Adding an msm_gem_object object to the inactive_list before completing its initialization is a bad idea because shrinker may pick it up from the inactive_list. Fix this by making sure that the initialization is complete before moving the msm_obj object to the inactive list.
This patch fixes the below error: [10027.553044] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000068 [10027.573305] Mem abort info: [10027.590160] ESR = 0x96000006 [10027.597905] EC = 0x25: DABT (current EL), IL = 32 bits [10027.614430] SET = 0, FnV = 0 [10027.624427] EA = 0, S1PTW = 0 [10027.632722] Data abort info: [10027.638039] ISV = 0, ISS = 0x00000006 [10027.647459] CM = 0, WnR = 0 [10027.654345] user pgtable: 4k pages, 39-bit VAs, pgdp=00000001e3a6a000 [10027.672681] [0000000000000068] pgd=0000000198c31003, pud=0000000198c31003, pmd=0000000000000000 [10027.693900] Internal error: Oops: 96000006 [#1] PREEMPT SMP [10027.738261] CPU: 3 PID: 214 Comm: kswapd0 Tainted: G S 5.4.40 #1 [10027.745766] Hardware name: Qualcomm Technologies, Inc. SC7180 IDP (DT) [10027.752472] pstate: 80c00009 (Nzcv daif +PAN +UAO) [10027.757409] pc : mutex_is_locked+0x14/0x2c [10027.761626] lr : msm_gem_shrinker_count+0x70/0xec [10027.766454] sp : ffffffc011323ad0 [10027.769867] x29: ffffffc011323ad0 x28: ffffffe677e4b878 [10027.775324] x27: 0000000000000cc0 x26: 0000000000000000 [10027.780783] x25: ffffff817114a708 x24: 0000000000000008 [10027.786242] x23: ffffff8023ab7170 x22: 0000000000000001 [10027.791701] x21: ffffff817114a080 x20: 0000000000000119 [10027.797160] x19: 0000000000000068 x18: 00000000000003bc [10027.802621] x17: 0000000004a34210 x16: 00000000000000c0 [10027.808083] x15: 0000000000000000 x14: 0000000000000000 [10027.813542] x13: ffffffe677e0a3c0 x12: 0000000000000000 [10027.819000] x11: 0000000000000000 x10: ffffff8174b94340 [10027.824461] x9 : 0000000000000000 x8 : 0000000000000000 [10027.829919] x7 : 00000000000001fc x6 : ffffffc011323c88 [10027.835373] x5 : 0000000000000001 x4 : ffffffc011323d80 [10027.840832] x3 : ffffffff0477b348 x2 : 0000000000000000 [10027.846290] x1 : ffffffc011323b68 x0 : 0000000000000068 [10027.851748] Call trace: [10027.854264] mutex_is_locked+0x14/0x2c [10027.858121] msm_gem_shrinker_count+0x70/0xec [10027.862603] shrink_slab+0xc0/0x4b4 [10027.866187] shrink_node+0x4a8/0x818 [10027.869860] kswapd+0x624/0x890 [10027.873097] kthread+0x11c/0x12c [10027.876424] ret_from_fork+0x10/0x18 [10027.880102] Code: f9000bf3 910003fd aa0003f3 d503201f (f9400268) [10027.886362] ---[ end trace df5849a1a3543251 ]--- [10027.891518] Kernel panic - not syncing: Fatal exception
Signed-off-by: Akhil P Oommen akhilpo@codeaurora.org --- drivers/gpu/drm/msm/msm_gem.c | 36 +++++++++++++++++++++--------------- 1 file changed, 21 insertions(+), 15 deletions(-)
