linux_dsm_epyc7002/fs/proc
Peter Feiner 68b5a65248 mm: softdirty: respect VM_SOFTDIRTY in PTE holes
After a VMA is created with the VM_SOFTDIRTY flag set, /proc/pid/pagemap
should report that the VMA's virtual pages are soft-dirty until
VM_SOFTDIRTY is cleared (i.e., by the next write of "4" to
/proc/pid/clear_refs).  However, pagemap ignores the VM_SOFTDIRTY flag
for virtual addresses that fall in PTE holes (i.e., virtual addresses
that don't have a PMD, PUD, or PGD allocated yet).

To observe this bug, use mmap to create a VMA large enough such that
there's a good chance that the VMA will occupy an unused PMD, then test
the soft-dirty bit on its pages.  In practice, I found that a VMA that
covered a PMD's worth of address space was big enough.

This patch adds the necessary VMA lookup to the PTE hole callback in
/proc/pid/pagemap's page walk and sets soft-dirty according to the VMAs'
VM_SOFTDIRTY flag.

Signed-off-by: Peter Feiner <pfeiner@google.com>
Acked-by: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Hugh Dickins <hughd@google.com>
Acked-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-06 18:01:22 -07:00
..
array.c Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security 2014-08-06 08:06:39 -07:00
base.c
cmdline.c
consoles.c
cpuinfo.c
devices.c
fd.c
fd.h
generic.c
inode.c
internal.h
interrupts.c
Kconfig
kcore.c
kmsg.c
loadavg.c
Makefile
meminfo.c mm: export NR_SHMEM via sysinfo(2) / si_meminfo() interfaces 2014-08-06 18:01:19 -07:00
namespaces.c
nommu.c
page.c
proc_net.c
proc_sysctl.c
proc_tty.c
root.c
self.c
softirqs.c
stat.c /proc/stat: convert to single_open_size() 2014-07-03 09:21:54 -07:00
task_mmu.c mm: softdirty: respect VM_SOFTDIRTY in PTE holes 2014-08-06 18:01:22 -07:00
task_nommu.c
uptime.c
version.c
vmcore.c fs/proc/vmcore.c: remove NULL assignment to static 2014-06-06 16:08:12 -07:00