tree:   git://git.cmpxchg.org/linux-mmotm.git master
head:   59f7a5af1a6c9e19c6e5152f26548c494a2d7338
commit: 4cdffd629befd39da9ba6e949e1d4e3360c0a9c6 [310/365] eventfd: don't take the spinlock in eventfd_poll
config: avr32-atngw100_defconfig (attached as .config)
reproduce:
  wget https://git.kernel.org/cgit/linux/kernel/git/wfg/lkp-tests.git/plain/sbin/make.cross -O ~/bin/make.cross
  chmod +x ~/bin/make.cross
  git checkout 4cdffd629befd39da9ba6e949e1d4e3360c0a9c6
  # save the attached .config to linux build tree
  make.cross ARCH=avr32 

All warnings:

   fs/eventfd.c: In function 'eventfd_poll':
>> fs/eventfd.c:130: warning: comparison is always false due to limited range of data type
>> fs/eventfd.c:132: warning: comparison is always true due to limited range of data type
>> fs/eventfd.c:121: warning: unused variable 'flags'

vim +130 fs/eventfd.c

   115	}
   116	
   117	static unsigned int eventfd_poll(struct file *file, poll_table *wait)
   118	{
   119		struct eventfd_ctx *ctx = file->private_data;
   120		unsigned int events = 0;
 > 121		unsigned long flags;
   122		unsigned int count;
   123	
   124		poll_wait(file, &ctx->wqh, wait);
   125		smp_rmb();
   126		count = ctx->count;
   127	
   128		if (count > 0)
   129			events |= POLLIN;
 > 130		if (count == ULLONG_MAX)
   131			events |= POLLERR;
 > 132		if (ULLONG_MAX - 1 > count)
   133			events |= POLLOUT;
   134	
   135		return events;

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