diff --git a/drivers/gpu/drm/msm/msm_gem.c b/drivers/gpu/drm/msm/msm_gem.c index 6277fde..f63bb7e 100644 --- a/drivers/gpu/drm/msm/msm_gem.c +++ b/drivers/gpu/drm/msm/msm_gem.c @@ -994,10 +994,8 @@ int msm_gem_new_handle(struct drm_device *dev, struct drm_file *file,
static int msm_gem_new_impl(struct drm_device *dev, uint32_t size, uint32_t flags, - struct drm_gem_object **obj, - bool struct_mutex_locked) + struct drm_gem_object **obj) { - struct msm_drm_private *priv = dev->dev_private; struct msm_gem_object *msm_obj;
switch (flags & MSM_BO_CACHE_MASK) { @@ -1023,15 +1021,6 @@ static int msm_gem_new_impl(struct drm_device *dev, INIT_LIST_HEAD(&msm_obj->submit_entry); INIT_LIST_HEAD(&msm_obj->vmas);
- if (struct_mutex_locked) { - WARN_ON(!mutex_is_locked(&dev->struct_mutex)); - list_add_tail(&msm_obj->mm_list, &priv->inactive_list); - } else { - mutex_lock(&dev->struct_mutex); - list_add_tail(&msm_obj->mm_list, &priv->inactive_list); - mutex_unlock(&dev->struct_mutex); - } - *obj = &msm_obj->base;
return 0; @@ -1041,6 +1030,7 @@ static struct drm_gem_object *_msm_gem_new(struct drm_device *dev, uint32_t size, uint32_t flags, bool struct_mutex_locked) { struct msm_drm_private *priv = dev->dev_private; + struct msm_gem_object *msm_obj; struct drm_gem_object *obj = NULL; bool use_vram = false; int ret; @@ -1061,14 +1051,15 @@ static struct drm_gem_object *_msm_gem_new(struct drm_device *dev, if (size == 0) return ERR_PTR(-EINVAL);
- ret = msm_gem_new_impl(dev, size, flags, &obj, struct_mutex_locked); + ret = msm_gem_new_impl(dev, size, flags, &obj); if (ret) goto fail;
+ msm_obj = to_msm_bo(obj); + if (use_vram) { struct msm_gem_vma *vma; struct page **pages; - struct msm_gem_object *msm_obj = to_msm_bo(obj);
mutex_lock(&msm_obj->lock);
@@ -1103,6 +1094,15 @@ static struct drm_gem_object *_msm_gem_new(struct drm_device *dev, mapping_set_gfp_mask(obj->filp->f_mapping, GFP_HIGHUSER); }
+ if (struct_mutex_locked) { + WARN_ON(!mutex_is_locked(&dev->struct_mutex)); + list_add_tail(&msm_obj->mm_list, &priv->inactive_list); + } else { + mutex_lock(&dev->struct_mutex); + list_add_tail(&msm_obj->mm_list, &priv->inactive_list); + mutex_unlock(&dev->struct_mutex); + } + return obj;
fail: @@ -1125,6 +1125,7 @@ struct drm_gem_object *msm_gem_new(struct drm_device *dev, struct drm_gem_object *msm_gem_import(struct drm_device *dev, struct dma_buf *dmabuf, struct sg_table *sgt) { + struct msm_drm_private *priv = dev->dev_private; struct msm_gem_object *msm_obj; struct drm_gem_object *obj; uint32_t size; @@ -1138,7 +1139,7 @@ struct drm_gem_object *msm_gem_import(struct drm_device *dev,
size = PAGE_ALIGN(dmabuf->size);
- ret = msm_gem_new_impl(dev, size, MSM_BO_WC, &obj, false); + ret = msm_gem_new_impl(dev, size, MSM_BO_WC, &obj); if (ret) goto fail;
@@ -1163,6 +1164,11 @@ struct drm_gem_object *msm_gem_import(struct drm_device *dev, }
mutex_unlock(&msm_obj->lock); + + mutex_lock(&dev->struct_mutex); + list_add_tail(&msm_obj->mm_list, &priv->inactive_list); + mutex_unlock(&dev->struct_mutex); + return obj;
fail: