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authorBoris Ostrovsky <boris.ostrovsky@oracle.com>2019-09-30 16:44:41 -0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2019-11-06 12:43:13 +0100
commit588c0f3282207a7b25951de0e96e5485b3bfa62d (patch)
treed570954aa0dbf6f414d6844d6f3407fb906ecab0 /Documentation
parent11d172c77de4b7a771c65af2e8e2ef4eaf9a1304 (diff)
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x86/xen: Return from panic notifier
[ Upstream commit c6875f3aacf2a5a913205accddabf0bfb75cac76 ] Currently execution of panic() continues until Xen's panic notifier (xen_panic_event()) is called at which point we make a hypercall that never returns. This means that any notifier that is supposed to be called later as well as significant part of panic() code (such as pstore writes from kmsg_dump()) is never executed. There is no reason for xen_panic_event() to be this last point in execution since panic()'s emergency_restart() will call into xen_emergency_restart() from where we can perform our hypercall. Nevertheless, we will provide xen_legacy_crash boot option that will preserve original behavior during crash. This option could be used, for example, if running kernel dumper (which happens after panic notifiers) is undesirable. Reported-by: James Dingwall <james@dingwall.me.uk> Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Reviewed-by: Juergen Gross <jgross@suse.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/admin-guide/kernel-parameters.txt4
1 files changed, 4 insertions, 0 deletions
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index b67a6cd08ca1..671f518b09ee 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -4875,6 +4875,10 @@
the unplug protocol
never -- do not unplug even if version check succeeds
+ xen_legacy_crash [X86,XEN]
+ Crash from Xen panic notifier, without executing late
+ panic() code such as dumping handler.
+
xen_nopvspin [X86,XEN]
Disables the ticketlock slowpath using Xen PV
optimizations.