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Re: registration error (rc -84) and -DSTP_OVERLOAD_THRESHOLD
On Tue, Jun 14, 2011 at 10:09:43AM -0400, Frank Ch. Eigler wrote:
> Hi -
>
> On Tue, Jun 14, 2011 at 03:08:12PM +0100, Richard W.M. Jones wrote:
> > On Tue, Jun 14, 2011 at 09:53:56AM -0400, Frank Ch. Eigler wrote:
> > > Look for the pc=.text+0xdbe offset field in there. That'd be area
> > > to sic objdump onto:
> >
> > What would I objdump? /proc/kcore?? Can you show me an example
> > command line?
>
> % objdump -drS /lib/modules/`uname -r`/kernel/fs/ext2/ext2.ko
Oh I see.
stap after phase 2 shows this for one of the problematic probes:
module("ext2").statement("ext2_try_to_allocate_with_rsv@fs/ext2/balloc.c:1162") /* pc=.text+0x982 */ /* <- module("ext2").statement("*@*.c:*") */
and here is the disassembled code around that place in the module:
972: e8 00 00 00 00 callq 977 <ext2_try_to_allocate_with_rs
v+0x3ba>
973: R_X86_64_PC32 _raw_spin_trylock-0x4
977: 85 c0 test %eax,%eax
979: 48 8b 8d 50 ff ff ff mov -0xb0(%rbp),%rcx
980: 74 4d je 9cf <ext2_try_to_allocate_with_rs
v+0x412>
982: 44 29 f9 sub %r15d,%ecx
985: 48 89 df mov %rbx,%rdi
988: 41 89 cf mov %ecx,%r15d
98b: e8 00 00 00 00 callq 990 <ext2_try_to_allocate_with_rsv+0x3d3>
98c: R_X86_64_PC32 rb_next-0x4
990: 48 85 c0 test %rax,%rax
993: 4d 63 ff movslq %r15d,%r15
996: 48 8b 95 58 ff ff ff mov -0xa8(%rbp),%rdx
99d: 75 06 jne 9a5 <ext2_try_to_allocate_with_rsv+0x3e8>
99f: 4c 01 7b 28 add %r15,0x28(%rbx)
Here's another one picked at random:
module("ext2").statement("ext2_readdir@fs/ext2/dir.c:342") /* pc=.text+0x198f */ /* <- module("ext2").statement("*@*.c:*") */
197e: e9 8f 00 00 00 jmpq 1a12 <ext2_readdir+0x28c>
1983: 45 8b 04 24 mov (%r12),%r8d
1987: 45 85 c0 test %r8d,%r8d
198a: 74 47 je 19d3 <ext2_readdir+0x24d>
198c: 45 31 c9 xor %r9d,%r9d
198f: 4d 85 ff test %r15,%r15
1992: 74 10 je 19a4 <ext2_readdir+0x21e>
1994: 41 8a 44 24 07 mov 0x7(%r12),%al
1999: 3c 07 cmp $0x7,%al
199b: 77 07 ja 19a4 <ext2_readdir+0x21e>
199d: 0f b6 c0 movzbl %al,%eax
19a0: 45 8a 0c 07 mov (%r15,%rax,1),%r9b
HTH, Rich.
--
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
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