Re: [PATCH] dmaengine: stm32: Don't use %pK through printk
From: Amelie Delaunay
Date: Mon Apr 14 2025 - 07:19:39 EST
On 4/7/25 10:26, Thomas Weißschuh wrote:
In the past %pK was preferable to %p as it would not leak raw pointer
values into the kernel log.
Since commit ad67b74d2469 ("printk: hash addresses printed with %p")
the regular %p has been improved to avoid this issue.
Furthermore, restricted pointers ("%pK") were never meant to be used
through printk(). They can still unintentionally leak raw pointers or
acquire sleeping looks in atomic contexts.
I forgot to highlight this typo:
s/looks/locks
Switch to the regular pointer formatting which is safer and
easier to reason about.
There are still a few users of %pK left, but these use it through seq_file,
for which its usage is safe.
Signed-off-by: Thomas Weißschuh <thomas.weissschuh@xxxxxxxxxxxxx>
---
drivers/dma/stm32/stm32-dma.c | 10 +++++-----
drivers/dma/stm32/stm32-dma3.c | 10 +++++-----
drivers/dma/stm32/stm32-mdma.c | 8 ++++----
3 files changed, 14 insertions(+), 14 deletions(-)
diff --git a/drivers/dma/stm32/stm32-dma.c b/drivers/dma/stm32/stm32-dma.c
index 917f8e9223739af853e492d97cecac0e95e0aea3..ee9246c6888ffde2d416270f25890c04c72daff7 100644
--- a/drivers/dma/stm32/stm32-dma.c
+++ b/drivers/dma/stm32/stm32-dma.c
@@ -613,7 +613,7 @@ static void stm32_dma_start_transfer(struct stm32_dma_chan *chan)
reg->dma_scr |= STM32_DMA_SCR_EN;
stm32_dma_write(dmadev, STM32_DMA_SCR(chan->id), reg->dma_scr);
- dev_dbg(chan2dev(chan), "vchan %pK: started\n", &chan->vchan);
+ dev_dbg(chan2dev(chan), "vchan %p: started\n", &chan->vchan);
}
static void stm32_dma_configure_next_sg(struct stm32_dma_chan *chan)
@@ -676,7 +676,7 @@ static void stm32_dma_handle_chan_paused(struct stm32_dma_chan *chan)
chan->status = DMA_PAUSED;
- dev_dbg(chan2dev(chan), "vchan %pK: paused\n", &chan->vchan);
+ dev_dbg(chan2dev(chan), "vchan %p: paused\n", &chan->vchan);
}
static void stm32_dma_post_resume_reconfigure(struct stm32_dma_chan *chan)
@@ -728,7 +728,7 @@ static void stm32_dma_post_resume_reconfigure(struct stm32_dma_chan *chan)
dma_scr |= STM32_DMA_SCR_EN;
stm32_dma_write(dmadev, STM32_DMA_SCR(chan->id), dma_scr);
- dev_dbg(chan2dev(chan), "vchan %pK: reconfigured after pause/resume\n", &chan->vchan);
+ dev_dbg(chan2dev(chan), "vchan %p: reconfigured after pause/resume\n", &chan->vchan);
}
static void stm32_dma_handle_chan_done(struct stm32_dma_chan *chan, u32 scr)
@@ -820,7 +820,7 @@ static void stm32_dma_issue_pending(struct dma_chan *c)
spin_lock_irqsave(&chan->vchan.lock, flags);
if (vchan_issue_pending(&chan->vchan) && !chan->desc && !chan->busy) {
- dev_dbg(chan2dev(chan), "vchan %pK: issued\n", &chan->vchan);
+ dev_dbg(chan2dev(chan), "vchan %p: issued\n", &chan->vchan);
stm32_dma_start_transfer(chan);
}
@@ -922,7 +922,7 @@ static int stm32_dma_resume(struct dma_chan *c)
spin_unlock_irqrestore(&chan->vchan.lock, flags);
- dev_dbg(chan2dev(chan), "vchan %pK: resumed\n", &chan->vchan);
+ dev_dbg(chan2dev(chan), "vchan %p: resumed\n", &chan->vchan);
return 0;
}
diff --git a/drivers/dma/stm32/stm32-dma3.c b/drivers/dma/stm32/stm32-dma3.c
