[ltt-dev] Unable to stop trace when started with -a option
Dany Madden
dany.r.madden at gmail.com
Tue Jul 21 19:37:21 EDT 2009
Hello,
I wanted to follow up on my post from last week. Is this a bug in lttctl or
is there something wrong with the way I am calling lttctl? Any suggestions
on how to get to the bottom of this issue is much appreciated.
Thanks,
Dany
On Thu, Jul 16, 2009 at 8:25 AM, Dany Madden <dany.r.madden at gmail.com>wrote:
> Hi,
>
> When I started a trace with the -a option, destroying the trace later would
> hang. These are the ltt versions that I am using:
>
> lttv: 0.12.7
> lttng: 0.72 (patched in sles11 2.6.27.19 kernel)
> lttcontrol: 0.64
>
> It appears that lttctl is waiting on lttd to die, but lttd is waiting for
> something else to finish. Please see sysrq-t output below.
>
> Restart tracing with append option -a
>
> ------------------------------------------------------
>
> punetest3:~ # lttctl -C -w /tmp/trace1 trace2 -a
> Linux Trace Toolkit Trace Control 0.64-14012009
>
> Controlling trace : trace2
>
> lttctl: Creating trace
>
> lttctl: Forking lttd
> Linux Trace Toolkit Trace Daemon 0.64-14012009
>
> Reading from debugfs directory : /sys/kernel/debug/ltt/trace2
> Writing to trace directory : /tmp/trace1
>
> lttctl: Starting trace
> punetest3:~ # echo $?
>
> 0
>
> Stop tracing hangs
> ----------------------------------------
> punetest3:~ # lttctl -D trace1
> Linux Trace Toolkit Trace Control 0.64-14012009
>
> Controlling trace : trace1
>
> lttctl: Pausing trace
>
> lttctl: Destroying trace
> ^C
>
> ---> Ran it thru gdb
>
> Program received signal SIGINT, Interrupt.
> 0xffffe430 in __kernel_vsyscall ()
> (gdb) bt
> #0 0xffffe430 in __kernel_vsyscall ()
> #1 0xb7f34bb3 in write () from /lib/libc.so.6
>
> #2 0xb7fd013c in lttctl_sendop (fname=0xbfffe5cc
> "/sys/kernel/debug/ltt/destroy_trace", op=0xbffff843 "trace3") at
> liblttctl.c:120
> #3 0xb7fd0ecb in lttctl_destroy_trace (name=0xbffff843 "trace3") at
>
> liblttctl.c:284
> #4 0x080498d6 in main (argc=1667330676, argv=0x4c003365) at lttctl.c:823
>
> --> It hangs in lttctl_sendop() while doing write.
>
> lttctl_sendop (fname=0xbfffe5bc "/sys/kernel/debug/ltt/destroy_trace",
>
> op=0xbffff83c "trace7")
> at liblttctl.c:108
> 108 if (!fname) {
> (gdb)
> 105 {
> (gdb)
> 108 if (!fname) {
> (gdb)
> 113 fd = open(fname, O_WRONLY);
> (gdb)
>
> 114 if (fd == -1) {
> (gdb)
> 113 fd = open(fname, O_WRONLY);
> (gdb)
> 114 if (fd == -1) {
> (gdb)
> 120 if (write(fd, op, strlen(op)) == -1) {
> (gdb) p fd
> $3 = <value optimized out>
>
> (gdb) p op
> $4 = 0xbffff83c "trace7"
> (gdb) p strlen(op)
> $5 = 6
> (gdb) c
> Continuing.
