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From: Tim Kientzle <kientzle@freebsd.org>
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Subject: Trashed registers returning from kernel?
Date: Sun, 21 Oct 2012 18:40:08 -0700
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On the BeagleBone, I'm seeing a similar crash in several different user =
land programs.  I suspect it's a kernel bug.

Symptom: program is killed with SIGSEGV.  Most of the registers contain =
values above 0xc0000000 (pointing into kernel space).

Theory:
 * Registers are not always getting correctly restored on a kernel->user =
transition.
 * SEGV is a consequence.

I can reproduce it semi-consistently by running "emacs existing-file" =
just after a reboot.  (But I'm pretty sure this is the same symptoms =
I've seen with several other programs, so I don't think it's a bug in =
emacs.)

Has anyone else seen this on an armv6 system?

Does anyone have suggestions for how to go about debugging this?

Suggestions appreciated.

Cheers,

Tim