RELENG_5: panic: ffs_blkfree: freeing free block

[Pierre Beyssac]

RELENG_5 sources from yesterday.

This was after attempting a dump -L (snapshot before dump) on a
huge (5TB) gconcat filesystem while scp'ing massive amounts of data
to it. The snapshot failed with ETOOLARGE; the system became very
sluggish after that then paniced a few minutes later.

I'm keeping a copy of the crash dump and debug kernel in case someone
wants to know more.

#13 0xc05524a0 in ffs_blkfree (fs=0xc990f800, devvp=0xc4aa4840, bno=1, 
    size=16384, inum=1) at ../../../ufs/ffs/ffs_alloc.c:1751
#14 0xc0560913 in indir_trunc (freeblks=0xc83c6700, dbn=5677551840, level=0, 
    lbn=268441612, countp=0xe64ffc3c) at ../../../ufs/ffs/ffs_softdep.c:2628
#15 0xc05608ed in indir_trunc (freeblks=0xc83c6700, dbn=5676799200, level=1, 
    lbn=268437516, countp=0xe64ffc3c) at ../../../ufs/ffs/ffs_softdep.c:2624
#16 0xc05608ed in indir_trunc (freeblks=0xc83c6700, dbn=8097653792, level=2, 
    lbn=4196364, countp=0xe64ffc3c) at ../../../ufs/ffs/ffs_softdep.c:2624
#17 0xc0560474 in handle_workitem_freeblocks (freeblks=0xc83c6700, flags=0)
    at ../../../ufs/ffs/ffs_softdep.c:2483
#18 0xc055dbf4 in process_worklist_item (matchmnt=0x0, flags=0)
    at ../../../ufs/ffs/ffs_softdep.c:758
#19 0xc055d984 in softdep_process_worklist (matchmnt=0x0)
    at ../../../ufs/ffs/ffs_softdep.c:624
#20 0xc04f9fd2 in sched_sync () at ../../../kern/vfs_subr.c:1675
#21 0xc049cb04 in fork_exit (callout=0xc04f9bb8 <sched_sync>, arg=0x0, 
    frame=0xe64ffd48) at ../../../kern/kern_fork.c:807
#22 0xc05aa3cc in fork_trampoline () at ../../../i386/i386/exception.s:209
-- 
A: Yes.					  Pierre Beyssac pb at enst.fr
>Q: Are you sure?
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