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* kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
@ 2022-05-22 12:30 kernel test robot
  2022-05-23 10:30 ` Toke Høiland-Jørgensen
  0 siblings, 1 reply; 10+ messages in thread
From: kernel test robot @ 2022-05-22 12:30 UTC (permalink / raw)
  To: Toke Høiland-Jørgensen
  Cc: kbuild-all, linux-kernel, Daniel Borkmann

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   eaea45fc0e7b6ae439526b4a41d91230c8517336
commit: 782347b6bcad07ddb574422e01e22c92e05928c8 xdp: Add proper __rcu annotations to redirect map entries
date:   11 months ago
config: ia64-randconfig-s031-20220522 (https://download.01.org/0day-ci/archive/20220522/202205222029.xpW3PM1y-lkp@intel.com/config)
compiler: ia64-linux-gcc (GCC) 11.3.0
reproduce:
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # apt-get install sparse
        # sparse version: v0.6.4-dirty
        # https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=782347b6bcad07ddb574422e01e22c92e05928c8
        git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
        git fetch --no-tags linus master
        git checkout 782347b6bcad07ddb574422e01e22c92e05928c8
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.3.0 make.cross C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' O=build_dir ARCH=ia64 SHELL=/bin/bash kernel/bpf/

If you fix the issue, kindly add following tag where applicable
Reported-by: kernel test robot <lkp@intel.com>


sparse warnings: (new ones prefixed by >>)
   kernel/bpf/devmap.c:561:29: sparse: sparse: incorrect type in assignment (different address spaces) @@     expected struct bpf_dtab_netdev *dst @@     got struct bpf_dtab_netdev [noderef] __rcu * @@
   kernel/bpf/devmap.c:561:29: sparse:     expected struct bpf_dtab_netdev *dst
   kernel/bpf/devmap.c:561:29: sparse:     got struct bpf_dtab_netdev [noderef] __rcu *
   kernel/bpf/devmap.c:657:29: sparse: sparse: incorrect type in assignment (different address spaces) @@     expected struct bpf_dtab_netdev *dst @@     got struct bpf_dtab_netdev [noderef] __rcu * @@
   kernel/bpf/devmap.c:657:29: sparse:     expected struct bpf_dtab_netdev *dst
   kernel/bpf/devmap.c:657:29: sparse:     got struct bpf_dtab_netdev [noderef] __rcu *
>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression

vim +/__rcu +1030 kernel/bpf/devmap.c

   990	
   991	static int dev_map_notification(struct notifier_block *notifier,
   992					ulong event, void *ptr)
   993	{
   994		struct net_device *netdev = netdev_notifier_info_to_dev(ptr);
   995		struct bpf_dtab *dtab;
   996		int i, cpu;
   997	
   998		switch (event) {
   999		case NETDEV_REGISTER:
  1000			if (!netdev->netdev_ops->ndo_xdp_xmit || netdev->xdp_bulkq)
  1001				break;
  1002	
  1003			/* will be freed in free_netdev() */
  1004			netdev->xdp_bulkq = alloc_percpu(struct xdp_dev_bulk_queue);
  1005			if (!netdev->xdp_bulkq)
  1006				return NOTIFY_BAD;
  1007	
  1008			for_each_possible_cpu(cpu)
  1009				per_cpu_ptr(netdev->xdp_bulkq, cpu)->dev = netdev;
  1010			break;
  1011		case NETDEV_UNREGISTER:
  1012			/* This rcu_read_lock/unlock pair is needed because
  1013			 * dev_map_list is an RCU list AND to ensure a delete
  1014			 * operation does not free a netdev_map entry while we
  1015			 * are comparing it against the netdev being unregistered.
  1016			 */
  1017			rcu_read_lock();
  1018			list_for_each_entry_rcu(dtab, &dev_map_list, list) {
  1019				if (dtab->map.map_type == BPF_MAP_TYPE_DEVMAP_HASH) {
  1020					dev_map_hash_remove_netdev(dtab, netdev);
  1021					continue;
  1022				}
  1023	
  1024				for (i = 0; i < dtab->map.max_entries; i++) {
  1025					struct bpf_dtab_netdev *dev, *odev;
  1026	
  1027					dev = rcu_dereference(dtab->netdev_map[i]);
  1028					if (!dev || netdev != dev->dev)
  1029						continue;
> 1030					odev = unrcu_pointer(cmpxchg(&dtab->netdev_map[i], RCU_INITIALIZER(dev), NULL));
  1031					if (dev == odev)
  1032						call_rcu(&dev->rcu,
  1033							 __dev_map_entry_free);
  1034				}
  1035			}
  1036			rcu_read_unlock();
  1037			break;
  1038		default:
  1039			break;
  1040		}
  1041		return NOTIFY_OK;
  1042	}
  1043	

-- 
0-DAY CI Kernel Test Service
https://01.org/lkp

^ permalink raw reply	[flat|nested] 10+ messages in thread
* Re: kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
  2022-05-22 12:30 kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression kernel test robot
@ 2022-05-23 10:30 ` Toke Høiland-Jørgensen
  2022-05-24 20:51   ` Paul E. McKenney
  2022-06-01  0:38   ` Luc Van Oostenryck
  0 siblings, 2 replies; 10+ messages in thread
From: Toke Høiland-Jørgensen @ 2022-05-23 10:30 UTC (permalink / raw)
  To: kernel test robot
  Cc: kbuild-all, linux-kernel, Daniel Borkmann, Paul E . McKenney

kernel test robot <lkp@intel.com> writes:

> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
> head:   eaea45fc0e7b6ae439526b4a41d91230c8517336
> commit: 782347b6bcad07ddb574422e01e22c92e05928c8 xdp: Add proper __rcu annotations to redirect map entries
> date:   11 months ago
> config: ia64-randconfig-s031-20220522 (https://download.01.org/0day-ci/archive/20220522/202205222029.xpW3PM1y-lkp@intel.com/config)
> compiler: ia64-linux-gcc (GCC) 11.3.0

Hmm, so this is ia64-only? Some kind of macro breakage? Paul, any ideas?

