Dropping this patch.

It's not needed because in mainstream it's obsoleted by

commit 1c90308e7a77af6742a97d1021cca923b23b7f0d
Author: Konstantin Khlebnikov <[email protected]>
Date:   Tue Sep 8 15:00:07 2015 -0700

    pagemap: hide physical addresses from non-privileged users

which already presents in vz8.

# git describe --contains 1c90308e7a77af6742a97d1021cca923b23b7f0d
v4.3-rc1~40^2~103

--
Best regards,

Konstantin Khorenko,
Virtuozzo Linux Kernel Team

On 06/02/2021 01:06 PM, Valeriy Vdovin wrote:
From: Vladimir Davydov <[email protected]>

Author: Konstantin Khorenko
Email: [email protected]
Subject: ms/pagemap: do not leak physical addresses to non-privileged userspace
Date: Mon, 23 Mar 2015 19:21:49 +0400

ms commit: ab676b7d6fbf4b294bf198fb27ade5b0e865c7ce

Original thread in LKML: https://lkml.org/lkml/2015/3/9/864

https://jira.sw.ru/browse/PSBM-32308

Signed-off-by: Konstantin Khorenko <[email protected]>

  From: "Kirill A. Shutemov" <[email protected]>
  Subject: pagemap: do not leak physical addresses to non-privileged userspace

As pointed by recent post[1] on exploiting DRAM physical imperfection,
/proc/PID/pagemap exposes sensitive information which can be used to do
attacks.

This disallows anybody without CAP_SYS_ADMIN to read the pagemap.

[1] 
http://googleprojectzero.blogspot.com/2015/03/exploiting-dram-rowhammer-bug-to-gain.html

[ Eventually we might want to do anything more finegrained, but for now
  this is the simple model.   - Linus ]

Signed-off-by: Kirill A. Shutemov <[email protected]>
Acked-by: Konstantin Khlebnikov <[email protected]>
Acked-by: Andy Lutomirski <[email protected]>
Cc: Pavel Emelyanov <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Mark Seaborn <[email protected]>
Cc: [email protected]
Signed-off-by: Linus Torvalds <[email protected]>
=============================================================================

Related to https://jira.sw.ru/browse/PSBM-33640

Signed-off-by: Vladimir Davydov <[email protected]>

[VvS RHEL77 rebase] it was lost during rebase.
https://jira.sw.ru/browse/PSBM-97881

Signed-off-by: Vasily Averin <[email protected]>
Signed-off-by: Valeriy Vdovin <[email protected]>
---
 fs/proc/task_mmu.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index ee0c6b420a36..b6e8e4483b91 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -1572,6 +1572,10 @@ static int pagemap_open(struct inode *inode, struct file 
*file)
 {
        struct mm_struct *mm;

+       /* do not disclose physical addresses: attack vector */
+       if (!capable(CAP_SYS_ADMIN))
+               return -EPERM;
+
        mm = proc_mem_open(inode, PTRACE_MODE_READ);
        if (IS_ERR(mm))
                return PTR_ERR(mm);

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