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From 1bcf4b3aaf39cedd42bb5b34a81c6044b8a02d5a Mon Sep 17 00:00:00 2001
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From: =?UTF-8?q?Nikola=20Forr=C3=B3?= <nforro@redhat.com>
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Date: Tue, 19 Jun 2018 13:13:18 +0200
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Subject: [PATCH] madvise.2: document MADV_WIPEONFORK and MADV_KEEPONFORK
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---
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man-pages/en/man2/madvise.2 | 39 +++++++++++++++++++++++++++++++++++++
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man-pages/man2/madvise.2 | 39 +++++++++++++++++++++++++++++++++++++
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2 files changed, 78 insertions(+)
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diff --git a/man-pages/en/man2/madvise.2 b/man-pages/en/man2/madvise.2
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index 4e693da..8a1c46d 100644
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--- a/man-pages/en/man2/madvise.2
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+++ b/man-pages/en/man2/madvise.2
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@@ -265,6 +265,33 @@ file (see
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.BR MADV_DODUMP " (since Linux 3.4)"
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Undo the effect of an earlier
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.BR MADV_DONTDUMP .
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+.TP
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+.BR MADV_WIPEONFORK " (since Linux 4.14)"
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+.\" commit d2cd9ede6e193dd7d88b6d27399e96229a551b19
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+Present the child process with zero-filled memory in this range after a
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+.BR fork (2).
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+This is useful in forking servers in order to ensure
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+that sensitive per-process data
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+(for example, PRNG seeds, cryptographic secrets, and so on)
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+is not handed to child processes.
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+.IP
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+The
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+.B MADV_WIPEONFORK
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+operation can be applied only to private anonymous pages (see
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+.BR mmap (2)).
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+.IP
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+Within the child created by
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+.BR fork (2),
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+the
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+.B MADV_WIPEONFORK
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+setting remains in place on the specified address range.
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+This setting is cleared during
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+.BR execve (2).
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+.TP
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+.BR MADV_KEEPONFORK " (since Linux 4.14)"
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+.\" commit d2cd9ede6e193dd7d88b6d27399e96229a551b19
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+Undo the effect of an earlier
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+.BR MADV_WIPEONFORK .
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.SH RETURN VALUE
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On success
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.BR madvise ()
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@@ -308,6 +335,18 @@ but the kernel was not configured with
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.BR CONFIG_KSM .
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.RE
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.TP
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+.B EINVAL
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+.I advice
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+is
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+.BR MADV_FREE
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+or
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+.BR MADV_WIPEONFORK
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+but the specified address range includes file, Huge TLB,
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+.BR MAP_SHARED ,
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+or
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+.BR VM_PFNMAP
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+ranges.
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+.TP
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.B EIO
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(for
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.BR MADV_WILLNEED )
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diff --git a/man-pages/man2/madvise.2 b/man-pages/man2/madvise.2
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index 4e693da..8a1c46d 100644
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--- a/man-pages/man2/madvise.2
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+++ b/man-pages/man2/madvise.2
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@@ -265,6 +265,33 @@ file (see
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eb7712 |
.BR MADV_DODUMP " (since Linux 3.4)"
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eb7712 |
Undo the effect of an earlier
|
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eb7712 |
.BR MADV_DONTDUMP .
|
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eb7712 |
+.TP
|
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eb7712 |
+.BR MADV_WIPEONFORK " (since Linux 4.14)"
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eb7712 |
+.\" commit d2cd9ede6e193dd7d88b6d27399e96229a551b19
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eb7712 |
+Present the child process with zero-filled memory in this range after a
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eb7712 |
+.BR fork (2).
|
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eb7712 |
+This is useful in forking servers in order to ensure
|
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eb7712 |
+that sensitive per-process data
|
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eb7712 |
+(for example, PRNG seeds, cryptographic secrets, and so on)
|
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eb7712 |
+is not handed to child processes.
|
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eb7712 |
+.IP
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eb7712 |
+The
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+.B MADV_WIPEONFORK
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+operation can be applied only to private anonymous pages (see
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eb7712 |
+.BR mmap (2)).
|
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eb7712 |
+.IP
|
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+Within the child created by
|
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+.BR fork (2),
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+the
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eb7712 |
+.B MADV_WIPEONFORK
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+setting remains in place on the specified address range.
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+This setting is cleared during
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+.BR execve (2).
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+.TP
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+.BR MADV_KEEPONFORK " (since Linux 4.14)"
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+.\" commit d2cd9ede6e193dd7d88b6d27399e96229a551b19
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+Undo the effect of an earlier
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eb7712 |
+.BR MADV_WIPEONFORK .
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eb7712 |
.SH RETURN VALUE
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eb7712 |
On success
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eb7712 |
.BR madvise ()
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eb7712 |
@@ -308,6 +335,18 @@ but the kernel was not configured with
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eb7712 |
.BR CONFIG_KSM .
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eb7712 |
.RE
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eb7712 |
.TP
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eb7712 |
+.B EINVAL
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eb7712 |
+.I advice
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+is
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+.BR MADV_FREE
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+or
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+.BR MADV_WIPEONFORK
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+but the specified address range includes file, Huge TLB,
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eb7712 |
+.BR MAP_SHARED ,
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+or
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eb7712 |
+.BR VM_PFNMAP
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+ranges.
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eb7712 |
+.TP
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eb7712 |
.B EIO
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eb7712 |
(for
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.BR MADV_WILLNEED )
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eb7712 |
--
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2.17.1
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