[Bug runtime/5051] New: backtrace() in return probes are failed on ia64

[Bug runtime/5051] New: backtrace() in return probes are failed on ia64

[mhiramat at redhat dot com]

I called the backtrace() at the return probe of __kmalloc() on ia64 (linux-2.6.22).
But the result seems be broken. Is this a known limitation?

Returning from: 0xa000000100146fe0 : __kmalloc+0x0/0x240 []
Returning to  : 0xa0000001001b3de0 : bio_copy_user+0xa0/0x540 []
 0xa0000001000588c0 : kretprobe_trampoline+0x0/0x20 []
 0xa0000001000588c0 : kretprobe_trampoline+0x0/0x20 []
 0xa0000001000588c0 : kretprobe_trampoline+0x0/0x20 []
 0xa0000001000588c0 : kretprobe_trampoline+0x0/0x20 []
 0xa0000001000588c0 : kretprobe_trampoline+0x0/0x20 []
 0xa0000001000588c0 : kretprobe_trampoline+0x0/0x20 []
 0xa0000001000588c0 : kretprobe_trampoline+0x0/0x20 []
 0xa0000001000588c0 : kretprobe_trampoline+0x0/0x20 []
 0xa0000001000588c0 : kretprobe_trampoline+0x0/0x20 []
 0xa0000001000588c0 : kretprobe_trampoline+0x0/0x20 []
 0xa0000001000588c0 : kretprobe_trampoline+0x0/0x20 []
 0xa0000001000588c0 : kretprobe_trampoline+0x0/0x20 []
 0xa0000001000588c0 : kretprobe_trampoline+0x0/0x20 []
 0xa0000001000588c0 : kretprobe_trampoline+0x0/0x20 []
 0xa0000001000588c0 : kretprobe_trampoline+0x0/0x20 []
 0xa0000001000588c0 : kretprobe_trampoline+0x0/0x20 []

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           Summary: backtrace() in return probes are failed on ia64
           Product: systemtap
           Version: unspecified
            Status: NEW
          Severity: normal
          Priority: P2
         Component: runtime
        AssignedTo: systemtap at sources dot redhat dot com
        ReportedBy: mhiramat at redhat dot com
  GCC host triplet: ia64


http://sourceware.org/bugzilla/show_bug.cgi?id=5051

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[Bug runtime/5051] backtrace() in return probes are failed on ia64

[jkenisto at us dot ibm dot com]

------- Additional Comments From jkenisto at us dot ibm dot com  2007-09-20 21:51 -------
I can't say for sure whether there's an ia64-specific problem here.  But the
fact that kretprobes messes up stack backtraces is documented.  Search for
"stack backtraces" in Documentation/kprobes.txt.

This limitation could be fixed, or at least mitigated, by adding a function to
kprobes that returns the return address from the Nth kretprobe_instance for the
indicated task in that task's bucket in kretprobe_inst_table[].  (Keep in mind
that if you have multiple kretprobes on the same function, only one of the
kretprobe_instances will have the true return address; the others will have the
kretprobe trampoline address.)

-- 


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[Bug runtime/5051] backtrace() in return probes are failed on ia64

[hunt at redhat dot com]

------- Additional Comments From hunt at redhat dot com  2007-09-24 15:26 -------
This is not a known problem.  Looking at the posted ia64 test results, there are
no failures listed for context.exp, which tests return probe backtraces. Strange.

On x86, this script
probe kernel.function("__kmalloc"), kernel.function("__kmalloc").return
{ 
	printf("backtrace from %s:\n", pp())
	print_backtrace()
	print("\n")
}
outputs
backtrace from kernel.function("__kmalloc@mm/slab.c:3721"):
 0xc0477c29 : __kmalloc+0x1/0xd2 []
 0xc06311ab : kretprobe_trampoline_holder+0x0/0x2f []
 0xc05c5848 : sock_alloc_send_skb+0x74/0x1ab []
 0xc05c8501 : skb_dequeue+0xf/0x3f []
 0xc062667c : unix_stream_sendmsg+0x150/0x311 []
 0xc05c2ed9 : sock_aio_write+0xf9/0x105 []
 0xc047ae81 : do_sync_readv_writev+0xc1/0xfe []
 0xc043bb59 : autoremove_wake_function+0x0/0x35 []
 0xc04f32a0 : copy_from_user+0x32/0x5e []
 0xc047ad3c : rw_copy_check_uvector+0x5c/0xb0 []
 0xc047b5e6 : do_readv_writev+0xbc/0x187 []
 0xc05c2de0 : sock_aio_write+0x0/0x105 []
 0xc04a966f : dnotify_parent+0x1a/0x5d []
 0xc047b6ee : vfs_writev+0x3d/0x48 []
 0xc047bb60 : sys_writev+0x41/0x95 []
 0xc0406e6e : sysenter_past_esp+0x5f/0x99 []

backtrace from kernel.function("__kmalloc@mm/slab.c:3721").return:
Returning from: 0xc0477c28 : __kmalloc+0x0/0xd2 []
Returning to  : 0xc05c91fc : __alloc_skb+0x49/0xf7 []
 0xc05c5848 : sock_alloc_send_skb+0x74/0x1ab []
 0xc05c8501 : skb_dequeue+0xf/0x3f []
 0xc062667c : unix_stream_sendmsg+0x150/0x311 []
 0xc05c2ed9 : sock_aio_write+0xf9/0x105 []
 0xc047ae81 : do_sync_readv_writev+0xc1/0xfe []
 0xc043bb59 : autoremove_wake_function+0x0/0x35 []
 0xc04f32a0 : copy_from_user+0x32/0x5e []
 0xc047ad3c : rw_copy_check_uvector+0x5c/0xb0 []
 0xc047b5e6 : do_readv_writev+0xbc/0x187 []
 0xc05c2de0 : sock_aio_write+0x0/0x105 []
 0xc04a966f : dnotify_parent+0x1a/0x5d []
 0xc047b6ee : vfs_writev+0x3d/0x48 []
 0xc047bb60 : sys_writev+0x41/0x95 []
 0xc0406e6e : sysenter_past_esp+0x5f/0x99 []


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[Bug runtime/5051] backtrace() in return probes are failed on ia64

[shaohua dot li at intel dot com]

------- Additional Comments From shaohua dot li at intel dot com  2007-11-13 07:19 -------
please try the patch http://marc.info/?l=linux-ia64&m=119493734125209&w=2, 
works for me.

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[Bug runtime/5051] backtrace() in return probes are failed on ia64

[mhiramat at redhat dot com]

------- Additional Comments From mhiramat at redhat dot com  2007-11-19 21:19 -------
(In reply to comment #3)
> please try the patch http://marc.info/?l=linux-ia64&m=119493734125209&w=2, 
> works for me.

Great! I tested it on 2.6.24-rc2 and it works for me.
Thank you



-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|                            |FIXED


http://sourceware.org/bugzilla/show_bug.cgi?id=5051

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