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| /linux/drivers/iommu/intel/ |
| H A D | svm.c | diff 420d42f6f9db27d88bc4f83e3e668fcdacbf7e29 Thu Dec 31 01:53:23 CET 2020 Lu Baolu <baolu.lu@linux.intel.com> iommu/vt-d: Fix lockdep splat in sva bind()/unbind()
Lock(&iommu->lock) without disabling irq causes lockdep warnings.
========================================================
WARNING: possible irq lock inversion dependency detected
5.11.0-rc1+ #828 Not tainted
--------------------------------------------------------
kworker/0:1H/120 just changed the state of lock:
ffffffffad9ea1b8 (device_domain_lock){..-.}-{2:2}, at:
iommu_flush_dev_iotlb.part.0+0x32/0x120
but this lock took another, SOFTIRQ-unsafe lock in the past:
(&iommu->lock){+.+.}-{2:2}
and interrupts could create inverse lock ordering between them.
other info that might help us debug this:
Possible interrupt unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&iommu->lock);
local_irq_disable();
lock(device_domain_lock);
lock(&iommu->lock);
<Interrupt>
lock(device_domain_lock);
*** DEADLOCK ***
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Link: https://lore.kernel.org/r/20201231005323.2178523-5-baolu.lu@linux.intel.com
Signed-off-by: Will Deacon <will@kernel.org>
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