[OpenAFS-devel] problems with current cvs on linux - oops's, possibly related to 1.32-1.34 changes in osi_vnodeops.c
Derek Atkins
warlord@MIT.EDU
14 Mar 2002 13:43:37 -0500
In a closer look there is DEFINITELY a double-free going on. I just
caught the following while breakpoints are set in both
osi_AllocLargeSpace() and osi_FreeLargeSpace():
Breakpoint 2, osi_FreeLargeSpace (adata=0xc77a9000)
at ../afs/afs_osi_alloc.c:71
71 AFS_STATCNT(osi_FreeLargeSpace);
(gdb)
Continuing.
Breakpoint 2, osi_FreeLargeSpace (adata=0xc4170000)
at ../afs/afs_osi_alloc.c:71
71 AFS_STATCNT(osi_FreeLargeSpace);
(gdb)
Continuing.
Breakpoint 2, osi_FreeLargeSpace (adata=0xc4170000)
at ../afs/afs_osi_alloc.c:71
71 AFS_STATCNT(osi_FreeLargeSpace);
Notice that it's trying to free 0xc4170000 twice? This last free()
is coming from:
(gdb) where
#0 osi_FreeLargeSpace (adata=0xc4170000) at ../afs/afs_osi_alloc.c:71
#1 0xc8896a5d in afs_linux_dentry_revalidate (dp=0xc3823260, flags=0)
at ../afs/osi_vnodeops.c:847
#2 0xc01420fd in cached_lookup (parent=0xc662d7c0, name=0xc5349f98, flags=0)
at namei.c:249
Unfortunately I didn't get a backtrace on the pentultimate free(). I'll
keep working on it. But this is definitely the cause of the problem --
the same packet is getting onto the freelist twice.
-derek
"Neulinger, Nathan" <nneul@umr.edu> writes:
> Derek was able to trace down the reason for the fault witn kgdb. I'd
> guess it likely has something to do with these recent changes to
> osi_vnodeops.c. I'll take a closer look, but I'm not really familiar
> with what's going on in the code here.
>
> -- Nathan
>
> ------------------------------------------------------------
> Nathan Neulinger EMail: nneul@umr.edu
> University of Missouri - Rolla Phone: (573) 341-4841
> Computing Services Fax: (573) 341-4216
>
>
> -----Original Message-----
> From: Neulinger, Nathan
> Sent: Thursday, March 14, 2002 12:29 PM
> To: 'Derek Atkins'
> Subject: RE: Have you had a succesful build+use with current openafs?
>
>
> FYI Looks like it was probably introduced in 1.33 of osi_vnodeops.c.
> There were a bunch of changes for revalidate_dnode.
>
> -- Nathan
>
> ------------------------------------------------------------
> Nathan Neulinger EMail: nneul@umr.edu
> University of Missouri - Rolla Phone: (573) 341-4841
> Computing Services Fax: (573) 341-4216
>
>
> > -----Original Message-----
> > From: Derek Atkins [mailto:warlord@MIT.EDU]
> > Sent: Thursday, March 14, 2002 12:23 PM
> > To: Neulinger, Nathan
> > Subject: Re: Have you had a succesful build+use with current openafs?
> >
> >
> > Yep. kgdb.sf.net. Requires two systems with a "serial" line
> > between them. In my case I'm using vmware :)
> >
> > We should definitely report this to openafs-devel! I'll look a
> > bit more but I've only got about 30 minutes more I can sink into
> > this today.
> >
> > -derek
> >
> > "Neulinger, Nathan" <nneul@umr.edu> writes:
> >
> > > Goody! :)
> > >
> > > Thanks. That's reassuring, nothing like having a bug like this screw
> > > with your head when you think that you've made a whole
> > bunch of changes
> > > that should not have any affect on code behavior.
> > >
> > > Are you using the kernel debugger patches? I definately
> > should dig into
> > > that some time.
