From d977d56ce5b3e8842236f2f9e7483d4914c9592e Mon Sep 17 00:00:00 2001
From: Konstantin Khlebnikov <koct9i@gmail.com>
Date: Tue, 2 Feb 2016 16:57:43 -0800
Subject: mm: warn about VmData over RLIMIT_DATA

This patch provides a way of working around a slight regression
introduced by commit 84638335900f ("mm: rework virtual memory
accounting").

Before that commit RLIMIT_DATA have control only over size of the brk
region.  But that change have caused problems with all existing versions
of valgrind, because it set RLIMIT_DATA to zero.

This patch fixes rlimit check (limit actually in bytes, not pages) and
by default turns it into warning which prints at first VmData misuse:

  "mmap: top (795): VmData 516096 exceed data ulimit 512000.  Will be forbidden soon."

Behavior is controlled by boot param ignore_rlimit_data=y/n and by sysfs
/sys/module/kernel/parameters/ignore_rlimit_data.  For now it set to "y".

[akpm@linux-foundation.org: tweak kernel-parameters.txt text[
Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.com>
Link: http://lkml.kernel.org/r/20151228211015.GL2194@uranus
Reported-by: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Vegard Nossum <vegard.nossum@oracle.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Vladimir Davydov <vdavydov@virtuozzo.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com>
Cc: Kees Cook <keescook@google.com>
Cc: Willy Tarreau <w@1wt.eu>
Cc: Pavel Emelyanov <xemul@virtuozzo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
 mm/internal.h | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

(limited to 'mm/internal.h')

diff --git a/mm/internal.h b/mm/internal.h
index ed8b5ffcf9b1..6e976302ddd8 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -216,6 +216,22 @@ static inline bool is_cow_mapping(vm_flags_t flags)
 	return (flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
 }
 
+static inline bool is_exec_mapping(vm_flags_t flags)
+{
+	return (flags & (VM_EXEC | VM_WRITE)) == VM_EXEC;
+}
+
+static inline bool is_stack_mapping(vm_flags_t flags)
+{
+	return (flags & (VM_STACK_FLAGS & (VM_GROWSUP | VM_GROWSDOWN))) != 0;
+}
+
+static inline bool is_data_mapping(vm_flags_t flags)
+{
+	return (flags & ((VM_STACK_FLAGS & (VM_GROWSUP | VM_GROWSDOWN)) |
+					VM_WRITE | VM_SHARED)) == VM_WRITE;
+}
+
 /* mm/util.c */
 void __vma_link_list(struct mm_struct *mm, struct vm_area_struct *vma,
 		struct vm_area_struct *prev, struct rb_node *rb_parent);
-- 
cgit 


From 30bdbb78009e67767983085e302bec6d97afc679 Mon Sep 17 00:00:00 2001
From: Konstantin Khlebnikov <koct9i@gmail.com>
Date: Tue, 2 Feb 2016 16:57:46 -0800
Subject: mm: polish virtual memory accounting

* add VM_STACK as alias for VM_GROWSUP/DOWN depending on architecture
* always account VMAs with flag VM_STACK as stack (as it was before)
* cleanup classifying helpers
* update comments and documentation

Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.com>
Tested-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Cc: Cyrill Gorcunov <gorcunov@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
 mm/internal.h | 23 +++++++++++++++++++----
 1 file changed, 19 insertions(+), 4 deletions(-)

(limited to 'mm/internal.h')

diff --git a/mm/internal.h b/mm/internal.h
index 6e976302ddd8..a38a21ebddb4 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -216,20 +216,35 @@ static inline bool is_cow_mapping(vm_flags_t flags)
 	return (flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
 }
 
+/*
+ * These three helpers classifies VMAs for virtual memory accounting.
+ */
+
+/*
+ * Executable code area - executable, not writable, not stack
+ */
 static inline bool is_exec_mapping(vm_flags_t flags)
 {
-	return (flags & (VM_EXEC | VM_WRITE)) == VM_EXEC;
+	return (flags & (VM_EXEC | VM_WRITE | VM_STACK)) == VM_EXEC;
 }
 
+/*
+ * Stack area - atomatically grows in one direction
+ *
+ * VM_GROWSUP / VM_GROWSDOWN VMAs are always private anonymous:
+ * do_mmap() forbids all other combinations.
+ */
 static inline bool is_stack_mapping(vm_flags_t flags)
 {
-	return (flags & (VM_STACK_FLAGS & (VM_GROWSUP | VM_GROWSDOWN))) != 0;
+	return (flags & VM_STACK) == VM_STACK;
 }
 
+/*
+ * Data area - private, writable, not stack
+ */
 static inline bool is_data_mapping(vm_flags_t flags)
 {
-	return (flags & ((VM_STACK_FLAGS & (VM_GROWSUP | VM_GROWSDOWN)) |
-					VM_WRITE | VM_SHARED)) == VM_WRITE;
+	return (flags & (VM_WRITE | VM_SHARED | VM_STACK)) == VM_WRITE;
 }
 
 /* mm/util.c */
-- 
cgit