From: 张忠山 <zzs213@126.com>
To: barebox@lists.infradead.org
Subject: Why sbrk clear the increased memory region
Date: Mon, 22 Apr 2019 11:13:30 +0800 [thread overview]
Message-ID: <d2890d42-bc87-3c65-4be4-6a2c748b9ddb@126.com> (raw)
Recently, I'm using barebox in a deep embedded project, and need some funtctions
in libc/libm, So I linked barebox with newlib
But whenever newlib call sbrk with negtive `increment`, barebox crash.
The reason is sbrk clean memory region using `increment`.
Why sbrk must clear the increased memory region?
--------------------------------8<-----------------------------
From dbaa658b60fe413e1d1818afad13a53e7ad000ce Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E5=BC=A0=E5=BF=A0=E5=B1=B1?= <zzs213@126.com>
Date: Mon, 22 Apr 2019 11:01:33 +0800
Subject: [PATCH] only clear memory when increasing head size
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Signed-off-by: 张忠山 <zzs213@126.com>
---
common/memory.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/common/memory.c b/common/memory.c
index 8f0b59891..0a8700d28 100644
--- a/common/memory.c
+++ b/common/memory.c
@@ -122,7 +122,7 @@ void *sbrk(ptrdiff_t increment)
void *old = sbrk_no_zero(increment);
/* Only clear increment, if valid address was returned */
- if (old != NULL)
+ if ((old != NULL) && (increment > 0))
memset(old, 0, increment);
return old;
--
2.21.0
--
Best Regards,
zzs
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next reply other threads:[~2019-04-22 3:13 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-22 3:13 张忠山 [this message]
2019-04-23 9:49 ` Sascha Hauer
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