$ xauth add :10 . 454534543543543530 $ Xnest :10 & $ DISPLAY=:10 gnome-session After gnome has got a reasonable way through startup, switch workspace and back again. Xnest crashes with: X Error of failed request: BadMatch (invalid parameter attributes) Major opcode of failed request: 73 (X_GetImage) Serial number of failed request: 40692 Current serial number in output stream: 40692 Using xorg-server 1.1.1-r3 on Gentoo.
Here's a trace: (gdb) bt full #0 _XDefaultError (dpy=0x83ff598, event=0xbf8076dc) at XlibInt.c:2748 No locals. #1 0xb7d412de in _XError (dpy=0x83ff598, rep=0xbf8077cc) at XlibInt.c:2905 rtn_val = <value optimized out> event = {type = 0, xany = {type = 0, serial = 138409368, send_event = 123734220, display = 0x3485, window = 3070249224}, xkey = { type = 0, serial = 138409368, send_event = 123734220, display = 0x3485, window = 3070249224, root = 3083905088, subwindow = 3084914688, time = 3212867376, x = -1208605267, y = -1210052168, x_root = 0, y_root = 1, state = 1, keycode = 0, same_screen = -1211049272}, xbutton = { type = 0, serial = 138409368, send_event = 123734220, display = 0x3485, window = 3070249224, root = 3083905088, subwindow = 3084914688, time = 3212867376, x = -1208605267, y = -1210052168, x_root = 0, y_root = 1, state = 1, button = 0, same_screen = -1211049272}, xmotion = { type = 0, serial = 138409368, send_event = 123734220, display = 0x3485, window = 3070249224, root = 3083905088, subwindow = 3084914688, time = 3212867376, x = -1208605267, y = -1210052168, x_root = 0, y_root = 1, state = 1, is_hint = 0 '\0', same_screen = -1211049272}, xcrossing = {type = 0, serial = 138409368, send_event = 123734220, display = 0x3485, window = 3070249224, root = 3083905088, subwindow = 3084914688, time = 3212867376, x = -1208605267, y = -1210052168, x_root = 0, y_root = 1, mode = 1, detail = 0, same_screen = -1211049272, focus = -1211084800, state = 1020136}, ---Type <return> to continue, or q <return> to quit--- xfocus = {type = 0, serial = 138409368, send_event = 123734220, display = 0x3485, window = 3070249224, mode = -1211062208, detail = -1210052608}, xexpose = {type = 0, serial = 138409368, send_event = 123734220, display = 0x3485, window = 3070249224, x = -1211062208, y = -1210052608, width = -1082099920, height = -1208605267, count = -1210052168}, xgraphicsexpose = {type = 0, serial = 138409368, send_event = 123734220, display = 0x3485, drawable = 3070249224, x = -1211062208, y = -1210052608, width = -1082099920, height = -1208605267, count = -1210052168, major_code = 0, minor_code = 1}, xnoexpose = {type = 0, serial = 138409368, send_event = 123734220, display = 0x3485, drawable = 3070249224, major_code = -1211062208, minor_code = -1210052608}, xvisibility = {type = 0, serial = 138409368, send_event = 123734220, display = 0x3485, window = 3070249224, state = -1211062208}, xcreatewindow = {type = 0, serial = 138409368, send_event = 123734220, display = 0x3485, parent = 3070249224, window = 3083905088, x = -1210052608, y = -1082099920, width = -1208605267, height = -1210052168, border_width = 0, override_redirect = 1}, xdestroywindow = {type = 0, serial = 138409368, send_event = 123734220, display = 0x3485, event = 3070249224, window = 3083905088}, xunmap = {type = 0, serial = 138409368, send_event = 123734220, display = 0x3485, event = 3070249224, window = 3083905088, from_configure = -1210052608}, xmap = {type = 0, ---Type <return> to continue, or q <return> to quit--- serial = 138409368, send_event = 123734220, display = 0x3485, event = 3070249224, window = 3083905088, override_redirect = -1210052608}, xmaprequest = {type = 0, serial = 138409368, send_event = 123734220, display = 0x3485, parent = 3070249224, window = 3083905088}, xreparent = { type = 0, serial = 138409368, send_event = 123734220, display = 0x3485, event = 3070249224, window = 3083905088, parent = 3084914688, x = -1082099920, y = -1208605267, override_redirect = -1210052168}, xconfigure = {type = 0, serial = 138409368, send_event = 123734220, display = 0x3485, event = 3070249224, window = 3083905088, x = -1210052608, y = -1082099920, width = -1208605267, height = -1210052168, border_width = 0, above = 1, override_redirect = 1}, xgravity = {type = 0, serial = 138409368, send_event = 123734220, display = 0x3485, event = 3070249224, window = 3083905088, x = -1210052608, y = -1082099920}, xresizerequest = {type = 0, serial = 138409368, send_event = 123734220, display = 0x3485, window = 3070249224, width = -1211062208, height = -1210052608}, xconfigurerequest = {type = 0, serial = 138409368, send_event = 123734220, display = 0x3485, parent = 3070249224, window = 3083905088, x = -1210052608, y = -1082099920, width = -1208605267, height = -1210052168, border_width = 0, above = 1, detail = 1, value_mask = 0}, xcirculate = {type = 0, serial = 138409368, send_event = 123734220, display = 0x3485, event = 3070249224, window = 3083905088, place = -1210052608}, xcirculaterequest = {type = 0, ---Type <return> to continue, or q <return> to quit--- serial = 138409368, send_event = 123734220, display = 0x3485, parent = 3070249224, window = 3083905088, place = -1210052608}, xproperty = {type = 0, serial = 138409368, send_event = 123734220, display = 0x3485, window = 3070249224, atom = 3083905088, time = 3084914688, state = -1082099920}, xselectionclear = {type = 0, serial = 138409368, send_event = 123734220, display = 0x3485, window = 3070249224, selection = 3083905088, time = 3084914688}, xselectionrequest = {type = 0, serial = 138409368, send_event = 123734220, display = 0x3485, owner = 3070249224, requestor = 3083905088, selection = 3084914688, target = 3212867376, property = 3086362029, time = 3084915128}, xselection = {type = 0, serial = 138409368, send_event = 123734220, display = 0x3485, requestor = 3070249224, selection = 3083905088, target = 3084914688, property = 3212867376, time = 3086362029}, xcolormap = {type = 0, serial = 138409368, send_event = 123734220, display = 0x3485, window = 3070249224, colormap = 3083905088, new = -1210052608, state = -1082099920}, xclient = { type = 0, serial = 138409368, send_event = 123734220, display = 0x3485, window = 3070249224, message_type = 3083905088, format = -1210052608, data = {b = "0w\200��%���\021��\000\000\000\000\001\000\000", s = {30512, -16512, 9645, -18442, 4536, -18464, 0, 0, 1, 0}, l = {-1082099920, -1208605267, -1210052168, 0, 1}}}, xmapping = {type = 0, serial = 138409368, send_event = 123734220, display = 0x3485, window = 3070249224, request = -1211062208, first_keycode = -1210052608, ---Type <return> to continue, or q <return> to quit--- count = -1082099920}, xerror = {type = 0, display = 0x83ff598, resourceid = 123734220, serial = 13445, error_code = 8 '\b', request_code = 73 'I', minor_code = 0 '\0'}, xkeymap = {type = 0, serial = 138409368, send_event = 123734220, display = 0x3485, window = 3070249224, key_vector = "@�з\000\020��0w\200��%���\021��\000\000\000\000\001\000\000\000\001\000\000"}, pad = {0, 138409368, 123734220, 13445, -1224718072, -1211062208, -1210052608, -1082099920, -1208605267, -1210052168, 0, 1, 1, 0, -1211049272, -1211084800, 1020136, -1211062208, -1210066172, 0, 138409368, -1082099832, -1208583280, -1210838549}} async = <value optimized out> next = <value optimized out> #2 0xb7d42f50 in _XReply (dpy=0x83ff598, rep=0xbf8077cc, extra=0, discard=0) at XlibInt.c:1831 ext = (_XExtension *) 0x0 ret = 138409368 ret_code = -1210831733 serial = 13445 cur_request = 13445 cvl = <value optimized out> #3 0xb7d24539 in XGetImage (dpy=0x83ff598, d=123734220, x=0, y=2, width=17, height=18, plane_mask=4294967295, format=2) at GetImage.c:75 rep = {type = 0 '\0', depth = 8 '\b', sequenceNumber = 13445, ---Type <return> to continue, or q <return> to quit--- length = 123734220, visual = 4784128, pad3 = 2, pad4 = 17, pad5 = 18, pad6 = 4294967295, pad7 = 134746569} nbytes = <value optimized out> image = <value optimized out> #4 0x080601a5 in xnestGetImage (pDrawable=0x8608de8, x=0, y=2, w=17, h=18, format=138409368, planeMask=4294967295, pImage=0xbf807870 "") at GCOps.c:107 ximage = <value optimized out> #5 0x0807168f in DoGetImage (client=0x8538568, format=2, drawable=41943074, x=0, y=2, width=17, height=<value