svn commit: r361010 - head/sys/riscv/riscv
Jessica Clarke
jrtc27 at FreeBSD.org
Wed May 13 17:20:52 UTC 2020
Author: jrtc27
Date: Wed May 13 17:20:51 2020
New Revision: 361010
URL: https://svnweb.freebsd.org/changeset/base/361010
Log:
riscv: Fix pmap_protect for superpages
When protecting a superpage, we would previously fall through to the
non-superpage case and read the contents of the superpage as PTEs,
potentially modifying them and trying to look up underlying VM pages that
don't exist if they happen to look like PTEs we would care about. This led
to nginx causing an unexpected page fault in pmap_protect that panic'ed the
kernel. Instead, if we see a superpage, we are done for this range and
should continue to the next.
Reviewed by: markj, jhb (mentor)
Approved by: markj, jhb (mentor)
Differential Revision: https://reviews.freebsd.org/D24827
Modified:
head/sys/riscv/riscv/pmap.c
Modified: head/sys/riscv/riscv/pmap.c
==============================================================================
--- head/sys/riscv/riscv/pmap.c Wed May 13 16:36:42 2020 (r361009)
+++ head/sys/riscv/riscv/pmap.c Wed May 13 17:20:51 2020 (r361010)
@@ -2329,6 +2329,7 @@ retryl2:
if (!atomic_fcmpset_long(l2, &l2e, l2e & ~mask))
goto retryl2;
anychanged = true;
+ continue;
} else {
if (!pv_lists_locked) {
pv_lists_locked = true;
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