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SubjectRe: [PATCH v2 bpf-next 0/5] ftrace: host klp and bpf trampoline together
Date
Hi Steven, 

> On Jun 2, 2022, at 12:37 PM, Song Liu <song@kernel.org> wrote:
>
> Changes v1 => v2:
> 1. Fix build errors for different config. (kernel test robot)
>
> Kernel Live Patch (livepatch, or klp) and bpf trampoline are important
> features for modern systems. This set allows the two to work on the same
> kernel function as the same time.
>
> live patch uses ftrace with IPMODIFY, while bpf trampoline use direct
> ftrace. Existing policy does not allow the two to attach to the same kernel
> function. This is changed by fine tuning ftrace IPMODIFY policy, and allows
> one non-DIRECT IPMODIFY ftrace_ops and one non-IPMODIFY DIRECT ftrace_ops
> on the same kernel function at the same time. Please see 3/5 for more
> details on this.
>
> Note that, one of the constraint here is to let bpf trampoline use direct
> call when it is not working on the same function as live patch. This is
> achieved by allowing ftrace code to ask bpf trampoline to make changes.

Could you please share your comments on this set?

Thanks!
Song

>
> Jiri Olsa (1):
> bpf, x64: Allow to use caller address from stack
>
> Song Liu (4):
> ftrace: allow customized flags for ftrace_direct_multi ftrace_ops
> ftrace: add modify_ftrace_direct_multi_nolock
> ftrace: introduce FTRACE_OPS_FL_SHARE_IPMODIFY
> bpf: trampoline: support FTRACE_OPS_FL_SHARE_IPMODIFY
>
> arch/x86/net/bpf_jit_comp.c | 13 +-
> include/linux/bpf.h | 8 ++
> include/linux/ftrace.h | 79 +++++++++++
> kernel/bpf/trampoline.c | 109 +++++++++++++--
> kernel/trace/ftrace.c | 269 +++++++++++++++++++++++++++++++-----
> 5 files changed, 424 insertions(+), 54 deletions(-)
>
> --
> 2.30.2

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