lkml.org 
[lkml]   [2018]   [Nov]   [8]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 0/2] tracing: Fix NULL pointer bug in hist key expressions
On Thu,  8 Nov 2018 08:41:47 -0600
Tom Zanussi <zanussi@kernel.org> wrote:

> From: Tom Zanussi <tom.zanussi@linux.intel.com>
>
> Hi Steve,
>
> This is a fix for a user-reported bug in the hist triggers, where if a
> variable reference is used in an expression in a histogram key, it
> results in a NULL pointer dereference and subsequent Oops.

How does one add a variable reference as an expression in a
histogram key?

Can you show an example?

-- Steve

>
> I separated the fix into two small patches, the first preventing the
> immediate problem bu disallowing a var_ref from ever accessing a NULL
> element, and the second disallowing a user from ever constructing such
> a key.
>
> Thanks,
>
> Tom
>
> The following changes since commit ee474b81fe5aa5dc0faae920bf66240fbf55f891:
>
> tracing/kprobes: Fix strpbrk() argument order (2018-11-05 09:47:14 -0500)
>
> are available in the git repository at:
>
> git://git.kernel.org/pub/scm/linux/kernel/git/zanussi/linux-trace.git ftrace/key-ref-fix
>
> Tom Zanussi (2):
> tracing: Prevent hist_field_var_ref() from accessing NULL
> tracing_map_elts
> tracing: Check keys for variable references in expressions too
>
> kernel/trace/trace_events_hist.c | 7 +++++--
> 1 file changed, 5 insertions(+), 2 deletions(-)
>

\
 
 \ /
  Last update: 2018-11-08 19:45    [W:0.062 / U:4.928 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site