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From: "Mika Penttilä" <mika.penttila@nextfour.com>
To: LKML <linux-kernel@vger.kernel.org>, linux-mm@kvack.org
Subject: [PATCH] mm: make apply_to_page_range more robust
Date: Fri, 15 Jan 2016 07:41:03 +0200	[thread overview]
Message-ID: <5698866F.1070802@nextfour.com> (raw)

Recent changes (4.4.0+) in module loader triggered oops on ARM. While
loading a module, size in :

apply_to_page_range(struct mm_struct *mm, unsigned long addr,   unsigned
long size, pte_fn_t fn, void *data);

can be 0 triggering the bug  BUG_ON(addr >= end);.

Fix by letting call with zero size succeed.

--Mika

Signed-off-by: mika.penttila@nextfour.com
---

diff --git a/mm/memory.c b/mm/memory.c
index c387430..c3d1a2e 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1884,6 +1884,9 @@ int apply_to_page_range(struct mm_struct *mm,
unsigned long addr,
        unsigned long end = addr + size;
        int err;

+       if (!size)
+               return 0;
+
        BUG_ON(addr >= end);
        pgd = pgd_offset(mm, addr);
        do {

--
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WARNING: multiple messages have this Message-ID (diff)
From: "Mika Penttilä" <mika.penttila@nextfour.com>
To: LKML <linux-kernel@vger.kernel.org>, <linux-mm@kvack.org>
Subject: [PATCH] mm: make apply_to_page_range more robust
Date: Fri, 15 Jan 2016 07:41:03 +0200	[thread overview]
Message-ID: <5698866F.1070802@nextfour.com> (raw)

Recent changes (4.4.0+) in module loader triggered oops on ARM. While
loading a module, size in :

apply_to_page_range(struct mm_struct *mm, unsigned long addr,   unsigned
long size, pte_fn_t fn, void *data);

can be 0 triggering the bug  BUG_ON(addr >= end);.

Fix by letting call with zero size succeed.

--Mika

Signed-off-by: mika.penttila@nextfour.com
---

diff --git a/mm/memory.c b/mm/memory.c
index c387430..c3d1a2e 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1884,6 +1884,9 @@ int apply_to_page_range(struct mm_struct *mm,
unsigned long addr,
        unsigned long end = addr + size;
        int err;

+       if (!size)
+               return 0;
+
        BUG_ON(addr >= end);
        pgd = pgd_offset(mm, addr);
        do {

             reply	other threads:[~2016-01-15  5:41 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-01-15  5:41 Mika Penttilä [this message]
2016-01-15  5:41 ` [PATCH] mm: make apply_to_page_range more robust Mika Penttilä
2016-01-17 10:02 ` Pekka Enberg
2016-01-17 10:02   ` Pekka Enberg
2016-01-19 22:21 ` David Rientjes
2016-01-19 22:21   ` David Rientjes

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