[PATCH] crash_core: optimize crash_exclude_mem_range()

From: Yuntao Wang
Date: Tue Dec 19 2023 - 11:34:38 EST


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@xxxxxxxxx>
---
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