-Toke

> reproduce:
>         wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
>         chmod +x ~/bin/make.cross
>         # apt-get install sparse
>         # sparse version: v0.6.4-dirty
>         # https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=782347b6bcad07ddb574422e01e22c92e05928c8
>         git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
>         git fetch --no-tags linus master
>         git checkout 782347b6bcad07ddb574422e01e22c92e05928c8
>         # save the config file
>         mkdir build_dir && cp config build_dir/.config
>         COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.3.0 make.cross C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' O=build_dir ARCH=ia64 SHELL=/bin/bash kernel/bpf/
>
> If you fix the issue, kindly add following tag where applicable
> Reported-by: kernel test robot <lkp@intel.com>
>
>
> sparse warnings: (new ones prefixed by >>)
>    kernel/bpf/devmap.c:561:29: sparse: sparse: incorrect type in assignment (different address spaces) @@     expected struct bpf_dtab_netdev *dst @@     got struct bpf_dtab_netdev [noderef] __rcu * @@
>    kernel/bpf/devmap.c:561:29: sparse:     expected struct bpf_dtab_netdev *dst
>    kernel/bpf/devmap.c:561:29: sparse:     got struct bpf_dtab_netdev [noderef] __rcu *
>    kernel/bpf/devmap.c:657:29: sparse: sparse: incorrect type in assignment (different address spaces) @@     expected struct bpf_dtab_netdev *dst @@     got struct bpf_dtab_netdev [noderef] __rcu * @@
>    kernel/bpf/devmap.c:657:29: sparse:     expected struct bpf_dtab_netdev *dst
>    kernel/bpf/devmap.c:657:29: sparse:     got struct bpf_dtab_netdev [noderef] __rcu *
>>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>
> vim +/__rcu +1030 kernel/bpf/devmap.c
>
>    990	
>    991	static int dev_map_notification(struct notifier_block *notifier,
>    992					ulong event, void *ptr)
>    993	{
>    994		struct net_device *netdev = netdev_notifier_info_to_dev(ptr);
>    995		struct bpf_dtab *dtab;
>    996		int i, cpu;
>    997	
>    998		switch (event) {
>    999		case NETDEV_REGISTER:
>   1000			if (!netdev->netdev_ops->ndo_xdp_xmit || netdev->xdp_bulkq)
>   1001				break;
>   1002	
>   1003			/* will be freed in free_netdev() */
>   1004			netdev->xdp_bulkq = alloc_percpu(struct xdp_dev_bulk_queue);
>   1005			if (!netdev->xdp_bulkq)
>   1006				return NOTIFY_BAD;
>   1007	
>   1008			for_each_possible_cpu(cpu)
>   1009				per_cpu_ptr(netdev->xdp_bulkq, cpu)->dev = netdev;
>   1010			break;
>   1011		case NETDEV_UNREGISTER:
>   1012			/* This rcu_read_lock/unlock pair is needed because
>   1013			 * dev_map_list is an RCU list AND to ensure a delete
>   1014			 * operation does not free a netdev_map entry while we
>   1015			 * are comparing it against the netdev being unregistered.
>   1016			 */
>   1017			rcu_read_lock();
>   1018			list_for_each_entry_rcu(dtab, &dev_map_list, list) {
>   1019				if (dtab->map.map_type == BPF_MAP_TYPE_DEVMAP_HASH) {
>   1020					dev_map_hash_remove_netdev(dtab, netdev);
>   1021					continue;
>   1022				}
>   1023	
>   1024				for (i = 0; i < dtab->map.max_entries; i++) {
>   1025					struct bpf_dtab_netdev *dev, *odev;
>   1026	
>   1027					dev = rcu_dereference(dtab->netdev_map[i]);
>   1028					if (!dev || netdev != dev->dev)
>   1029						continue;
>> 1030					odev = unrcu_pointer(cmpxchg(&dtab->netdev_map[i], RCU_INITIALIZER(dev), NULL));
>   1031					if (dev == odev)
>   1032						call_rcu(&dev->rcu,
>   1033							 __dev_map_entry_free);
>   1034				}
>   1035			}
>   1036			rcu_read_unlock();
>   1037			break;
>   1038		default:
>   1039			break;
>   1040		}
>   1041		return NOTIFY_OK;
>   1042	}
>   1043	
>
> -- 
> 0-DAY CI Kernel Test Service
> https://01.org/lkp


^ permalink raw reply	[flat|nested] 10+ messages in thread
* Re: kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
  2022-05-23 10:30 ` Toke Høiland-Jørgensen
@ 2022-05-24 20:51   ` Paul E. McKenney
  2022-06-01  0:38   ` Luc Van Oostenryck
  1 sibling, 0 replies; 10+ messages in thread
From: Paul E. McKenney @ 2022-05-24 20:51 UTC (permalink / raw)
  To: Toke Høiland-Jørgensen
  Cc: kernel test robot, kbuild-all, linux-kernel, Daniel Borkmann

On Mon, May 23, 2022 at 12:30:14PM +0200, Toke Høiland-Jørgensen wrote:
> kernel test robot <lkp@intel.com> writes:
> 
> > tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
> > head:   eaea45fc0e7b6ae439526b4a41d91230c8517336
> > commit: 782347b6bcad07ddb574422e01e22c92e05928c8 xdp: Add proper __rcu annotations to redirect map entries
> > date:   11 months ago
> > config: ia64-randconfig-s031-20220522 (https://download.01.org/0day-ci/archive/20220522/202205222029.xpW3PM1y-lkp@intel.com/config)
> > compiler: ia64-linux-gcc (GCC) 11.3.0
> 
> Hmm, so this is ia64-only? Some kind of macro breakage? Paul, any ideas?

Line 1030 looks to me like it is doing everything correctly.  I am not
sure why sparse would care about the architecture, but perhaps it does.
The unrcu_pointer() macro has not changed since March of 2020.

All I can suggest is to break that line up to make it easier to figure
out exactly what sparse is upset about.

							Thanx, Paul

> -Toke
> 
> > reproduce:
> >         wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
> >         chmod +x ~/bin/make.cross
> >         # apt-get install sparse
> >         # sparse version: v0.6.4-dirty
> >         # https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=782347b6bcad07ddb574422e01e22c92e05928c8
> >         git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
> >         git fetch --no-tags linus master
> >         git checkout 782347b6bcad07ddb574422e01e22c92e05928c8
> >         # save the config file
> >         mkdir build_dir && cp config build_dir/.config
> >         COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.3.0 make.cross C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' O=build_dir ARCH=ia64 SHELL=/bin/bash kernel/bpf/
> >
> > If you fix the issue, kindly add following tag where applicable
> > Reported-by: kernel test robot <lkp@intel.com>
> >
> >
> > sparse warnings: (new ones prefixed by >>)
> >    kernel/bpf/devmap.c:561:29: sparse: sparse: incorrect type in assignment (different address spaces) @@     expected struct bpf_dtab_netdev *dst @@     got struct bpf_dtab_netdev [noderef] __rcu * @@
> >    kernel/bpf/devmap.c:561:29: sparse:     expected struct bpf_dtab_netdev *dst
> >    kernel/bpf/devmap.c:561:29: sparse:     got struct bpf_dtab_netdev [noderef] __rcu *
> >    kernel/bpf/devmap.c:657:29: sparse: sparse: incorrect type in assignment (different address spaces) @@     expected struct bpf_dtab_netdev *dst @@     got struct bpf_dtab_netdev [noderef] __rcu * @@
> >    kernel/bpf/devmap.c:657:29: sparse:     expected struct bpf_dtab_netdev *dst
> >    kernel/bpf/devmap.c:657:29: sparse:     got struct bpf_dtab_netdev [noderef] __rcu *
> >>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
> >>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
> >>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
> >>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
> >>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
> >>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
> >>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
> >>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
> >>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
> >>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
> >>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
> >>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
> >>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
> >>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
> >>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
> >>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
> >>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
> >>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
> >>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
> >>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
> >>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
> >>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
> >>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
> >>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
> >>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
> >>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
> >>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
> >>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
> >
> > vim +/__rcu +1030 kernel/bpf/devmap.c
> >
> >    990	
> >    991	static int dev_map_notification(struct notifier_block *notifier,
> >    992					ulong event, void *ptr)
> >    993	{
> >    994		struct net_device *netdev = netdev_notifier_info_to_dev(ptr);
> >    995		struct bpf_dtab *dtab;
> >    996		int i, cpu;
> >    997	
> >    998		switch (event) {
> >    999		case NETDEV_REGISTER:
> >   1000			if (!netdev->netdev_ops->ndo_xdp_xmit || netdev->xdp_bulkq)
> >   1001				break;
> >   1002	
> >   1003			/* will be freed in free_netdev() */
> >   1004			netdev->xdp_bulkq = alloc_percpu(struct xdp_dev_bulk_queue);
> >   1005			if (!netdev->xdp_bulkq)
> >   1006				return NOTIFY_BAD;
> >   1007	
> >   1008			for_each_possible_cpu(cpu)
> >   1009				per_cpu_ptr(netdev->xdp_bulkq, cpu)->dev = netdev;
> >   1010			break;
> >   1011		case NETDEV_UNREGISTER:
> >   1012			/* This rcu_read_lock/unlock pair is needed because
> >   1013			 * dev_map_list is an RCU list AND to ensure a delete
> >   1014			 * operation does not free a netdev_map entry while we
> >   1015			 * are comparing it against the netdev being unregistered.
> >   1016			 */
> >   1017			rcu_read_lock();
> >   1018			list_for_each_entry_rcu(dtab, &dev_map_list, list) {
> >   1019				if (dtab->map.map_type == BPF_MAP_TYPE_DEVMAP_HASH) {
> >   1020					dev_map_hash_remove_netdev(dtab, netdev);
> >   1021					continue;
> >   1022				}
> >   1023	
> >   1024				for (i = 0; i < dtab->map.max_entries; i++) {
> >   1025					struct bpf_dtab_netdev *dev, *odev;
> >   1026	
> >   1027					dev = rcu_dereference(dtab->netdev_map[i]);
> >   1028					if (!dev || netdev != dev->dev)
> >   1029						continue;
> >> 1030					odev = unrcu_pointer(cmpxchg(&dtab->netdev_map[i], RCU_INITIALIZER(dev), NULL));
> >   1031					if (dev == odev)
> >   1032						call_rcu(&dev->rcu,
> >   1033							 __dev_map_entry_free);
> >   1034				}
> >   1035			}
> >   1036			rcu_read_unlock();
> >   1037			break;
> >   1038		default:
> >   1039			break;
> >   1040		}
> >   1041		return NOTIFY_OK;
> >   1042	}
> >   1043	
> >
> > -- 
> > 0-DAY CI Kernel Test Service
> > https://01.org/lkp
> 

