Date: Thu, 07 May 2015 22:59:46 +1000 From: Lawrence Stewart <lstewart@room52.net> To: =?UTF-8?B?RWR3YXJkIFRvbWFzeiBOYXBpZXJhxYJh?= <trasz@freebsd.org>, Ryan Stone <rysto32@gmail.com> Cc: "freebsd-hackers@freebsd.org" <freebsd-hackers@freebsd.org> Subject: Re: What's required to make removal of a mounted USB stick safe? Message-ID: <554B61C2.5000704@room52.net> In-Reply-To: <1306708F-0872-4D02-9C88-70F683018C39@FreeBSD.org> References: <CAFMmRNwTi2GOEHN1tDQ7o1-VAtykT%2Bz3g%2B70qaDMenThSrSRgQ@mail.gmail.com> <1306708F-0872-4D02-9C88-70F683018C39@FreeBSD.org>
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On 05/07/15 16:23, Edward Tomasz Napierała wrote:
>
> Dnia 6 maj 2015 o godz. 22:49 Ryan Stone <rysto32@gmail.com>
> napisał(a):
>
>> Currently FreeBSD stands a fair chance at panicking if a mounted
>> USB drive is removed while I/O is in flight. Does anybody know
>> what work is involved to have the kernel safely recover from this
>> case? Losing data from the drive is expected of course but there's
>> no reason that the entire kernel has to crash.
>
> I've spent some time on this few years ago, and got it to work,
> except for one case: UFS with softupdates. It's possible that some
> regressions have been introduced since then. What's the filesystem?
> Do you have a backtrace?
I had a recent crash caused by accidentally unplugging my phone which I
had the SD card mounted over USB cable. It had been automounted by KDE.
If I recall correctly, there was no IO in flight, but I had copied a
file from the phone to my laptop a minute or so prior to accidentally
unplugging. I have a vmcore if there would be any additional useful
information.
lstewart@lstewart-laptop> uname -a
FreeBSD lstewart-laptop 11.0-CURRENT FreeBSD 11.0-CURRENT #2 r279802:
Sat Mar 14 13:31:32 AEDT 2015
root@lstewart-laptop:/usr/obj/usr/src/sys/LSTEWART-LAPTOP amd64
Some info from core.txt:
panic: dead bo 0xfffff8015109e2a8
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 "amd64-marcel-freebsd"...
Unread portion of the kernel message buffer:
lock order reversal:
1st 0xfffff8033bf72418 zfs (zfs) @ /usr/src/sys/kern/vfs_mount.c:1229
2nd 0xfffff80151b69240 syncer (syncer) @ /usr/src/sys/kern/vfs_subr.c:2287
KDB: stack backtrace:
db_trace_self_wrapper() at db_trace_self_wrapper+0x2b/frame
0xfffffe0460ebd510
witness_checkorder() at witness_checkorder+0xe45/frame 0xfffffe0460ebd5a0
__lockmgr_args() at __lockmgr_args+0xacf/frame 0xfffffe0460ebd6d0
vop_stdlock() at vop_stdlock+0x3c/frame 0xfffffe0460ebd6f0
VOP_LOCK1_APV() at VOP_LOCK1_APV+0xfc/frame 0xfffffe0460ebd720
_vn_lock() at _vn_lock+0x8a/frame 0xfffffe0460ebd790
vputx() at vputx+0x232/frame 0xfffffe0460ebd7f0
dounmount() at dounmount+0x305/frame 0xfffffe0460ebd870
sys_unmount() at sys_unmount+0x2ec/frame 0xfffffe0460ebd9a0
amd64_syscall() at amd64_syscall+0x27f/frame 0xfffffe0460ebdab0
Xfast_syscall() at Xfast_syscall+0xfb/frame 0xfffffe0460ebdab0
--- syscall (22, FreeBSD ELF64, sys_unmount), rip = 0x8008990ea, rsp =
0x7fffffffda28, rbp = 0x7fffffffdb40 ---
lock order reversal:
1st 0xfffff8033bf72418 zfs (zfs) @ /usr/src/sys/kern/vfs_mount.c:1229
2nd 0xfffff8015109e240 devfs (devfs) @
/usr/src/sys/fs/msdosfs/msdosfs_vfsops.c:993
KDB: stack backtrace:
db_trace_self_wrapper() at db_trace_self_wrapper+0x2b/frame
0xfffffe0460ebd490
witness_checkorder() at witness_checkorder+0xe45/frame 0xfffffe0460ebd520
