diff options
| author | Arnd Bergmann <arnd@arndb.de> | 2023-08-01 13:13:58 +0200 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2023-08-02 14:14:17 -0700 |
| commit | 6a5a148aaf14747570cc634f9cdfcb0393f5617f (patch) | |
| tree | 009a80c481bd2624a9cf9c0da4fc9bea457b8d14 /kernel/bpf/core.c | |
| parent | 25ad10658dc1068a671553ff10e19a812c2a3783 (diff) | |
bpf: fix bpf_probe_read_kernel prototype mismatch
bpf_probe_read_kernel() has a __weak definition in core.c and another
definition with an incompatible prototype in kernel/trace/bpf_trace.c,
when CONFIG_BPF_EVENTS is enabled.
Since the two are incompatible, there cannot be a shared declaration in
a header file, but the lack of a prototype causes a W=1 warning:
kernel/bpf/core.c:1638:12: error: no previous prototype for 'bpf_probe_read_kernel' [-Werror=missing-prototypes]
On 32-bit architectures, the local prototype
u64 __weak bpf_probe_read_kernel(void *dst, u32 size, const void *unsafe_ptr)
passes arguments in other registers as the one in bpf_trace.c
BPF_CALL_3(bpf_probe_read_kernel, void *, dst, u32, size,
const void *, unsafe_ptr)
which uses 64-bit arguments in pairs of registers.
As both versions of the function are fairly simple and only really
differ in one line, just move them into a header file as an inline
function that does not add any overhead for the bpf_trace.c callers
and actually avoids a function call for the other one.
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/all/ac25cb0f-b804-1649-3afb-1dc6138c2716@iogearbox.net/
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/r/20230801111449.185301-1-arnd@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'kernel/bpf/core.c')
| -rw-r--r-- | kernel/bpf/core.c | 12 |
1 files changed, 3 insertions, 9 deletions
diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index baccdec22f19..0f8f036d8bd1 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -1650,12 +1650,6 @@ bool bpf_opcode_in_insntable(u8 code) } #ifndef CONFIG_BPF_JIT_ALWAYS_ON -u64 __weak bpf_probe_read_kernel(void *dst, u32 size, const void *unsafe_ptr) -{ - memset(dst, 0, size); - return -EFAULT; -} - /** * ___bpf_prog_run - run eBPF program on a given context * @regs: is the array of MAX_BPF_EXT_REG eBPF pseudo-registers @@ -2066,8 +2060,8 @@ out: DST = *(SIZE *)(unsigned long) (SRC + insn->off); \ CONT; \ LDX_PROBE_MEM_##SIZEOP: \ - bpf_probe_read_kernel(&DST, sizeof(SIZE), \ - (const void *)(long) (SRC + insn->off)); \ + bpf_probe_read_kernel_common(&DST, sizeof(SIZE), \ + (const void *)(long) (SRC + insn->off)); \ DST = *((SIZE *)&DST); \ CONT; @@ -2082,7 +2076,7 @@ out: DST = *(SIZE *)(unsigned long) (SRC + insn->off); \ CONT; \ LDX_PROBE_MEMSX_##SIZEOP: \ - bpf_probe_read_kernel(&DST, sizeof(SIZE), \ + bpf_probe_read_kernel_common(&DST, sizeof(SIZE), \ (const void *)(long) (SRC + insn->off)); \ DST = *((SIZE *)&DST); \ CONT; |