Re: [PATCH] tracing/uprobe: Fix to make trace_uprobe_filter alignment safe

[Steven Rostedt]

On Tue, 21 Jan 2020 16:46:19 +0900
Masami Hiramatsu <mhiramat@xxxxxxxxxx> wrote:

> Commit 99c9a923e97a ("tracing/uprobe: Fix double perf_event
> linking on multiprobe uprobe") moved trace_uprobe_filter on
> trace_probe_event. However, since it introduced a flexible
> data structure with char array and type casting, the
> alignment of trace_uprobe_filter can be broken.
> 
> This changes the type of the array to trace_uprobe_filter
> data strucure to fix it.
> 
> Fixes: 99c9a923e97a ("tracing/uprobe: Fix double perf_event linking on multiprobe uprobe")
> Suggested-by: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
> Signed-off-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
> ---
>  kernel/trace/trace_kprobe.c |    2 +-
>  kernel/trace/trace_probe.c  |    9 ++++++---
>  kernel/trace/trace_probe.h  |   10 ++++++++--
>  kernel/trace/trace_uprobe.c |   29 +++++++----------------------
>  4 files changed, 22 insertions(+), 28 deletions(-)


I hit the following build error with this:

/work/git/linux-trace.git/kernel/trace/trace_uprobe.c: In function âalloc_trace_uprobeâ:
/work/git/linux-trace.git/kernel/trace/trace_uprobe.c:355:39: error: âtu->tp.eventâ is a pointer; did you mean to use â->â?
  init_trace_uprobe_filter(tu->tp.event.filter);
                                       ^
                                       ->
In file included from /work/git/linux-trace.git/arch/x86/include/asm/bug.h:83,
                 from /work/git/linux-trace.git/include/linux/bug.h:5,
                 from /work/git/linux-trace.git/arch/x86/include/asm/paravirt.h:15,
                 from /work/git/linux-trace.git/arch/x86/include/asm/irqflags.h:72,
                 from /work/git/linux-trace.git/include/linux/irqflags.h:16,
                 from /work/git/linux-trace.git/include/linux/rcupdate.h:26,
                 from /work/git/linux-trace.git/include/linux/rbtree.h:22,
                 from /work/git/linux-trace.git/include/linux/key.h:15,
                 from /work/git/linux-trace.git/include/linux/security.h:26,
                 from /work/git/linux-trace.git/kernel/trace/trace_uprobe.c:10:
/work/git/linux-trace.git/kernel/trace/trace_uprobe.c: In function â__probe_event_disableâ:
/work/git/linux-trace.git/kernel/trace/trace_uprobe.c:1064:46: error: âtu->tp.eventâ is a pointer; did you mean to use â->â?
  WARN_ON(!uprobe_filter_is_empty(tu->tp.event.filter));
                                              ^
/work/git/linux-trace.git/include/asm-generic/bug.h:113:25: note: in definition of macro âWARN_ONâ
  int __ret_warn_on = !!(condition);    \
                         ^~~~~~~~~
/work/git/linux-trace.git/kernel/trace/trace_uprobe.c: In function âprobe_event_enableâ:
/work/git/linux-trace.git/kernel/trace/trace_uprobe.c:1105:46: error: âtu->tp.eventâ is a pointer; did you mean to use â->â?
  WARN_ON(!uprobe_filter_is_empty(tu->tp.event.filter));
                                              ^
/work/git/linux-trace.git/include/asm-generic/bug.h:113:25: note: in definition of macro âWARN_ONâ
  int __ret_warn_on = !!(condition);    \
                         ^~~~~~~~~
/work/git/linux-trace.git/kernel/trace/trace_uprobe.c: In function âuprobe_perf_closeâ:
/work/git/linux-trace.git/kernel/trace/trace_uprobe.c:1269:45: error: âtu->tp.eventâ is a pointer; did you mean to use â->â?
  if (trace_uprobe_filter_remove(tu->tp.event.filter, event))
                                             ^
                                             ->
/work/git/linux-trace.git/kernel/trace/trace_uprobe.c: In function âuprobe_perf_openâ:
/work/git/linux-trace.git/kernel/trace/trace_uprobe.c:1294:42: error: âtu->tp.eventâ is a pointer; did you mean to use â->â?
  if (trace_uprobe_filter_add(tu->tp.event.filter, event))
                                          ^
                                          ->
/work/git/linux-trace.git/kernel/trace/trace_uprobe.c: In function âuprobe_perf_filterâ:
/work/git/linux-trace.git/kernel/trace/trace_uprobe.c:1316:23: error: âtu->tp.eventâ is a pointer; did you mean to use â->â?
  filter = tu->tp.event.filter;
                       ^
                       ->
make[3]: *** [/work/git/linux-trace.git/scripts/Makefile.build:266: kernel/trace/trace_uprobe.o] Error 1
make[3]: *** Waiting for unfinished jobs....


Config attached.

-- Steve

Attachment: config.gz
Description: application/gzip