Re: [PATCH net-next] lib: move strncpy_from_unsafe() into mm/maccess.c

From: Guenter Roeck
Date: Mon Aug 31 2015 - 15:43:29 EST

On 08/31/2015 12:36 PM, David Miller wrote:
From: Alexei Starovoitov <ast@xxxxxxxxxxxx>
Date: Mon, 31 Aug 2015 08:57:10 -0700

To fix build errors:
kernel/built-in.o: In function `bpf_trace_printk':
bpf_trace.c:(.text+0x11a254): undefined reference to `strncpy_from_unsafe'
kernel/built-in.o: In function `fetch_memory_string':
trace_kprobe.c:(.text+0x11acf8): undefined reference to `strncpy_from_unsafe'

move strncpy_from_unsafe() next to probe_kernel_read/write()
which use the same memory access style.

Reported-by: Fengguang Wu <fengguang.wu@xxxxxxxxx>
Reported-by: Guenter Roeck <linux@xxxxxxxxxxxx>

Too late, but:

Tested-by: Guenter Roeck <linux@xxxxxxxxxxxx>


Fixes: 1a6877b9c0c2 ("lib: introduce strncpy_from_unsafe()")
Signed-off-by: Alexei Starovoitov <ast@xxxxxxxxxxxx>
For configs without kprobes and bpf the cost of this unused function is
~200 bytes which I think is a better trade off vs creating
new Kconfig selector just for this single function.
Another alternative is to move it to kernel/trace/trace_kprobe.c,
but then it will lose generality and probably should be removed
from include/linux/uaccess.h, so mm/maccess.c looks the best.

Ok, applied.

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