--- /dev/null
+From 9cc3a5bd40067b9a0fbd49199d0780463fc2140f Mon Sep 17 00:00:00 2001
+From: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
+Date: Wed, 17 Apr 2013 15:58:30 -0700
+Subject: hugetlbfs: add swap entry check in follow_hugetlb_page()
+
+From: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
+
+commit 9cc3a5bd40067b9a0fbd49199d0780463fc2140f upstream.
+
+With applying the previous patch "hugetlbfs: stop setting VM_DONTDUMP in
+initializing vma(VM_HUGETLB)" to reenable hugepage coredump, if a memory
+error happens on a hugepage and the affected processes try to access the
+error hugepage, we hit VM_BUG_ON(atomic_read(&page->_count) <= 0) in
+get_page().
+
+The reason for this bug is that coredump-related code doesn't recognise
+"hugepage hwpoison entry" with which a pmd entry is replaced when a memory
+error occurs on a hugepage.
+
+In other words, physical address information is stored in different bit
+layout between hugepage hwpoison entry and pmd entry, so
+follow_hugetlb_page() which is called in get_dump_page() returns a wrong
+page from a given address.
+
+The expected behavior is like this:
+
+ absent is_swap_pte FOLL_DUMP Expected behavior
+ -------------------------------------------------------------------
+ true false false hugetlb_fault
+ false true false hugetlb_fault
+ false false false return page
+ true false true skip page (to avoid allocation)
+ false true true hugetlb_fault
+ false false true return page
+
+With this patch, we can call hugetlb_fault() and take proper actions (we
+wait for migration entries, fail with VM_FAULT_HWPOISON_LARGE for
+hwpoisoned entries,) and as the result we can dump all hugepages except
+for hwpoisoned ones.
+
+Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
+Cc: Rik van Riel <riel@redhat.com>
+Acked-by: Michal Hocko <mhocko@suse.cz>
+Cc: HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>
+Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
+Acked-by: David Rientjes <rientjes@google.com>
+Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
+Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+
+---
+ mm/hugetlb.c | 12 +++++++++++-
+ 1 file changed, 11 insertions(+), 1 deletion(-)
+
+--- a/mm/hugetlb.c
++++ b/mm/hugetlb.c
+@@ -2906,7 +2906,17 @@ int follow_hugetlb_page(struct mm_struct
+ break;
+ }
+
+- if (absent ||
++ /*
++ * We need call hugetlb_fault for both hugepages under migration
++ * (in which case hugetlb_fault waits for the migration,) and
++ * hwpoisoned hugepages (in which case we need to prevent the
++ * caller from accessing to them.) In order to do this, we use
++ * here is_swap_pte instead of is_hugetlb_entry_migration and
++ * is_hugetlb_entry_hwpoisoned. This is because it simply covers
++ * both cases, and because we can't follow correct pages
++ * directly from any kind of swap entries.
++ */
++ if (absent || is_swap_pte(huge_ptep_get(pte)) ||
+ ((flags & FOLL_WRITE) && !pte_write(huge_ptep_get(pte)))) {
+ int ret;
+
--- /dev/null
+From b9e146d8eb3b9ecae5086d373b50fa0c1f3e7f0f Mon Sep 17 00:00:00 2001
+From: Emese Revfy <re.emese@gmail.com>
+Date: Wed, 17 Apr 2013 15:58:36 -0700
+Subject: kernel/signal.c: stop info leak via the tkill and the tgkill syscalls
+
+From: Emese Revfy <re.emese@gmail.com>
+
+commit b9e146d8eb3b9ecae5086d373b50fa0c1f3e7f0f upstream.
+
+This fixes a kernel memory contents leak via the tkill and tgkill syscalls
+for compat processes.
+
+This is visible in the siginfo_t->_sifields._rt.si_sigval.sival_ptr field
+when handling signals delivered from tkill.
+
+The place of the infoleak:
+
+int copy_siginfo_to_user32(compat_siginfo_t __user *to, siginfo_t *from)
+{
+ ...
+ put_user_ex(ptr_to_compat(from->si_ptr), &to->si_ptr);
+ ...
+}
+
+Signed-off-by: Emese Revfy <re.emese@gmail.com>
+Reviewed-by: PaX Team <pageexec@freemail.hu>
+Signed-off-by: Kees Cook <keescook@chromium.org>
+Cc: Al Viro <viro@zeniv.linux.org.uk>
+Cc: Oleg Nesterov <oleg@redhat.com>
+Cc: "Eric W. Biederman" <ebiederm@xmission.com>
+Cc: Serge Hallyn <serge.hallyn@canonical.com>
+Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
+Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+
+---
+ kernel/signal.c | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+--- a/kernel/signal.c
++++ b/kernel/signal.c
+@@ -2867,7 +2867,7 @@ do_send_specific(pid_t tgid, pid_t pid,
+
+ static int do_tkill(pid_t tgid, pid_t pid, int sig)
+ {
+- struct siginfo info;
++ struct siginfo info = {};
+
+ info.si_signo = sig;
+ info.si_errno = 0;
projects / thirdparty / kernel / stable-queue.git / commitdiff
