Comment 1 Samuel Mannehed 2015-06-23 11:32:17 CEST

Got more segfaults, slightly different but triggered again by a client-initiated resizes. I have found a way to reproduce the crash almost always (with Xvnc from both ThinLinc 4.3.0 and 4.4.0):

1. Open a session in the HTML5 client on a touch device
2. Do a server-side resize to make the session large (xrandr -s 1920x1200)
3. Use panning to move the viewport away from the top left corner of the session
4. Rotate the device to trigger a client-initiated resize
5. Xvnc crashes here 9 out of 10 times, if not -> just repeat steps 2 to 4

It would seem like our HTML5 client doesn't change the coordinates of the viewport when the session is resized and thus try to use coordinates which are outside of the framebuffer. Xvnc doesn't seem to be able to handle this case properly.




Tue Jun 23 09:24:50 2015
 XserverDesktop: Got request for framebuffer resize to 768x891
 XserverDesktop: 1 screen(s)
             0 (0x00000000): 768x891+0+0 (flags
              0x00000000)

 PixelBuffer: reallocating managed buffer (24x24)
 Cursor:      cropping 24x24 to 7x16
 PixelBuffer: reallocating managed buffer (24x24)
 Cursor:      cropping 24x24 to 12x20
 PixelBuffer: reallocating managed buffer (24x24)
 Cursor:      cropping 24x24 to 18x17
 PixelBuffer: reallocating managed buffer (18x17)
 VNCSConnST:  FramebufferUpdateRequest 768x635 at 120,91 exceeds framebuffer
              768x891
 VNCSConnST:  FramebufferUpdateRequest 768x256 at 120,726 exceeds framebuffer
              768x891
 VNCSConnST:  FramebufferUpdateRequest 768x891 at 120,91 exceeds framebuffer
              768x891
 PixelBuffer: reallocating managed buffer (768x891)
(EE) 
(EE) Backtrace:
(EE) 0: /opt/thinlinc/libexec/Xvnc (xorg_backtrace+0x34) [0x5d4b64]
(EE) 1: /opt/thinlinc/libexec/Xvnc (0x400000+0x1d88f9) [0x5d88f9]
(EE) 2: /lib64/libpthread.so.0 (0x3cdfe00000+0xf6d0) [0x3cdfe0f6d0]
(EE) 3: /opt/thinlinc/libexec/Xvnc (_ZN3rfb13EncodeManager14checkSolidTileERKNS_4RectEPKhPKNS_11PixelBufferE+0xee) [0x61454e]
(EE) 4: /opt/thinlinc/libexec/Xvnc (_ZN3rfb13EncodeManager22extendSolidAreaByBlockERKNS_4RectEPKhPKNS_11PixelBufferEPS1_+0xa0) [0x6146a0]
(EE) 5: /opt/thinlinc/libexec/Xvnc (_ZN3rfb13EncodeManager13findSolidRectERKNS_4RectEPNS_6RegionEPKNS_11PixelBufferE+0x159) [0x614a89]
(EE) 6: /opt/thinlinc/libexec/Xvnc (_ZN3rfb13EncodeManager13findSolidRectERKNS_4RectEPNS_6RegionEPKNS_11PixelBufferE+0x30c) [0x614c3c]
(EE) 7: /opt/thinlinc/libexec/Xvnc (_ZN3rfb13EncodeManager15writeSolidRectsEPNS_6RegionEPKNS_11PixelBufferE+0x61) [0x614d51]
(EE) 8: /opt/thinlinc/libexec/Xvnc (_ZN3rfb13EncodeManager11writeUpdateERKNS_10UpdateInfoEPKNS_11PixelBufferEPKNS_14RenderedCursorE+0xb1) [0x616451]
(EE) 9: /opt/thinlinc/libexec/Xvnc (_ZN3rfb16VNCSConnectionST22writeFramebufferUpdateEv+0x4e2) [0x60f802]
(EE) 10: /opt/thinlinc/libexec/Xvnc (_ZN3rfb16VNCSConnectionST15processMessagesEv+0xdc) [0x61033c]
(EE) 11: /opt/thinlinc/libexec/Xvnc (_ZN14XserverDesktop17readWakeupHandlerEP6fd_seti+0x1f9) [0x5f08d9]
(EE) 12: /opt/thinlinc/libexec/Xvnc (vncCallReadWakeupHandlers+0x2a) [0x5e69fa]
(EE) 13: /opt/thinlinc/libexec/Xvnc (0x400000+0x1ee25c) [0x5ee25c]
(EE) 14: /opt/thinlinc/libexec/Xvnc (WakeupHandler+0x6b) [0x57b09b]
(EE) 15: /opt/thinlinc/libexec/Xvnc (WaitForSomething+0x492) [0x5d1942]
(EE) 16: /opt/thinlinc/libexec/Xvnc (Dispatch+0xa2) [0x576622]
(EE) 17: /opt/thinlinc/libexec/Xvnc (main+0x3ca) [0x45adea]
(EE) 18: /lib64/libc.so.6 (__libc_start_main+0xf5) [0x3cdfa21d65]
(EE) 19: /opt/thinlinc/libexec/Xvnc (0x400000+0x5c45d) [0x45c45d]
(EE) 
(EE) Segmentation fault at address 0x4460010

