From 632f96d2652e0d4188de837f88a977eedb55aee1 Mon Sep 17 00:00:00 2001 From: Ilya Leoshkevich Date: Thu, 21 Oct 2021 12:46:58 +0200 Subject: [PATCH] libbpf: Fix ptr_is_aligned() usages Currently ptr_is_aligned() takes size, and not alignment, as a parameter, which may be overly pessimistic e.g. for __i128 on s390, which must be only 8-byte aligned. Fix by using btf__align_of(). Signed-off-by: Ilya Leoshkevich Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20211021104658.624944-2-iii@linux.ibm.com --- tools/lib/bpf/btf_dump.c | 20 ++++++++++++-------- 1 file changed, 12 insertions(+), 8 deletions(-) diff --git a/tools/lib/bpf/btf_dump.c b/tools/lib/bpf/btf_dump.c index e98c201f29b5..e9e5801ece4c 100644 --- a/tools/lib/bpf/btf_dump.c +++ b/tools/lib/bpf/btf_dump.c @@ -1657,9 +1657,15 @@ static int btf_dump_base_type_check_zero(struct btf_dump *d, return 0; } -static bool ptr_is_aligned(const void *data, int data_sz) +static bool ptr_is_aligned(const struct btf *btf, __u32 type_id, + const void *data) { - return ((uintptr_t)data) % data_sz == 0; + int alignment = btf__align_of(btf, type_id); + + if (alignment == 0) + return false; + + return ((uintptr_t)data) % alignment == 0; } static int btf_dump_int_data(struct btf_dump *d, @@ -1681,7 +1687,7 @@ static int btf_dump_int_data(struct btf_dump *d, /* handle packed int data - accesses of integers not aligned on * int boundaries can cause problems on some platforms. */ - if (!ptr_is_aligned(data, sz)) { + if (!ptr_is_aligned(d->btf, type_id, data)) { memcpy(buf, data, sz); data = buf; } @@ -1770,7 +1776,7 @@ static int btf_dump_float_data(struct btf_dump *d, int sz = t->size; /* handle unaligned data; copy to local union */ - if (!ptr_is_aligned(data, sz)) { + if (!ptr_is_aligned(d->btf, type_id, data)) { memcpy(&fl, data, sz); flp = &fl; } @@ -1933,7 +1939,7 @@ static int btf_dump_ptr_data(struct btf_dump *d, __u32 id, const void *data) { - if (ptr_is_aligned(data, d->ptr_sz) && d->ptr_sz == sizeof(void *)) { + if (ptr_is_aligned(d->btf, id, data) && d->ptr_sz == sizeof(void *)) { btf_dump_type_values(d, "%p", *(void **)data); } else { union ptr_data pt; @@ -1953,10 +1959,8 @@ static int btf_dump_get_enum_value(struct btf_dump *d, __u32 id, __s64 *value) { - int sz = t->size; - /* handle unaligned enum value */ - if (!ptr_is_aligned(data, sz)) { + if (!ptr_is_aligned(d->btf, id, data)) { __u64 val; int err;