Date: Fri, 20 Nov 2009 13:55:16 -0800 From: Doug Barton <dougb@FreeBSD.org> To: Kostik Belousov <kostikbel@gmail.com> Cc: freebsd-current@freebsd.org, delphij@freebsd.org, bug-followup@freebsd.org Subject: Re: ports/140648 multimedia/vlc causes a panic if media files are on msdosfs Message-ID: <4B071044.2030708@FreeBSD.org> In-Reply-To: <20091120110123.GG2331@deviant.kiev.zoral.com.ua> References: <4B05C709.2090005@dougbarton.us> <20091120110123.GG2331@deviant.kiev.zoral.com.ua>
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Kostik Belousov wrote: > On Thu, Nov 19, 2009 at 02:30:33PM -0800, Doug Barton wrote: >> Please see http://www.freebsd.org/cgi/query-pr.cgi?pr=140648 for more >> information, including a trace. >> >> There is also some evidence that the same problem is triggered by >> accessing files on an NTFS partition. The VLC folks have suggested >> that the problem may be related to threading. > > This is because msdosfs and ntfs are not mpsafe, and it seems that > VLC using recently added F_RDAHEAD/F_READAHEAD fcntls. > > Please try this. > > diff --git a/sys/kern/kern_descrip.c b/sys/kern/kern_descrip.c > index 434f54a..676de65 100644 > --- a/sys/kern/kern_descrip.c > +++ b/sys/kern/kern_descrip.c > @@ -718,14 +718,15 @@ kern_fcntl(struct thread *td, int fd, int cmd, intptr_t arg) > do { > new = old = fp->f_flag; > new |= FRDAHEAD; > - } while (atomic_cmpset_rel_int(&fp->f_flag, old, new) == 0); > + } while (!atomic_cmpset_rel_int(&fp->f_flag, old, new)); > readahead_vnlock_fail: > VFS_UNLOCK_GIANT(vfslocked); > + vfslocked = 0; > } else { > do { > new = old = fp->f_flag; > new &= ~FRDAHEAD; > - } while (atomic_cmpset_rel_int(&fp->f_flag, old, new) == 0); > + } while (!atomic_cmpset_rel_int(&fp->f_flag, old, new)); > } > fdrop(fp, td); > break; Voila! Thanks. Doug -- Improve the effectiveness of your Internet presence with a domain name makeover! http://SupersetSolutions.com/
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