* Naveen N. Rao <naveen.n....@linux.vnet.ibm.com> wrote:
> Similar to commit 90ec5e89e393c ("kretprobes: Ensure probe location is
> at function entry"), ensure that the jprobe probepoint is at function
> entry.
>
> Signed-off-by: Naveen N. Rao <naveen.n....@linux.vnet.ibm.com>
> ---
> kernel/kprobes.c | 9 +++++++--
> 1 file changed, 7 insertions(+), 2 deletions(-)
>
> diff --git a/kernel/kprobes.c b/kernel/kprobes.c
> index adfe3b4cfe05..950018609339 100644
> --- a/kernel/kprobes.c
> +++ b/kernel/kprobes.c
> @@ -1776,9 +1776,14 @@ int register_jprobes(struct jprobe **jps, int num)
> jp = jps[i];
> addr = arch_deref_entry_point(jp->entry);
>
> - /* Verify probepoint is a function entry point */
> + /*
> + * Verify probepoint as well as the jprobe handler are
> + * function entry points.
> + */
> if (kallsyms_lookup_size_offset(addr, NULL, &offset) &&
> - offset == 0) {
> + offset == 0 &&
> + function_offset_within_entry(jp->kp.addr,
> + jp->kp.symbol_name, jp->kp.offset)) {
> jp->kp.pre_handler = setjmp_pre_handler;
> jp->kp.break_handler = longjmp_break_handler;
> ret = register_kprobe(&jp->kp);
Yeah, so I agree with the fix, but the line breaks there are disgusting.
One solution would be to split out the iterator into a register_jprobe()
function.
Also, introduce a 'kp' temporary variable to simplify and shorten usage.
Also, 'function_offset_within_entry' is way too long a name, and it's also a
minomer I think. The purpose of this function is to enforce that the relative
'offset' of a new probe is at the standard function entry offset: i.e. 0 on
most
architectures, and some ABI dependent constant on PowerPC, right?
That's not at all clear from that name, plus it's a global namespace symbol,
yet
has no 'kprobes' prefix. So it should be named something like
'kprobe_offset_valid()' or such, with an arch_kprobe_offset_valid() counterpart.
All of these cleanups should be in separate patches - with the fix in the end.
Thanks,
Ingo
