Date: Wed, 26 Oct 2005 20:30:26 GMT From: Frank Mayhar <frank@exit.com> To: freebsd-bugs@FreeBSD.org Subject: Re: kern/87861: "panic: initiate_write_inodeblock_ufs2: already started" on 6.0-RC1 Message-ID: <200510262030.j9QKUQnp074222@freefall.freebsd.org>
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The following reply was made to PR kern/87861; it has been noted by GNATS.
From: Frank Mayhar <frank@exit.com>
To: bug-followup@FreeBSD.org
Cc:
Subject: Re: kern/87861: "panic: initiate_write_inodeblock_ufs2: already
started" on 6.0-RC1
Date: Wed, 26 Oct 2005 13:28:33 -0700
More information. I built the kernel with INVARIANTS and managed to
catch a KASSERT() at the beginning of bundirty():
panic: bundirty: buffer 0xd6d6cc00 still on queue 1
Queue 1 is the QUEUE_CLEAN queue, for (from the commentary)
"non-B_DELWRI buffers."
The buffer in question looks like:
(kgdb) print $buf
$4 = (struct buf *) 0xd6d6cc00
(kgdb) print *$buf
$5 = {
b_bufobj = 0xc4dff2e0,
b_bcount = 0x4000,
b_caller1 = 0x0,
b_data = 0xda0c5000 "",
b_error = 0x10,
b_iocmd = 0x2,
b_ioflags = 0x2,
b_iooffset = 0xed9a84000,
b_resid = 0x4000,
b_iodone = 0,
b_blkno = 0x76cd420,
b_offset = 0xed9a84000,
b_bobufs = {
tqe_next = 0xd6e265f0,
tqe_prev = 0xc4dff2f4
},
b_left = 0x0,
b_right = 0x0,
b_vflags = 0x0,
b_freelist = {
tqe_next = 0xd6d16960,
tqe_prev = 0xc06f75a8
},
b_qindex = 0x1,
b_flags = 0xa084,
b_xflags = 0x21,
b_lock = {
lk_interlock = 0xc06a8368,
lk_flags = 0x40000,
lk_sharecount = 0x0,
lk_waitcount = 0x0,
lk_exclusivecount = 0x1,
lk_prio = 0x50,
lk_wmesg = 0xc0655b94 "bufwait",
lk_timo = 0x0,
lk_lockholder = 0xfffffffe,
lk_newlock = 0x0
},
b_bufsize = 0x4000,
b_runningbufspace = 0x0,
b_kvabase = 0xda0c5000 "",
b_kvasize = 0x4000,
b_lblkno = 0x76cd420,
b_vp = 0xc4dff220,
b_dirtyoff = 0x0,
b_dirtyend = 0x0,
b_rcred = 0x0,
b_wcred = 0x0,
b_saveaddr = 0xda0c5000,
b_pager = {
pg_reqpage = 0x0
},
b_cluster = {
cluster_head = {
tqh_first = 0xd6e257d8,
tqh_last = 0xd6dbeb70
},
cluster_entry = {
tqe_next = 0xd6e257d8,
tqe_prev = 0xd6dbeb70
}
},
b_pages = {0xc29d8868, 0xc29d91b0, 0xc29dacf8, 0xc29c1840, 0x0
<repeats 28 times>},
b_npages = 0x4,
b_dep = {
lh_first = 0x0
}
}
(kgdb) print *$buf->b_bufobj
$8 = {
bo_mtx = 0xc4dff29c,
bo_clean = {
bv_hd = {
tqh_first = 0xd6cda498,
tqh_last = 0xd6e13e30
},
bv_root = 0xd6dcd908,
bv_cnt = 0xf
},
bo_dirty = {
bv_hd = {
tqh_first = 0xd6d6cc00,
tqh_last = 0xd6d2a380
},
bv_root = 0xd6e81bd8,
bv_cnt = 0x27
},
bo_numoutput = 0x7,
bo_flag = 0x1,
bo_ops = 0xc0694b9c,
bo_bsize = 0x200,
bo_object = 0xc596f210,
bo_synclist = {
le_next = 0xc50623f0,
le_prev = 0xc2d6b320
},
bo_private = 0xc47e0480,
__bo_vnode = 0xc4dff220
}
Somewhat more interesting is this error message from just before the
panic. There are 200+ of these messages, but this one appears to be
associated with this buffer, since the offset and length match:
g_vfs_done():da6s1e[WRITE(offset=63781224448, length=16384)]error = 16
Error 16 is EBUSY.
Unfortunately the stack is messed up (apparently because of a panic
cascade) so I can't extract a backtrace for this one.
--
Frank Mayhar frank@exit.com http://www.exit.com/
Exit Consulting http://www.gpsclock.com/
http://www.exit.com/blog/frank/
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