Date: Sat, 21 Nov 2009 18:46:02 +0100 From: Rainer Hurling <rhurlin@gwdg.de> To: dougb@dougbarton.us Cc: Kostik Belousov <kostikbel@gmail.com>, Aditya Sarawgi <sarawgi.aditya@gmail.com>, freebsd-current@freebsd.org, delphij@freebsd.org Subject: Re: multimedia/vlc causes a panic if media files are on msdosfs Message-ID: <4B08275A.3070209@gwdg.de> In-Reply-To: <4B06BCC5.1000806@gwdg.de> References: <4B05C709.2090005@dougbarton.us> <20091120110123.GG2331@deviant.kiev.zoral.com.ua> <4b069fec.141bf30a.7f54.ffff8735@mx.google.com> <4B06BCC5.1000806@gwdg.de>
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On 20.11.2009 16:59 (UTC+1), Rainer Hurling wrote: > On 20.11.2009 20:26 (UTC+1), Aditya Sarawgi wrote: >> On Fri, Nov 20, 2009 at 01:01:23PM +0200, 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; >> >> I have been getting panics with VLC on UFS filesytem too, Although the >> frequency of panics on a UFS filesystem is pretty low as compared to >> msdosfs and ntfs systems and they are very abrupt. I will try getting >> a trace. > > I am observing panics also with newest vlc port on ufs2. System panics > whenever playing .flv files. With this patch even my panics went away :-) Thank you very much, Rainer Hurling
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