[PATCH v2 4/5] drm/i915: Drop user contexts on driver remove

Janusz Krzysztofik janusz.krzysztofik at linux.intel.com
Sun Jun 7 16:46:15 UTC 2020


Contexts associated with open device file descriptors together with
their assigned address spaces are now closed on device file close.  On
address space closure its associated DMA mappings are revoked.  If the
device is removed while being open, subsequent attempts to revoke
those mappings while closing the device file descriptor may may be
judged by intel-iommu code as a bug and result in kernel panic.

Since user contexts become useless after the device is no longer
available, drop them on device removal.  As the code of a new helper
duplicates that of i915_gem_context_close() to a significant extent,
refactor the latter to call the former.

<4> [36.900985] ------------[ cut here ]------------
<2> [36.901005] kernel BUG at drivers/iommu/intel-iommu.c:3717!
<4> [36.901105] invalid opcode: 0000 [#1] PREEMPT SMP NOPTI
<4> [36.901117] CPU: 0 PID: 39 Comm: kworker/u8:1 Tainted: G     U  W         5.7.0-rc5-CI-CI_DRM_8485+ #1
<4> [36.901133] Hardware name: Intel Corporation Elkhart Lake Embedded Platform/ElkhartLake LPDDR4x T3 CRB, BIOS EHLSFWI1.R00.1484.A00.1911290833 11/29/2019
<4> [36.901250] Workqueue: i915 __i915_vm_release [i915]
<4> [36.901264] RIP: 0010:intel_unmap+0x1f5/0x230
<4> [36.901274] Code: 01 e8 9f bc a9 ff 85 c0 74 09 80 3d df 60 09 01 00 74 19 65 ff 0d 13 12 97 7e 0f 85 fc fe ff ff e8 82 b0 95 ff e9 f2 fe ff ff <0f> 0b e8 d4 bd a9 ff 85 c0 75 de 48 c7 c2 10 84 2c 82 be 54 00 00
<4> [36.901302] RSP: 0018:ffffc900001ebdc0 EFLAGS: 00010246
<4> [36.901313] RAX: 0000000000000000 RBX: ffff8882561dd000 RCX: 0000000000000000
<4> [36.901324] RDX: 0000000000001000 RSI: 00000000ffd9c000 RDI: ffff888274c94000
<4> [36.901336] RBP: ffff888274c940b0 R08: 0000000000000000 R09: 0000000000000001
<4> [36.901348] R10: 000000000a25d812 R11: 00000000112af2d4 R12: ffff888252c70200
<4> [36.901360] R13: 00000000ffd9c000 R14: 0000000000001000 R15: ffff8882561dd010
<4> [36.901372] FS:  0000000000000000(0000) GS:ffff888278000000(0000) knlGS:0000000000000000
<4> [36.901386] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
<4> [36.901396] CR2: 00007f06def54950 CR3: 0000000255844000 CR4: 0000000000340ef0
<4> [36.901408] Call Trace:
<4> [36.901418]  ? process_one_work+0x1de/0x600
<4> [36.901494]  cleanup_page_dma+0x37/0x70 [i915]
<4> [36.901573]  free_pd+0x9/0x20 [i915]
<4> [36.901644]  gen8_ppgtt_cleanup+0x59/0xc0 [i915]
<4> [36.901721]  __i915_vm_release+0x14/0x30 [i915]
<4> [36.901733]  process_one_work+0x268/0x600
<4> [36.901744]  ? __schedule+0x307/0x8d0
<4> [36.901756]  worker_thread+0x37/0x380
<4> [36.901766]  ? process_one_work+0x600/0x600
<4> [36.901775]  kthread+0x140/0x160
<4> [36.901783]  ? kthread_park+0x80/0x80
<4> [36.901792]  ret_from_fork+0x24/0x50
<4> [36.901804] Modules linked in: mei_hdcp i915 x86_pkg_temp_thermal coretemp crct10dif_pclmul crc32_pclmul ghash_clmulni_intel ax88179_178a usbnet mii mei_me mei prime_numbers intel_lpss_pci
<4> [36.901857] ---[ end trace 52d1b4d81f8d1ea7 ]---

v2: Iterate drm_device->filelist elements for simplicity (Michał).

