Messages in this thread | | | Date | Wed, 16 Dec 2015 11:19:21 -0700 | Subject | 4.4-rc5 Setting trap flag inside nmi handler results in HARD LOCKUP | From | Jeff Merkey <> |
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Setting the (trap flag | resume flag) inside of an nmi handler results in a hard lockup while setting the resume flag works fine.
The watchdog detector fails to detect the lockup. I am currently examining the trap gate and interrupt gate setup on Linux and if anyone has any ideas it would be nice to be able to debug and step through the nmi handlers. I got breakpoints to work. I noticed kgdb/kdb just punts here and refuses to allow someone to step inside an nmi handler.
There is no reason Linux should not allow this to work since windows does and every other OS out there. I have seen this across some rex64 sysret calls as well this lockup behavior.
Anyone who is an intel expert with any clues would love some input if you know about this problem.
Jeff
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