diff options
| author | Ian Rogers <irogers@google.com> | 2023-10-06 21:44:38 -0700 |
|---|---|---|
| committer | Andrii Nakryiko <andrii@kernel.org> | 2023-10-09 09:36:51 -0700 |
| commit | 23671f4dfd10b48b4a2fee4768886f0d8ec55b7e (patch) | |
| tree | f7ceaabf5fa48283752f94b512f06ca24e5ff282 /tools/bpf | |
| parent | 0d7ae06860753bb30b3731302b994da071120d00 (diff) | |
| download | lwn-23671f4dfd10b48b4a2fee4768886f0d8ec55b7e.tar.gz lwn-23671f4dfd10b48b4a2fee4768886f0d8ec55b7e.zip | |
bpftool: Align output skeleton ELF code
libbpf accesses the ELF data requiring at least 8 byte alignment,
however, the data is generated into a C string that doesn't guarantee
alignment. Fix this by assigning to an aligned char array. Use sizeof
on the array, less one for the \0 terminator, rather than generating a
constant.
Fixes: a6cc6b34b93e ("bpftool: Provide a helper method for accessing skeleton's embedded ELF data")
Signed-off-by: Ian Rogers <irogers@google.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: Alan Maguire <alan.maguire@oracle.com>
Acked-by: Quentin Monnet <quentin@isovalent.com>
Link: https://lore.kernel.org/bpf/20231007044439.25171-1-irogers@google.com
Diffstat (limited to 'tools/bpf')
| -rw-r--r-- | tools/bpf/bpftool/gen.c | 15 |
1 files changed, 9 insertions, 6 deletions
diff --git a/tools/bpf/bpftool/gen.c b/tools/bpf/bpftool/gen.c index 04c47745b3ea..882bf8e6e70e 100644 --- a/tools/bpf/bpftool/gen.c +++ b/tools/bpf/bpftool/gen.c @@ -1209,7 +1209,7 @@ static int do_skeleton(int argc, char **argv) codegen("\ \n\ \n\ - s->data = %2$s__elf_bytes(&s->data_sz); \n\ + s->data = %1$s__elf_bytes(&s->data_sz); \n\ \n\ obj->skeleton = s; \n\ return 0; \n\ @@ -1218,12 +1218,12 @@ static int do_skeleton(int argc, char **argv) return err; \n\ } \n\ \n\ - static inline const void *%2$s__elf_bytes(size_t *sz) \n\ + static inline const void *%1$s__elf_bytes(size_t *sz) \n\ { \n\ - *sz = %1$d; \n\ - return (const void *)\"\\ \n\ - " - , file_sz, obj_name); + static const char data[] __attribute__((__aligned__(8))) = \"\\\n\ + ", + obj_name + ); /* embed contents of BPF object file */ print_hex(obj_data, file_sz); @@ -1231,6 +1231,9 @@ static int do_skeleton(int argc, char **argv) codegen("\ \n\ \"; \n\ + \n\ + *sz = sizeof(data) - 1; \n\ + return (const void *)data; \n\ } \n\ \n\ #ifdef __cplusplus \n\ |