2e1e5c5532
As intel_runtime_pm_get/_put may be called from any blockable context, we need to avoid allowing reclaim from our mallocs, as we need to avoid tainting any mutexes held by the callers (as they may themselves not allow for allocations as they are taken in the shrinker). <4> [435.339331] WARNING: possible circular locking dependency detected <4> [435.339364] 5.1.0-rc4-CI-Trybot_4116+ #1 Tainted: G U <4> [435.339395] ------------------------------------------------------ <4> [435.339426] gem_caching/1334 is trying to acquire lock: <4> [435.339456] 000000004505c39b (wakeref#3){+.+.}, at: intel_engine_pm_put+0x1b/0x40 [i915] <4> [435.339788] but task is already holding lock: <4> [435.339819] 00000000ee77b4ed (fs_reclaim){+.+.}, at: fs_reclaim_acquire.part.24+0x0/0x30 <4> [435.339879] which lock already depends on the new lock. <4> [435.339918] the existing dependency chain (in reverse order) is: <4> [435.339952] -> #1 (fs_reclaim){+.+.}: <4> [435.339998] fs_reclaim_acquire.part.24+0x24/0x30 <4> [435.340035] kmem_cache_alloc_trace+0x2a/0x290 <4> [435.340311] __print_intel_runtime_pm_wakeref+0x24/0x160 [i915] <4> [435.340590] untrack_intel_runtime_pm_wakeref+0x16e/0x1d0 [i915] <4> [435.340869] intel_runtime_pm_put_unchecked+0xd/0x30 [i915] <4> [435.341147] __intel_wakeref_put_once+0x22/0x40 [i915] <4> [435.341508] i915_request_retire+0x477/0xaf0 [i915] <4> [435.341871] ring_retire_requests+0x86/0x160 [i915] <4> [435.342226] i915_retire_requests+0x58/0xc0 [i915] <4> [435.342576] retire_work_handler+0x5b/0x70 [i915] <4> [435.342615] process_one_work+0x245/0x610 <4> [435.342646] worker_thread+0x37/0x380 <4> [435.342679] kthread+0x119/0x130 <4> [435.342714] ret_from_fork+0x3a/0x50 <4> [435.342739] -> #0 (wakeref#3){+.+.}: <4> [435.342788] lock_acquire+0xa6/0x1c0 <4> [435.342822] __mutex_lock+0x8c/0x960 <4> [435.342853] atomic_dec_and_mutex_lock+0x33/0x50 <4> [435.343151] intel_engine_pm_put+0x1b/0x40 [i915] <4> [435.343501] i915_request_retire+0x477/0xaf0 [i915] <4> [435.343851] ring_retire_requests+0x86/0x160 [i915] <4> [435.344202] i915_retire_requests+0x58/0xc0 [i915] <4> [435.344543] i915_gem_shrink+0xd8/0x5b0 [i915] <4> [435.344835] i915_drop_caches_set+0x17b/0x250 [i915] <4> [435.344877] simple_attr_write+0xb0/0xd0 <4> [435.344911] full_proxy_write+0x51/0x80 <4> [435.344943] vfs_write+0xbd/0x1b0 <4> [435.344972] ksys_write+0x55/0xe0 <4> [435.345002] do_syscall_64+0x55/0x190 <4> [435.345040] entry_SYSCALL_64_after_hwframe+0x49/0xbe Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20190409174108.19396-1-chris@chris-wilson.co.uk
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.