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printing kernel backtrace
- From: Nikolay Borisov <n dot borisov at siteground dot com>
- To: systemtap at sourceware dot org
- Date: Sat, 12 Dec 2015 14:33:04 +0200
- Subject: printing kernel backtrace
- Authentication-results: sourceware.org; auth=none
Hello,
I've started experimenting with systemtamp and I'd like to print the
callstack leading to the probed function. To that effect I have created
the following very simple tapset:
probe module("dm_thin_pool").function("do_waker") {
print_syms(callers(-1))
printf("finished backtrace\n");
}
However the output I get is something like that:
0xffffffffa0152c80 : do_waker+0x0/0x40 [dm_thin_pool]
0xffffffff810a5025 : 0xffffffff810a5025
0xffffffffa0152c80 : do_waker+0x0/0x40 [dm_thin_pool]
0xffffffffa0152c80 : do_waker+0x0/0x40 [dm_thin_pool]
0xffffffffa0152c80 : do_waker+0x0/0x40 [dm_thin_pool]
0xffffffffa0152c80 : do_waker+0x0/0x40 [dm_thin_pool]
0xffffffffa0152c80 : do_waker+0x0/0x40 [dm_thin_pool]
0xffffffffa0152c80 : do_waker+0x0/0x40 [dm_thin_pool]
0xffffffffa0152c80 : do_waker+0x0/0x40 [dm_thin_pool]
0xffffffffa0152c80 : do_waker+0x0/0x40 [dm_thin_pool]
0xffffffffa0152c80 : do_waker+0x0/0x40 [dm_thin_pool]
0xffffffffa0152c80 : do_waker+0x0/0x40 [dm_thin_pool]
0xffffffffa0152c80 : do_waker+0x0/0x40 [dm_thin_pool]
0xffffffffa0152c80 : do_waker+0x0/0x40 [dm_thin_pool]
0xffffffffa0152c80 : do_waker+0x0/0x40 [dm_thin_pool]
0xffffffffa0152c80 : do_waker+0x0/0x40 [dm_thin_pool]
0xffffffffa0152c80 : do_waker+0x0/0x40 [dm_thin_pool]
0xffffffffa0152c80 : do_waker+0x0/0x40 [dm_thin_pool]
0xffffffffa0152c80 : do_waker+0x0/0x40 [dm_thin_pool]
0xffffffffa0152c80 : do_waker+0x0/0x40 [dm_thin_pool]
0xffffffffa0152c80 : do_waker+0x0/0x40 [dm_thin_pool]
0xffffffffa0152c80 : do_waker+0x0/0x40 [dm_thin_pool]
0xffffffffa0152c80 : do_waker+0x0/0x40 [dm_thin_pool]
0xffffffffa0152c80 : do_waker+0x0/0x40 [dm_thin_pool]
0xffffffffa0152c80 : do_waker+0x0/0x40 [dm_thin_pool]
0xffffffffa0152c80 : do_waker+0x0/0x40 [dm_thin_pool]
0xffffffffa0152c8 : 0xffffffffa0152c8
finished backtrace
It seems that systemtap is unable to unwind the debug information? I
believe I have compiled systemtap with the necessary unwidn libraries
but how do I check that for sure?