Messages in this thread | | | Date | Mon, 19 Mar 2018 14:40:51 +0100 | From | Oleg Nesterov <> | Subject | Re: [PATCH 6/8] trace_uprobe/sdt: Fix multiple update of same reference counter |
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Hi Ravi,
On 03/19, Ravi Bangoria wrote: > > On 03/16/2018 11:20 PM, Oleg Nesterov wrote: > > > > And it seems that you are trying to confuse yourself, not only me ;) Just > > suppose that an application does mmap+munmap in a loop and the mapped region > > contains uprobe but not the counter. > > this is fine because ...
Yes, I guess I tried to say "counter but not uprobe" but possibly I was actually confused.
> Our initial design was to increment counter in install_breakpoint() but > uprobed instruction gets patched in a very early stage of binary loading > and vma that holds the counter may not be mapped yet.
Yes, yes, I understand this is not that simple...
> > Btw, why do we need a counter, not a boolean? Who else can modify it? > > Or different uprobes can share the same counter? > > Yes, multiple SDT markers can share the counter.
OK, thanks.
Oleg.
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