Call "bpy.ops.screen.screen_full_area()" 2 times causes EXCEPTION_ACCESS_VIOLATION #78968

New Issue

hyyou · 2020-07-16T06:35:53+02:00

hyyou commented

2020-07-16 06:35:53 +02:00

System Information
Operating system: Windows-10-10.0.19041-SP0 64 Bits
Graphics card: GeForce RTX 2060/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 432.00

Blender Version
Broken: version: 2.83.0, branch: master, commit date: 2020-06-03 14:38, hash: 211b6c29f7
Worked: None

Short description of error
In text editor, the below code work fines :-

override = {'window': window, 'screen': screen, 'area': area}
bpy.ops.screen.screen_full_area(override)
#bpy.ops.screen.screen_full_area(override)

However, if I uncomment the line, Blender will crash.

Exact steps for others to reproduce the error
Try to run this script :-

import os.path
import bpy

print("=========BEGIN ====")
str_contextName='VIEW_3D'
bool_found = False
for window in bpy.context.window_manager.windows:
    screen = window.screen
    for area in screen.areas:
        if area.type == str_contextName:
            print(" ==> found context ")
            bpy.context.window.scene = bpy.context.scene
            override = {'window': window, 'screen': screen, 'area': area}
            bpy.ops.screen.screen_full_area(override)
            bpy.ops.screen.screen_full_area(override) #: try to uncomment = crash
            #^ will get "exception_access_violation" when exit this XXX.py 
            bool_found=True
            break
    
print("=========END====")

**System Information** Operating system: Windows-10-10.0.19041-SP0 64 Bits Graphics card: GeForce RTX 2060/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 432.00 **Blender Version** Broken: version: 2.83.0, branch: master, commit date: 2020-06-03 14:38, hash: `211b6c29f7` Worked: None **Short description of error** In text editor, the below code work fines :- ``` override = {'window': window, 'screen': screen, 'area': area} bpy.ops.screen.screen_full_area(override) #bpy.ops.screen.screen_full_area(override) ``` However, if I uncomment the line, Blender will crash. **Exact steps for others to reproduce the error** Try to run this script :- ``` import os.path import bpy print("=========BEGIN ====") str_contextName='VIEW_3D' bool_found = False for window in bpy.context.window_manager.windows: screen = window.screen for area in screen.areas: if area.type == str_contextName: print(" ==> found context ") bpy.context.window.scene = bpy.context.scene override = {'window': window, 'screen': screen, 'area': area} bpy.ops.screen.screen_full_area(override) bpy.ops.screen.screen_full_area(override) #: try to uncomment = crash #^ will get "exception_access_violation" when exit this XXX.py bool_found=True break print("=========END====") ```

hyyou commented

2020-07-16 06:35:53 +02:00

Added subscriber: @hyyou

Germano Cavalcante commented

2020-07-16 14:56:02 +02:00

Added subscriber: @mano-wii

Germano Cavalcante commented

2020-07-16 14:56:02 +02:00

Changed status from 'Needs Triage' to: 'Confirmed'

Germano Cavalcante commented

2020-07-16 14:56:02 +02:00

This is related to the same problem described in #77419
Solving that problem will probably solve this one too.

But even without working as it should, the crash should be replaced with an error message.
Just as it should be in #54468

This is related to the same problem described in #77419 Solving that problem will probably solve this one too. But even without working as it should, the crash should be replaced with an error message. Just as it should be in #54468

Campbell Barton commented

2020-08-23 14:14:14 +02:00

Added subscriber: @ideasman42

Campbell Barton commented

2020-08-23 14:14:14 +02:00

Looked into a fix, although the root of the error is that the area & screen being passed on the second call are invalid (freed memory).

A more general fix for this would be to validate all context members passed as overrides to operators from Python, to properly raise errors, as doing this from the operator would end up causing checks all over.

