Messages in this thread | | | Date | Wed, 16 Dec 2015 16:49:37 -0300 | From | Arnaldo Carvalho de Melo <> | Subject | Re: [PATCH v5 02/14] perf tools: Prevent calling machine__delete() on non-allocated machine |
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Em Wed, Dec 16, 2015 at 09:37:18AM +0800, Wangnan (F) escreveu: > > > On 2015/12/15 20:36, Jiri Olsa wrote: > >On Mon, Dec 14, 2015 at 10:39:11AM +0000, Wang Nan wrote: > > > >SNIP > > > >>@@ -137,12 +138,15 @@ void machine__exit(struct machine *machine) > >> void machine__delete(struct machine *machine) > >> { > >> machine__exit(machine); > >>- free(machine); > >>+ if (machine->allocated) > >>+ free(machine); > >>+ else > >>+ pr_warning("WARNING: delete a non-allocated machine. Skip.\n"); > >we used WARN_ONCE several times already in similar cases > > > >jirka > > Will switch to: > > @@ -136,13 +138,13 @@ void machine__exit(struct machine *machine) > > void machine__delete(struct machine *machine) > { > - machine__exit(machine);
Better keep the above.
And I wonder if we would go on sprinkling these kinds of checks for all classes we have :-\
I think this is a job for some static analisys tool, that or we figure out a way to find out if an address is for a stack or heap and use that instead, and in a bpf based tool, perhaps, one that would hook into all *__delete() tools and check if the object it is using should or not be in fact free()ed.
I could think about hooking __new*() calls, hashing the return value, then at __delete() time check it, for instance.
- Arnaldo
> - free(machine); > + WARN_ONCE((machine->allocated ? free(machine), 0 : -1), > + "WARNING: deleting a non-allocated machine. Skip.\n"); > } > > Thank you.
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