477c8135fb
backport-libbpf-Avoid-uninitialized-value-in-BPF_CORE_READ_BI.patch (cherry picked from commit 78ea29a9e9d3de9a8a1e6df63e97a24feab7635d)
57 lines
2.0 KiB
Diff
57 lines
2.0 KiB
Diff
From 3827aa514cba7db16b81236712a46e8b70260fcd Mon Sep 17 00:00:00 2001
|
|
From: "Jose E. Marchesi" <jose.marchesi@oracle.com>
|
|
Date: Wed, 8 May 2024 12:13:13 +0200
|
|
Subject: [PATCH] bpf: Avoid uninitialized value in BPF_CORE_READ_BITFIELD
|
|
|
|
[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
|
|
|
|
Conflict: NA
|
|
Reference:https://github.com/libbpf/libbpf/commit/3827aa514cba7db16b81236712a46e8b70260fcd
|
|
---
|
|
src/bpf_core_read.h | 1 +
|
|
1 file changed, 1 insertion(+)
|
|
|
|
diff --git a/src/bpf_core_read.h b/src/bpf_core_read.h
|
|
index b5c7ce5c2..c0e13cdf9 100644
|
|
--- a/src/bpf_core_read.h
|
|
+++ b/src/bpf_core_read.h
|
|
@@ -104,6 +104,7 @@ 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)) \
|
|
|
|
|