From: gregkh@linuxfoundation•org (gregkh at linuxfoundation.org)
To: linux-arm-kernel@lists•infradead.org
Subject: Patch "x86/mm: Disable ioremap free page handling on x86-PAE" has been added to the 4.9-stable tree
Date: Thu, 16 Aug 2018 13:58:05 +0200 [thread overview]
Message-ID: <1534420685211199@kroah.com> (raw)
This is a note to let you know that I've just added the patch titled
x86/mm: Disable ioremap free page handling on x86-PAE
to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
x86-mm-disable-ioremap-free-page-handling-on-x86-pae.patch
and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger•kernel.org> know about it.
>From f967db0b9ed44ec3057a28f3b28efc51df51b835 Mon Sep 17 00:00:00 2001
From: Toshi Kani <toshi.kani@hpe•com>
Date: Wed, 27 Jun 2018 08:13:46 -0600
Subject: x86/mm: Disable ioremap free page handling on x86-PAE
From: Toshi Kani <toshi.kani@hpe•com>
commit f967db0b9ed44ec3057a28f3b28efc51df51b835 upstream.
ioremap() supports pmd mappings on x86-PAE. However, kernel's pmd
tables are not shared among processes on x86-PAE. Therefore, any
update to sync'd pmd entries need re-syncing. Freeing a pte page
also leads to a vmalloc fault and hits the BUG_ON in vmalloc_sync_one().
Disable free page handling on x86-PAE. pud_free_pmd_page() and
pmd_free_pte_page() simply return 0 if a given pud/pmd entry is present.
This assures that ioremap() does not update sync'd pmd entries at the
cost of falling back to pte mappings.
Fixes: 28ee90fe6048 ("x86/mm: implement free pmd/pte page interfaces")
Reported-by: Joerg Roedel <joro@8bytes•org>
Signed-off-by: Toshi Kani <toshi.kani@hpe•com>
Signed-off-by: Thomas Gleixner <tglx@linutronix•de>
Cc: mhocko at suse.com
Cc: akpm at linux-foundation.org
Cc: hpa at zytor.com
Cc: cpandya at codeaurora.org
Cc: linux-mm at kvack.org
Cc: linux-arm-kernel at lists.infradead.org
Cc: stable at vger.kernel.org
Cc: Andrew Morton <akpm@linux-foundation•org>
Cc: Michal Hocko <mhocko@suse•com>
Cc: "H. Peter Anvin" <hpa@zytor•com>
Cc: <stable@vger•kernel.org>
Link: https://lkml.kernel.org/r/20180627141348.21777-2-toshi.kani at hpe.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation•org>
---
arch/x86/mm/pgtable.c | 19 +++++++++++++++++++
1 file changed, 19 insertions(+)
--- a/arch/x86/mm/pgtable.c
+++ b/arch/x86/mm/pgtable.c
@@ -653,6 +653,7 @@ int pmd_clear_huge(pmd_t *pmd)
return 0;
}
+#ifdef CONFIG_X86_64
/**
* pud_free_pmd_page - Clear pud entry and free pmd page.
* @pud: Pointer to a PUD.
@@ -700,4 +701,22 @@ int pmd_free_pte_page(pmd_t *pmd)
return 1;
}
+
+#else /* !CONFIG_X86_64 */
+
+int pud_free_pmd_page(pud_t *pud)
+{
+ return pud_none(*pud);
+}
+
+/*
+ * Disable free page handling on x86-PAE. This assures that ioremap()
+ * does not update sync'd pmd entries. See vmalloc_sync_one().
+ */
+int pmd_free_pte_page(pmd_t *pmd)
+{
+ return pmd_none(*pmd);
+}
+
+#endif /* CONFIG_X86_64 */
#endif /* CONFIG_HAVE_ARCH_HUGE_VMAP */
Patches currently in stable-queue which might be from toshi.kani at hpe.com are
queue-4.9/x86-mm-disable-ioremap-free-page-handling-on-x86-pae.patch
reply other threads:[~2018-08-16 11:58 UTC|newest]
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