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| author | Anton Protopopov <a.s.protopopov@gmail.com> | 2025-05-02 19:30:31 +0000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2025-06-27 11:05:12 +0100 |
| commit | 9c5268e5d6334057bd0efdc9e8d7c6ca7143ae81 (patch) | |
| tree | 56cfa43a27953d795e4fe8fe8e12f1949c3e4aa0 /tools | |
| parent | f9784da76ad7be66230e829e743bdf68a2c49e56 (diff) | |
| download | linux-9c5268e5d6334057bd0efdc9e8d7c6ca7143ae81.tar.gz linux-9c5268e5d6334057bd0efdc9e8d7c6ca7143ae81.tar.bz2 linux-9c5268e5d6334057bd0efdc9e8d7c6ca7143ae81.zip | |
bpf: Fix uninitialized values in BPF_{CORE,PROBE}_READ
[ Upstream commit 41d4ce6df3f4945341ec509a840cc002a413b6cc ]
With the latest LLVM bpf selftests build will fail with
the following error message:
progs/profiler.inc.h:710:31: error: default initialization of an object of type 'typeof ((parent_task)->real_cred->uid.val)' (aka 'const unsigned int') leaves the object uninitialized and is incompatible with C++ [-Werror,-Wdefault-const-init-unsafe]
710 | proc_exec_data->parent_uid = BPF_CORE_READ(parent_task, real_cred, uid.val);
| ^
tools/testing/selftests/bpf/tools/include/bpf/bpf_core_read.h:520:35: note: expanded from macro 'BPF_CORE_READ'
520 | ___type((src), a, ##__VA_ARGS__) __r; \
| ^
This happens because BPF_CORE_READ (and other macro) declare the
variable __r using the ___type macro which can inherit const modifier
from intermediate types.
Fix this by using __typeof_unqual__, when supported. (And when it
is not supported, the problem shouldn't appear, as older compilers
haven't complained.)
Fixes: 792001f4f7aa ("libbpf: Add user-space variants of BPF_CORE_READ() family of macros")
Fixes: a4b09a9ef945 ("libbpf: Add non-CO-RE variants of BPF_CORE_READ() macro family")
Signed-off-by: Anton Protopopov <a.s.protopopov@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20250502193031.3522715-1-a.s.protopopov@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'tools')
| -rw-r--r-- | tools/lib/bpf/bpf_core_read.h | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/tools/lib/bpf/bpf_core_read.h b/tools/lib/bpf/bpf_core_read.h index b8e68a17f3f1..442551a50176 100644 --- a/tools/lib/bpf/bpf_core_read.h +++ b/tools/lib/bpf/bpf_core_read.h @@ -272,7 +272,13 @@ enum bpf_enum_value_kind { #define ___arrow10(a, b, c, d, e, f, g, h, i, j) a->b->c->d->e->f->g->h->i->j #define ___arrow(...) ___apply(___arrow, ___narg(__VA_ARGS__))(__VA_ARGS__) +#if defined(__clang__) && (__clang_major__ >= 19) +#define ___type(...) __typeof_unqual__(___arrow(__VA_ARGS__)) +#elif defined(__GNUC__) && (__GNUC__ >= 14) +#define ___type(...) __typeof_unqual__(___arrow(__VA_ARGS__)) +#else #define ___type(...) typeof(___arrow(__VA_ARGS__)) +#endif #define ___read(read_fn, dst, src_type, src, accessor) \ read_fn((void *)(dst), sizeof(*(dst)), &((src_type)(src))->accessor) |