svn commit: r367714 - head/sys/kern

[Mateusz Guzik]

I see what the bug is, will think about the right fix.

Is this reproducible for you?

On 12/1/20, Hans Petter Selasky <hps at selasky.org> wrote:
> On 11/16/20 4:12 AM, Mateusz Guzik wrote:
>> Author: mjg
>> Date: Mon Nov 16 03:12:21 2020
>> New Revision: 367714
>> URL: https://svnweb.freebsd.org/changeset/base/367714
>>
>> Log:
>>    select: call seltdfini on process and thread exit
>>
>>    Since thread_zone is marked NOFREE the thread_fini callback is never
>>    executed, meaning memory allocated by seltdinit is never released.
>>
>>    Adding the call to thread_dtor is not sufficient as exiting processes
>>    cache the main thread.
>>
>> Modified:
>>    head/sys/kern/kern_exit.c
>>    head/sys/kern/kern_thread.c
>>
>> Modified: head/sys/kern/kern_exit.c
>> ==============================================================================
>> --- head/sys/kern/kern_exit.c	Mon Nov 16 03:09:18 2020	(r367713)
>> +++ head/sys/kern/kern_exit.c	Mon Nov 16 03:12:21 2020	(r367714)
>> @@ -355,6 +355,7 @@ exit1(struct thread *td, int rval, int signo)
>>   	PROC_UNLOCK(p);
>>
>>   	umtx_thread_exit(td);
>> +	seltdfini(td);
>>
>>   	/*
>>   	 * Reset any sigio structures pointing to us as a result of
>>
>> Modified: head/sys/kern/kern_thread.c
>> ==============================================================================
>> --- head/sys/kern/kern_thread.c	Mon Nov 16 03:09:18 2020	(r367713)
>> +++ head/sys/kern/kern_thread.c	Mon Nov 16 03:12:21 2020	(r367714)
>> @@ -329,6 +329,7 @@ thread_ctor(void *mem, int size, void *arg, int
>> flags)
>>   	audit_thread_alloc(td);
>>   #endif
>>   	umtx_thread_alloc(td);
>> +	MPASS(td->td_sel == NULL);
>>   	return (0);
>>   }
>>
>> @@ -369,6 +370,7 @@ thread_dtor(void *mem, int size, void *arg)
>>   	osd_thread_exit(td);
>>   	td_softdep_cleanup(td);
>>   	MPASS(td->td_su == NULL);
>> +	seltdfini(td);
>>   }
>>
>>   /*
>> @@ -405,7 +407,7 @@ thread_fini(void *mem, int size)
>>   	turnstile_free(td->td_turnstile);
>>   	sleepq_free(td->td_sleepqueue);
>>   	umtx_thread_fini(td);
>> -	seltdfini(td);
>> +	MPASS(td->td_sel == NULL);
>>   }
>>
>>   /*
>
> Hi,
>
> The following panic() has been observed after this change:
>
> panic: Assertion mtx_unowned(m) failed at /usr/src/sys/kern/kern_mutex:1181
> cpuid = 6
> ....
> panic()
> _mtx_destroy()
> seltdfini()
> exit1()
> postsig()
> ast()
> doreti_ast()
>
> --HPS
>
>


-- 
Mateusz Guzik <mjguzik gmail.com>