> > >
> > > -- Nathan
> > >
> > > ------------------------------------------------------------
> > > Nathan Neulinger EMail: nneul@umr.edu
> > > University of Missouri - Rolla Phone: (573) 341-4841
> > > Computing Services Fax: (573) 341-4216
> > >
> > >
> > > > -----Original Message-----
> > > > From: Derek Atkins [mailto:warlord@MIT.EDU]
> > > > Sent: Thursday, March 14, 2002 12:17 PM
> > > > To: Neulinger, Nathan
> > > > Subject: Re: Have you had a succesful build+use with
> > current openafs?
> > > >
> > > >
> > > > Here is the stack trace of what's going on. I have no idea why
> > > > freePacketList is being set to '1'. I'll keep looking, but this
> > > > is clearly not "just you" :)
> > > >
> > > > -derek
> > > >
> > > > Program received signal SIGSEGV, Segmentation fault.
> > > > 0xc8863031 in osi_AllocLargeSpace (size=720) at
> > > > ../afs/afs_osi_alloc.c:201
> > > > 201 if ( tp ) freePacketList = tp->next;
> > > > (gdb) where
> > > > #0 0xc8863031 in osi_AllocLargeSpace (size=720) at
> > > > ../afs/afs_osi_alloc.c:201
> > > > #1 0xc8872a91 in afs_DoBulkStat (adp=0xc8936658, dirCookie=480,
> > > > areqp=0xc5347e68) at ../afs/afs_vnop_lookup.c:426
> > > > #2 0xc8874c25 in afs_lookup (adp=0xc8936658,
> > aname=0xc13ded80 "CVS",
> > > > avcp=0xc5347ec4, acred=0xc412a000) at
> > > > ../afs/afs_vnop_lookup.c:1190
> > > > #3 0xc8896c14 in afs_linux_lookup (dip=0xc8936658, dp=0xc13ded20)
> > > > at ../afs/osi_vnodeops.c:993
> > > > #4 0xc0142175 in real_lookup (parent=0xc79210c0,
> > > > name=0xc5347f4c, flags=0)
> > > > at namei.c:284
> > > > #5 0xc0142936 in path_walk (name=0xc76bf011 "",
> > > > nd=0xc5347f98) at namei.c:564
> > > > #6 0xc014313a in __user_walk (name=0xbfffb820
> > > > "../../src/doc/CVS", flags=9,
> > > > nd=0xc5347f98) at namei.c:805
> > > > #7 0xc013fcf6 in sys_stat64 (filename=0xbfffb820
> > > > "../../src/doc/CVS",
> > > > statbuf=0xbfff96b0, flags=1075171668) at stat.c:337
> > > > #8 0xc0106fcb in system_call () at af_packet.c:1879
> > > > (gdb) p tp
> > > > $1 = (struct osi_packet *) 0x1
> > > > (gdb) p freePacketList
> > > > $2 = (struct osi_packet *) 0x1
> > > >
> > > > --
> > > > Derek Atkins, SB '93 MIT EE, SM '95 MIT Media Laboratory
> > > > Member, MIT Student Information Processing Board (SIPB)
> > > > URL: http://web.mit.edu/warlord/ PP-ASEL-IA N1NWH
> > > > warlord@MIT.EDU PGP key available
> > > >
> >
> > --
> > Derek Atkins, SB '93 MIT EE, SM '95 MIT Media Laboratory
> > Member, MIT Student Information Processing Board (SIPB)
> > URL: http://web.mit.edu/warlord/ PP-ASEL-IA N1NWH
> > warlord@MIT.EDU PGP key available
> >
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--
Derek Atkins, SB '93 MIT EE, SM '95 MIT Media Laboratory
Member, MIT Student Information Processing Board (SIPB)
URL: http://web.mit.edu/warlord/ PP-ASEL-IA N1NWH
warlord@MIT.EDU PGP key available