Futex Wait Called

I am working on fedora core 7, kernel version 2.6.21, gcc version
4.1.2. I have my user space application which communicate with my char
driver using write and read system calls. I have a thread in
application to send data to driver and concurrently a signal handler
(user space) is register. write calls is invoking continuously and
read call is also invoking continuously on notification from driver.
Here am facing a problem of "futex_wait" at one time. Even though my
user space application has no mutex locking, FUTEX_WAIT is called and
nothing proceeds after this.

I got below lines form strace of my process and always getting lock at
same address.

--- SIGRT_15 (Real-time signal 13) @ 0 (0) ---
futex(0x4aa700b0, FUTEX_WAIT, 2, NULL

please guide me to solve this issue or what could be reason for above
things.

if need any more info, i will give u.

On Thu, 22 Oct 2009 20:44:17 -0700 (PDT), pandi wrote:
> I am working on fedora core 7, kernel version 2.6.21, gcc version
> 4.1.2. I have my user space application which communicate with my char
> driver using write and read system calls. I have a thread in
> application to send data to driver and concurrently a signal handler
> (user space) is register. write calls is invoking continuously and

Note that the set of functions your are allowed to use in a signal handler
is very limited (i.e. only async signal safe functions). To me it looks like
you are trying to call a non async signal safe function which causes the
problem.

Can you show use the code for the signal handler?


Christof

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