Re: [PATCH 0/8] tracing: Allow system call tracepoints to handle page faults

[Andrii Nakryiko]

On Mon, Sep 9, 2024 at 1:17 PM Mathieu Desnoyers
<mathieu.desnoyers@xxxxxxxxxxxx> wrote:
>
> Wire up the system call tracepoints with Tasks Trace RCU to allow
> the ftrace, perf, and eBPF tracers to handle page faults.
>
> This series does the initial wire-up allowing tracers to handle page
> faults, but leaves out the actual handling of said page faults as future
> work.
>
> This series was compile and runtime tested with ftrace and perf syscall
> tracing and raw syscall tracing, adding a WARN_ON_ONCE() in the
> generated code to validate that the intended probes are used for raw
> syscall tracing. The might_fault() added within those probes validate
> that they are called from a context where handling a page fault is OK.
>
> For ebpf, this series is compile-tested only.

What tree/branch was this based on? I can't apply it cleanly anywhere I tried...

>
> This series replaces the "Faultable Tracepoints v6" series found at [1].
>
> Thanks,
>
> Mathieu
>
> Link: https://lore.kernel.org/lkml/20240828144153.829582-1-mathieu.desnoyers@xxxxxxxxxxxx/ # [1]
> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
> Cc: Alexei Starovoitov <ast@xxxxxxxxxx>
> Cc: Yonghong Song <yhs@xxxxxx>
> Cc: Paul E. McKenney <paulmck@xxxxxxxxxx>
> Cc: Ingo Molnar <mingo@xxxxxxxxxx>
> Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
> Cc: Mark Rutland <mark.rutland@xxxxxxx>
> Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
> Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
> Cc: Andrii Nakryiko <andrii.nakryiko@xxxxxxxxx>
> Cc: bpf@xxxxxxxxxxxxxxx
> Cc: Joel Fernandes <joel@xxxxxxxxxxxxxxxxx>
> Cc: linux-trace-kernel@xxxxxxxxxxxxxxx
>
> Mathieu Desnoyers (8):
>   tracing: Declare system call tracepoints with TRACE_EVENT_SYSCALL
>   tracing/ftrace: guard syscall probe with preempt_notrace
>   tracing/perf: guard syscall probe with preempt_notrace
>   tracing/bpf: guard syscall probe with preempt_notrace
>   tracing: Allow system call tracepoints to handle page faults
>   tracing/ftrace: Add might_fault check to syscall probes
>   tracing/perf: Add might_fault check to syscall probes
>   tracing/bpf: Add might_fault check to syscall probes
>
>  include/linux/tracepoint.h      | 87 +++++++++++++++++++++++++--------
>  include/trace/bpf_probe.h       | 13 +++++
>  include/trace/define_trace.h    |  5 ++
>  include/trace/events/syscalls.h |  4 +-
>  include/trace/perf.h            | 43 ++++++++++++++--
>  include/trace/trace_events.h    | 61 +++++++++++++++++++++--
>  init/Kconfig                    |  1 +
>  kernel/entry/common.c           |  4 +-
>  kernel/trace/trace_syscalls.c   | 36 ++++++++++++--
>  9 files changed, 218 insertions(+), 36 deletions(-)
>
> --
> 2.39.2