On 17 Jun, Alfred Perlstein wrote: > * Don Lewis <truckman_at_FreeBSD.org> [030617 12:00] wrote: >> It's not legal to attempt to aquire Giant in fdrop_locked(), while >> FILE_LOCK() is held. The problem is that FILE_LOCK uses the mutex pool, >> which should only be used for leaf mutexes. >> >> It also looks like there is a potential for a lock order reversal if >> some callers aquire Giant before FILE_LOCK() and fdrop_locked() does the >> opposite. >> >> It also appears that witness ignores the mutex pool ... > > Yes, but I think the fix is as simple as just dropping the FILE_LOCK > after the decrement as we're the last holders of it, can you try > this: I like simple fixes, especially when the code shrinks ;-) Unfortunately, I think your point about this only happening because this process is the last holder of the file means that this doesn't explain Peter's deadlock. > Index: kern_descrip.c > =================================================================== > RCS file: /home/ncvs/src/sys/kern/kern_descrip.c,v > retrieving revision 1.199 > diff -u -r1.199 kern_descrip.c > --- kern_descrip.c 11 Jun 2003 00:56:55 -0000 1.199 > +++ kern_descrip.c 17 Jun 2003 19:07:01 -0000 > _at__at_ -2003,6 +2003,7 _at__at_ > FILE_UNLOCK(fp); > return (0); > } > + FILE_UNLOCK(fp); > mtx_lock(&Giant); > if (fp->f_count < 0) > panic("fdrop: count < 0"); > _at__at_ -2012,10 +2013,8 _at__at_ > lf.l_len = 0; > lf.l_type = F_UNLCK; > vp = fp->f_data; > - FILE_UNLOCK(fp); > (void) VOP_ADVLOCK(vp, (caddr_t)fp, F_UNLCK, &lf, F_FLOCK); > - } else > - FILE_UNLOCK(fp); > + } > if (fp->f_ops != &badfileops) > error = fo_close(fp, td); > else > >Received on Tue Jun 17 2003 - 11:06:57 UTC
This archive was generated by hypermail 2.4.0 : Wed May 19 2021 - 11:37:12 UTC