Bug 194973

Summary:	Infinite recursion in ahash_def_finup_done2 when ghash_clmulni_intel is loaded
Product:	Other	Reporter:	John Morrissey (jwm)
Component:	Modules	Assignee:	other_modules
Status:	NEW ---
Severity:	normal
Priority:	P1
Hardware:	Intel
OS:	Linux
Kernel Version:	4.9.13	Subsystem:
Regression:	No	Bisected commit-id:
Attachments:	Kernel trace output

Description John Morrissey 2017-03-23 17:26:35 UTC

Created attachment 255489 [details]
Kernel trace output

I'm experiencing lockups due to seemingly infinite recursion in ahash_def_finup_done2 when ghash_clmulni_intel is loaded on an ASRock IMB-150 (http://www.asrock.com/IPC/overview.asp?Model=IMB-150) with a Celeron J1900. Attached is the full trace output.

I can reliably reproduce the lockups by bringing up an IPSec VPN connection from an OS X client to the affected system (running StrongSwan 5.5.1) and starting a Time Machine backup from the OS X client over that IPSec connection. After a minute or two, the affected system locks up.

Blacklisting ghash_clmulni_intel (and letting ghash_generic load) works around this problem.

This is with 4.9.13 from Debian backports, but Debian doesn't patch the ghash subsystem in their non-RT kernels, so this is AFAICT stock code. The affected code doesn't seem to have changed materially since 4.9.13.