^ permalink raw reply	[flat|nested] 10+ messages in thread
* Re: kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
  2022-05-23 10:30 ` Toke Høiland-Jørgensen
  2022-05-24 20:51   ` Paul E. McKenney
@ 2022-06-01  0:38   ` Luc Van Oostenryck
  2022-06-01 10:26     ` Toke Høiland-Jørgensen
  1 sibling, 1 reply; 10+ messages in thread
From: Luc Van Oostenryck @ 2022-06-01  0:38 UTC (permalink / raw)
  To: Toke Høiland-Jørgensen
  Cc: kernel test robot, kbuild-all, linux-kernel, Daniel Borkmann,
	Paul E . McKenney

On Mon, May 23, 2022 at 12:30:14PM +0200, Toke Høiland-Jørgensen wrote:
> kernel test robot <lkp@intel.com> writes:
> 
> > tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
> > head:   eaea45fc0e7b6ae439526b4a41d91230c8517336
> > commit: 782347b6bcad07ddb574422e01e22c92e05928c8 xdp: Add proper __rcu annotations to redirect map entries
> > date:   11 months ago
> > config: ia64-randconfig-s031-20220522 (https://download.01.org/0day-ci/archive/20220522/202205222029.xpW3PM1y-lkp@intel.com/config)
> > compiler: ia64-linux-gcc (GCC) 11.3.0
> 
> Hmm, so this is ia64-only? Some kind of macro breakage? Paul, any ideas?

Hi,

It's surely IA64's cmpxchg() which contains lines like:
	_r_ = ia64_cmpxchg8_##sem((__u64 *) ptr, new, _o_); 

-- Luc 

^ permalink raw reply	[flat|nested] 10+ messages in thread
* Re: kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
  2022-06-01  0:38   ` Luc Van Oostenryck
@ 2022-06-01 10:26     ` Toke Høiland-Jørgensen
  2022-06-01 12:00       ` Luc Van Oostenryck
  2022-06-05 16:07       ` [PATCH] ia64: fix sparse warnings with cmpxchg() & xchg() Luc Van Oostenryck
  0 siblings, 2 replies; 10+ messages in thread
From: Toke Høiland-Jørgensen @ 2022-06-01 10:26 UTC (permalink / raw)
  To: Luc Van Oostenryck
  Cc: kernel test robot, kbuild-all, linux-kernel, Daniel Borkmann,
	Paul E . McKenney

Luc Van Oostenryck <luc.vanoostenryck@gmail.com> writes:

> On Mon, May 23, 2022 at 12:30:14PM +0200, Toke Høiland-Jørgensen wrote:
>> kernel test robot <lkp@intel.com> writes:
>> 
>> > tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
>> > head:   eaea45fc0e7b6ae439526b4a41d91230c8517336
>> > commit: 782347b6bcad07ddb574422e01e22c92e05928c8 xdp: Add proper __rcu annotations to redirect map entries
>> > date:   11 months ago
>> > config: ia64-randconfig-s031-20220522 (https://download.01.org/0day-ci/archive/20220522/202205222029.xpW3PM1y-lkp@intel.com/config)
>> > compiler: ia64-linux-gcc (GCC) 11.3.0
>> 
>> Hmm, so this is ia64-only? Some kind of macro breakage? Paul, any ideas?
>
> Hi,
>
> It's surely IA64's cmpxchg() which contains lines like:
> 	_r_ = ia64_cmpxchg8_##sem((__u64 *) ptr, new, _o_); 

Oh, right. Hmm, well, if the cmpxchg does an internal cast that
complicates things a bit. My immediate thought was to move the
unrcu_pointer() inside the calls to cmpxchg(), like:

diff --git a/kernel/bpf/devmap.c b/kernel/bpf/devmap.c
index 980f8928e977..3b6dc6d34177 100644
--- a/kernel/bpf/devmap.c
+++ b/kernel/bpf/devmap.c
@@ -1098,7 +1098,7 @@ static int dev_map_notification(struct notifier_block *notifier,
                                dev = rcu_dereference(dtab->netdev_map[i]);
                                if (!dev || netdev != dev->dev)
                                        continue;
-                               odev = unrcu_pointer(cmpxchg(&dtab->netdev_map[i], RCU_INITIALIZER(dev), NULL));
+                               odev = cmpxchg(unrcu_pointer(&dtab->netdev_map[i]), dev, NULL);
                                if (dev == odev)
                                        call_rcu(&dev->rcu,
                                                 __dev_map_entry_free);


But that seems to confuse sparse because these are ptr-to-ptr
constructs:

kernel/bpf/devmap.c:1101:40: error: incompatible types in comparison expression (different address spaces):
kernel/bpf/devmap.c:1101:40:    struct bpf_dtab_netdev [noderef] __rcu *[noderef] __rcu *
kernel/bpf/devmap.c:1101:40:    struct bpf_dtab_netdev [noderef] __rcu **
kernel/bpf/devmap.c:1101:40: error: incompatible types in comparison expression (different address spaces):
kernel/bpf/devmap.c:1101:40:    struct bpf_dtab_netdev [noderef] __rcu *[noderef] __rcu *
kernel/bpf/devmap.c:1101:40:    struct bpf_dtab_netdev [noderef] __rcu **

which I'm not sure how to fix. And not really sure if it's the
semantically right thing to do either in this case...

