&priv->lock);
if (use_ptemod)
mmu_notifier_unregister(&priv->mn, priv->mm);
@@ -562,10 +560,11 @@ static long gntdev_ioctl_unmap_grant_ref(struct gntdev_priv *priv,
map = gntdev_find_map_index(priv, op.index >> PAGE_SHIFT, op.count);
if (map) {
list_del(&map->next);
- gntdev_put_map(map);
err = 0;
}
spin_unlock(&priv->lock);
+ if (map)
+ gntdev_put_map(map);
return err;
}