Once valid data is passed to the operator, this patch makes the functionality possible.

diff --git a/source/blender/editors/screen/screen_edit.c b/source/blender/editors/screen/screen_edit.c
index f534296bd0b..230970bed81 100644
--- a/source/blender/editors/screen/screen_edit.c
+++ b/source/blender/editors/screen/screen_edit.c
@@ -1259,6 +1259,7 @@ ScrArea *ED_screen_state_toggle(bContext *C, wmWindow *win, ScrArea *area, const
     oldscreen = WM_window_get_active_screen(win); /* the one disappearing */
 
     BLI_assert(BKE_workspace_layout_screen_get(layout_old) != screen);
+    BLI_assert(BKE_workspace_layout_screen_get(layout_old) == oldscreen);
     BLI_assert(BKE_workspace_layout_screen_get(layout_old)->state != SCREENNORMAL);
 
     screen->state = SCREENNORMAL;
@@ -1312,6 +1313,8 @@ ScrArea *ED_screen_state_toggle(bContext *C, wmWindow *win, ScrArea *area, const
      * Without doing so, the screen handling gets wrong area coords,
      * which in worst case can lead to crashes (see T43139) */
     screen->skip_handling = true;
+
+    WM_window_set_active_screen(win, workspace, screen);
   }
   else {
     /* change from SCREENNORMAL to new state */
@@ -1378,7 +1381,11 @@ ScrArea *ED_screen_state_toggle(bContext *C, wmWindow *win, ScrArea *area, const
     ED_screen_change(C, screen);
   }
 
+  BLI_assert(workspace = WM_window_get_active_workspace(win));
+  BLI_assert(win == CTX_wm_window(C));
+
   /* XXX bad code: setscreen() ends with first area active. fullscreen render assumes this too */
+  CTX_wm_screen_set(C, screen);
   CTX_wm_area_set(C, screen->areabase.first);
 
   return screen->areabase.first;
diff --git a/source/blender/editors/screen/screen_ops.c b/source/blender/editors/screen/screen_ops.c
index aff19ddacf1..cc2152d6bfd 100644
--- a/source/blender/editors/screen/screen_ops.c
+++ b/source/blender/editors/screen/screen_ops.c
@@ -3162,7 +3162,8 @@ static void SCREEN_OT_screen_set(wmOperatorType *ot)
 /* function to be called outside UI context, or for redo */
 static int screen_maximize_area_exec(bContext *C, wmOperator *op)
 {
-  bScreen *screen = CTX_wm_screen(C);
+  wmWindow *win = CTX_wm_window(C);
+  bScreen *screen = WM_window_get_active_screen(win);
   ScrArea *area = NULL;
   const bool hide_panels = RNA_boolean_get(op->ptr, "use_hide_panels");
 
@@ -3183,13 +3184,13 @@ static int screen_maximize_area_exec(bContext *C, wmOperator *op)
     if (!ELEM(screen->state, SCREENNORMAL, SCREENFULL)) {
       return OPERATOR_CANCELLED;
     }
-    ED_screen_state_toggle(C, CTX_wm_window(C), area, SCREENFULL);
+    ED_screen_state_toggle(C, win, area, SCREENFULL);
   }
   else {
     if (!ELEM(screen->state, SCREENNORMAL, SCREENMAXIMIZED)) {
       return OPERATOR_CANCELLED;
     }
-    ED_screen_state_toggle(C, CTX_wm_window(C), area, SCREENMAXIMIZED);
+    ED_screen_state_toggle(C, win, area, SCREENMAXIMIZED);
   }
 
   return OPERATOR_FINISHED;

