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[ Upstream commit 420d42f6f9 ]
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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Linux kernel
============
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In order to build the documentation, use ``make htmldocs`` or
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There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
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