Messages in this thread | | | Date | Wed, 23 Apr 2014 09:33:56 -0400 (EDT) | From | Vince Weaver <> | Subject | Re: [perf] yet another 32/64-bit range check failure |
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On Wed, 23 Apr 2014, Peter Zijlstra wrote: > > So perf_event_open() -> err_alloc: -> free_event() -> __free_event() -> > call_rcu() -> free_event_rcu() -> kfree(). > > Would explain that, right? The memory is RCU freed, which means we need > to wait a grace period before releasing it.
ah yes, RCU. That does make debugging this issue a lot harder.
Back to trying to get the bug to trigger in a useful location while ftrace is running. I keep triggering it immediately after the compiler generates helpful code like mov 0x40(%rbx),%rbx so the address is lost and the register dump just holds 0x6b6b6b6b6b6b6b6b.
Vince
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