-Toke


^ permalink raw reply related	[flat|nested] 10+ messages in thread
* Re: kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
  2022-06-01 10:26     ` Toke Høiland-Jørgensen
@ 2022-06-01 12:00       ` Luc Van Oostenryck
  2022-06-05 16:07       ` [PATCH] ia64: fix sparse warnings with cmpxchg() & xchg() Luc Van Oostenryck
  1 sibling, 0 replies; 10+ messages in thread
From: Luc Van Oostenryck @ 2022-06-01 12:00 UTC (permalink / raw)
  To: Toke Høiland-Jørgensen
  Cc: kernel test robot, kbuild-all, linux-kernel, Daniel Borkmann,
	Paul E . McKenney, linux-ia64

On Wed, Jun 01, 2022 at 12:26:27PM +0200, Toke Høiland-Jørgensen wrote:
> Luc Van Oostenryck <luc.vanoostenryck@gmail.com> writes:
> 
> > On Mon, May 23, 2022 at 12:30:14PM +0200, Toke Høiland-Jørgensen wrote:
> >> kernel test robot <lkp@intel.com> writes:
> >> 
> >> > tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
> >> > head:   eaea45fc0e7b6ae439526b4a41d91230c8517336
> >> > commit: 782347b6bcad07ddb574422e01e22c92e05928c8 xdp: Add proper __rcu annotations to redirect map entries
> >> > date:   11 months ago
> >> > config: ia64-randconfig-s031-20220522 (https://download.01.org/0day-ci/archive/20220522/202205222029.xpW3PM1y-lkp@intel.com/config)
> >> > compiler: ia64-linux-gcc (GCC) 11.3.0
> >> 
> >> Hmm, so this is ia64-only? Some kind of macro breakage? Paul, any ideas?
> >
> > Hi,
> >
> > It's surely IA64's cmpxchg() which contains lines like:
> > 	_r_ = ia64_cmpxchg8_##sem((__u64 *) ptr, new, _o_); 
> 
> Oh, right. Hmm, well, if the cmpxchg does an internal cast that
> complicates things a bit. My immediate thought was to move the
> unrcu_pointer() inside the calls to cmpxchg(), like:
 
> But that seems to confuse sparse because these are ptr-to-ptr
> constructs:

Yes, that can't work because it applies on the wrong level (same difference as
between "int const ** ptr" and "int * const * ptr").

I've taken a quick look and the problem is really to be solved in IA64's
macros for cmpxchg() and friends. Two things need to be done:
1) avoid casts like the "(__u64 *) ptr" here above (ideally no cast would
   be needed but a "(__u64 __force *) ptr" would be pefectly acceptable in
   such macros.
2) the value returned by these macros must match the type of the pointer
   and the old/new values. For example, on x86 such macros are written as:
	({
		__typeof__ (*(ptr)) __ret = (arg);
		switch (sizeof(*(ptr))) { 
		case ...
			... use ptr without dropping the address space ..

		__ret;
	)}

See, for example, arch/x86/include/asm/cmpxchg.h

-- Luc

^ permalink raw reply	[flat|nested] 10+ messages in thread
* [PATCH] ia64: fix sparse warnings with cmpxchg() & xchg()
  2022-06-01 10:26     ` Toke Høiland-Jørgensen
  2022-06-01 12:00       ` Luc Van Oostenryck
@ 2022-06-05 16:07       ` Luc Van Oostenryck
  2022-06-05 19:58         ` Paul E. McKenney
  2022-06-06  7:53         ` Toke Høiland-Jørgensen
  1 sibling, 2 replies; 10+ messages in thread
From: Luc Van Oostenryck @ 2022-06-05 16:07 UTC (permalink / raw)
  To: Arnd Bergmann
  Cc: Andrew Morton, linux-ia64, linux-kernel, Paul E. McKenney,
	Luc Van Oostenryck, kernel test robot,
	Toke Høiland-Jørgensen

On IA64, new sparse's warnings where issued after fixing
some __rcu annotations in kernel/bpf/.

These new warnings are false positives and appear on IA64 because
on this architecture, the macros for cmpxchg() and xchg() make
casts that ignore sparse annotations.

This patch contains the minimal patch to fix this issue:
adding a missing cast and some missing '__force'.

Link: https://lore.kernel.org/r/20220601120013.bq5a3ynbkc3hngm5@mail
Reported-by: kernel test robot <lkp@intel.com>
Cc: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
---

Note: This patch is only compile tested on defconfig. The corresponding
      binary is unchanged (except some .rodata with the kernel version)
      as it should be.

