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Jose E. Marchesi b694989bb1 bpf: Avoid uninitialized value in BPF_CORE_READ_BITFIELD

[ 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>

2024-07-18 13:05:41 +02:00

accounting

…

arch

x86/insn: Fix PUSH instruction in x86 instruction decoder opcode map

2024-06-16 13:32:13 +02:00

bootconfig

bootconfig: Fix testcase to increase max node

2023-04-05 11:23:34 +02:00

bpf

bpf: Fix potential integer overflow in resolve_btfids

2024-06-16 13:32:28 +02:00