sparc64 images fail to compile with gcc 11.x, reporting the following
errors.
arch/sparc/kernel/mdesc.c:647:22: error:
'strcmp' reading 1 or more bytes from a region of size 0
arch/sparc/kernel/mdesc.c:692:22: error:
'strcmp' reading 1 or more bytes from a region of size 0
arch/sparc/kernel/mdesc.c:719:21:
error: 'strcmp' reading 1 or more bytes from a region of size 0
The underlying problem is that node_block() returns a pointer beyond
the end of struct mdesc_hdr. gcc 11.x detects that and reports the error.
Adding an additional zero-length field to struct mdesc_hdr and pointing
to that field fixes the problem.
Cc: Arnd Bergmann <arnd@xxxxxxxxxx>
Cc: David Laight <David.Laight@xxxxxxxxxx>
Cc: Anatoly Pugachev <matorola@xxxxxxxxx>
Cc: Sam Ravnborg <sam@xxxxxxxxxxxx>
Signed-off-by: Guenter Roeck <linux@xxxxxxxxxxxx>
---
v2: data[0] => data[]
I am not sure if there was agreement to accept this patch or not, but
I was asked to resend it with the above change, so here it is. An open
question was if it is acceptable to have a structure named xxx_hdr
include an element pointing to the data following that header.
If this patch is not acceptable, the patch in buildbot may be a possible
alternative to consider.
https://git.busybox.net/buildroot/commit/?id=6e1106b4a9aee25d1556310d5cd1cb6dde2e6e3f
arch/sparc/kernel/mdesc.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/arch/sparc/kernel/mdesc.c b/arch/sparc/kernel/mdesc.c
index 8e645ddac58e..83e1f699bc32 100644
--- a/arch/sparc/kernel/mdesc.c
+++ b/arch/sparc/kernel/mdesc.c
@@ -39,6 +39,7 @@ struct mdesc_hdr {
u32 node_sz; /* node block size */
u32 name_sz; /* name block size */
u32 data_sz; /* data block size */
+ char data[];
} __attribute__((aligned(16)));
struct mdesc_elem {
@@ -612,7 +613,7 @@ EXPORT_SYMBOL(mdesc_get_node_info);
static struct mdesc_elem *node_block(struct mdesc_hdr *mdesc)
{
- return (struct mdesc_elem *) (mdesc + 1);
+ return (struct mdesc_elem *) (mdesc->data);
}
static void *name_block(struct mdesc_hdr *mdesc)
--
2.33.0
