CVS commit: src/sys/arch/x86/x86

["Maxime Villard" <maxv%netbsd.org@localhost>]

Module Name:    src
Committed By:   maxv
Date:           Sun Dec 31 15:41:05 UTC 2017

Modified Files:
        src/sys/arch/x86/x86: pmap.c

Log Message:
Ah, finally found you. Fix two bugs in pmap_remap_largepages(), that
could cause KASLR kernels to crash early during the boot procedure.

pmap_remap_largepages assumes that the kernel is far from the end of
the VM space, but this assumption does not hold with KASLR, since the
kernel sections are allowed to reside in the very last page of the VM
space.

Doing +NBPD_L2 or roundup() in such cases caused an integer overflow,
which caused a page fault when touching &L2_BASE, which in turn caused
an immediate CPU reset and a reboot.

Took me a while to reproduce and debug this issue.


To generate a diff of this commit:
cvs rdiff -u -r1.270 -r1.271 src/sys/arch/x86/x86/pmap.c

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.