Re: [PATCH 10/14] dmaengine: dma350: Alloc command[] from dma pool

[Dan Carpenter <dan.carpenter@linaro.org>]

Hi Jisheng,

kernel test robot noticed the following build warnings:

https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Jisheng-Zhang/dmaengine-dma350-Fix-CH_CTRL_USESRCTRIGIN-definition/20250824-000425
base:   https://git.kernel.org/pub/scm/linux/kernel/git/vkoul/dmaengine.git next
patch link:    https://lore.kernel.org/r/20250823154009.25992-11-jszhang%40kernel.org
patch subject: [PATCH 10/14] dmaengine: dma350: Alloc command[] from dma pool
config: arm-randconfig-r073-20250829 (https://download.01.org/0day-ci/archive/20250829/202508291556.kjNumYgR-lkp@intel.com/config)
compiler: arm-linux-gnueabi-gcc (GCC) 13.4.0

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
| Closes: https://lore.kernel.org/r/202508291556.kjNumYgR-lkp@intel.com/

smatch warnings:
drivers/dma/arm-dma350.c:387 d350_get_residue() error: uninitialized symbol 'sgcur'.

vim +/sgcur +387 drivers/dma/arm-dma350.c

5d099706449d54 Robin Murphy  2025-03-12  360  static u32 d350_get_residue(struct d350_chan *dch)
5d099706449d54 Robin Murphy  2025-03-12  361  {
eae79fde2ff50c Jisheng Zhang 2025-08-23  362  	u32 res, xsize, xsizehi, linkaddr, linkaddrhi, hi_new;
eae79fde2ff50c Jisheng Zhang 2025-08-23  363  	int i, sgcur, retries = 3; /* 1st time unlucky, 2nd improbable, 3rd just broken */
eae79fde2ff50c Jisheng Zhang 2025-08-23  364  	struct d350_desc *desc = dch->desc;
5d099706449d54 Robin Murphy  2025-03-12  365  
5d099706449d54 Robin Murphy  2025-03-12  366  	hi_new = readl_relaxed(dch->base + CH_XSIZEHI);
5d099706449d54 Robin Murphy  2025-03-12  367  	do {
5d099706449d54 Robin Murphy  2025-03-12  368  		xsizehi = hi_new;
5d099706449d54 Robin Murphy  2025-03-12  369  		xsize = readl_relaxed(dch->base + CH_XSIZE);
5d099706449d54 Robin Murphy  2025-03-12  370  		hi_new = readl_relaxed(dch->base + CH_XSIZEHI);
5d099706449d54 Robin Murphy  2025-03-12  371  	} while (xsizehi != hi_new && --retries);
5d099706449d54 Robin Murphy  2025-03-12  372  
eae79fde2ff50c Jisheng Zhang 2025-08-23  373  	hi_new = readl_relaxed(dch->base + CH_LINKADDRHI);
eae79fde2ff50c Jisheng Zhang 2025-08-23  374  	do {
eae79fde2ff50c Jisheng Zhang 2025-08-23  375  		linkaddrhi = hi_new;
eae79fde2ff50c Jisheng Zhang 2025-08-23  376  		linkaddr = readl_relaxed(dch->base + CH_LINKADDR);
eae79fde2ff50c Jisheng Zhang 2025-08-23  377  		hi_new = readl_relaxed(dch->base + CH_LINKADDRHI);
eae79fde2ff50c Jisheng Zhang 2025-08-23  378  	} while (linkaddrhi != hi_new && --retries);
eae79fde2ff50c Jisheng Zhang 2025-08-23  379  
eae79fde2ff50c Jisheng Zhang 2025-08-23  380  	for (i = 0; i < desc->sglen; i++) {
eae79fde2ff50c Jisheng Zhang 2025-08-23  381  		if (desc->sg[i].phys == (((u64)linkaddrhi << 32) | (linkaddr & ~CH_LINKADDR_EN)))
eae79fde2ff50c Jisheng Zhang 2025-08-23  382  			sgcur = i;

I'm suprised there isn't a break statement after this assignment.
What if we exit the loop with i == desc->sglen?

eae79fde2ff50c Jisheng Zhang 2025-08-23  383  	}
eae79fde2ff50c Jisheng Zhang 2025-08-23  384  
5d099706449d54 Robin Murphy  2025-03-12  385  	res = FIELD_GET(CH_XY_DES, xsize);
5d099706449d54 Robin Murphy  2025-03-12  386  	res |= FIELD_GET(CH_XY_DES, xsizehi) << 16;
eae79fde2ff50c Jisheng Zhang 2025-08-23 @387  	res <<= desc->sg[sgcur].tsz;
                                                                 ^^^^^
Uninitialized.

eae79fde2ff50c Jisheng Zhang 2025-08-23  388  
eae79fde2ff50c Jisheng Zhang 2025-08-23  389  	for (i = sgcur + 1; i < desc->sglen; i++)
eae79fde2ff50c Jisheng Zhang 2025-08-23  390  		res += (((u32)desc->sg[i].xsizehi << 16 | desc->sg[i].xsize) << desc->sg[i].tsz);
5d099706449d54 Robin Murphy  2025-03-12  391  
eae79fde2ff50c Jisheng Zhang 2025-08-23  392  	return res;
5d099706449d54 Robin Murphy  2025-03-12  393  }

-- 
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https://github.com/intel/lkp-tests/wiki