diff options
Diffstat (limited to 'mm-fix-new-crash-in-unmapped_area_topdown.patch')
| -rw-r--r-- | mm-fix-new-crash-in-unmapped_area_topdown.patch | 53 |
1 files changed, 53 insertions, 0 deletions
diff --git a/mm-fix-new-crash-in-unmapped_area_topdown.patch b/mm-fix-new-crash-in-unmapped_area_topdown.patch new file mode 100644 index 000000000..20da9556f --- /dev/null +++ b/mm-fix-new-crash-in-unmapped_area_topdown.patch @@ -0,0 +1,53 @@ +From patchwork Tue Jun 20 09:10:44 2017 +Content-Type: text/plain; charset="utf-8" +MIME-Version: 1.0 +Content-Transfer-Encoding: 7bit +Subject: mm: fix new crash in unmapped_area_topdown() +From: Hugh Dickins <hughd@google.com> +X-Patchwork-Id: 9798991 +Message-Id: <alpine.LSU.2.11.1706200206210.10925@eggly.anvils> +To: Linus Torvalds <torvalds@linux-foundation.org> +Cc: Dave Jones <davej@codemonkey.org.uk>, Oleg Nesterov <oleg@redhat.com>, + Michal Hocko <mhocko@suse.com>, linux-kernel@vger.kernel.org, + linux-mm@kvack.org +Date: Tue, 20 Jun 2017 02:10:44 -0700 (PDT) + +Trinity gets kernel BUG at mm/mmap.c:1963! in about 3 minutes of +mmap testing. That's the VM_BUG_ON(gap_end < gap_start) at the +end of unmapped_area_topdown(). Linus points out how MAP_FIXED +(which does not have to respect our stack guard gap intentions) +could result in gap_end below gap_start there. Fix that, and +the similar case in its alternative, unmapped_area(). + +Cc: stable@vger.kernel.org +Fixes: 1be7107fbe18 ("mm: larger stack guard gap, between vmas") +Reported-by: Dave Jones <davej@codemonkey.org.uk> +Debugged-by: Linus Torvalds <torvalds@linux-foundation.org> +Signed-off-by: Hugh Dickins <hughd@google.com> +--- + + mm/mmap.c | 6 ++++-- + 1 file changed, 4 insertions(+), 2 deletions(-) + +--- 4.12-rc6/mm/mmap.c 2017-06-19 09:06:10.035407505 -0700 ++++ linux/mm/mmap.c 2017-06-19 21:09:28.616707311 -0700 +@@ -1817,7 +1817,8 @@ unsigned long unmapped_area(struct vm_un + /* Check if current node has a suitable gap */ + if (gap_start > high_limit) + return -ENOMEM; +- if (gap_end >= low_limit && gap_end - gap_start >= length) ++ if (gap_end >= low_limit && ++ gap_end > gap_start && gap_end - gap_start >= length) + goto found; + + /* Visit right subtree if it looks promising */ +@@ -1920,7 +1921,8 @@ unsigned long unmapped_area_topdown(stru + gap_end = vm_start_gap(vma); + if (gap_end < low_limit) + return -ENOMEM; +- if (gap_start <= high_limit && gap_end - gap_start >= length) ++ if (gap_start <= high_limit && ++ gap_end > gap_start && gap_end - gap_start >= length) + goto found; + + /* Visit left subtree if it looks promising */ |