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Date: Thu, 11 Jan 2007 20:58:24 +0100
From: Fabrice Bellard <fabrice@bellard.org>
Subject: Re: [Qemu-devel] [PATCH] better handling of removal in	IOHandlerRecord
	list
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To: qemu-devel@nongnu.org

I think a more complete patch is needed to fully correct the problem.

Regards,

Fabrice.

jerome Arbez-Gindre wrote:
> On Thu, 2007-01-11 at 14:56 +0100, jerome Arbez-Gindre wrote:
> 
>>On Wed, 2007-01-10 at 17:34 +0100, jerome Arbez-Gindre wrote:
>>
>>>Hi,
>>>
>>>by a call to qemu_set_fd_handler(fd,NULL,NULL,NULL) in the fd_read
>>>callback, I have generated a "Segmentation fault" in vl.c.
>>>
>>>My solution is not very smart... but it is very simple.
>>
>>I reply to myself because I did not sleep last night:
>>
>>Here is the fix without the double IOHandlerRecord list iteration.
> 
> 
> Here is a little fix to handle the case when a IOHandler removes an
> other IOHandler.
> 
> --- vl.c.mine	2007-01-11 15:06:47.000000000 +0100
> +++ vl.c	2007-01-11 15:27:27.000000000 +0100
> @@ -5912,11 +5912,13 @@
>          pioh = &first_io_handler ;
>          for(ioh = first_io_handler; ioh != NULL; ioh = ioh_next) {
>              ioh_next = ioh->next;
> -            if (FD_ISSET(ioh->fd, &rfds)) {
> +            /* ioh->fd_read could have been set to null by an other
> +               IOHandlerRecord callback */
> +            if (ioh->fd_read && FD_ISSET(ioh->fd, &rfds)) {
>                  ioh->fd_read(ioh->opaque);
>              }
>              /* ioh->fd_write could have been set to null */
> -            if ((ioh->fd_write) && (FD_ISSET(ioh->fd, &wfds))) {
> +            if (ioh->fd_write && FD_ISSET(ioh->fd, &wfds)) {
>                  ioh->fd_write(ioh->opaque);
>              }
>              /* the ioh could have been supressed */
> 
> 
> 
> 
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