Re: [patch 1/2] oProfile: oops when profile_pc() return ~0LU

From: Linus Torvalds
Date: Tue Oct 23 2007 - 12:55:31 EST




On Tue, 23 Oct 2007, Philippe Elie wrote:
>
> For the signed-offs I thought the From: was an implicit Signed-offs.

No, there are no implicit sign-offs. The point of sign-offs is that it
makes the copyright and flow of patches explicit, so an "implicit
sign-off" would defeat the whole point.

> Test was done privately, Sami helped to narrow down the trouble, but
> he didn't test the last patch, nothing bad on Sami side, I was too
> confident the fix was obvious after narrowing it.

Well, I just wanted an ack that it was tested, since it seemed a bit
subtle and (like the sign-offs) that explicit "yes, this was tested" was
missing. Looks like I was right in asking for it:

> > The previous patch I tested by Philippe, oprof-fix-profile_pc-use.patch,
> > worked ok, but with this latest patch oprofiled aborts.
> > But kernel does not oops or print msgs.
>
> argh, I just moved the wrong eip from kernel to user space where the same
> problem occur too, *sighs*, since I can't reproduce Sami problem, my own
> test obviously worked...
>
> Sami, can you test this new patch. After testing can you report
> the contents of /dev/oprofile/stats/cpu*/sample_invalid_eip ?
>
> Linus, there is two way to fix this problem, the attached patch fix it
> by sanitizing the sampled eip,

I'm perfectly happy with the attached patch, I just want it to be
properly tested and have all the sign-offs (and explanations etc) in
place, and I can apply it.

Of course, I cannot think of a single architecture where an EIP of ~0UL is
valid anyway, so I'm also not opposed to just keeping ~0UL as the magic
value.

Linus
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