net/core/dev.c:6917 napi_disable() error: uninitialized symbol 'new'.

[Dan Carpenter]

Jakub, could you change the netdev patchwork bot to include the Link:
tag so I can look up the thread for this with b4?  The LKP robot sets
the In-Reply-To header when it pulls the patch from a thread.  In this
case, it's pulling it from a git tree but it could be modified to use
the Link tag as well if it doesn't already.

I don't know how we would handle patches with multiple Link: tags,
though.  I guess it's supposed to be in chronological order so the last
lore.kernel.org tag is the correct one?

regards,
dan carpenter

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   cb690f5238d71f543f4ce874aa59237cf53a877c
commit: 719c571970109b0d0af24745d31b202affc9365f net: make napi_disable() symmetric with enable
config: i386-randconfig-m021-20210928 (attached as .config)
compiler: gcc-9 (Debian 9.3.0-22) 9.3.0

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

smatch warnings:
net/core/dev.c:6917 napi_disable() error: uninitialized symbol 'new'.

vim +/new +6917 net/core/dev.c

3b47d30396bae4 Eric Dumazet   2014-11-06  6901  void napi_disable(struct napi_struct *n)
3b47d30396bae4 Eric Dumazet   2014-11-06  6902  {
719c571970109b Jakub Kicinski 2021-09-24  6903  	unsigned long val, new;
719c571970109b Jakub Kicinski 2021-09-24  6904  
3b47d30396bae4 Eric Dumazet   2014-11-06  6905  	might_sleep();
3b47d30396bae4 Eric Dumazet   2014-11-06  6906  	set_bit(NAPI_STATE_DISABLE, &n->state);
3b47d30396bae4 Eric Dumazet   2014-11-06  6907  
719c571970109b Jakub Kicinski 2021-09-24  6908  	do {
719c571970109b Jakub Kicinski 2021-09-24  6909  		val = READ_ONCE(n->state);
719c571970109b Jakub Kicinski 2021-09-24  6910  		if (val & (NAPIF_STATE_SCHED | NAPIF_STATE_NPSVC)) {
719c571970109b Jakub Kicinski 2021-09-24  6911  			usleep_range(20, 200);
719c571970109b Jakub Kicinski 2021-09-24  6912  			continue;

Can we hit this continue on the first iteration through the loop?

719c571970109b Jakub Kicinski 2021-09-24  6913  		}
719c571970109b Jakub Kicinski 2021-09-24  6914  
719c571970109b Jakub Kicinski 2021-09-24  6915  		new = val | NAPIF_STATE_SCHED | NAPIF_STATE_NPSVC;
719c571970109b Jakub Kicinski 2021-09-24  6916  		new &= ~(NAPIF_STATE_THREADED | NAPIF_STATE_PREFER_BUSY_POLL);
719c571970109b Jakub Kicinski 2021-09-24 @6917  	} while (cmpxchg(&n->state, val, new) != val);
                                                                                         ^^^
Warning.

3b47d30396bae4 Eric Dumazet   2014-11-06  6918  
3b47d30396bae4 Eric Dumazet   2014-11-06  6919  	hrtimer_cancel(&n->timer);
3b47d30396bae4 Eric Dumazet   2014-11-06  6920  
3b47d30396bae4 Eric Dumazet   2014-11-06  6921  	clear_bit(NAPI_STATE_DISABLE, &n->state);
3b47d30396bae4 Eric Dumazet   2014-11-06  6922  }

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