__lockmgr_args() at __lockmgr_args+0xacf/frame 0xfffffe0460ebd650
vop_stdlock() at vop_stdlock+0x3c/frame 0xfffffe0460ebd670
VOP_LOCK1_APV() at VOP_LOCK1_APV+0xfc/frame 0xfffffe0460ebd6a0
_vn_lock() at _vn_lock+0x8a/frame 0xfffffe0460ebd710
msdosfs_sync() at msdosfs_sync+0x192/frame 0xfffffe0460ebd7a0
msdosfs_unmount() at msdosfs_unmount+0x20/frame 0xfffffe0460ebd7f0
dounmount() at dounmount+0x42c/frame 0xfffffe0460ebd870
sys_unmount() at sys_unmount+0x2ec/frame 0xfffffe0460ebd9a0
amd64_syscall() at amd64_syscall+0x27f/frame 0xfffffe0460ebdab0
Xfast_syscall() at Xfast_syscall+0xfb/frame 0xfffffe0460ebdab0
--- syscall (22, FreeBSD ELF64, sys_unmount), rip = 0x8008990ea, rsp =
0x7fffffffda28, rbp = 0x7fffffffdb40 ---
panic: dead bo 0xfffff8015109e2a8
cpuid = 3
KDB: stack backtrace:
db_trace_self_wrapper() at db_trace_self_wrapper+0x2b/frame
0xfffffe0460ebd520
vpanic() at vpanic+0x189/frame 0xfffffe0460ebd5a0
kassert_panic() at kassert_panic+0x132/frame 0xfffffe0460ebd610
buf_vlist_add() at buf_vlist_add+0x15c/frame 0xfffffe0460ebd640
getblk() at getblk+0x8ed/frame 0xfffffe0460ebd700
breadn_flags() at breadn_flags+0x2d/frame 0xfffffe0460ebd740
markvoldirty() at markvoldirty+0xc4/frame 0xfffffe0460ebd7a0
msdosfs_unmount() at msdosfs_unmount+0x7e/frame 0xfffffe0460ebd7f0
dounmount() at dounmount+0x42c/frame 0xfffffe0460ebd870
sys_unmount() at sys_unmount+0x2ec/frame 0xfffffe0460ebd9a0
amd64_syscall() at amd64_syscall+0x27f/frame 0xfffffe0460ebdab0
Xfast_syscall() at Xfast_syscall+0xfb/frame 0xfffffe0460ebdab0
--- syscall (22, FreeBSD ELF64, sys_unmount), rip = 0x8008990ea, rsp =
0x7fffffffda28, rbp = 0x7fffffffdb40 ---
KDB: enter: panic
Reading symbols from /boot/kernel/zfs.ko.symbols...done.
Loaded symbols for /boot/kernel/zfs.ko.symbols
Reading symbols from /boot/kernel/opensolaris.ko.symbols...done.
Loaded symbols for /boot/kernel/opensolaris.ko.symbols
Reading symbols from /boot/kernel/sem.ko.symbols...done.
Loaded symbols for /boot/kernel/sem.ko.symbols
Reading symbols from /boot/kernel/ums.ko.symbols...done.
Loaded symbols for /boot/kernel/ums.ko.symbols
Reading symbols from /boot/kernel/ng_ubt.ko.symbols...done.
Loaded symbols for /boot/kernel/ng_ubt.ko.symbols
Reading symbols from /boot/kernel/netgraph.ko.symbols...done.
Loaded symbols for /boot/kernel/netgraph.ko.symbols
Reading symbols from /boot/kernel/ng_hci.ko.symbols...done.
Loaded symbols for /boot/kernel/ng_hci.ko.symbols
Reading symbols from /boot/kernel/ng_bluetooth.ko.symbols...done.
Loaded symbols for /boot/kernel/ng_bluetooth.ko.symbols
Reading symbols from /boot/kernel/ng_l2cap.ko.symbols...done.
Loaded symbols for /boot/kernel/ng_l2cap.ko.symbols
Reading symbols from /boot/kernel/ng_btsocket.ko.symbols...done.
Loaded symbols for /boot/kernel/ng_btsocket.ko.symbols
Reading symbols from /boot/kernel/ng_socket.ko.symbols...done.
Loaded symbols for /boot/kernel/ng_socket.ko.symbols
Reading symbols from /boot/kernel/linux.ko.symbols...done.
Loaded symbols for /boot/kernel/linux.ko.symbols
Reading symbols from /boot/kernel/i915kms.ko.symbols...done.
Loaded symbols for /boot/kernel/i915kms.ko.symbols
Reading symbols from /boot/kernel/drm2.ko.symbols...done.
Loaded symbols for /boot/kernel/drm2.ko.symbols
Reading symbols from /boot/kernel/iicbus.ko.symbols...done.
Loaded symbols for /boot/kernel/iicbus.ko.symbols
Reading symbols from /boot/kernel/iic.ko.symbols...done.
Loaded symbols for /boot/kernel/iic.ko.symbols
Reading symbols from /boot/kernel/iicbb.ko.symbols...done.
