[PATCH] RLIMIT_DATA affects mmap (2) since 4.7

[PATCH] RLIMIT_DATA affects mmap (2) since 4.7

[Jonas Grabber]

>From 9e3c8ac6f7ac8a490e020eea5dc68fca5244b354 Mon Sep 17 00:00:00 2001
From: Jonas Grabber <jobegrabber-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Date: Mon, 28 Aug 2017 16:08:15 +0200
Subject: [PATCH] RLIMIT_DATA affects mmap (2) since 4.7

Starting with Linux kernel 4.5 and 84638335900f1995495838fe1bd4870c43ec1f67
(mm: rework virtual memory accounting) RLIMIT_DATA affects mmap (2).
With d977d56ce5b3e8842236f2f9e7483d4914c9592e (mm: warn about VmData
over RLIMIT_DATA) only warnings are emmitted when going over the
specified RLIMIT_DATA in 4.5.

As of 4.7 and f4fcd55841fc9e46daac553b39361572453c2b88 (mm: enable
RLIMIT_DATA by default with workaround for valgrind) going over
RLIMIT_DATA through mmap (2) is forbidden.

This updates man-pages 4.13 to reflect these changes.
---
 man2/getrlimit.2 | 11 ++++++++---
 man2/mmap.2      |  8 ++++++++
 man3/malloc.3    |  2 +-
 3 files changed, 17 insertions(+), 4 deletions(-)

diff --git a/man2/getrlimit.2 b/man2/getrlimit.2
index 84f04d695..fd414fc54 100644
--- a/man2/getrlimit.2
+++ b/man2/getrlimit.2
@@ -179,9 +179,14 @@ perform an orderly termination upon first receipt of
 This is the maximum size of the process's data segment (initialized data,
 uninitialized data, and heap).
 This limit affects calls to
-.BR brk (2)
-and
-.BR sbrk (2),
+.BR brk (2),
+.BR sbrk (2)
+and as of Linux 4.7 also
+.BR mmap (2)
+.\" commits 84638335900f1995495838fe1bd4870c43ec1f67
+.\" ("mm: rework virtual memory accounting"),
+.\" f4fcd55841fc9e46daac553b39361572453c2b88
+.\" (mm: enable RLIMIT_DATA by default with workaround for valgrind).
 which fail with the error
 .B ENOMEM
 upon encountering the soft limit of this resource.
diff --git a/man2/mmap.2 b/man2/mmap.2
index df527809e..e5f134e4f 100644
--- a/man2/mmap.2
+++ b/man2/mmap.2
@@ -493,6 +493,14 @@ when unmapping a region in the middle of an
existing mapping,
 since this results in two smaller mappings on either side of
 the region being unmapped.
 .TP
+.B ENOMEM
+(since Linux 4.7)
+The process's
+.B RLIMIT_DATA
+limit, described in
+.BR getrlimit (2),
+would have been exceeded.
+.TP
 .B EOVERFLOW
 On 32-bit architecture together with the large file extension
 (i.e., using 64-bit
diff --git a/man3/malloc.3 b/man3/malloc.3
index d0e12fcfc..ac78662f7 100644
--- a/man3/malloc.3
+++ b/man3/malloc.3
@@ -292,7 +292,7 @@ Allocations performed using
 .BR mmap (2)
 are unaffected by the
 .B RLIMIT_DATA
-resource limit (see
+resource limit only prior to Linux kernel 4.7 (see
 .BR getrlimit (2)).
 .PP
 To avoid corruption in multithreaded applications,
-- 
2.13.5
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Re: [PATCH] RLIMIT_DATA affects mmap (2) since 4.7

[Michael Kerrisk (man-opages)]

Hello Jonas,

On 08/28/2017 04:10 PM, Jonas Grabber wrote:
>  From 9e3c8ac6f7ac8a490e020eea5dc68fca5244b354 Mon Sep 17 00:00:00 2001
> From: Jonas Grabber <jobegrabber-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
> Date: Mon, 28 Aug 2017 16:08:15 +0200
> Subject: [PATCH] RLIMIT_DATA affects mmap (2) since 4.7
> 
> Starting with Linux kernel 4.5 and 84638335900f1995495838fe1bd4870c43ec1f67
> (mm: rework virtual memory accounting) RLIMIT_DATA affects mmap (2).
> With d977d56ce5b3e8842236f2f9e7483d4914c9592e (mm: warn about VmData
> over RLIMIT_DATA) only warnings are emmitted when going over the
> specified RLIMIT_DATA in 4.5.
> 
> As of 4.7 and f4fcd55841fc9e46daac553b39361572453c2b88 (mm: enable
> RLIMIT_DATA by default with workaround for valgrind) going over
> RLIMIT_DATA through mmap (2) is forbidden.
> 
> This updates man-pages 4.13 to reflect these changes.

Thanks for the patch! Applied.

Cheers,

Michael


> ---
>   man2/getrlimit.2 | 11 ++++++++---
>   man2/mmap.2      |  8 ++++++++
>   man3/malloc.3    |  2 +-
>   3 files changed, 17 insertions(+), 4 deletions(-)
> 
> diff --git a/man2/getrlimit.2 b/man2/getrlimit.2
> index 84f04d695..fd414fc54 100644
> --- a/man2/getrlimit.2
> +++ b/man2/getrlimit.2
> @@ -179,9 +179,14 @@ perform an orderly termination upon first receipt of
>   This is the maximum size of the process's data segment (initialized data,
>   uninitialized data, and heap).
>   This limit affects calls to
> -.BR brk (2)
> -and
> -.BR sbrk (2),
> +.BR brk (2),
> +.BR sbrk (2)
> +and as of Linux 4.7 also
> +.BR mmap (2)
> +.\" commits 84638335900f1995495838fe1bd4870c43ec1f67
> +.\" ("mm: rework virtual memory accounting"),
> +.\" f4fcd55841fc9e46daac553b39361572453c2b88
> +.\" (mm: enable RLIMIT_DATA by default with workaround for valgrind).
>   which fail with the error
>   .B ENOMEM
>   upon encountering the soft limit of this resource.
> diff --git a/man2/mmap.2 b/man2/mmap.2
> index df527809e..e5f134e4f 100644
> --- a/man2/mmap.2
> +++ b/man2/mmap.2
> @@ -493,6 +493,14 @@ when unmapping a region in the middle of an
> existing mapping,
>   since this results in two smaller mappings on either side of
>   the region being unmapped.
>   .TP
> +.B ENOMEM
> +(since Linux 4.7)
> +The process's
> +.B RLIMIT_DATA
> +limit, described in
> +.BR getrlimit (2),
> +would have been exceeded.
> +.TP
>   .B EOVERFLOW
>   On 32-bit architecture together with the large file extension
>   (i.e., using 64-bit
> diff --git a/man3/malloc.3 b/man3/malloc.3
> index d0e12fcfc..ac78662f7 100644
> --- a/man3/malloc.3
> +++ b/man3/malloc.3
> @@ -292,7 +292,7 @@ Allocations performed using
>   .BR mmap (2)
>   are unaffected by the
>   .B RLIMIT_DATA
> -resource limit (see
> +resource limit only prior to Linux kernel 4.7 (see
>   .BR getrlimit (2)).
>   .PP
>   To avoid corruption in multithreaded applications,
> 
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