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From: zijun_hu <zijun_hu@zoho.com>
To: akpm@linux-foundation.org
Cc: ard.biesheuvel@linaro.org, david@gibson.dropbear.id.au,
	dev@g0hl1n.net, kuleshovmail@gmail.com, tangchen@cn.fujitsu.com,
	tj@kernel.org, weiyang@linux.vnet.ibm.com,
	mm-commits@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-mm@kvack.org, torvalds@linux-foundation.org
Subject: Re: [PATCH] mm/memblock.c: fix NULL dereference error
Date: Tue, 2 Aug 2016 13:39:25 +0800	[thread overview]
Message-ID: <57A0320D.6070102@zoho.com> (raw)
In-Reply-To: <57A029A9.6060303@zoho.com>

Hi All,

this mail correct the following mistakes in last mail
1, remove test patch attached 
2, format patch to satisfy rules
i am so sorry for my mistake

Hi Andrew,

this patch is part of https://lkml.org/lkml/2016/7/26/347 and isn't merged in
as you advised in another mail, i release this patch against linus's mainline
for fixing relevant bugs completely

WARNING: multiple messages have this Message-ID (diff)
From: zijun_hu <zijun_hu@zoho.com>
To: akpm@linux-foundation.org
Cc: ard.biesheuvel@linaro.org, david@gibson.dropbear.id.au,
	dev@g0hl1n.net, kuleshovmail@gmail.com, tangchen@cn.fujitsu.com,
	tj@kernel.org, weiyang@linux.vnet.ibm.com,
	mm-commits@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-mm@kvack.org, torvalds@linux-foundation.org
Subject: Re: [PATCH] mm/memblock.c: fix NULL dereference error
Date: Tue, 2 Aug 2016 13:39:25 +0800	[thread overview]
Message-ID: <57A0320D.6070102@zoho.com> (raw)
In-Reply-To: <57A029A9.6060303@zoho.com>

Hi All,

this mail correct the following mistakes in last mail
1, remove test patch attached 
2, format patch to satisfy rules
i am so sorry for my mistake

Hi Andrew,

this patch is part of https://lkml.org/lkml/2016/7/26/347 and isn't merged in
as you advised in another mail, i release this patch against linus's mainline
for fixing relevant bugs completely

>From 5d79c31d755dc3f03ecc5b4134f21793258636cd Mon Sep 17 00:00:00 2001
From: zijun_hu <zijun_hu@htc.com>
Date: Tue, 2 Aug 2016 12:35:28 +0800
Subject: [PATCH] mm/memblock.c: fix NULL dereference error

it causes NULL dereference error and failure to get type_a->regions[0] info
if parameter type_b of __next_mem_range_rev() == NULL

the bugs are fixed by checking before dereferring and initializing idx_b
to 0

the approach is tested by dumping all types of region via
__memblock_dump_all() and __next_mem_range_rev() fixed to UART separately
the result is okay after checking the logs

Signed-off-by: zijun_hu <zijun_hu@htc.com>
Tested-by: zijun_hu <zijun_hu@htc.com>
Acked-by: Tejun Heo <tj@kernel.org>
---
 mm/memblock.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/mm/memblock.c b/mm/memblock.c
index ff5ff3b..250dd48 100644
--- a/mm/memblock.c
+++ b/mm/memblock.c
@@ -994,7 +994,10 @@ void __init_memblock __next_mem_range_rev(u64 *idx, int nid, ulong flags,
 
 	if (*idx == (u64)ULLONG_MAX) {
 		idx_a = type_a->cnt - 1;
-		idx_b = type_b->cnt;
+		if (type_b != NULL)
+			idx_b = type_b->cnt;
+		else
+			idx_b = 0;
 	}
 
 	for (; idx_a >= 0; idx_a--) {
-- 
1.9.1

  parent reply	other threads:[~2016-08-02  5:42 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-08-02  5:03 [PATCH] mm/memblock.c: fix NULL dereference error zijun_hu
2016-08-02  5:03 ` zijun_hu
2016-08-02  5:20 ` zijun_hu
2016-08-02  5:20   ` zijun_hu
2016-08-02  5:23 ` kbuild test robot
2016-08-02  5:32   ` zijun_hu
2016-08-02  5:32     ` zijun_hu
2016-08-02  5:39 ` zijun_hu [this message]
2016-08-02  5:39   ` zijun_hu

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