From: Darrick J. Wong <djwong@kernel.org>
Date: Fri, 12 Jan 2024 02:07:03 +0000 (-0800)
Subject: libxfs: fix krealloc to allow freeing data
X-Git-Tag: v6.6.0~5^2
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=55021e7533bc55100f8ae0125aec513885cc5987;p=thirdparty%2Fxfsprogs-dev.git

libxfs: fix krealloc to allow freeing data

A recent refactoring to xfs_idata_realloc in the kernel made it depend
on krealloc returning NULL if the new size is zero.  The xfsprogs
wrapper instead aborts, so we need to make it follow the kernel
behavior.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
---

diff --git a/libxfs/kmem.c b/libxfs/kmem.c
index 42d813088..c264be018 100644
--- a/libxfs/kmem.c
+++ b/libxfs/kmem.c
@@ -98,6 +98,16 @@ kmem_zalloc(size_t size, int flags)
 void *
 krealloc(void *ptr, size_t new_size, int flags)
 {
+	/*
+	 * If @new_size is zero, Linux krealloc will free the memory and return
+	 * NULL, so force that behavior here.  The return value of realloc with
+	 * a zero size is implementation dependent, so we cannot use that.
+	 */
+	if (!new_size) {
+		free(ptr);
+		return NULL;
+	}
+
 	ptr = realloc(ptr, new_size);
 	if (ptr == NULL) {
 		fprintf(stderr, _("%s: realloc failed (%d bytes): %s\n"),