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Re: PR3498: more efficient dwfl searching


Frank Ch. Eigler wrote:
Hi -

I committed some code to dramatically improve the pass-2 and pass-3
processing times for scripts that target the kernel, especially for
kernel build trees that have oodles of files under
/lib/modules/.../build.  It's basically using the offline module
search function's predicate vigorously, so that stap doesn't bother
open all .ko's on the system just for a kernel probe.

My early testing shows no problems, just speedups, but if you notice
debuginfo being found less well than before, please let me know.

- FChE

I found one regression since this commit.

$ stap -l nfsd.create*
Segmentation fault
[78375.044067] <6>stap[24911]: segfault at 0 ip 0000000000480efb sp 00007ffffe706400 error 4 in stap[400000+142000]


In fact, nfsd.create* includes nfsd.create and nfsd.createv3. In my
machine,
$ stap -l nfsd.create
nfsd.create
$ stap -l nfsd.createv3
semantic error: no match while resolving probe point nfsd.createv3

But nfsd.create* will get the error. Gdb said
Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread 140517345056560 (LWP 24971)]
base_query (this=0x7fffd6b68950, dw=@0x0, params=@0x7fffd6b68b40) at tapsets.cxx:442
442 sess(dw.sess), dw(dw)


If nfsd.createv3 existed in the kernel, there will be OK.

Regards,
Wenji


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