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From: Corinna Vinschen <>
Subject: [newlib-cygwin] Fix null-pointer dereference in nano-malloc
Date: Wed, 26 Jan 2022 12:14:21 +0000 (GMT)	[thread overview]
Message-ID: <> (raw);h=73d515fcfecd1004ccffef8fcd0c7223b9eec6ab

commit 73d515fcfecd1004ccffef8fcd0c7223b9eec6ab
Author: Cyril Yared <>
Date:   Tue Jan 25 07:44:10 2022 -0800

    Fix null-pointer dereference in nano-malloc
    If p is NULL, then the free_list is empty and we should return the
    correct failure values.

 newlib/libc/stdlib/nano-mallocr.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/newlib/libc/stdlib/nano-mallocr.c b/newlib/libc/stdlib/nano-mallocr.c
index 6fb08a616..0c5fb2885 100644
--- a/newlib/libc/stdlib/nano-mallocr.c
+++ b/newlib/libc/stdlib/nano-mallocr.c
@@ -322,7 +322,7 @@ void * nano_malloc(RARG malloc_size_t s)
-            if ((char *)p + p->size == (char *)_SBRK_R(RCALL 0))
+            if (p != NULL && (char *)p + p->size == (char *)_SBRK_R(RCALL 0))
                /* The last free item has the heap end as neighbour.
                 * Let's ask for a smaller amount and merge */

                 reply	other threads:[~2022-01-26 12:14 UTC|newest]

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