Attachment 99376 Details for Bug 77884 – 0001-mi-don-t-process-events-from-disabled-devices-77884.patch

[patch] 0001-mi-don-t-process-events-from-disabled-devices-77884.patch

0001-mi-don-t-process-events-from-disabled-devices-77884.patch (text/plain), 2.51 KB, created by Peter Hutterer on 2014-05-20 04:28:27 UTC

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Creator: Peter Hutterer

Created: 2014-05-20 04:28:27 UTC

Size: 2.51 KB

patch

obsolete

>From f6a2ee1c5c20de43e88f69413cc775b700d208c6 Mon Sep 17 00:00:00 2001
>From: Peter Hutterer <peter.hutterer@who-t.net>
>Date: Tue, 20 May 2014 13:48:27 +1000
>Subject: [PATCH] mi: don't process events from disabled devices (#77884)
>
>Once a device is disabled, it doesn't have a sprite pointer anymore. If an
>event is still in the queue and processed after DisableDevice finished, a
>dereference causes a crash. Example backtrace (crash forced by injecting an
>event at the right time):
>
>(EE) 0: /opt/xorg/bin/Xorg (OsSigHandler+0x3c) [0x48d334]
>(EE) 1: /lib64/libpthread.so.0 (__restore_rt+0x0) [0x37fcc0f74f]
>(EE) 2: /opt/xorg/bin/Xorg (mieqMoveToNewScreen+0x38) [0x609240]
>(EE) 3: /opt/xorg/bin/Xorg (mieqProcessDeviceEvent+0xd4) [0x609389]
>(EE) 4: /opt/xorg/bin/Xorg (mieqProcessInputEvents+0x206) [0x609720]
>(EE) 5: /opt/xorg/bin/Xorg (ProcessInputEvents+0xd) [0x4aeb58]
>(EE) 6: /opt/xorg/bin/Xorg (xf86VTSwitch+0x1a6) [0x4af457]
>(EE) 7: /opt/xorg/bin/Xorg (xf86Wakeup+0x2bf) [0x4af0a7]
>(EE) 8: /opt/xorg/bin/Xorg (WakeupHandler+0x83) [0x4445cb]
>(EE) 9: /opt/xorg/bin/Xorg (WaitForSomething+0x3fe) [0x491bf6]
>(EE) 10: /opt/xorg/bin/Xorg (Dispatch+0x97) [0x435748]
>(EE) 11: /opt/xorg/bin/Xorg (dix_main+0x61d) [0x4438a9]
>(EE) 12: /opt/xorg/bin/Xorg (main+0x28) [0x49ba28]
>(EE) 13: /lib64/libc.so.6 (__libc_start_main+0xf5) [0x37fc821d65]
>(EE) 14: /opt/xorg/bin/Xorg (_start+0x29) [0x425e69]
>(EE) 15: ? (?+0x29) [0x29]
>
>xf86VTSwitch() calls ProcessInputEvents() before disabling a device, and
>DisableDevice() calls mieqProcessInputEvents() again when flushing touches and
>button events. Between that and disabling the device (which causes new events
>to be refused) there is a window where events may be triggered and enqueued.
>On the next call to PIE that event is processed on a now defunct device,
>causing the crash.
>
>The simplest fix to this is to discard events from disabled devices. We flush
>the queue often enough before disabling that when we get here, we really don't
>care about the events from this device.
>
>X.Org Bug 77884 <http://bugs.freedesktop.org/show_bug.cgi?id=77884>
>---
> mi/mieq.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
>diff --git a/mi/mieq.c b/mi/mieq.c
>index 4c07480..188a0b0 100644
>--- a/mi/mieq.c
>+++ b/mi/mieq.c
>@@ -515,6 +515,10 @@ mieqProcessDeviceEvent(DeviceIntPtr dev, InternalEvent *event, ScreenPtr screen)
> 
>     verify_internal_event(event);
> 
>+    /* refuse events from disabled devices */
>+    if (!dev->enabled)
>+        return 0;
>+
>     /* Custom event handler */
>     handler = miEventQueue.handlers[event->any.type];
> 
>-- 
>1.9.0
>

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