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Vasant Hegde
84b1cec4fa
LOCKDEP detector reported below warning:
----------------------------------------
[ 23.796949] ========================================================
[ 23.796950] WARNING: possible irq lock inversion dependency detected
[ 23.796952] 6.8.0fix+ #811 Not tainted
[ 23.796954] --------------------------------------------------------
[ 23.796954] kworker/0:1/8 just changed the state of lock:
[ 23.796956] ff365325e084a9b8 (&domain->lock){..-.}-{3:3}, at: amd_iommu_flush_iotlb_all+0x1f/0x50
[ 23.796969] but this lock took another, SOFTIRQ-unsafe lock in the past:
[ 23.796970] (pd_bitmap_lock){+.+.}-{3:3}
[ 23.796972]
and interrupts could create inverse lock ordering between them.
[ 23.796973]
other info that might help us debug this:
[ 23.796974] Chain exists of:
&domain->lock --> &dev_data->lock --> pd_bitmap_lock
[ 23.796980] Possible interrupt unsafe locking scenario:
[ 23.796981] CPU0 CPU1
[ 23.796982] ---- ----
[ 23.796983] lock(pd_bitmap_lock);
[ 23.796985] local_irq_disable();
[ 23.796985] lock(&domain->lock);
[ 23.796988] lock(&dev_data->lock);
[ 23.796990] <Interrupt>
[ 23.796991] lock(&domain->lock);
Fix this issue by disabling interrupt when acquiring pd_bitmap_lock.
Note that this is temporary fix. We have a plan to replace custom bitmap
allocator with IDA allocator.
Fixes: 87a6f1f22c ("iommu/amd: Introduce per-device domain ID to fix potential TLB aliasing issue")
Reviewed-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Signed-off-by: Vasant Hegde <vasant.hegde@amd.com>
Link: https://lore.kernel.org/r/20240404102717.6705-1-vasant.hegde@amd.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>
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 reStructuredText 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.