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ded3ad780c
Fix a potential deadlock caused by inconsistent spinlock usage
between interrupt and process contexts in the userq fence driver.
The issue occurs when amdgpu_userq_fence_driver_process() is called
from both:
- Interrupt context: gfx_v11_0_eop_irq() -> amdgpu_userq_fence_driver_process()
- Process context: amdgpu_eviction_fence_suspend_worker() ->
amdgpu_userq_fence_driver_force_completion() -> amdgpu_userq_fence_driver_process()
In interrupt context, the spinlock was acquired without disabling
interrupts, leaving it in {IN-HARDIRQ-W} state. When the same lock
is acquired in process context, the kernel detects inconsistent
locking since the process context acquisition would enable interrupts
while holding a lock previously acquired in interrupt context.
Kernel log shows:
[ 4039.310790] inconsistent {IN-HARDIRQ-W} -> {HARDIRQ-ON-W} usage.
[ 4039.310804] kworker/7:2/409 [HC0[0]:SC0[0]:HE1:SE1] takes:
[ 4039.310818] ffff9284e1bed000 (&fence_drv->fence_list_lock){?...}-{3:3},
[ 4039.310993] {IN-HARDIRQ-W} state was registered at:
[ 4039.311004] lock_acquire+0xc6/0x300
[ 4039.311018] _raw_spin_lock+0x39/0x80
[ 4039.311031] amdgpu_userq_fence_driver_process.part.0+0x30/0x180 [amdgpu]
[ 4039.311146] amdgpu_userq_fence_driver_process+0x17/0x30 [amdgpu]
[ 4039.311257] gfx_v11_0_eop_irq+0x132/0x170 [amdgpu]
Fix by using spin_lock_irqsave()/spin_unlock_irqrestore() to properly
manage interrupt state regardless of calling context.
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Jesse Zhang <Jesse.Zhang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
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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.