This is a note to let you know that I've just added the patch titled
dmaengine: stm32-dma: avoid bitfield overflow assertion
to the 6.6-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
dmaengine-stm32-dma-avoid-bitfield-overflow-assertion.patch
and it can be found in the queue-6.6 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 54bed6bafa0f38daf9697af50e3aff5ff1354fe1 Mon Sep 17 00:00:00 2001
From: Amelie Delaunay <amelie.delaunay@xxxxxxxxxxx>
Date: Mon, 6 Nov 2023 14:48:32 +0100
Subject: dmaengine: stm32-dma: avoid bitfield overflow assertion
From: Amelie Delaunay <amelie.delaunay@xxxxxxxxxxx>
commit 54bed6bafa0f38daf9697af50e3aff5ff1354fe1 upstream.
stm32_dma_get_burst() returns a negative error for invalid input, which
gets turned into a large u32 value in stm32_dma_prep_dma_memcpy() that
in turn triggers an assertion because it does not fit into a two-bit field:
drivers/dma/stm32-dma.c: In function 'stm32_dma_prep_dma_memcpy':
include/linux/compiler_types.h:354:38: error: call to '__compiletime_assert_282' declared with attribute error: FIELD_PREP: value too large for the field
_compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
^
include/linux/compiler_types.h:335:4: note: in definition of macro '__compiletime_assert'
prefix ## suffix(); \
^~~~~~
include/linux/compiler_types.h:354:2: note: in expansion of macro '_compiletime_assert'
_compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
^~~~~~~~~~~~~~~~~~~
include/linux/build_bug.h:39:37: note: in expansion of macro 'compiletime_assert'
#define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg)
^~~~~~~~~~~~~~~~~~
include/linux/bitfield.h:68:3: note: in expansion of macro 'BUILD_BUG_ON_MSG'
BUILD_BUG_ON_MSG(__builtin_constant_p(_val) ? \
^~~~~~~~~~~~~~~~
include/linux/bitfield.h:114:3: note: in expansion of macro '__BF_FIELD_CHECK'
__BF_FIELD_CHECK(_mask, 0ULL, _val, "FIELD_PREP: "); \
^~~~~~~~~~~~~~~~
drivers/dma/stm32-dma.c:1237:4: note: in expansion of macro 'FIELD_PREP'
FIELD_PREP(STM32_DMA_SCR_PBURST_MASK, dma_burst) |
^~~~~~~~~~
As an easy workaround, assume the error can happen, so try to handle this
by failing stm32_dma_prep_dma_memcpy() before the assertion. It replicates
what is done in stm32_dma_set_xfer_param() where stm32_dma_get_burst() is
also used.
Fixes: 1c32d6c37cc2 ("dmaengine: stm32-dma: use bitfield helpers")
Fixes: a2b6103b7a8a ("dmaengine: stm32-dma: Improve memory burst management")
Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
Signed-off-by: Amelie Delaunay <amelie.delaunay@xxxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Reported-by: kernel test robot <lkp@xxxxxxxxx>
Closes: https://lore.kernel.org/oe-kbuild-all/202311060135.Q9eMnpCL-lkp@xxxxxxxxx/
Link: https://lore.kernel.org/r/20231106134832.1470305-1-amelie.delaunay@xxxxxxxxxxx
Signed-off-by: Vinod Koul <vkoul@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/dma/stm32-dma.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
--- a/drivers/dma/stm32-dma.c
+++ b/drivers/dma/stm32-dma.c
@@ -1249,8 +1249,8 @@ static struct dma_async_tx_descriptor *s
enum dma_slave_buswidth max_width;
struct stm32_dma_desc *desc;
size_t xfer_count, offset;
- u32 num_sgs, best_burst, dma_burst, threshold;
- int i;
+ u32 num_sgs, best_burst, threshold;
+ int dma_burst, i;
num_sgs = DIV_ROUND_UP(len, STM32_DMA_ALIGNED_MAX_DATA_ITEMS);
desc = kzalloc(struct_size(desc, sg_req, num_sgs), GFP_NOWAIT);
@@ -1268,6 +1268,10 @@ static struct dma_async_tx_descriptor *s
best_burst = stm32_dma_get_best_burst(len, STM32_DMA_MAX_BURST,
threshold, max_width);
dma_burst = stm32_dma_get_burst(chan, best_burst);
+ if (dma_burst < 0) {
+ kfree(desc);
+ return NULL;
+ }
stm32_dma_clear_reg(&desc->sg_req[i].chan_reg);
desc->sg_req[i].chan_reg.dma_scr =
Patches currently in stable-queue which might be from amelie.delaunay@xxxxxxxxxxx are
queue-6.6/dmaengine-stm32-dma-avoid-bitfield-overflow-assertion.patch
