Messages in this thread | | | From | Vince Weaver <> | Date | Mon, 22 Aug 2016 22:54:32 -0400 (EDT) | Subject | Re: perf: fuzzer crashes immediately on AMD system |
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> > > > > > > > perf stat -a -e amd_nb/config=0x37,config1=0x20/ /bin/ls > amd_uncore_find_online_sibling() > function is broken.
and that's the problem. uncore_find_online_sibling() does all kinds of wrong things including sticking active uncore structures in uncore->free_when_cpu_online
Then uncore_online() comes along and frees those structures.
Then some other part of the kernel comes and re-uses the free'd data.
Then when we try to start an event, all of the fields are invalid because the uncore pointer is pointing to re-used data.
I don't have a patch because I am not 100% clear on what uncore_find_online_sibling() is doing in the first place.
Vince
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