From: Konstantin Khlebnikov <koct9i@xxxxxxxxx>
Subject: mm: enable RLIMIT_DATA by default with workaround for valgrind
Since commit 84638335900f ("mm: rework virtual memory accounting")
RLIMIT_DATA limits both brk() and private mmap() but this's disabled by
default because of incompatibility with older versions of valgrind.
Valgrind always set limit to zero and fails if RLIMIT_DATA is enabled.
Fortunately it changes only rlim_cur and keeps rlim_max for reverting
limit back when needed.
This patch checks current usage also against rlim_max if rlim_cur is zero.
This is safe because task anyway can increase rlim_cur up to rlim_max.
Size of brk is still checked against rlim_cur, so this part is completely
compatible - zero rlim_cur forbids brk() but allows private mmap().
Link: http://lkml.kernel.org/r/56A28613.5070104@xxxxxxxxxx
Signed-off-by: Konstantin Khlebnikov <koct9i@xxxxxxxxx>
Acked-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Cyrill Gorcunov <gorcunov@xxxxxxxxxx>
Cc: Christian Borntraeger <borntraeger@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/mmap.c | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)
diff -puN mm/mmap.c~mm-enable-rlimit_data-by-default-with-workaround-for-valgrind mm/mmap.c
--- a/mm/mmap.c~mm-enable-rlimit_data-by-default-with-workaround-for-valgrind
+++ a/mm/mmap.c
@@ -66,7 +66,7 @@ const int mmap_rnd_compat_bits_max = CON
int mmap_rnd_compat_bits __read_mostly = CONFIG_ARCH_MMAP_RND_COMPAT_BITS;
#endif
-static bool ignore_rlimit_data = true;
+static bool ignore_rlimit_data;
core_param(ignore_rlimit_data, ignore_rlimit_data, bool, 0644);
static void unmap_region(struct mm_struct *mm,
@@ -2886,13 +2886,17 @@ bool may_expand_vm(struct mm_struct *mm,
if (is_data_mapping(flags) &&
mm->data_vm + npages > rlimit(RLIMIT_DATA) >> PAGE_SHIFT) {
- if (ignore_rlimit_data)
- pr_warn_once("%s (%d): VmData %lu exceed data ulimit %lu. Will be forbidden soon.\n",
+ /* Workaround for Valgrind */
+ if (rlimit(RLIMIT_DATA) == 0 &&
+ mm->data_vm + npages <= rlimit_max(RLIMIT_DATA) >> PAGE_SHIFT)
+ return true;
+ if (!ignore_rlimit_data) {
+ pr_warn_once("%s (%d): VmData %lu exceed data ulimit %lu. Update limits or use boot option ignore_rlimit_data.\n",
current->comm, current->pid,
(mm->data_vm + npages) << PAGE_SHIFT,
rlimit(RLIMIT_DATA));
- else
return false;
+ }
}
return true;
_
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