* [PATCH v4] tracing: Fix out of bounds write in get_trace_buf
@ 2020-10-29 16:19 Qiujun Huang
2020-10-29 18:49 ` Steven Rostedt
0 siblings, 1 reply; 2+ messages in thread
From: Qiujun Huang @ 2020-10-29 16:19 UTC (permalink / raw)
To: rostedt, mingo, linux-kernel; +Cc: Qiujun Huang
The subscript should be nesting - 1, as nesting had self-added.
Fixes: 3d9622c12c887 ("tracing: Add barrier to trace_printk() buffer nesting modification")
Signed-off-by: Qiujun Huang <hqjagain@gmail.com>
---
v4:
Find the right patch which cause the problem.
v3:
Modify the way of array reference instead.
v2:
Fix a typo in the title.
---
kernel/trace/trace.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 528971714fc6..daa96215e294 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -3132,7 +3132,7 @@ static char *get_trace_buf(void)
/* Interrupts must see nesting incremented before we use the buffer */
barrier();
- return &buffer->buffer[buffer->nesting][0];
+ return &buffer->buffer[buffer->nesting - 1][0];
}
static void put_trace_buf(void)
--
2.17.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH v4] tracing: Fix out of bounds write in get_trace_buf
2020-10-29 16:19 [PATCH v4] tracing: Fix out of bounds write in get_trace_buf Qiujun Huang
@ 2020-10-29 18:49 ` Steven Rostedt
0 siblings, 0 replies; 2+ messages in thread
From: Steven Rostedt @ 2020-10-29 18:49 UTC (permalink / raw)
To: Qiujun Huang; +Cc: mingo, linux-kernel, Andy Lutomirski
On Fri, 30 Oct 2020 00:19:05 +0800
Qiujun Huang <hqjagain@gmail.com> wrote:
> The subscript should be nesting - 1, as nesting had self-added.
>
> Fixes: 3d9622c12c887 ("tracing: Add barrier to trace_printk() buffer nesting modification")
Thanks, I'll still use the updated change log.
-- Steve
> Signed-off-by: Qiujun Huang <hqjagain@gmail.com>
> ---
> v4:
> Find the right patch which cause the problem.
> v3:
> Modify the way of array reference instead.
> v2:
> Fix a typo in the title.
> ---
> kernel/trace/trace.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
> index 528971714fc6..daa96215e294 100644
> --- a/kernel/trace/trace.c
> +++ b/kernel/trace/trace.c
> @@ -3132,7 +3132,7 @@ static char *get_trace_buf(void)
>
> /* Interrupts must see nesting incremented before we use the buffer */
> barrier();
> - return &buffer->buffer[buffer->nesting][0];
> + return &buffer->buffer[buffer->nesting - 1][0];
> }
>
> static void put_trace_buf(void)
^ permalink raw reply [flat|nested] 2+ messages in thread
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