Re: panic in softdep_slowdown()

On Wed, Jan 28, 2015 at 12:48:42PM +0200, Konstantin Belousov wrote:
K> > Stopped at      softdep_slowdown+0x1d3: idivl   %ecx,%eax
K> > db> bt
K> > Tracing pid 49 tid 100045 td 0xfffff800026ee000
K> > softdep_slowdown() at softdep_slowdown+0x1d3/frame 0xfffffe001eb5f2b0
K> > ffs_truncate() at ffs_truncate+0x1be/frame 0xfffffe001eb5f640
K> > ufs_setattr() at ufs_setattr+0x4e5/frame 0xfffffe001eb5f6a0
K> > VOP_SETATTR_APV() at VOP_SETATTR_APV+0x22a/frame 0xfffffe001eb5f710
K> > VOP_SETATTR() at VOP_SETATTR+0x45/frame 0xfffffe001eb5f760
K> > vn_truncate() at vn_truncate+0x196/frame 0xfffffe001eb5f870
K> > fo_truncate() at fo_truncate+0x41/frame 0xfffffe001eb5f8b0
K> > kern_ftruncate() at kern_ftruncate+0x16d/frame 0xfffffe001eb5f920
K> > sys_ftruncate() at sys_ftruncate+0x27/frame 0xfffffe001eb5f940
K> > syscallenter() at syscallenter+0x46e/frame 0xfffffe001eb5f9b0
K> > amd64_syscall() at amd64_syscall+0x1f/frame 0xfffffe001eb5fab0
K> > Xfast_syscall() at Xfast_syscall+0xfb/frame 0xfffffe001eb5fab0
K> > --- syscall (480, FreeBSD ELF64, sys_ftruncate), rip = 0x800b511fa, rsp = 0x7fffffffe998, rbp = 0x7fffffffeb90 ---
K> > db> call doadump
K> > Dumping 60 out of 495 MB:..27%..54%..80%
K> > Dump complete
K> > = 0
K> > db>
K> > 
K> > I've got the core file.
K> 
K> At least the source line for the panic is needed.
K> Also, print out the value of stat_flush_threads.

(kgdb) fr 11
#11 0xffffffff80895d63 in softdep_slowdown (vp=0xfffff800028011d8)
    at /usr/src/ifnet/sys/ufs/ffs/ffs_softdep.c:13055
13055           if (dep_current[D_DIRREM] < max_softdeps_hard / 2 &&
(kgdb) p dep_current
$1 = {1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 
  0, 0, 0, 0}
(kgdb) p max_softdeps_hard
$2 = 153357
(kgdb) p *ump
$4 = {um_mountp = 0xfffff80002707330, um_dev = 0xfffff800026cbc00, 
  um_cp = 0xfffff80002717480, um_bo = 0xfffff8000271edb8, 
  um_devvp = 0xfffff8000271ece8, um_fstype = 2, um_fs = 0xfffff8000273b000, 
  um_extattr = {uepm_lock = {lock_object = {lo_name = 0x0, lo_flags = 0, 
        lo_data = 0, lo_witness = 0x0}, sx_lock = 0}, uepm_list = {
      lh_first = 0x0}, uepm_ucred = 0x0, uepm_flags = 0}, um_nindir = 4096, 
  um_bptrtodb = 3, um_seqinc = 8, um_lock = {lock_object = {
      lo_name = 0xffffffff80a53d30 "FFS", lo_flags = 16973824, lo_data = 0, 
      lo_witness = 0xfffffe00008e3400}, mtx_lock = 4}, um_fsckpid = 0, 
  um_softdep = 0xfffff800027a0200, um_quotas = {0x0, 0x0}, um_cred = {0x0, 
    0x0}, um_btime = {0, 0}, um_itime = {0, 0}, um_qflags = "\000", 
  um_savedmaxfilesize = 0, um_candelete = 0, um_writesuspended = 0, 
  um_balloc = 0xffffffff8086eb90 <ffs_balloc_ufs2>, 
  um_blkatoff = 0xffffffff808a8170 <ffs_blkatoff>, 
  um_truncate = 0xffffffff808717b0 <ffs_truncate>, 
  um_update = 0xffffffff80871090 <ffs_update>, 
  um_valloc = 0xffffffff808660c0 <ffs_valloc>, 
  um_vfree = 0xffffffff808677b0 <ffs_vfree>, 
  um_ifree = 0xffffffff808af420 <ffs_ifree>, 
  um_rdonly = 0xffffffff808741c0 <ffs_rdonly>, 
  um_snapgone = 0xffffffff80879b70 <ffs_snapgone>}
(kgdb) p stat_flush_threads
$5 = 1

I can't see where integer divide fault can happen with stat_flush_threads=1 :(

-- 
Totus tuus, Glebius.