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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2021-09-06 16:06:04 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-10-06 10:22:24 +0200 |
| commit | 57a94ec7157991aa35c84db09be4fa20553c5a89 (patch) | |
| tree | 28980f8eaed360fc78315047d37e8765823c594c | |
| parent | daa5f7c13b0203e43431daf221f50ea5f0a8d48c (diff) | |
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>
| -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 6f80936e0eea..75445ba7e237 100644 --- a/arch/sparc/kernel/mdesc.c +++ b/arch/sparc/kernel/mdesc.c @@ -37,6 +37,7 @@ 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 { @@ -369,7 +370,7 @@ out: 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) |