| Message ID | 20220602193706.2607681-1-song@kernel.org (mailing list archive) |
|---|---|
| Headers | show |
| Series | ftrace: host klp and bpf trampoline together | expand |
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
I just realized that none of the live kernel patching folks are Cc'd on this thread. I think they will care much more about this than I do. -- Steve On Thu, 2 Jun 2022 12:37:01 -0700 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. > > 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
> On Jul 11, 2022, at 4:55 PM, Steven Rostedt <rostedt@goodmis.org> wrote: > > I just realized that none of the live kernel patching folks are Cc'd on > this thread. I think they will care much more about this than I do. vger.kernel.org often drops my email when the CC list is too long. So I try to keep the list short. In this case, since we are not changing live patch code, and there isn't any negative impact for live patch side, I didn't CC live patch folks. I will at least CC live-patching@ in the next version. Thanks, Song PS: I am the live patch guy at Meta. :) > > -- Steve > > > On Thu, 2 Jun 2022 12:37:01 -0700 > 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. >> >> 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 >
On Tue, 12 Jul 2022 05:15:26 +0000 Song Liu <songliubraving@fb.com> wrote: > > On Jul 11, 2022, at 4:55 PM, Steven Rostedt <rostedt@goodmis.org> wrote: > > > > I just realized that none of the live kernel patching folks are Cc'd on > > this thread. I think they will care much more about this than I do. > > vger.kernel.org often drops my email when the CC list is too long. So I Oh, they fixed that. I've had over 20 Cc's and it still works. ;-) > try to keep the list short. In this case, since we are not changing live > patch code, and there isn't any negative impact for live patch side, I > didn't CC live patch folks. It affects them indirectly, and they should be aware of what is happening underneath. > > I will at least CC live-patching@ in the next version. Thanks. -- Steve