[dm-crypt] crypsetup segfaulting during luksFormat

Arno Wagner arno at wagner.name
Wed Jul 7 22:19:55 CEST 2010


On Wed, Jul 07, 2010 at 07:49:04PM +0200, Sven Eschenberg wrote:
> Hummm,
> 
> should I consider this geek humor or are you serious, the CPU is rather
> slow (imho)?

Par humor, part serious. But if the CPU is rather slow, then
this is somethin else, I guess.
 
> Anyway, tweaking the iterationcount didn't chaneg a thing, messing with
> the params did not help either.

Hmm.

> The Backtrace does not really help a lot, I guess:
> 
> (gdb) bt
> #0  0x000000000040d3fe in sigvtalarm ()
> #1  0x0f0000000fc0c748 in ?? ()
> #2  0x0000000000000000 in ?? ()
> 
> Well at least we know the crash happens in sigvtalarm, which I assume is
> a signal handler of some sort within cryptsetup.

Looks like it. SIGVTALARM is what you get when you set
the ITIMER_VIRTUAL interval timer and it expires. YThe
virtual timer is decremented only when the process runns
that set it. Hence it can be used to measure (userspace)
CPU time of a process. My guess would be that it is
not supposed to expire and handling the SIGVTALARM
somehow fails. 

Arno




 
> Regards
> 
> -Sven
> 
> On Wed, 2010-07-07 at 19:36 +0200, Arno Wagner wrote:
> > Just a guess: Your CPU is too fast, the time
> > measurement for the PKBF2 iterations did not 
> > expect that and does nonesense, resutling in 
> > the segfault.
> > 
> > Tht would be a classic ;-)
> > 
> > Arno
> > 
> > On Wed, Jul 07, 2010 at 07:19:38PM +0200, Sven Eschenberg wrote:
> > > Hi list,
> > > 
> > > I was just trying to setup a new luks device, and for some reason (I
> > > cannot determine yet) cryptsetup just segfaults (setting up the old
> > > mappings works as usual).
> > > 
> > > These are the last couple lines before cryptsetup dies:
> > > 2370  read(4, "|\27\211<e\263\36\35j\201j\204e\326 \270\364\277\373
> > > \300LY[\343d[\215\32\17\315N\333", 32) = 32
> > > 2370  open("/dev/md125", O_RDONLY)      = 5
> > > 2370  ioctl(5, BLKIOMIN, 0x7fff561ea000) = 0
> > > 2370  ioctl(5, BLKIOOPT, 0x7fff561e9ff8) = 0
> > > 2370  ioctl(5, BLKALIGNOFF, 0x7fff561ea00c) = 0
> > > 2370  close(5)                          = 0
> > > 2370  read(4, "\242\270\205|\207@\253\227 \321)\f\r/\"R>EN(wo\224\205\7e
> > > \36\313g\232\n\33", 32) = 32
> > > 2370  rt_sigaction(SIGVTALRM, {0x40d3f0, [VTALRM], SA_RESTORER|
> > > SA_RESTART, 0xf0000000fc0c748}, {SIG_DFL, [], 0}, 8) = 0
> > > 2370  setitimer(ITIMER_VIRTUAL, {it_interval={0, 0}, it_value={1, 0}},
> > > NULL) = 0
> > > 2370  --- SIGVTALRM (Virtual timer expired) @ 0 (0) ---
> > > 2370  --- SIGSEGV (Segmentation fault) @ 0 (0) ---
> > > 2370  +++ killed by SIGSEGV +++
> > > 
> > > where /dev/md125 is the device I am trying to setup via luksFormat.
> > > 
> > > Anyone with any suggestion what the problem can be?
> > > 
> > > Oh I forgot:
> > > cryptsetup --version
> > > cryptsetup 1.1.2
> > > 
> > > Regards
> > > 
> > > -Sven
> > > 
> > > 
> > > _______________________________________________
> > > dm-crypt mailing list
> > > dm-crypt at saout.de
> > > http://www.saout.de/mailman/listinfo/dm-crypt
> > > 
> > 
> 
> 
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> 

-- 
Arno Wagner, Dr. sc. techn., Dipl. Inform., CISSP -- Email: arno at wagner.name 
GnuPG:  ID: 1E25338F  FP: 0C30 5782 9D93 F785 E79C  0296 797F 6B50 1E25 338F
----
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