optimized out>, planemask=4294967295, im_return=0x0) at dispatch.c:2231 pDraw = (DrawablePtr) 0x8608de8 nlines = 18 linesPerBuf = 18 linesDone = 0 widthBytesLine = 68 length = <value optimized out> plane = 0 pBuf = 0xbf807870 "" xgi = {type = 1 '\001', depth = 24 '\030', sequenceNumber = 538, length = 306, visual = 34, pad3 = 3212869080, pad4 = 137826375, pad5 = 139819208, pad6 = 139824832, pad7 = 4096} pVisibleRegion = (RegionPtr) 0x0 ---Type <return> to continue, or q <return> to quit--- #6 0x08071846 in ProcGetImage (client=0x83ff598) at dispatch.c:2324 No locals. #7 0x0807457d in Dispatch () at dispatch.c:459 result = <value optimized out> client = (ClientPtr) 0x8538568 nready = 0 start_tick = 11880 #8 0x08087f6e in main (argc=2, argv=0xbf808314, envp=0x6) at main.c:447 pScreen = <value optimized out> i = 1 error = -1082096864 xauthfile = <value optimized out> alwaysCheckForInput = {0, 1} #9 0xb7bc283c in __libc_start_main (main=0x8087af0 <main>, argc=2, ubp_av=0xbf808314, init=0x837cd00 <__libc_csu_init>, fini=0x837ccf0 <__libc_csu_fini>, rtld_fini=0xb7f62ee0 <_dl_fini>, stack_end=0xbf80830c) at libc-start.c:238 result = <value optimized out> unwind_buf = {cancel_jmp_buf = {{jmp_buf = {-1211301900, -1208550240, 0, -1082096920, -987628191, -853714960}, mask_was_saved = 0}}, priv = { pad = {0x0, 0x0, 0xb7f67b90, 0xb7bc276d}, data = {prev = 0x0, cleanup = 0x0, canceltype = -1208583280}}} not_first_call = <value optimized out> ---Type <return> to continue, or q <return> to quit--- #10 0x0805c941 in _start () No symbol table info available.
Info on the relevant (host server) drawable: $ xwininfo -id 123734220 xwininfo: Window id: 0x76008cc (has no name) Absolute upper-left X: 977 Absolute upper-left Y: 49 Relative upper-left X: 0 Relative upper-left Y: 0 Width: 17 Height: 23 Depth: 24 Visual Class: TrueColor Border width: 0 Class: InputOutput Colormap: 0x760008d (not installed) Bit Gravity State: NorthWestGravity Window Gravity State: NorthWestGravity Backing Store State: NotUseful Save Under State: no Map State: IsViewable Override Redirect State: no Corners: +977+49 -606+49 -606-952 +977-952 -geometry 17x23+0+27
I think the issue is that when the XGetImage call arrives the window is unviewable (being on another workspace). There is AFAICT no way for dix to tell this is the case, nor pass the error back up, so about all we can do is in xnestGetImage wrap the XGetImage call in a fake error handler.
Created attachment 8244 [details] [review] xnest-XGetImage-ignore-errors.patch Suggested patch.
Sorry about the phenomenal bug spam, guys. Adding xorg-team@ to the QA contact so bugs don't get lost in future.
We should certainly do something here. Probably best if Xnest were to throw the same error back to the application, since otherwise it'll get garbage without knowing that it's garbage.
Punt to 7.5, not critical. Might be best to treat the obscured areas as censored in the XACE sense of the word. But at any rate, returning garbage for the ungettable parts of the image is totally legal, since there's no way you could know if someone went and drew on your stuff while you weren't looking.
(In reply to comment #7) > Punt to 7.5, not critical. Might be best to treat the obscured areas as > censored in the XACE sense of the word. But at any rate, returning garbage for > the ungettable parts of the image is totally legal, since there's no way you > could know if someone went and drew on your stuff while you weren't looking. indeed. pushing to 7.6 with the same rationale.
As of: commit 6d5883bd7e5b765f8f0548501b825d9e56840799 Author: Keith Packard <keithp@keithp.com> Date: Sat Nov 23 16:19:46 2013 -0800 xnest: Ignore GetImage() error in xnestGetImage() (v3) commit 65fca558848acd907483d3c85c7cd4db5560f1b4 Author: Radek Doulik <rodo@novell.com> Date: Tue Aug 13 08:45:47 2013 +0200 xnest: Ignore GetImage() error in xnestGetImage() we no longer throw BadMatch for this, and (presumably) the gotten image will contain some garbage, so I think this is fixed now.
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