Hello Michael, Am 12.04.2012 um 22:28 Uhr schrieb Michael Tokarev <[email protected]>: > On 13.04.2012 00:22, Markus Hochholdinger wrote: > > Am 12.04.2012 um 21:38 Uhr schrieb Michael Tokarev <[email protected]>: > >> On 31.03.2012 01:28, Markus Hochholdinger wrote: > >>> Package: mdadm > >>> Version: 3.2.3-2 > >>> Followup-For: Bug #664088 > >>> Dear Maintainer, > >>> seems I've been stumbled over this bug. I'm running wheezy and can > >>> reproduce a crash: mdadm --grow /dev/md0 --bitmap=none > >>> mdadm --grow /dev/md0 --bitmap=internal > >>> A few seconds after this, the system is still alive, I see the newly > >>> created bitmap in /proc/mdstat, and then the system crashes: [ > >>> 342.437949] md0: bitmap file is out of date (0 < 322) -- forcing full > >>> recovery [ 342.437967] created bitmap (1 pages) for device md0 > >>> [ 347.949946] BUG: unable to handle kernel NULL pointer dereference at > >>> 00000008 [ 347.949969] IP: [<eda5edbd>] bitmap_endwrite+0x138/0x199 > >>> [md_mod] [ 347.949991] *pdpt = 0000000002660007 *pde = > >>> 0000000000000000 [ 347.950010] Oops: 0000 [#1] SMP > >> Oh. This is a kernel bug, kernel should not crash like this even if > >> incorrect bitmap is created. > >> Marcus, what's your kernel version? > > Linux 3.2.0-2-686-pae from wheezy. > This was obvious from your initial message, but I wasn't clear. > I meant to ask what kernel PACKAGE version is that.
oh, sorry. The installed kernel package is: ii linux-image-3.2.0-2-686-pae 3.2.12-1 Linux 3.2 for modern PCs ii linux-image-686-pae 3.2+44 Linux for moder I still can reproduce this: mdadm --grow /dev/md0 --bitmap=none mdadm --grow /dev/md0 --bitmap=internal And a few seconds later, the kernel crashes. > Sigh, how many times I suggested kernel folks to include debian > package version in the kernel OOPs test, but has been ignored > every time... :( I understand and will include kernel package versions in the future. > > Hm, perhaps I could use mdadm from squeeze to check weather the kernel > > also crashes. > I doubt it is easily reproducible. The original bug in mdadm (which is > fixed upstream btw, in git, not any released version) does not initialize It's sad, that there's no released version of mdadm which fixes this issue. > bitmap, leaving some garbage in it. Obviously not every garbage triggers > the bug in kernel. So if another attempt will not crash your kernel it > does not tell anything. Well, I can clearly reproduce this behaviour. > I asked for the kernel package version in order to clone and reassign > this bugreport to kernel properly. Wow, that would be very kind of you! So I'll do a little try and error, perhaps it helps for the kernel bugreport: * I've done "aptitude update && aptitude safe-upgrade" now and rebooted. * Still using mdadm (3.2.3-2) and linux-image-3.2.0-2-686-pae (3.2.12-1). Doing "mdadm --grow /dev/md0 --bitmap=none" and "mdadm --grow /dev/md0 --bitmap=internal" still crashes the kernel as reported in this bug. * Now using (a very old) statically linked mdadm (v2.6.7 - 6th June 2008) which I used successful for years removing and making raid1 bitmaps. Doing "mdadm.static --grow /dev/md0 --bitmap=none" and "mdadm.static --grow /dev/md0 --bitmap=internal" works as expected and the kernel doesn't crash. * Using mdadm.static to remove the bitmap and mdadm to add it also crashes the kernel. * (mdadm from squeeze has a dependency problem with initscripts, so I can't simple use this version.) So far so good. Hope it helps a little. Now I will try this with arch amd64 instead of i386... -- greetings eMHa
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