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Daniel De Graaf authored
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>
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