Re: [BUG] problem with timer_create(2) for SIGEV_NONE ??

[george anzinger <george@mvista.com>]

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Attached is a fix.

Change log:

Fix the sig_notify filtering code for the timer_create system call to 
properly check for the signal number being small enought, but only if 
SIG_NONE is not specified.

Eliminate useless test of sig_notify.

george


Aniruddha M Marathe wrote:
> George,
> 
>  timer_create(2) fails in the case where sigev_notify parameter of
> sigevent structure is SIGEV_NONE. I believe this should not happen.
> 
    ~snip~

>  
> Line 377:
> SIGEV_NONE & ~(SIGEV_SIGNAL | SIGEV_THREAD_ID)
> = 001 & ~(000 | 100)
> = 001 & ~(100)
> = 001 & 011
> = 001
> therefore the if condition is true
> therefore the function returns NULL from line 378.
>  
> Now in sys_timer_create() at line number 462
> Process = NULL
>  
> Now at line 489
> if (!process) becomes TRUE
> and function returns with EINVAL
> 
> Is my analysis right? If so can you comment on this behaviour?
> 
Looks like a bug :(  I feel a patch coming on...

-- 
George Anzinger   george@mvista.com
High-res-timers:  http://sourceforge.net/projects/high-res-timers/
Preemption patch: http://www.kernel.org/pub/linux/kernel/people/rml



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--- linux-2.5.69-org/kernel/posix-timers.c	2003-05-05 15:34:09.000000000 -0700
+++ linux/kernel/posix-timers.c	2003-05-06 00:24:21.000000000 -0700
@@ -357,13 +357,10 @@
 			rtn->tgid != current->tgid))
 		return NULL;
 
-	if ((event->sigev_notify & SIGEV_SIGNAL & MIPS_SIGEV) &&
+	if ((event->sigev_notify & ~SIGEV_NONE & MIPS_SIGEV) &&
 			((unsigned) (event->sigev_signo > SIGRTMAX)))
 		return NULL;
 
-	if (event->sigev_notify & ~(SIGEV_SIGNAL | SIGEV_THREAD_ID))
-		return NULL;
-
 	return rtn;
 }