Re: registration error (rc -84) and -DSTP_OVERLOAD_THRESHOLD

["Richard W.M. Jones" <rjones at redhat dot com>]

On Wed, Jun 01, 2011 at 09:37:31AM -0400, Frank Ch. Eigler wrote:
> 
> mglt.biz wrote:
> 
> > [...]  While running my tap script, I receive WARNINGs and would
> > like to knwo how to consider them. [...]
> 
> > WARNING: probe
> > kernel.function("tcp_new_space@net/ipv4/tcp_input.c:4885") (address
> > 0xffffffff814064f0) registration error (rc -84)
> 
> This is an error (-EILSEQ) that comes from the kernel, most likely
> arch/x86/kernel/kprobes.c.  It may be a somehow blacklisted function,
> or perhaps a problem with the 'optimized kprobes' widget.  It may help
> to get a vmlinux disassembly around that 0xffffffff814064f0 address.

I'm also receiving these warnings.  My script attempts to add a probe
at every line in a module (yes, there's a good reason for it):

  probe module("ext2").statement ("*@*.c:*") {
    printf ("%s\n", pp());
  }

and I get maybe about 100 warnings like this:

  WARNING: probe module("ext2").statement("ext2_try_to_allocate_with_rsv@fs/ext2/balloc.c:1162") (address 0xffffffffa055f982) registration error (rc -84)
  WARNING: probe module("ext2").statement("ext2_new_blocks@fs/ext2/balloc.c:1270") (address 0xffffffffa055ff3b) registration error (rc -84)
  WARNING: probe module("ext2").statement("ext2_new_blocks@fs/ext2/balloc.c:1272") (address 0xffffffffa055ff3e) registration error (rc -84)
  WARNING: probe module("ext2").statement("ext2_new_blocks@fs/ext2/balloc.c:1277") (address 0xffffffffa055ffd4) registration error (rc -84)
  WARNING: probe module("ext2").statement("ext2_readdir@fs/ext2/dir.c:342") (address 0xffffffffa056098f) registration error (rc -84)
  WARNING: probe module("ext2").statement("ext2_find_entry@fs/ext2/dir.c:426") (address 0xffffffffa0560b28) registration error (rc -84)

Apart from the warnings, systemtap functions correctly.

Because these addresses are in a module, I couldn't work out the right
invocation of gdb / objdump to get it to disassemble those addresses.
But if you tell me how, I'll be glad to provide that information.

Fedora 15, 2.6.38.7-30.fc15.x86_64

Rich.

-- 
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