[kbuild] drivers/net/ethernet/mscc/ocelot_vsc7514.c:554 ocelot_xtr_irq_handler() error: uninitialized symbol 'err'.

[kbuild] drivers/net/ethernet/mscc/ocelot_vsc7514.c:554 ocelot_xtr_irq_handler() error: uninitialized symbol 'err'.

[Dan Carpenter]

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git  master
head:   77dd11439b86e3f7990e4c0c9e0b67dca82750ba
commit: 924ee317f72459a49ac4130272c7d33063e60339 net: mscc: ocelot: refactor ocelot_xtr_irq_handler into ocelot_xtr_poll
config: openrisc-randconfig-m031-20210827 (attached as .config)
compiler: or1k-linux-gcc (GCC) 11.2.0

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>

smatch warnings:
drivers/net/ethernet/mscc/ocelot_vsc7514.c:554 ocelot_xtr_irq_handler() error: uninitialized symbol 'err'.

vim +/err +554 drivers/net/ethernet/mscc/ocelot_vsc7514.c

a556c76adc052c drivers/net/ethernet/mscc/ocelot_board.c   Alexandre Belloni 2018-05-14  534  static irqreturn_t ocelot_xtr_irq_handler(int irq, void *arg)
a556c76adc052c drivers/net/ethernet/mscc/ocelot_board.c   Alexandre Belloni 2018-05-14  535  {
a556c76adc052c drivers/net/ethernet/mscc/ocelot_board.c   Alexandre Belloni 2018-05-14  536  	struct ocelot *ocelot = arg;
924ee317f72459 drivers/net/ethernet/mscc/ocelot_vsc7514.c Vladimir Oltean   2021-02-14  537  	int grp = 0, err;
a556c76adc052c drivers/net/ethernet/mscc/ocelot_board.c   Alexandre Belloni 2018-05-14  538  
f833ca293dd121 drivers/net/ethernet/mscc/ocelot_vsc7514.c Vladimir Oltean   2021-02-14  539  	while (ocelot_read(ocelot, QS_XTR_DATA_PRESENT) & BIT(grp)) {

Can this condition be false on the first iteration through the loop?

4e3b0468e6d7f3 drivers/net/ethernet/mscc/ocelot_board.c   Antoine Tenart    2019-08-12  540  		struct sk_buff *skb;
a556c76adc052c drivers/net/ethernet/mscc/ocelot_board.c   Alexandre Belloni 2018-05-14  541  
924ee317f72459 drivers/net/ethernet/mscc/ocelot_vsc7514.c Vladimir Oltean   2021-02-14  542  		err = ocelot_xtr_poll_frame(ocelot, grp, &skb);
924ee317f72459 drivers/net/ethernet/mscc/ocelot_vsc7514.c Vladimir Oltean   2021-02-14  543  		if (err)
a94306cea56fe4 drivers/net/ethernet/mscc/ocelot_vsc7514.c Vladimir Oltean   2021-02-14  544  			goto out;
a94306cea56fe4 drivers/net/ethernet/mscc/ocelot_vsc7514.c Vladimir Oltean   2021-02-14  545  
924ee317f72459 drivers/net/ethernet/mscc/ocelot_vsc7514.c Vladimir Oltean   2021-02-14  546  		skb->dev->stats.rx_bytes += skb->len;
924ee317f72459 drivers/net/ethernet/mscc/ocelot_vsc7514.c Vladimir Oltean   2021-02-14  547  		skb->dev->stats.rx_packets++;
a556c76adc052c drivers/net/ethernet/mscc/ocelot_board.c   Alexandre Belloni 2018-05-14  548  
b2e118f638fb89 drivers/net/ethernet/mscc/ocelot_board.c   Antoine Tenart    2020-05-26  549  		if (!skb_defer_rx_timestamp(skb))
a556c76adc052c drivers/net/ethernet/mscc/ocelot_board.c   Alexandre Belloni 2018-05-14  550  			netif_rx(skb);
f833ca293dd121 drivers/net/ethernet/mscc/ocelot_vsc7514.c Vladimir Oltean   2021-02-14  551  	}
a556c76adc052c drivers/net/ethernet/mscc/ocelot_board.c   Alexandre Belloni 2018-05-14  552  
a94306cea56fe4 drivers/net/ethernet/mscc/ocelot_vsc7514.c Vladimir Oltean   2021-02-14  553  out:
d7795f8f26d944 drivers/net/ethernet/mscc/ocelot_vsc7514.c Vladimir Oltean   2021-02-14 @554  	if (err < 0)
a556c76adc052c drivers/net/ethernet/mscc/ocelot_board.c   Alexandre Belloni 2018-05-14  555  		while (ocelot_read(ocelot, QS_XTR_DATA_PRESENT) & BIT(grp))
a556c76adc052c drivers/net/ethernet/mscc/ocelot_board.c   Alexandre Belloni 2018-05-14  556  			ocelot_read_rix(ocelot, QS_XTR_RD, grp);
a556c76adc052c drivers/net/ethernet/mscc/ocelot_board.c   Alexandre Belloni 2018-05-14  557  
a556c76adc052c drivers/net/ethernet/mscc/ocelot_board.c   Alexandre Belloni 2018-05-14  558  	return IRQ_HANDLED;
a556c76adc052c drivers/net/ethernet/mscc/ocelot_board.c   Alexandre Belloni 2018-05-14  559  }

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Re: [kbuild] drivers/net/ethernet/mscc/ocelot_vsc7514.c:554 ocelot_xtr_irq_handler() error: uninitialized symbol 'err'.

[Vladimir Oltean]

On Fri, Aug 27, 2021 at 10:06:42AM +0300, Dan Carpenter wrote:
> static irqreturn_t ocelot_xtr_irq_handler(int irq, void *arg)
> {
> 	struct ocelot *ocelot = arg;
> 	int grp = 0, err;
>
> 	while (ocelot_read(ocelot, QS_XTR_DATA_PRESENT) & BIT(grp)) {
>
> Can this condition be false on the first iteration through the loop?

Functionally speaking, no, but if it helps anyone to initialize "err"
with 0, I guess we could...
>
> 		struct sk_buff *skb;
>
> 		err = ocelot_xtr_poll_frame(ocelot, grp, &skb);
> 		if (err)
> 			goto out;
>
> 		skb->dev->stats.rx_bytes += skb->len;
> 		skb->dev->stats.rx_packets++;
>
> 		if (!skb_defer_rx_timestamp(skb))
> 			netif_rx(skb);
> 	}
>
> out:
> 	if (err < 0)
> 		while (ocelot_read(ocelot, QS_XTR_DATA_PRESENT) & BIT(grp))
> 			ocelot_read_rix(ocelot, QS_XTR_RD, grp);
>
> 	return IRQ_HANDLED;
> }