[    1.828887] iommu: Adding device 0000:00:14.5 to group 10
[    1.831805] ------------[ cut here ]------------
[    1.831814] WARNING: CPU: 0 PID: 1 at drivers/iommu/amd_iommu.c:1958 
0xffffffff812d6449()
[    1.831817] Modules linked in:
[    1.831827] CPU: 0 PID: 1 Comm: swapper/0 Tainted: G W       4.4.1-rt6+ #5
[    1.831831] Hardware name: empty empty/S8225, BIOS 'V3.03   ' 11/01/2012
[    1.831835]  ffffffff815fd5cc ffffffff81224d47 0000000000000000 ffffffff81034e17
[    1.831847]  ffff8804231a5a00 ffff880422bb8420 ffff88042310e898 ffff880423934000
[    1.831858]  ffff880422bb8400 ffffffff812d6449 ffff880422b5e7f8 ffff880422b5e8e8
[    1.831868] Call Trace:
[    1.831873]  [<ffffffff81224d47>] ? 0xffffffff81224d47
[    1.831878]  [<ffffffff81034e17>] ? 0xffffffff81034e17
[    1.831883]  [<ffffffff812d6449>] ? 0xffffffff812d6449
[    1.831889]  [<ffffffff812d398c>] ? 0xffffffff812d398c
[    1.831894]  [<ffffffff812d40c2>] ? 0xffffffff812d40c2
[    1.831899]  [<ffffffff812d7313>] ? 0xffffffff812d7313
[    1.831904]  [<ffffffff812d3080>] ? 0xffffffff812d3080
[    1.831909]  [<ffffffff812d30a0>] ? 0xffffffff812d30a0
[    1.831913]  [<ffffffff8130fce7>] ? 0xffffffff8130fce7
[    1.831918]  [<ffffffff812d3bab>] ? 0xffffffff812d3bab
[    1.831923]  [<ffffffff8173b173>] ? 0xffffffff8173b173
[    1.831928]  [<ffffffff8171c2de>] ? 0xffffffff8171c2de
[    1.831933]  [<ffffffff8173b2be>] ? 0xffffffff8173b2be
[    1.831937]  [<ffffffff8173b339>] ? 0xffffffff8173b339
[    1.831942]  [<ffffffff8171c2ec>] ? 0xffffffff8171c2ec
[    1.831946]  [<ffffffff810003e2>] ? 0xffffffff810003e2
[    1.831952]  [<ffffffff81718e0d>] ? 0xffffffff81718e0d
[    1.831956]  [<ffffffff81504810>] ? 0xffffffff81504810
[    1.831961]  [<ffffffff81504815>] ? 0xffffffff81504815
[    1.831966]  [<ffffffff8150936f>] ? 0xffffffff8150936f
[    1.831971]  [<ffffffff81504810>] ? 0xffffffff81504810
[    1.831976] ---[ end trace 0000000000000010 ]---

---

Called from amd_iommu.c,  __attach_device() from  attach_device()

static int __attach_device(struct iommu_dev_data *dev_data,
                            struct protection_domain *domain)
{
         int ret;

         /*
          * Must be called with IRQs disabled. Warn here to detect early
          * when its not.
          */
         WARN_ON(!irqs_disabled());
         ^^^^^^^^^^^^^^^^^^^^^^^^^^  WARNING
...
}


static int attach_device(struct device *dev,
                          struct protection_domain *domain)
{
...
         }

         write_lock_irqsave(&amd_iommu_devtable_lock, flags);
         ret = __attach_device(dev_data, domain);
         write_unlock_irqrestore(&amd_iommu_devtable_lock, flags);
...