>
> ----> Output from sysrq-t
>
> Jul 15 17:47:27 elm3b36 kernel: lttd S 00000000 0 3979 1
>
> Jul 15 17:47:27 elm3b36 kernel: f6373e20 00000086 0000000c 00000000
> 00000000 00013e36 c05bd67c c05c0380
> Jul 15 17:47:27 elm3b36 kernel: c05c0380 c05c0380 c05c0380 f785f2c0
> f785f534 c2225380 00000002 c017f8b0
>
> Jul 15 17:47:27 elm3b36 kernel: b7e8b000 b7e8bbd8 f6373ea8 f785f534
> ffffef5d c05521d8 00000001 00000000
> Jul 15 17:47:27 elm3b36 kernel: Call Trace:
> Jul 15 17:47:27 elm3b36 kernel: [<c0147cd9>] futex_wait+0x207/0x3d0
>
> Jul 15 17:47:27 elm3b36 kernel: [<c01490e5>] do_futex+0x7a/0x8c9
> Jul 15 17:47:27 elm3b36 kernel: [<c0149a33>] sys_futex+0xff/0x112
> Jul 15 17:47:27 elm3b36 kernel: [<c0104de2>] syscall_call+0x7/0xb
>
> Jul 15 17:47:27 elm3b36 kernel: [<ffffe430>] 0xffffe430
> Jul 15 17:47:27 elm3b36 kernel: =======================
> Jul 15 17:47:27 elm3b36 kernel: lttd S c1000000 0 3980 1
> Jul 15 17:47:27 elm3b36 kernel: f6375dc0 00000086 0007f4a0 c1000000
>
> b7ff1c40 00011668 c05bd67c c05c0380
> Jul 15 17:47:27 elm3b36 kernel: c05c0380 c05c0380 c05c0380 f7bb62b0
> f7bb6524 c221b380 00000001 00000000
> Jul 15 17:47:27 elm3b36 kernel: f6f60848 f6354b7c 00000000 f7bb6524
>
> 000005b7 00000004 00000004 00000000
> Jul 15 17:47:27 elm3b36 kernel: Call Trace:
> Jul 15 17:47:27 elm3b36 kernel: [<c01989e3>] pipe_wait+0x50/0x6e
> Jul 15 17:47:27 elm3b36 kernel: [<c01afe80>] splice_to_pipe+0x164/0x1e9
>
> Jul 15 17:47:27 elm3b36 kernel: [<c023db08>] subbuf_splice_actor+0x167/0x172
> Jul 15 17:47:27 elm3b36 kernel: [<c023db40>]
> ltt_relay_file_splice_read+0x2d/0x6b
> Jul 15 17:47:27 elm3b36 kernel: [<c01af28c>] do_splice_to+0x56/0x64
>
> Jul 15 17:47:27 elm3b36 kernel: [<c01af419>] sys_splice+0x17f/0x1de
> Jul 15 17:47:27 elm3b36 kernel: [<c0104ceb>] sysenter_do_call+0x12/0x2f
> Jul 15 17:47:27 elm3b36 kernel: [<ffffe430>] 0xffffe430
>
> Jul 15 17:47:27 elm3b36 kernel: =======================
> Jul 15 17:47:27 elm3b36 kernel: lttctl S 00000086 0 3981 3869
> Jul 15 17:47:27 elm3b36 kernel: f6c03d10 00000082 00000001 00000086
> f6375c7c 0001f77c c05bd67c c05c0380
>
> Jul 15 17:47:27 elm3b36 kernel: c05c0380 c05c0380 c05c0380 f74dc3b0
> f74dc624 c222f380 00000003 f624f790
> Jul 15 17:47:27 elm3b36 kernel: 00000282 00000003 f624f790 f74dc624
> 000005b3 c05ce964 f79b4c00 00000000
>
> Jul 15 17:47:27 elm3b36 kernel: Call Trace:
> Jul 15 17:47:27 elm3b36 kernel: [<c023bbdc>] __ltt_trace_destroy+0xdc/0xfb
> Jul 15 17:47:27 elm3b36 kernel: [<c023be4d>] ltt_trace_destroy+0x2d/0x77
> Jul 15 17:47:27 elm3b36 kernel: [<f89cd070>] destroy_trace_write+0x70/0x13b
>
> [ltt_trace_control]
> Jul 15 17:47:27 elm3b36 kernel: [<c019337c>] vfs_write+0x8b/0x13d
> Jul 15 17:47:27 elm3b36 kernel: [<c0193526>] sys_write+0x45/0x94
> Jul 15 17:47:27 elm3b36 kernel: [<c0104de2>] syscall_call+0x7/0xb
>
> Jul 15 17:47:27 elm3b36 kernel: [<ffffe430>] 0xffffe430
>
>
>
> --
> -----
> ~ Dany Madden
>
--
-----
~ Dany Madden
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.casi.polymtl.ca/pipermail/lttng-dev/attachments/20090721/de2fdfb9/attachment-0003.htm>
More information about the lttng-dev
mailing list