* Re: [PATCH v2] dmaengine: fsl-edma: tracing: no ptr dereference during log output
From: Frank Li @ 2026-07-18 14:52 UTC (permalink / raw)
To: Martin Kaiser
Cc: Frank Li, Vinod Koul, Steven Rostedt, Masami Hiramatsu,
linux-kernel, linux-trace-kernel, imx, dmaengine, stable
In-Reply-To: <20260718130024.341243-1-martin@kaiser.cx>
On Sat, Jul 18, 2026 at 02:58:48PM +0200, Martin Kaiser wrote:
> The fsl edma events store a pointer to a struct fsl_edma_engine in the
> ringbuffer and dereference it when a log entry is printed. At this time,
> the pointer may no longer be valid.
>
> Event injection can be used to trigger a crash:
>
> $ cd /sys/kernel/tracing
> $ echo 'value = 0' > events/fsl_edma/edma_writeb/inject
> $ cat trace
>
> The log output needs only edma->membase. Add a membase field at the end
> of the event and use the new field for log output. Keep the existing
> fields for backward compatibility.
>
> Fixes: 11102d0c343b ("dmaengine: fsl-edma: add trace event support")
> Cc: stable@vger.kernel.org
> Reviewed-by: Steven Rostedt <rostedt@goodmis.org>
> Signed-off-by: Martin Kaiser <martin@kaiser.cx>
> ---
Reviewed-by: Frank Li <Frank.Li@nxp.com>
> v2:
> - dmaengine prefix in the subject line
> - Cc stable
> - Steven's Reviewed tag
>
> drivers/dma/fsl-edma-trace.h | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/dma/fsl-edma-trace.h b/drivers/dma/fsl-edma-trace.h
> index d3541301a247..45d964a3726d 100644
> --- a/drivers/dma/fsl-edma-trace.h
> +++ b/drivers/dma/fsl-edma-trace.h
> @@ -19,14 +19,16 @@ DECLARE_EVENT_CLASS(edma_log_io,
> __field(struct fsl_edma_engine *, edma)
> __field(void __iomem *, addr)
> __field(u32, value)
> + __field(void __iomem *, membase)
> ),
> TP_fast_assign(
> __entry->edma = edma;
> __entry->addr = addr;
> __entry->value = value;
> + __entry->membase = edma->membase;
> ),
> TP_printk("offset %08x: value %08x",
> - (u32)(__entry->addr - __entry->edma->membase), __entry->value)
> + (u32)(__entry->addr - __entry->membase), __entry->value)
> );
>
> DEFINE_EVENT(edma_log_io, edma_readl,
> --
> 2.43.7
>
^ permalink raw reply
page: | prev (newer) | latest
- recent:[subjects (threaded)|topics (new)|topics (active)]
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox