panic: ffs_blkfree_cg: freeing free block

[deeptech71 at gmail.com]

On Fri, Oct 28, 2011 at 11:16 AM, deeptech71 at gmail.com
<deeptech71 at gmail.com> wrote:
> I don't have the intermediate object files for the kernel; now I'm
> building the kernel again (from the appropriate, exact sources). That
> shouldn't harm debugging, should it?

On Sat, Oct 29, 2011 at 2:35 AM, Garrett Cooper <yanegomi at gmail.com> wrote:
> On Fri, Oct 28, 2011 at 4:34 PM, deeptech71 at gmail.com
> <deeptech71 at gmail.com> wrote:
>> With object files which were built using the original kernel
>> configuration file (no debugging symbols included):
>>
>> #kgdb kernel /var/crash/vmcore.4
>> GNU gdb 6.1.1 [FreeBSD]
>> Copyright 2004 Free Software Foundation, Inc.
>> GDB is free software, covered by the GNU General Public License, and you are
>> welcome to change it and/or distribute copies of it under certain conditions.
>> Type "show copying" to see the conditions.
>> There is absolutely no warranty for GDB.  Type "show warranty" for details.
>> This GDB was configured as "i386-marcel-freebsd"...(no debugging
>> symbols found)...
>> Attempt to extract a component of a value that is not a structure pointer.
>> Attempt to extract a component of a value that is not a structure pointer.
>> #0  0xc0687d88 in doadump ()
>> (kgdb) bt
>> #0  0xc0687d88 in doadump ()
>> #1  0xc0688302 in kern_reboot ()
>> #2  0xc0688768 in panic ()
>> #3  0xc07f92bf in ffs_blkfree_cg ()
>> #4  0xc07f9417 in ffs_blkfree ()
>> #5  0xc0803259 in ffs_indirtrunc ()
>> #6  0xc08042e1 in ffs_truncate ()
>> #7  0xc083171c in ufs_inactive ()
>> #8  0xc0712718 in vinactive ()
>> #9  0xc0716e2a in vputx ()
>> #10 0xc071affb in kern_unlinkat ()
>> #11 0xc071b1a6 in kern_unlink ()
>> #12 0xc071b1ca in sys_unlink ()
>> #13 0xc089c954 in syscall ()
>> #14 0xc0887021 in Xint0x80_syscall ()
>> #15 0x00000033 in ?? ()
>> Previous frame inner to this frame (corrupt stack?)
>>
>> wtf?
>>
>> With object files which were built using a kernel configuration file
>> that had ``makeoptions DEBUG=-g'' inserted compared to the original
>> configuration file:
>>
>> #kgdb kernel.debug /var/crash/vmcore.4
>> GNU gdb 6.1.1 [FreeBSD]
>> Copyright 2004 Free Software Foundation, Inc.
>> GDB is free software, covered by the GNU General Public License, and you are
>> welcome to change it and/or distribute copies of it under certain conditions.
>> Type "show copying" to see the conditions.
>> There is absolutely no warranty for GDB.  Type "show warranty" for details.
>> This GDB was configured as "i386-marcel-freebsd"...
>> Cannot access memory at address 0x0
>> (kgdb) bt
>> #0  0x00000000 in ?? ()
>>
>> wtf?
>
> Something stomped on the stack.

More like: the release build doesn't have enough debug information in
itself, and the release build is not debuggable at all using debug
objects that have been built posteriorly.

> What was the previous version of
> FreeBSD (major.minor.subminor, svn revision) at worked?

Not applicable.
The panic occured, out of nowhere, on an r226289 kernel that has been
working well and is still working well, with the exception of the
panic.