 arch/ia64/include/uapi/asm/cmpxchg.h | 28 ++++++++++++++--------------
 1 file changed, 14 insertions(+), 14 deletions(-)

diff --git a/arch/ia64/include/uapi/asm/cmpxchg.h b/arch/ia64/include/uapi/asm/cmpxchg.h
index 2c2f3cfeaa77..ca2e02685343 100644
--- a/arch/ia64/include/uapi/asm/cmpxchg.h
+++ b/arch/ia64/include/uapi/asm/cmpxchg.h
@@ -33,24 +33,24 @@ extern void ia64_xchg_called_with_bad_pointer(void);
 									\
 	switch (size) {							\
 	case 1:								\
-		__xchg_result = ia64_xchg1((__u8 *)ptr, x);		\
+		__xchg_result = ia64_xchg1((__u8 __force *)ptr, x);	\
 		break;							\
 									\
 	case 2:								\
-		__xchg_result = ia64_xchg2((__u16 *)ptr, x);		\
+		__xchg_result = ia64_xchg2((__u16 __force *)ptr, x);	\
 		break;							\
 									\
 	case 4:								\
-		__xchg_result = ia64_xchg4((__u32 *)ptr, x);		\
+		__xchg_result = ia64_xchg4((__u32 __force *)ptr, x);	\
 		break;							\
 									\
 	case 8:								\
-		__xchg_result = ia64_xchg8((__u64 *)ptr, x);		\
+		__xchg_result = ia64_xchg8((__u64 __force *)ptr, x);	\
 		break;							\
 	default:							\
 		ia64_xchg_called_with_bad_pointer();			\
 	}								\
-	__xchg_result;							\
+	(__typeof__ (*(ptr)) __force) __xchg_result;			\
 })
 
 #ifndef __KERNEL__
@@ -76,42 +76,42 @@ extern long ia64_cmpxchg_called_with_bad_pointer(void);
 									\
 	switch (size) {							\
 	case 1:								\
-		_o_ = (__u8) (long) (old);				\
+		_o_ = (__u8) (long __force) (old);			\
 		break;							\
 	case 2:								\
-		_o_ = (__u16) (long) (old);				\
+		_o_ = (__u16) (long __force) (old);			\
 		break;							\
 	case 4:								\
-		_o_ = (__u32) (long) (old);				\
+		_o_ = (__u32) (long __force) (old);			\
 		break;							\
 	case 8:								\
-		_o_ = (__u64) (long) (old);				\
+		_o_ = (__u64) (long __force) (old);			\
 		break;							\
 	default:							\
 		break;							\
 	}								\
 	switch (size) {							\
 	case 1:								\
-		_r_ = ia64_cmpxchg1_##sem((__u8 *) ptr, new, _o_);	\
+		_r_ = ia64_cmpxchg1_##sem((__u8 __force *) ptr, new, _o_);	\
 		break;							\
 									\
 	case 2:								\
-		_r_ = ia64_cmpxchg2_##sem((__u16 *) ptr, new, _o_);	\
+		_r_ = ia64_cmpxchg2_##sem((__u16 __force *) ptr, new, _o_);	\
 		break;							\
 									\
 	case 4:								\
-		_r_ = ia64_cmpxchg4_##sem((__u32 *) ptr, new, _o_);	\
+		_r_ = ia64_cmpxchg4_##sem((__u32 __force *) ptr, new, _o_);	\
 		break;							\
 									\
 	case 8:								\
-		_r_ = ia64_cmpxchg8_##sem((__u64 *) ptr, new, _o_);	\
+		_r_ = ia64_cmpxchg8_##sem((__u64 __force *) ptr, new, _o_);	\
 		break;							\
 									\
 	default:							\
 		_r_ = ia64_cmpxchg_called_with_bad_pointer();		\
 		break;							\
 	}								\
-	(__typeof__(old)) _r_;						\
+	(__typeof__(old) __force) _r_;					\
 })
 
 #define cmpxchg_acq(ptr, o, n)	\
-- 
2.36.1


^ permalink raw reply related	[flat|nested] 10+ messages in thread
* Re: [PATCH] ia64: fix sparse warnings with cmpxchg() & xchg()
  2022-06-05 16:07       ` [PATCH] ia64: fix sparse warnings with cmpxchg() & xchg() Luc Van Oostenryck
@ 2022-06-05 19:58         ` Paul E. McKenney
  2022-06-06  7:53         ` Toke Høiland-Jørgensen
  1 sibling, 0 replies; 10+ messages in thread
From: Paul E. McKenney @ 2022-06-05 19:58 UTC (permalink / raw)
  To: Luc Van Oostenryck
  Cc: Arnd Bergmann, Andrew Morton, linux-ia64, linux-kernel,
	kernel test robot, Toke Høiland-Jørgensen

On Sun, Jun 05, 2022 at 06:07:38PM +0200, Luc Van Oostenryck wrote:
> On IA64, new sparse's warnings where issued after fixing
> some __rcu annotations in kernel/bpf/.
> 
> These new warnings are false positives and appear on IA64 because
> on this architecture, the macros for cmpxchg() and xchg() make
> casts that ignore sparse annotations.
> 
> This patch contains the minimal patch to fix this issue:
> adding a missing cast and some missing '__force'.
> 
> Link: https://lore.kernel.org/r/20220601120013.bq5a3ynbkc3hngm5@mail
> Reported-by: kernel test robot <lkp@intel.com>
> Cc: Toke Høiland-Jørgensen <toke@redhat.com>
> Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>

Looks good to me!

