[linux-next:master 12091/12437] drivers/i2c/busses/i2c-xiic.c:932 xiic_recv_atomic() warn: variable dereferenced before check 'i2c->rx_msg' (see line 930)

[linux-next:master 12091/12437] drivers/i2c/busses/i2c-xiic.c:932 xiic_recv_atomic() warn: variable dereferenced before check 'i2c->rx_msg' (see line 930)

[kernel test robot]

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BCC: lkp@intel.com
CC: oe-kbuild-all@lists.linux.dev
TO: Manikanta Guntupalli <manikanta.guntupalli@amd.com>
CC: Andi Shyti <andi.shyti@kernel.org>

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master
head:   decc701f41d07481893fdea942c0ac6b226e84cd
commit: 8bba86687c0b6a22f05ed4a7398c519d3796bc74 [12091/12437] i2c: xiic: Add atomic transfer support
:::::: branch date: 7 hours ago
:::::: commit date: 2 days ago
config: i386-randconfig-141-20241121 (https://download.01.org/0day-ci/archive/20241121/202411212051.BPlSgiPR-lkp@intel.com/config)
compiler: clang version 19.1.3 (https://github.com/llvm/llvm-project ab51eccf88f5321e7c60591c5546b254b6afab99)

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 <error27@gmail.com>
| Closes: https://lore.kernel.org/r/202411212051.BPlSgiPR-lkp@intel.com/

smatch warnings:
drivers/i2c/busses/i2c-xiic.c:932 xiic_recv_atomic() warn: variable dereferenced before check 'i2c->rx_msg' (see line 930)

vim +932 drivers/i2c/busses/i2c-xiic.c

e1d5b6598cdc33 Richard Röjfors      2010-02-11  927  
8bba86687c0b6a Manikanta Guntupalli 2024-10-11  928  static void xiic_recv_atomic(struct xiic_i2c *i2c)
8bba86687c0b6a Manikanta Guntupalli 2024-10-11  929  {
8bba86687c0b6a Manikanta Guntupalli 2024-10-11 @930  	while (xiic_rx_space(i2c)) {
8bba86687c0b6a Manikanta Guntupalli 2024-10-11  931  		if (xiic_getreg32(i2c, XIIC_IISR_OFFSET) & XIIC_INTR_RX_FULL_MASK) {
8bba86687c0b6a Manikanta Guntupalli 2024-10-11 @932  			if (!i2c->rx_msg) {
8bba86687c0b6a Manikanta Guntupalli 2024-10-11  933  				xiic_clear_rx_fifo(i2c);
8bba86687c0b6a Manikanta Guntupalli 2024-10-11  934  				break;
8bba86687c0b6a Manikanta Guntupalli 2024-10-11  935  			}
8bba86687c0b6a Manikanta Guntupalli 2024-10-11  936  			xiic_read_rx(i2c);
8bba86687c0b6a Manikanta Guntupalli 2024-10-11  937  
8bba86687c0b6a Manikanta Guntupalli 2024-10-11  938  			/* Clear Rx full and Tx error interrupts. */
8bba86687c0b6a Manikanta Guntupalli 2024-10-11  939  			xiic_irq_clr_en(i2c, XIIC_INTR_RX_FULL_MASK |
8bba86687c0b6a Manikanta Guntupalli 2024-10-11  940  					XIIC_INTR_TX_ERROR_MASK);
8bba86687c0b6a Manikanta Guntupalli 2024-10-11  941  		}
8bba86687c0b6a Manikanta Guntupalli 2024-10-11  942  		if (xiic_error_check(i2c))
8bba86687c0b6a Manikanta Guntupalli 2024-10-11  943  			return;
8bba86687c0b6a Manikanta Guntupalli 2024-10-11  944  	}
8bba86687c0b6a Manikanta Guntupalli 2024-10-11  945  
8bba86687c0b6a Manikanta Guntupalli 2024-10-11  946  	i2c->rx_msg = NULL;
8bba86687c0b6a Manikanta Guntupalli 2024-10-11  947  	xiic_irq_clr_en(i2c, XIIC_INTR_TX_ERROR_MASK);
8bba86687c0b6a Manikanta Guntupalli 2024-10-11  948  
8bba86687c0b6a Manikanta Guntupalli 2024-10-11  949  	/* send next message if this wasn't the last. */
8bba86687c0b6a Manikanta Guntupalli 2024-10-11  950  	if (i2c->nmsgs > 1) {
8bba86687c0b6a Manikanta Guntupalli 2024-10-11  951  		i2c->nmsgs--;
8bba86687c0b6a Manikanta Guntupalli 2024-10-11  952  		i2c->tx_msg++;
8bba86687c0b6a Manikanta Guntupalli 2024-10-11  953  		__xiic_start_xfer(i2c);
8bba86687c0b6a Manikanta Guntupalli 2024-10-11  954  	}
8bba86687c0b6a Manikanta Guntupalli 2024-10-11  955  }
8bba86687c0b6a Manikanta Guntupalli 2024-10-11  956  

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