Looked into a fix, although the root of the error is that the area & screen being passed on the second call are invalid (freed memory). A more general fix for this would be to validate all context members passed as overrides to operators from Python, to properly raise errors, as doing this from the operator would end up causing checks all over. Once valid data is passed to the operator, this patch makes the functionality possible. ``` diff --git a/source/blender/editors/screen/screen_edit.c b/source/blender/editors/screen/screen_edit.c index f534296bd0b..230970bed81 100644 --- a/source/blender/editors/screen/screen_edit.c +++ b/source/blender/editors/screen/screen_edit.c @@ -1259,6 +1259,7 @@ ScrArea *ED_screen_state_toggle(bContext *C, wmWindow *win, ScrArea *area, const oldscreen = WM_window_get_active_screen(win); /* the one disappearing */ BLI_assert(BKE_workspace_layout_screen_get(layout_old) != screen); + BLI_assert(BKE_workspace_layout_screen_get(layout_old) == oldscreen); BLI_assert(BKE_workspace_layout_screen_get(layout_old)->state != SCREENNORMAL); screen->state = SCREENNORMAL; @@ -1312,6 +1313,8 @@ ScrArea *ED_screen_state_toggle(bContext *C, wmWindow *win, ScrArea *area, const * Without doing so, the screen handling gets wrong area coords, * which in worst case can lead to crashes (see T43139) */ screen->skip_handling = true; + + WM_window_set_active_screen(win, workspace, screen); } else { /* change from SCREENNORMAL to new state */ @@ -1378,7 +1381,11 @@ ScrArea *ED_screen_state_toggle(bContext *C, wmWindow *win, ScrArea *area, const ED_screen_change(C, screen); } + BLI_assert(workspace = WM_window_get_active_workspace(win)); + BLI_assert(win == CTX_wm_window(C)); + /* XXX bad code: setscreen() ends with first area active. fullscreen render assumes this too */ + CTX_wm_screen_set(C, screen); CTX_wm_area_set(C, screen->areabase.first); return screen->areabase.first; diff --git a/source/blender/editors/screen/screen_ops.c b/source/blender/editors/screen/screen_ops.c index aff19ddacf1..cc2152d6bfd 100644 --- a/source/blender/editors/screen/screen_ops.c +++ b/source/blender/editors/screen/screen_ops.c @@ -3162,7 +3162,8 @@ static void SCREEN_OT_screen_set(wmOperatorType *ot) /* function to be called outside UI context, or for redo */ static int screen_maximize_area_exec(bContext *C, wmOperator *op) { - bScreen *screen = CTX_wm_screen(C); + wmWindow *win = CTX_wm_window(C); + bScreen *screen = WM_window_get_active_screen(win); ScrArea *area = NULL; const bool hide_panels = RNA_boolean_get(op->ptr, "use_hide_panels"); @@ -3183,13 +3184,13 @@ static int screen_maximize_area_exec(bContext *C, wmOperator *op) if (!ELEM(screen->state, SCREENNORMAL, SCREENFULL)) { return OPERATOR_CANCELLED; } - ED_screen_state_toggle(C, CTX_wm_window(C), area, SCREENFULL); + ED_screen_state_toggle(C, win, area, SCREENFULL); } else { if (!ELEM(screen->state, SCREENNORMAL, SCREENMAXIMIZED)) { return OPERATOR_CANCELLED; } - ED_screen_state_toggle(C, CTX_wm_window(C), area, SCREENMAXIMIZED); + ED_screen_state_toggle(C, win, area, SCREENMAXIMIZED); } return OPERATOR_FINISHED; ```

Campbell Barton commented

2020-09-23 08:05:19 +02:00

Changed status from 'Confirmed' to: 'Archived'

Campbell Barton closed this issue

2020-09-23 08:05:19 +02:00

Campbell Barton self-assigned this 2020-09-23 08:05:19 +02:00

Campbell Barton commented

2020-09-23 08:05:19 +02:00

Closing this report as screen_full_area sets a new screen and area which is needed for the second call to works as expected.

This works:

import os.path
import bpy

print("=========BEGIN ====")
str_contextName='VIEW_3D'
bool_found = False
for window in bpy.context.window_manager.windows:
    screen = window.screen
    for area in screen.areas:
        if area.type == str_contextName:
            print(" ==> found context A")
            bpy.context.window.scene = bpy.context.scene
            override = {'window': window, 'screen': screen, 'area': area}
            bpy.ops.screen.screen_full_area(override)
            break
    screen = window.screen
    for area in screen.areas:
        if area.type == str_contextName:
            print(" ==> found context B")
            override = {'window': window, 'screen': screen, 'area': area}
            bpy.ops.screen.screen_full_area(override)
            break
print("=========END====")

Closing this report as `screen_full_area` sets a new screen and area which is needed for the second call to works as expected. This works: ``` import os.path import bpy print("=========BEGIN ====") str_contextName='VIEW_3D' bool_found = False for window in bpy.context.window_manager.windows: screen = window.screen for area in screen.areas: if area.type == str_contextName: print(" ==> found context A") bpy.context.window.scene = bpy.context.scene override = {'window': window, 'screen': screen, 'area': area} bpy.ops.screen.screen_full_area(override) break screen = window.screen for area in screen.areas: if area.type == str_contextName: print(" ==> found context B") override = {'window': window, 'screen': screen, 'area': area} bpy.ops.screen.screen_full_area(override) break print("=========END====") ```

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Call "bpy.ops.screen.screen_full_area()" 2 times causes EXCEPTION_ACCESS_VIOLATION #78968