6.6-stable review patch. If anyone has any objections, please let me know.
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From: Amelie Delaunay amelie.delaunay@foss.st.com
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@arndb.de Signed-off-by: Amelie Delaunay amelie.delaunay@foss.st.com Cc: stable@vger.kernel.org Reported-by: kernel test robot lkp@intel.com Closes: https://lore.kernel.org/oe-kbuild-all/202311060135.Q9eMnpCL-lkp@intel.com/ Link: https://lore.kernel.org/r/20231106134832.1470305-1-amelie.delaunay@foss.st.c... Signed-off-by: Vinod Koul vkoul@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- 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 =