Re: [PATCH] mm/memblock.c: fix index adjustment error in __next_mem_range_rev()
From: Tejun Heo <tj@kernel.org>
Date: 2016-07-26 16:50:46
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Hello, On Tue, Jul 26, 2016 at 03:03:58PM +0000, zijun_hu@htc.com wrote:
I am sorry, I don't take any test for the patch attached in previous mail, and it can't fix the bug completely, please ignore it I provide a new patch attached in this mail which pass test and can fix the issue described below __next_mem_range_rev() defined in mm/memblock.c doesn't Achieve desired purpose if parameter type_b ==NULL This new patch can fix the issue and get the last reversed region contained in type_a rightly
Can you please flow future mails to 80 column?
The new patch is descripted as follows From 0e242eda7696f176a9a2e585a1db01f0575b39c9 Mon Sep 17 00:00:00 2001 From: zijun_hu <redacted> Date: Mon, 25 Jul 2016 15:06:57 +0800 Subject: [PATCH] mm/memblock.c: fix index adjustment error in __next_mem_range_rev() fix region index adjustment error when parameter type_b of __next_mem_range_rev() == NULL
The patch is now fixing two bugs. It'd be nice to describe each in the description and how the patch was tested.
quoted hunk ↗ jump to hunk
@@ -991,7 +991,11 @@ 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; + /* in order to get the last reversed region rightly */
Before, it would trigger null deref. I don't think the above comment is necessary.
quoted hunk ↗ jump to hunk
+ if (type_b != NULL) + idx_b = type_b->cnt; + else + idx_b = 0; } for (; idx_a >= 0; idx_a--) {@@ -1024,7 +1028,7 @@ void __init_memblock __next_mem_range_rev(u64 *idx, int nid, ulong flags, *out_end = m_end; if (out_nid) *out_nid = m_nid; - idx_a++; + idx_a--; *idx = (u32)idx_a | (u64)idx_b << 32; return; }
Both changes look good to me. Provided the changes are tested, Acked-by: Tejun Heo <tj@kernel.org> Thanks. -- tejun -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>