utouch-patched synaptics driver causes X crash

[Timo Kluck]

I noticed the following snippet in a lightdm log after an X crash (see below). It sounds to me like grail_open is being called from a signal handler. This would be unsafe because grail_open calls calloc, which is not reentrant [1].

A look at the source shows that grail_open is called from EventDeviceOnHook. I am not familiar with the synaptics protocol, so I don't know if my guess about this being a signal handler is right.

I cannot reliably reproduce the crash, so I don't know how to do any extra debugging. I'll attach the entire logfile for reference.

--
[1] this was recently pointed out to me by Chase Douglas in another bug report related to utouch.

--
*** glibc detected *** /usr/bin/X: corrupted double-linked list: 0x00000000030408f0 ***
======= Backtrace: =========
/lib/x86_64-linux-gnu/libc.so.6(+0x78a96)[0x7f6977c85a96]
/lib/x86_64-linux-gnu/libc.so.6(+0x7ad6d)[0x7f6977c87d6d]
/lib/x86_64-linux-gnu/libc.so.6(__libc_calloc+0xc2)[0x7f6977c8aa92]
/usr/local/lib/libutouch-frame.so.1(+0xc83)[0x7f69735c0c83]
/usr/local/lib/libutouch-frame.so.1(utouch_frame_new_engine_raw+0xd3)[0x7f69735c0e13]
/usr/local/lib/libutouch-grail.so.1(grail_open+0x19a)[0x7f6973bd21aa]
/usr/lib/xorg/modules/input/synaptics_drv.so(+0xb621)[0x7f6973025621]
/usr/lib/xorg/modules/input/synaptics_drv.so(+0xa45a)[0x7f697302445a]
/usr/lib/xorg/modules/input/synaptics_drv.so(+0x327d)[0x7f697301d27d]
/usr/bin/X(EnableDevice+0xac)[0x4282ec]
/usr/bin/X(xf86Wakeup+0x476)[0x46e3c6]
/usr/bin/X(WakeupHandler+0x5b)[0x433a0b]
/usr/bin/X(WaitForSomething+0x1b6)[0x45df66]
/usr/bin/X[0x42f8c2]
/usr/bin/X[0x4232ae]
/lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xed)[0x7f6977c2e30d]
/usr/bin/X[0x42359d]

[Chase Douglas (chasedouglas)]

The utouch stack has moved to the client side of X. The synaptics patch is obsolete now.