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From: Yuntao Wang <ytcoode@gmail.com>
To: akpm@linux-foundation.org
Cc: bhe@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com,
	dyoung@redhat.com, hbathini@linux.ibm.com, hpa@zytor.com,
	kexec@lists.infradead.org, linux-kernel@vger.kernel.org,
	mingo@redhat.com, seanjc@google.com, tglx@linutronix.de,
	tiwai@suse.de, vgoyal@redhat.com, x86@kernel.org,
	ytcoode@gmail.com
Subject: [PATCH] crash_core: optimize crash_exclude_mem_range()
Date: Wed, 20 Dec 2023 00:34:18 +0800	[thread overview]
Message-ID: <20231219163418.108591-1-ytcoode@gmail.com> (raw)
In-Reply-To: <20231218092902.9fae480cfcad3874e9e7236f@linux-foundation.org>

Because memory ranges in mem->ranges are stored in ascending order, when we
detect `p_end < start`, we can break the for loop early, as the subsequent
memory ranges must also be outside the range we are looking for.

Signed-off-by: Yuntao Wang <ytcoode@gmail.com>
---
Hi Andrew,

Patch "[PATCH 2/2] crash_core: fix out-of-bounds access check in
crash_exclude_mem_range()" can be ignored, use this patch instead.

 kernel/crash_core.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/kernel/crash_core.c b/kernel/crash_core.c
index 9a219a918638..d425c4a106cd 100644
--- a/kernel/crash_core.c
+++ b/kernel/crash_core.c
@@ -575,9 +575,12 @@ int crash_exclude_mem_range(struct crash_mem *mem,
 		p_start = mstart;
 		p_end = mend;
 
-		if (p_start > end || p_end < start)
+		if (p_start > end)
 			continue;
 
+		if (p_end < start)
+			break;
+
 		/* Truncate any area outside of range */
 		if (p_start < start)
 			p_start = start;
-- 
2.43.0


  parent reply	other threads:[~2023-12-19 16:34 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-12-18  8:19 [PATCH 0/2] crash: fix potential cmem->ranges array overflow Yuntao Wang
2023-12-18  8:19 ` [PATCH 1/2] x86/crash: " Yuntao Wang
2023-12-18  8:19 ` [PATCH 2/2] crash_core: fix out-of-bounds access check in crash_exclude_mem_range() Yuntao Wang
2023-12-18 17:29   ` Andrew Morton
2023-12-19  2:02     ` Yuntao Wang
2023-12-19  3:32       ` Baoquan He
2023-12-19  4:31         ` Yuntao Wang
2023-12-19 14:22           ` Baoquan He
2023-12-19 16:00             ` Yuntao Wang
2023-12-19 16:34     ` Yuntao Wang [this message]
2023-12-29 20:10       ` [PATCH] crash_core: optimize crash_exclude_mem_range() Andrew Morton
2023-12-30 10:28         ` Baoquan He
2024-01-02 15:20           ` Yuntao Wang
2023-12-18 13:45 ` [PATCH 0/2] crash: fix potential cmem->ranges array overflow Baoquan He

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