Messages in this thread | | | Date | Fri, 14 Jun 2019 06:03:04 -0400 (EDT) | From | Mathieu Desnoyers <> | Subject | Re: [PATCH 1/5] glibc: Perform rseq(2) registration at C startup and thread creation (v10) |
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----- On Jun 12, 2019, at 4:00 PM, Mathieu Desnoyers mathieu.desnoyers@efficios.com wrote:
> ----- On Jun 10, 2019, at 4:43 PM, carlos carlos@redhat.com wrote: > >> On 6/6/19 7:57 AM, Florian Weimer wrote: >>> Let me ask the key question again: Does it matter if code observes the >>> rseq area first without kernel support, and then with kernel support? >>> If we don't expect any problems immediately, we do not need to worry >>> much about the constructor ordering right now. I expect that over time, >>> fixing this properly will become easier. >> >> I just wanted to chime in and say that splitting this into: >> >> * Ownership (__rseq_handled) >> >> * Initialization (__rseq_abi) >> >> Makes sense to me. >> >> I agree we need an answer to this question of ownership but not yet >> initialized, to owned and initialized. >> >> I like the idea of having __rseq_handled in ld.so. > > Very good, so I'll implement this approach. Sorry for the delayed > feedback, I am traveling this week.
I had issues with cases where application or LD_PRELOAD library also define the __rseq_handled symbol. They appear not to see the same address as the one initialized by ld.so.
I tried using the GL() macro in ld.so to set __rseq_handled, but it's the wrong address compared to what the preload lib and application observe.
Any thoughts on how to solve this ?
Thanks,
Mathieu
-- Mathieu Desnoyers EfficiOS Inc. http://www.efficios.com
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