From f4fcd55841fc9e46daac553b39361572453c2b88 Mon Sep 17 00:00:00 2001 From: Konstantin Khlebnikov Date: Fri, 20 May 2016 16:57:45 -0700 Subject: [PATCH] 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 Acked-by: Linus Torvalds Cc: Cyrill Gorcunov Cc: Christian Borntraeger Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/mmap.c | 12 ++++++++---- 1 file 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; -- 2.20.1