6.6-stable review patch. If anyone has any objections, please let me know.
------------------
From: Jose E. Marchesi jose.marchesi@oracle.com
[ Upstream commit 009367099eb61a4fc2af44d4eb06b6b4de7de6db ]
[Changes from V1: - Use a default branch in the switch statement to initialize `val'.]
GCC warns that `val' may be used uninitialized in the BPF_CRE_READ_BITFIELD macro, defined in bpf_core_read.h as:
[...] unsigned long long val; \ [...] \ switch (__CORE_RELO(s, field, BYTE_SIZE)) { \ case 1: val = *(const unsigned char *)p; break; \ case 2: val = *(const unsigned short *)p; break; \ case 4: val = *(const unsigned int *)p; break; \ case 8: val = *(const unsigned long long *)p; break; \ } \ [...] val; \ } \
This patch adds a default entry in the switch statement that sets `val' to zero in order to avoid the warning, and random values to be used in case __builtin_preserve_field_info returns unexpected values for BPF_FIELD_BYTE_SIZE.
Tested in bpf-next master. No regressions.
Signed-off-by: Jose E. Marchesi jose.marchesi@oracle.com Signed-off-by: Andrii Nakryiko andrii@kernel.org Link: https://lore.kernel.org/bpf/20240508101313.16662-1-jose.marchesi@oracle.com Signed-off-by: Sasha Levin sashal@kernel.org --- tools/lib/bpf/bpf_core_read.h | 1 + 1 file changed, 1 insertion(+)
diff --git a/tools/lib/bpf/bpf_core_read.h b/tools/lib/bpf/bpf_core_read.h index 1ac57bb7ac55f..e2b9e8415c044 100644 --- a/tools/lib/bpf/bpf_core_read.h +++ b/tools/lib/bpf/bpf_core_read.h @@ -102,6 +102,7 @@ enum bpf_enum_value_kind { case 2: val = *(const unsigned short *)p; break; \ case 4: val = *(const unsigned int *)p; break; \ case 8: val = *(const unsigned long long *)p; break; \ + default: val = 0; break; \ } \ val <<= __CORE_RELO(s, field, LSHIFT_U64); \ if (__CORE_RELO(s, field, SIGNED)) \