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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2021-09-07 02:06:04 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-09-30 11:11:07 +0300 |
| commit | 5520d27f02a15831e240e14c1f1a19ea6b3f467f (patch) | |
| tree | 9efe6156254beaac27f1b46e77fc4d90ffcc6fe1 /arch/sparc | |
| parent | 8d768beaf0efb0709fc23f9d826072c414a75938 (diff) | |
| download | linux-5520d27f02a15831e240e14c1f1a19ea6b3f467f.tar.xz | |
sparc: avoid stringop-overread errors
[ Upstream commit fc7c028dcdbfe981bca75d2a7b95f363eb691ef3 ]
The sparc mdesc code does pointer games with 'struct mdesc_hdr', but
didn't describe to the compiler how that header is then followed by the
data that the header describes.
As a result, gcc is now unhappy since it does stricter pointer range
tracking, and doesn't understand about how these things work. This
results in various errors like:
arch/sparc/kernel/mdesc.c: In function ‘mdesc_node_by_name’:
arch/sparc/kernel/mdesc.c:647:22: error: ‘strcmp’ reading 1 or more bytes from a region of size 0 [-Werror=stringop-overread]
647 | if (!strcmp(names + ep[ret].name_offset, name))
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
which are easily avoided by just describing 'struct mdesc_hdr' better,
and making the node_block() helper function look into that unsized
data[] that follows the header.
This makes the sparc64 build happy again at least for my cross-compiler
version (gcc version 11.2.1).
Link: https://lore.kernel.org/lkml/CAHk-=wi4NW3NC0xWykkw=6LnjQD6D_rtRtxY9g8gQAJXtQMi8A@mail.gmail.com/
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'arch/sparc')
| -rw-r--r-- | arch/sparc/kernel/mdesc.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/arch/sparc/kernel/mdesc.c b/arch/sparc/kernel/mdesc.c index 8e645ddac58e..30f171b7b00c 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) |