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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>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
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
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.