svn commit: r212465 - head/sys/cddl/contrib/opensolaris/uts/common/dtrace

Rui Paulo rpaulo at freebsd.org
Sat Sep 11 13:50:59 UTC 2010


On 11 Sep 2010, at 14:46, Kostik Belousov wrote:

> On Sat, Sep 11, 2010 at 02:36:26PM +0100, Rui Paulo wrote:
>> On 11 Sep 2010, at 14:23, Kostik Belousov wrote:
>> 
>>> On Sat, Sep 11, 2010 at 12:58:31PM +0000, Rui Paulo wrote:
>>>> Author: rpaulo
>>>> Date: Sat Sep 11 12:58:31 2010
>>>> New Revision: 212465
>>>> URL: http://svn.freebsd.org/changeset/base/212465
>>>> 
>>>> Log:
>>>> Avoid a LOR (sleepable after non-sleepable) in
>>>> fasttrap_tracepoint_enable().
>>>> 
>>>> Sponsored by:	The FreeBSD Foundation
>>>> 
>>>> Modified:
>>>> head/sys/cddl/contrib/opensolaris/uts/common/dtrace/fasttrap.c
>>>> 
>>>> Modified: head/sys/cddl/contrib/opensolaris/uts/common/dtrace/fasttrap.c
>>>> ==============================================================================
>>>> --- head/sys/cddl/contrib/opensolaris/uts/common/dtrace/fasttrap.c	Sat Sep 11 12:51:01 2010	(r212464)
>>>> +++ head/sys/cddl/contrib/opensolaris/uts/common/dtrace/fasttrap.c	Sat Sep 11 12:58:31 2010	(r212465)
>>>> @@ -591,7 +591,9 @@ fasttrap_tracepoint_enable(proc_t *p, fa
>>>> 	 * Before we make any modifications, make sure we've imposed a barrier
>>>> 	 * on the generation in which this probe was last modified.
>>>> 	 */
>>>> +	PROC_UNLOCK(p);
>>>> 	fasttrap_mod_barrier(probe->ftp_gen);
>>>> +	PROC_LOCK(p);
>>>> 
>>>> 	bucket = &fasttrap_tpoints.fth_table[FASTTRAP_TPOINTS_INDEX(pid, pc)];
>>>> 
>>> I suspect that you should hold the process around unlocked region.
>> 
>> The unlocked region in the diff ? You're saying I shouldn't unlock/lock here?
> No, I am saying that you should do _PHOLD before dropping process lock.

That makes a lot more sense. Will do it, thanks.

> 
>> 
>>> fasttrap_pid_enable() also does unlock, so it might be better to hold
>>> the process immediately after pfind().
>> 
>> You mean use _PHOLD after pfind()?
> Yes.
> 
> 
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Regards,
--
Rui Paulo




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