Re: [PATCH v2] dmaengine: fsl-edma: tracing: no ptr dereference during log output
From: Frank Li <hidden>
Date: 2026-07-18 14:52:17
Also in:
dmaengine, imx, lkml, stable
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 <redacted>
---Reviewed-by: Frank Li <Frank.Li@nxp.com>
quoted hunk ↗ jump to hunk
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