Bug 221594 - PT_TO_SCX kernel panic on arm64
Summary: PT_TO_SCX kernel panic on arm64
Status: Closed FIXED
Alias: None
Product: Base System
Classification: Unclassified
Component: kern (show other bugs)
Version: CURRENT
Hardware: arm64 Any
: --- Affects Only Me
Assignee: Ed Maste
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2017-08-17 18:41 UTC by Shawn Webb
Modified: 2017-08-17 21:32 UTC (History)
1 user (show)

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Description Shawn Webb 2017-08-17 18:41:12 UTC 
The below-linked code will cause a kernel panic on FreeBSD 12-CURRENT/arm64:

https://github.com/lattera/exploits/blob/master/FreeBSD/PTrace_arm64/001-scx.c
Comment 1 Shawn Webb 2017-08-17 18:44:06 UTC 
Note that since security.bsd.unprivileged_proc_debug is enabled by default on FreeBSD, this panic can be triggered as an unprivileged user.
Comment 2 Conrad Meyer freebsd_committer freebsd_triage 2017-08-17 21:01:26 UTC 
Next time, please include the kernel panic text and backtrace when filing bug reports about panics.

This was resolved by r322627.
Comment 3 Shawn Webb 2017-08-17 21:10:40 UTC 
(In reply to Conrad Meyer from comment #2)
I generally try to, but in this case, I didn't have access to such information.
Comment 4 Conrad Meyer freebsd_committer freebsd_triage 2017-08-17 21:17:45 UTC 
If you have space to dump cores (might not on arm64), that + the savecore rc.d service with the crashinfo option will write out a nice human readable panic message + backtrace to a file in /var/crash the next time the machine boots.  That might be an ok option.
Comment 5 Shawn Webb 2017-08-17 21:32:16 UTC 
(In reply to Conrad Meyer from comment #4)
I'm very familiar with getting kernel crash dumps. I just didn't have access this particular time.