Loaded symbols for /boot/kernel/iicbb.ko.symbols
Reading symbols from /boot/modules/vboxdrv.ko...done.
Loaded symbols for /boot/modules/vboxdrv.ko
Reading symbols from /boot/modules/vboxnetadp.ko...done.
Loaded symbols for /boot/modules/vboxnetadp.ko
Reading symbols from /boot/modules/vboxnetflt.ko...done.
Loaded symbols for /boot/modules/vboxnetflt.ko
Reading symbols from /boot/kernel/ng_ether.ko.symbols...done.
Loaded symbols for /boot/kernel/ng_ether.ko.symbols
Reading symbols from /boot/kernel/ipfw.ko.symbols...done.
Loaded symbols for /boot/kernel/ipfw.ko.symbols
#0 doadump (textdump=Unhandled dwarf expression opcode 0x93
) at pcpu.h:219
219 pcpu.h: No such file or directory.
in pcpu.h
(kgdb) #0 doadump (textdump=Unhandled dwarf expression opcode 0x93
) at pcpu.h:219
#1 0xffffffff80355e66 in db_fncall (dummy1=<value optimized out>,
dummy2=<value optimized out>, dummy3=<value optimized out>,
dummy4=<value optimized out>) at /usr/src/sys/ddb/db_command.c:568
#2 0xffffffff80355b4c in db_command (cmd_table=0x0)
at /usr/src/sys/ddb/db_command.c:440
#3 0xffffffff803558b4 in db_command_loop ()
at /usr/src/sys/ddb/db_command.c:493
#4 0xffffffff803583f0 in db_trap (type=<value optimized out>,
code=Unhandled dwarf expression opcode 0x93
)
at /usr/src/sys/ddb/db_main.c:251
#5 0xffffffff8098af9e in kdb_trap (type=Unhandled dwarf expression
opcode 0x93
) at /usr/src/sys/kern/subr_kdb.c:654
#6 0xffffffff80d7280b in trap (frame=0xfffffe0460ebd450)
at /usr/src/sys/amd64/amd64/trap.c:542
#7 0xffffffff80d51d02 in calltrap ()
at /usr/src/sys/amd64/amd64/exception.S:235
#8 0xffffffff8098a68e in kdb_enter (why=0xffffffff8100c329 "panic",
msg=0x80 <Address 0x80 out of bounds>) at cpufunc.h:63
#9 0xffffffff8094e609 in vpanic (fmt=<value optimized out>,
ap=<value optimized out>) at /usr/src/sys/kern/kern_shutdown.c:740
#10 0xffffffff8094e452 in kassert_panic (fmt=<value optimized out>)
at /usr/src/sys/kern/kern_shutdown.c:635
#11 0xffffffff80a02b3c in buf_vlist_add (bp=0xfffffe03d9f3c618,
bo=0xfffff8015109e2a8, xflags=Unhandled dwarf expression opcode 0x93
) at /usr/src/sys/kern/vfs_subr.c:1582
#12 0xffffffff809e8bdd in getblk (vp=0xfffff8015109e1d8, blkno=18,
size=4096,
slpflag=<value optimized out>, slptimeo=0, flags=<value optimized out>)
at /usr/src/sys/kern/vfs_bio.c:3276
#13 0xffffffff809e972d in breadn_flags (vp=0xfffff8015109e1d8, blkno=128,
size=Unhandled dwarf expression opcode 0x93
) at /usr/src/sys/kern/vfs_bio.c:1158
#14 0xffffffff80836df4 in markvoldirty (pmp=0xfffff801308e6800,
dirty=Unhandled dwarf expression opcode 0x93
)
at /usr/src/sys/fs/msdosfs/msdosfs_fat.c:1097
#15 0xffffffff8083b2de in msdosfs_unmount (mp=0xfffff8001b0a0990,
mntflags=<value optimized out>)
at /usr/src/sys/fs/msdosfs/msdosfs_vfsops.c:811
#16 0xffffffff809fcb9c in dounmount (mp=<value optimized out>,
flags=Unhandled dwarf expression opcode 0x93
)
at /usr/src/sys/kern/vfs_mount.c:1316
#17 0xffffffff809fc74c in sys_unmount (td=0xfffff803da4b6940,
uap=0xfffffe0460ebda40) at /usr/src/sys/kern/vfs_mount.c:1207
#18 0xffffffff80d7372f in amd64_syscall (td=0xfffff803da4b6940, traced=0)
at subr_syscall.c:133
#19 0xffffffff80d51feb in Xfast_syscall ()
at /usr/src/sys/amd64/amd64/exception.S:395
#20 0x00000008008990ea in ?? ()
Previous frame inner to this frame (corrupt stack?)
Current language: auto; currently minimal
Cheers,
Lawrence
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