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authorKonstantin Khlebnikov <koct9i@gmail.com>2016-05-21 02:57:45 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2016-05-21 03:58:30 +0300
commitf4fcd55841fc9e46daac553b39361572453c2b88 (patch)
tree56d0e92a579868fe7074df81b177889969a5fade
parentd5957d2fc232a689543bdbed1a5ff8002f0e9843 (diff)
downloadlinux-f4fcd55841fc9e46daac553b39361572453c2b88.tar.xz
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@de.ibm.com Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--mm/mmap.c12
1 files changed, 8 insertions, 4 deletions
diff --git a/mm/mmap.c b/mm/mmap.c
index fba246b8f1a5..b9274a0c82c9 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -66,7 +66,7 @@ const int mmap_rnd_compat_bits_max = CONFIG_ARCH_MMAP_RND_COMPAT_BITS_MAX;
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, vm_flags_t flags, unsigned long npages)
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;