Signed-off-by: Janusz Krzysztofik <janusz.krzysztofik at linux.intel.com>
Cc: Michał Winiarski <michal.winiarski at intel.com>
---
 drivers/gpu/drm/i915/gem/i915_gem_context.c | 37 ++++++++++++++++-----
 drivers/gpu/drm/i915/gem/i915_gem_context.h |  1 +
 drivers/gpu/drm/i915/i915_gem.c             |  3 ++
 3 files changed, 33 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context.c b/drivers/gpu/drm/i915/gem/i915_gem_context.c
index f5d59d18cd5b..7203adfb2973 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_context.c
@@ -927,6 +927,33 @@ void i915_gem_driver_release__contexts(struct drm_i915_private *i915)
 	rcu_barrier(); /* and flush the left over RCU frees */
 }
 
+static void remove_file_contexts(struct drm_i915_file_private *file_priv)
+{
+	struct i915_address_space *vm;
+	struct i915_gem_context *ctx;
+	unsigned long idx;
+
+	xa_for_each(&file_priv->context_xa, idx, ctx) {
+		xa_erase(&file_priv->context_xa, idx);
+		context_close(ctx);
+	}
+
+	xa_for_each(&file_priv->vm_xa, idx, vm) {
+		xa_erase(&file_priv->vm_xa, idx);
+		i915_vm_put(vm);
+	}
+}
+
+void i915_gem_driver_remove__contexts(struct drm_i915_private *i915)
+{
+	struct drm_file *file_priv, *fn;
+
+	list_for_each_entry_safe(file_priv, fn, &i915->drm.filelist, lhead)
+		remove_file_contexts(file_priv->driver_priv);
+
+	i915_gem_driver_release__contexts(i915);
+}
+
 static int gem_context_register(struct i915_gem_context *ctx,
 				struct drm_i915_file_private *fpriv,
 				u32 *id)
@@ -992,16 +1019,10 @@ void i915_gem_context_close(struct drm_file *file)
 {
 	struct drm_i915_file_private *file_priv = file->driver_priv;
 	struct drm_i915_private *i915 = file_priv->dev_priv;
-	struct i915_address_space *vm;
-	struct i915_gem_context *ctx;
-	unsigned long idx;
 
-	xa_for_each(&file_priv->context_xa, idx, ctx)
-		context_close(ctx);
-	xa_destroy(&file_priv->context_xa);
+	remove_file_contexts(file_priv);
 
-	xa_for_each(&file_priv->vm_xa, idx, vm)
-		i915_vm_put(vm);
+	xa_destroy(&file_priv->context_xa);
 	xa_destroy(&file_priv->vm_xa);
 
 	contexts_flush_free(&i915->gem.contexts);
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context.h b/drivers/gpu/drm/i915/gem/i915_gem_context.h
index 3702b2fb27ab..62808bea9239 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_context.h
+++ b/drivers/gpu/drm/i915/gem/i915_gem_context.h
@@ -110,6 +110,7 @@ i915_gem_context_clear_user_engines(struct i915_gem_context *ctx)
 
 /* i915_gem_context.c */
 void i915_gem_init__contexts(struct drm_i915_private *i915);
+void i915_gem_driver_remove__contexts(struct drm_i915_private *i915);
 void i915_gem_driver_release__contexts(struct drm_i915_private *i915);
 
 int i915_gem_context_open(struct drm_i915_private *i915,
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 4ef88d715a19..26de1d824d0c 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -1229,6 +1229,9 @@ void i915_gem_driver_remove(struct drm_i915_private *dev_priv)
 	intel_wakeref_auto_fini(&dev_priv->ggtt.userfault_wakeref);
 
 	i915_gem_suspend_late(dev_priv);
+
+	i915_gem_driver_remove__contexts(dev_priv);
+
 	intel_gt_driver_remove(&dev_priv->gt);
 	dev_priv->uabi_engines = RB_ROOT;
 
-- 
2.21.1



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