Fatal server error:
Caught signal 11 (Segmentation fault). Server aborting






Tue Jun 23 11:29:33 2015
 Timer:       handleTimeout(0x2222368)
 VNCSConnST:  FramebufferUpdateRequest 768x635 at 87,121 exceeds framebuffer
              768x891
 VNCSConnST:  FramebufferUpdateRequest 768x256 at 87,756 exceeds framebuffer
              768x891
 VNCSConnST:  FramebufferUpdateRequest 768x891 at 87,121 exceeds framebuffer
              768x891
 PixelBuffer: reallocating managed buffer (768x891)
(EE) 
(EE) Backtrace:
(EE) 0: /opt/thinlinc/libexec/Xvnc (xorg_backtrace+0x36) [0x5dac96]
(EE) 1: /opt/thinlinc/libexec/Xvnc (0x400000+0x1deb69) [0x5deb69]
(EE) 2: /lib64/libpthread.so.0 (0x3cdfe00000+0xf6d0) [0x3cdfe0f6d0]
(EE) 3: /opt/thinlinc/libexec/Xvnc (_ZN3rfb13EncodeManager11analyseRectEPKNS_11PixelBufferEPNS_8RectInfoEi+0x3dd) [0x61af2d]
(EE) 4: /opt/thinlinc/libexec/Xvnc (_ZN3rfb13EncodeManager12writeSubRectERKNS_4RectEPKNS_11PixelBufferE+0xef) [0x61bdcf]
(EE) 5: /opt/thinlinc/libexec/Xvnc (_ZN3rfb13EncodeManager10writeRectsERKNS_6RegionEPKNS_11PixelBufferE+0x117) [0x61c167]
(EE) 6: /opt/thinlinc/libexec/Xvnc (_ZN3rfb13EncodeManager11writeUpdateERKNS_10UpdateInfoEPKNS_11PixelBufferEPKNS_14RenderedCursorE+0xbe) [0x61c92e]
(EE) 7: /opt/thinlinc/libexec/Xvnc (_ZN3rfb16VNCSConnectionST22writeFramebufferUpdateEv+0x4eb) [0x61600b]
(EE) 8: /opt/thinlinc/libexec/Xvnc (_ZN3rfb16VNCSConnectionST15processMessagesEv+0xdc) [0x61676c]
(EE) 9: /opt/thinlinc/libexec/Xvnc (_ZN14XserverDesktop13wakeupHandlerEP6fd_seti+0xe8) [0x5f7858]
(EE) 10: /opt/thinlinc/libexec/Xvnc (0x400000+0x1ee1b4) [0x5ee1b4]
(EE) 11: /opt/thinlinc/libexec/Xvnc (WakeupHandler+0x5b) [0x57f9fb]
(EE) 12: /opt/thinlinc/libexec/Xvnc (WaitForSomething+0x4b6) [0x5d7976]
(EE) 13: /opt/thinlinc/libexec/Xvnc (Dispatch+0xb2) [0x57ae92]
(EE) 14: /opt/thinlinc/libexec/Xvnc (main+0x3da) [0x56888a]
(EE) 15: /lib64/libc.so.6 (__libc_start_main+0xf5) [0x3cdfa21d65]
(EE) 16: /opt/thinlinc/libexec/Xvnc (0x400000+0x57529) [0x457529]
(EE) 
(EE) Segmentation fault at address 0x4b86000

Fatal server error:
Caught signal 11 (Segmentation fault). Server aborting

Comment 2 Pierre Ossman 2015-09-21 10:33:13 CEST

We are unable to reproduce this crash anymore, even when using old versions of ThinLinc. Closing for now.