index 0c6c4258b19561c94f1c68f26ade16b82660ebe6..50e7106c5cb73394c1de52ad5f571f6db63750e6 100644
--- a/drivers/dma/stm32/stm32-dma3.c
+++ b/drivers/dma/stm32/stm32-dma3.c
@@ -801,7 +801,7 @@ static void stm32_dma3_chan_start(struct stm32_dma3_chan *chan)
chan->dma_status = DMA_IN_PROGRESS;
- dev_dbg(chan2dev(chan), "vchan %pK: started\n", &chan->vchan);
+ dev_dbg(chan2dev(chan), "vchan %p: started\n", &chan->vchan);
}
static int stm32_dma3_chan_suspend(struct stm32_dma3_chan *chan, bool susp)
@@ -1452,7 +1452,7 @@ static int stm32_dma3_pause(struct dma_chan *c)
chan->dma_status = DMA_PAUSED;
- dev_dbg(chan2dev(chan), "vchan %pK: paused\n", &chan->vchan);
+ dev_dbg(chan2dev(chan), "vchan %p: paused\n", &chan->vchan);
return 0;
}
@@ -1465,7 +1465,7 @@ static int stm32_dma3_resume(struct dma_chan *c)
chan->dma_status = DMA_IN_PROGRESS;
- dev_dbg(chan2dev(chan), "vchan %pK: resumed\n", &chan->vchan);
+ dev_dbg(chan2dev(chan), "vchan %p: resumed\n", &chan->vchan);
return 0;
}
@@ -1490,7 +1490,7 @@ static int stm32_dma3_terminate_all(struct dma_chan *c)
spin_unlock_irqrestore(&chan->vchan.lock, flags);
vchan_dma_desc_free_list(&chan->vchan, &head);
- dev_dbg(chan2dev(chan), "vchan %pK: terminated\n", &chan->vchan);
+ dev_dbg(chan2dev(chan), "vchan %p: terminated\n", &chan->vchan);
return 0;
}
@@ -1543,7 +1543,7 @@ static void stm32_dma3_issue_pending(struct dma_chan *c)
spin_lock_irqsave(&chan->vchan.lock, flags);
if (vchan_issue_pending(&chan->vchan) && !chan->swdesc) {
- dev_dbg(chan2dev(chan), "vchan %pK: issued\n", &chan->vchan);
+ dev_dbg(chan2dev(chan), "vchan %p: issued\n", &chan->vchan);
stm32_dma3_chan_start(chan);
}
diff --git a/drivers/dma/stm32/stm32-mdma.c b/drivers/dma/stm32/stm32-mdma.c
index e6d525901de7ecf822d218b87b95aba6bbf0a3ef..080c1c725216cb627675c372591b4c0c227c3cea 100644
--- a/drivers/dma/stm32/stm32-mdma.c
+++ b/drivers/dma/stm32/stm32-mdma.c
@@ -1187,7 +1187,7 @@ static void stm32_mdma_start_transfer(struct stm32_mdma_chan *chan)
chan->busy = true;
- dev_dbg(chan2dev(chan), "vchan %pK: started\n", &chan->vchan);
+ dev_dbg(chan2dev(chan), "vchan %p: started\n", &chan->vchan);
}
static void stm32_mdma_issue_pending(struct dma_chan *c)
@@ -1200,7 +1200,7 @@ static void stm32_mdma_issue_pending(struct dma_chan *c)
if (!vchan_issue_pending(&chan->vchan))
goto end;
- dev_dbg(chan2dev(chan), "vchan %pK: issued\n", &chan->vchan);
+ dev_dbg(chan2dev(chan), "vchan %p: issued\n", &chan->vchan);
if (!chan->desc && !chan->busy)
stm32_mdma_start_transfer(chan);
@@ -1220,7 +1220,7 @@ static int stm32_mdma_pause(struct dma_chan *c)
spin_unlock_irqrestore(&chan->vchan.lock, flags);
if (!ret)
- dev_dbg(chan2dev(chan), "vchan %pK: pause\n", &chan->vchan);
+ dev_dbg(chan2dev(chan), "vchan %p: pause\n", &chan->vchan);
return ret;
}
@@ -1261,7 +1261,7 @@ static int stm32_mdma_resume(struct dma_chan *c)
spin_unlock_irqrestore(&chan->vchan.lock, flags);
- dev_dbg(chan2dev(chan), "vchan %pK: resume\n", &chan->vchan);
+ dev_dbg(chan2dev(chan), "vchan %p: resume\n", &chan->vchan);
return 0;
}
---
base-commit: e48e99b6edf41c69c5528aa7ffb2daf3c59ee105
change-id: 20250404-restricted-pointers-dma-29cf839a1a0b
Best regards,