From 2e1e5c5532ffe14ff48811ffe96a40f7dce8645c Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Tue, 9 Apr 2019 18:41:08 +0100 Subject: [PATCH] drm/i915: Avoid reclaim taints from runtime-pm debug 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 Reviewed-by: Mika Kuoppala Link: https://patchwork.freedesktop.org/patch/msgid/20190409174108.19396-1-chris@chris-wilson.co.uk --- drivers/gpu/drm/i915/intel_runtime_pm.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/i915/intel_runtime_pm.c b/drivers/gpu/drm/i915/intel_runtime_pm.c index e6d1e59..3107a74 100644 --- a/drivers/gpu/drm/i915/intel_runtime_pm.c +++ b/drivers/gpu/drm/i915/intel_runtime_pm.c @@ -162,7 +162,7 @@ static void cancel_intel_runtime_pm_wakeref(struct drm_i915_private *i915, rpm->debug.count, atomic_read(&rpm->wakeref_count))) { char *buf; - buf = kmalloc(PAGE_SIZE, GFP_KERNEL); + buf = kmalloc(PAGE_SIZE, GFP_NOWAIT | __GFP_NOWARN); if (!buf) return; @@ -198,7 +198,7 @@ __print_intel_runtime_pm_wakeref(struct drm_printer *p, unsigned long i; char *buf; - buf = kmalloc(PAGE_SIZE, GFP_KERNEL); + buf = kmalloc(PAGE_SIZE, GFP_NOWAIT | __GFP_NOWARN); if (!buf) return; @@ -282,7 +282,9 @@ void print_intel_runtime_pm_wakeref(struct drm_i915_private *i915, if (dbg.count <= alloc) break; - s = krealloc(dbg.owners, dbg.count * sizeof(*s), GFP_KERNEL); + s = krealloc(dbg.owners, + dbg.count * sizeof(*s), + GFP_NOWAIT | __GFP_NOWARN); if (!s) goto out; -- 2.7.4