linux-kernel - [tip:x86/pti] Revert "perf/core: Make sure the ring-buffer is mapped in all page-tables"

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <tip-0e664eee65337082be49fbbd2ee24aa0d111d0f2@git.kernel.org>
Date:   Mon, 30 Jul 2018 04:58:25 -0700
From:   tip-bot for Joerg Roedel <tipbot@...or.com>
To:     linux-tip-commits@...r.kernel.org
Cc:     dave.hansen@...el.com, linux-kernel@...r.kernel.org,
        aarcange@...hat.com, dhgutteridge@...patico.ca, luto@...nel.org,
        David.Laight@...lab.com, peterz@...radead.org, namhyung@...nel.org,
        mingo@...nel.org, jroedel@...e.de, jolsa@...hat.com,
        dvlasenk@...hat.com, brgerst@...il.com, eduval@...zon.com,
        boris.ostrovsky@...cle.com, alexander.shishkin@...ux.intel.com,
        llong@...hat.com, torvalds@...ux-foundation.org, pavel@....cz,
        tglx@...utronix.de, gregkh@...uxfoundation.org, jgross@...e.com,
        jkosina@...e.cz, jpoimboe@...hat.com, hpa@...or.com,
        will.deacon@....com, bp@...en8.de, acme@...nel.org
Subject: [tip:x86/pti] Revert "perf/core: Make sure the ring-buffer is
 mapped in all page-tables"

Commit-ID:  0e664eee65337082be49fbbd2ee24aa0d111d0f2
Gitweb:     https://git.kernel.org/tip/0e664eee65337082be49fbbd2ee24aa0d111d0f2
Author:     Joerg Roedel <jroedel@...e.de>
AuthorDate: Wed, 25 Jul 2018 17:48:02 +0200
Committer:  Thomas Gleixner <tglx@...utronix.de>
CommitDate: Mon, 30 Jul 2018 13:53:48 +0200

Revert "perf/core: Make sure the ring-buffer is mapped in all page-tables"

This reverts commit 77754cfa09a6c528c38cbca9ee4cc4f7cf6ad6f2.

The patch was necessary to silence a WARN_ON_ONCE(in_nmi())
that triggered in the vmalloc_fault() function when PTI was
enabled on x86-32.

Faulting in an NMI handler turned out to be safe and the
warning in vmalloc_fault() is gone now. So the above patch
can be reverted.

Signed-off-by: Joerg Roedel <jroedel@...e.de>
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Tested-by: David H. Gutteridge <dhgutteridge@...patico.ca>
Cc: "H . Peter Anvin" <hpa@...or.com>
Cc: linux-mm@...ck.org
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Andy Lutomirski <luto@...nel.org>
Cc: Dave Hansen <dave.hansen@...el.com>
Cc: Josh Poimboeuf <jpoimboe@...hat.com>
Cc: Juergen Gross <jgross@...e.com>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Borislav Petkov <bp@...en8.de>
Cc: Jiri Kosina <jkosina@...e.cz>
Cc: Boris Ostrovsky <boris.ostrovsky@...cle.com>
Cc: Brian Gerst <brgerst@...il.com>
Cc: David Laight <David.Laight@...lab.com>
Cc: Denys Vlasenko <dvlasenk@...hat.com>
Cc: Eduardo Valentin <eduval@...zon.com>
Cc: Greg KH <gregkh@...uxfoundation.org>
Cc: Will Deacon <will.deacon@....com>
Cc: aliguori@...zon.com
Cc: daniel.gruss@...k.tugraz.at
Cc: hughd@...gle.com
Cc: keescook@...gle.com
Cc: Andrea Arcangeli <aarcange@...hat.com>
Cc: Waiman Long <llong@...hat.com>
Cc: Pavel Machek <pavel@....cz>
Cc: Arnaldo Carvalho de Melo <acme@...nel.org>
Cc: Alexander Shishkin <alexander.shishkin@...ux.intel.com>
Cc: Jiri Olsa <jolsa@...hat.com>
Cc: Namhyung Kim <namhyung@...nel.org>
Cc: joro@...tes.org
Link: https://lkml.kernel.org/r/1532533683-5988-3-git-send-email-joro@8bytes.org

---
 kernel/events/ring_buffer.c | 16 ----------------
 1 file changed, 16 deletions(-)

diff --git a/kernel/events/ring_buffer.c b/kernel/events/ring_buffer.c
index df2d8cf0072c..5d3cf407e374 100644
--- a/kernel/events/ring_buffer.c
+++ b/kernel/events/ring_buffer.c
@@ -814,13 +814,6 @@ static void rb_free_work(struct work_struct *work)

 	vfree(base);
 	kfree(rb);
-
-	/*
-	 * FIXME: PAE workaround for vmalloc_fault(): Make sure buffer is
-	 * unmapped in all page-tables.
-	 */
-	if (IS_ENABLED(CONFIG_X86_PAE))
-		vmalloc_sync_all();
 }

 void rb_free(struct ring_buffer *rb)
@@ -847,15 +840,6 @@ struct ring_buffer *rb_alloc(int nr_pages, long watermark, int cpu, int flags)
 	if (!all_buf)
 		goto fail_all_buf;

-	/*
-	 * FIXME: PAE workaround for vmalloc_fault(): The buffer is
-	 * accessed in NMI handlers, make sure it is mapped in all
-	 * page-tables in the system so that we don't fault on the range in
-	 * an NMI handler.
-	 */
-	if (IS_ENABLED(CONFIG_X86_PAE))
-		vmalloc_sync_all();
-
 	rb->user_page = all_buf;
 	rb->data_pages[0] = all_buf + PAGE_SIZE;
 	if (nr_pages) {