From: Steven Rostedt <rostedt@goodmis.org>
To: Tom Zanussi <zanussi@kernel.org>
Cc: vincent@bernat.ch, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 0/2] tracing: Fix NULL pointer bug in hist key expressions
Date: Thu, 8 Nov 2018 13:45:07 -0500 [thread overview]
Message-ID: <20181108134507.2c343e6b@gandalf.local.home> (raw)
In-Reply-To: <cover.1541687121.git.tom.zanussi@linux.intel.com>
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(-)
>
next prev parent reply other threads:[~2018-11-08 18:45 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-08 14:41 [PATCH 0/2] tracing: Fix NULL pointer bug in hist key expressions Tom Zanussi
2018-11-08 14:41 ` [PATCH 1/2] tracing: Prevent hist_field_var_ref() from accessing NULL tracing_map_elts Tom Zanussi
2018-11-08 14:41 ` [PATCH 2/2] tracing: Check keys for variable references in expressions too Tom Zanussi
2018-11-08 18:45 ` Steven Rostedt [this message]
2018-11-08 19:12 ` [PATCH 0/2] tracing: Fix NULL pointer bug in hist key expressions Tom Zanussi
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