Acked-by: Paul E. McKenney <paulmck@kernel.org>

> ---
> 
> Note: This patch is only compile tested on defconfig. The corresponding
>       binary is unchanged (except some .rodata with the kernel version)
>       as it should be.
> 
>  arch/ia64/include/uapi/asm/cmpxchg.h | 28 ++++++++++++++--------------
>  1 file changed, 14 insertions(+), 14 deletions(-)
> 
> diff --git a/arch/ia64/include/uapi/asm/cmpxchg.h b/arch/ia64/include/uapi/asm/cmpxchg.h
> index 2c2f3cfeaa77..ca2e02685343 100644
> --- a/arch/ia64/include/uapi/asm/cmpxchg.h
> +++ b/arch/ia64/include/uapi/asm/cmpxchg.h
> @@ -33,24 +33,24 @@ extern void ia64_xchg_called_with_bad_pointer(void);
>  									\
>  	switch (size) {							\
>  	case 1:								\
> -		__xchg_result = ia64_xchg1((__u8 *)ptr, x);		\
> +		__xchg_result = ia64_xchg1((__u8 __force *)ptr, x);	\
>  		break;							\
>  									\
>  	case 2:								\
> -		__xchg_result = ia64_xchg2((__u16 *)ptr, x);		\
> +		__xchg_result = ia64_xchg2((__u16 __force *)ptr, x);	\
>  		break;							\
>  									\
>  	case 4:								\
> -		__xchg_result = ia64_xchg4((__u32 *)ptr, x);		\
> +		__xchg_result = ia64_xchg4((__u32 __force *)ptr, x);	\
>  		break;							\
>  									\
>  	case 8:								\
> -		__xchg_result = ia64_xchg8((__u64 *)ptr, x);		\
> +		__xchg_result = ia64_xchg8((__u64 __force *)ptr, x);	\
>  		break;							\
>  	default:							\
>  		ia64_xchg_called_with_bad_pointer();			\
>  	}								\
> -	__xchg_result;							\
> +	(__typeof__ (*(ptr)) __force) __xchg_result;			\
>  })
>  
>  #ifndef __KERNEL__
> @@ -76,42 +76,42 @@ extern long ia64_cmpxchg_called_with_bad_pointer(void);
>  									\
>  	switch (size) {							\
>  	case 1:								\
> -		_o_ = (__u8) (long) (old);				\
> +		_o_ = (__u8) (long __force) (old);			\
>  		break;							\
>  	case 2:								\
> -		_o_ = (__u16) (long) (old);				\
> +		_o_ = (__u16) (long __force) (old);			\
>  		break;							\
>  	case 4:								\
> -		_o_ = (__u32) (long) (old);				\
> +		_o_ = (__u32) (long __force) (old);			\
>  		break;							\
>  	case 8:								\
> -		_o_ = (__u64) (long) (old);				\
> +		_o_ = (__u64) (long __force) (old);			\
>  		break;							\
>  	default:							\
>  		break;							\
>  	}								\
>  	switch (size) {							\
>  	case 1:								\
> -		_r_ = ia64_cmpxchg1_##sem((__u8 *) ptr, new, _o_);	\
> +		_r_ = ia64_cmpxchg1_##sem((__u8 __force *) ptr, new, _o_);	\
>  		break;							\
>  									\
>  	case 2:								\
> -		_r_ = ia64_cmpxchg2_##sem((__u16 *) ptr, new, _o_);	\
> +		_r_ = ia64_cmpxchg2_##sem((__u16 __force *) ptr, new, _o_);	\
>  		break;							\
>  									\
>  	case 4:								\
> -		_r_ = ia64_cmpxchg4_##sem((__u32 *) ptr, new, _o_);	\
> +		_r_ = ia64_cmpxchg4_##sem((__u32 __force *) ptr, new, _o_);	\
>  		break;							\
>  									\
>  	case 8:								\
> -		_r_ = ia64_cmpxchg8_##sem((__u64 *) ptr, new, _o_);	\
> +		_r_ = ia64_cmpxchg8_##sem((__u64 __force *) ptr, new, _o_);	\
>  		break;							\
>  									\
>  	default:							\
>  		_r_ = ia64_cmpxchg_called_with_bad_pointer();		\
>  		break;							\
>  	}								\
> -	(__typeof__(old)) _r_;						\
> +	(__typeof__(old) __force) _r_;					\
>  })
>  
>  #define cmpxchg_acq(ptr, o, n)	\
> -- 
> 2.36.1
> 

^ permalink raw reply	[flat|nested] 10+ messages in thread
* Re: [PATCH] ia64: fix sparse warnings with cmpxchg() & xchg()
  2022-06-05 16:07       ` [PATCH] ia64: fix sparse warnings with cmpxchg() & xchg() Luc Van Oostenryck
  2022-06-05 19:58         ` Paul E. McKenney
@ 2022-06-06  7:53         ` Toke Høiland-Jørgensen
  1 sibling, 0 replies; 10+ messages in thread
From: Toke Høiland-Jørgensen @ 2022-06-06  7:53 UTC (permalink / raw)
  To: Luc Van Oostenryck, Arnd Bergmann
  Cc: Andrew Morton, linux-ia64, linux-kernel, Paul E. McKenney,
	Luc Van Oostenryck, kernel test robot

Luc Van Oostenryck <luc.vanoostenryck@gmail.com> writes:

> On IA64, new sparse's warnings where issued after fixing
> some __rcu annotations in kernel/bpf/.
>
> These new warnings are false positives and appear on IA64 because
> on this architecture, the macros for cmpxchg() and xchg() make
> casts that ignore sparse annotations.
>
> This patch contains the minimal patch to fix this issue:
> adding a missing cast and some missing '__force'.
>
> Link: https://lore.kernel.org/r/20220601120013.bq5a3ynbkc3hngm5@mail
> Reported-by: kernel test robot <lkp@intel.com>
> Cc: Toke Høiland-Jørgensen <toke@redhat.com>
> Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>

Ah, thank you for taking care of this! :)

Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>


^ permalink raw reply	[flat|nested] 10+ messages in thread
* kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
@ 2021-11-20  1:45 kernel test robot
  0 siblings, 0 replies; 10+ messages in thread
From: kernel test robot @ 2021-11-20  1:45 UTC (permalink / raw)
  To: Toke Høiland-Jørgensen
  Cc: kbuild-all, linux-kernel, Daniel Borkmann

[-- Attachment #1: Type: text/plain, Size: 6725 bytes --]

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   a90af8f15bdc9449ee2d24e1d73fa3f7e8633f81
commit: 782347b6bcad07ddb574422e01e22c92e05928c8 xdp: Add proper __rcu annotations to redirect map entries
date:   5 months ago
config: ia64-randconfig-s032-20211116 (attached as .config)
compiler: ia64-linux-gcc (GCC) 11.2.0
reproduce:
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # apt-get install sparse
        # sparse version: v0.6.4-dirty
        # https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=782347b6bcad07ddb574422e01e22c92e05928c8
        git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
        git fetch --no-tags linus master
        git checkout 782347b6bcad07ddb574422e01e22c92e05928c8
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' O=build_dir ARCH=ia64 SHELL=/bin/bash kernel/bpf/ lib/

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


sparse warnings: (new ones prefixed by >>)
   kernel/bpf/devmap.c:561:29: sparse: sparse: incorrect type in assignment (different address spaces) @@     expected struct bpf_dtab_netdev *dst @@     got struct bpf_dtab_netdev [noderef] __rcu * @@
   kernel/bpf/devmap.c:561:29: sparse:     expected struct bpf_dtab_netdev *dst
   kernel/bpf/devmap.c:561:29: sparse:     got struct bpf_dtab_netdev [noderef] __rcu *
   kernel/bpf/devmap.c:657:29: sparse: sparse: incorrect type in assignment (different address spaces) @@     expected struct bpf_dtab_netdev *dst @@     got struct bpf_dtab_netdev [noderef] __rcu * @@
   kernel/bpf/devmap.c:657:29: sparse:     expected struct bpf_dtab_netdev *dst
   kernel/bpf/devmap.c:657:29: sparse:     got struct bpf_dtab_netdev [noderef] __rcu *
>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression

vim +/__rcu +1030 kernel/bpf/devmap.c

   990	
   991	static int dev_map_notification(struct notifier_block *notifier,
   992					ulong event, void *ptr)
   993	{
   994		struct net_device *netdev = netdev_notifier_info_to_dev(ptr);
   995		struct bpf_dtab *dtab;
   996		int i, cpu;
   997	
   998		switch (event) {
   999		case NETDEV_REGISTER:
  1000			if (!netdev->netdev_ops->ndo_xdp_xmit || netdev->xdp_bulkq)
  1001				break;
  1002	
  1003			/* will be freed in free_netdev() */
  1004			netdev->xdp_bulkq = alloc_percpu(struct xdp_dev_bulk_queue);
  1005			if (!netdev->xdp_bulkq)
  1006				return NOTIFY_BAD;
  1007	
  1008			for_each_possible_cpu(cpu)
  1009				per_cpu_ptr(netdev->xdp_bulkq, cpu)->dev = netdev;
  1010			break;
  1011		case NETDEV_UNREGISTER:
  1012			/* This rcu_read_lock/unlock pair is needed because
  1013			 * dev_map_list is an RCU list AND to ensure a delete
  1014			 * operation does not free a netdev_map entry while we
  1015			 * are comparing it against the netdev being unregistered.
  1016			 */
  1017			rcu_read_lock();
  1018			list_for_each_entry_rcu(dtab, &dev_map_list, list) {
  1019				if (dtab->map.map_type == BPF_MAP_TYPE_DEVMAP_HASH) {
  1020					dev_map_hash_remove_netdev(dtab, netdev);
  1021					continue;
  1022				}
  1023	
  1024				for (i = 0; i < dtab->map.max_entries; i++) {
  1025					struct bpf_dtab_netdev *dev, *odev;
  1026	
  1027					dev = rcu_dereference(dtab->netdev_map[i]);
  1028					if (!dev || netdev != dev->dev)
  1029						continue;
> 1030					odev = unrcu_pointer(cmpxchg(&dtab->netdev_map[i], RCU_INITIALIZER(dev), NULL));
  1031					if (dev == odev)
  1032						call_rcu(&dev->rcu,
  1033							 __dev_map_entry_free);
  1034				}
  1035			}
  1036			rcu_read_unlock();
  1037			break;
  1038		default:
  1039			break;
  1040		}
  1041		return NOTIFY_OK;
  1042	}
  1043	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org

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^ permalink raw reply	[flat|nested] 10+ messages in thread
end of thread, other threads:[~2022-06-06  7:53 UTC | newest]

Thread overview: 10+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-05-22 12:30 kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression kernel test robot
2022-05-23 10:30 ` Toke Høiland-Jørgensen
2022-05-24 20:51   ` Paul E. McKenney
2022-06-01  0:38   ` Luc Van Oostenryck
2022-06-01 10:26     ` Toke Høiland-Jørgensen
2022-06-01 12:00       ` Luc Van Oostenryck
2022-06-05 16:07       ` [PATCH] ia64: fix sparse warnings with cmpxchg() & xchg() Luc Van Oostenryck
2022-06-05 19:58         ` Paul E. McKenney
2022-06-06  7:53         ` Toke Høiland-Jørgensen
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2021-11-20  1:45 kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression kernel test robot

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