[PATCH V8 07/10] riscv: Add qspinlock support

Guo Ren guoren at kernel.org
Wed Jul 27 20:35:03 PDT 2022


Hi Palmer,

The warning is from a clang problem.

drivers/net/wireguard/queueing.c:
static void __wg_prev_queue_enqueue(struct prev_queue *queue, struct
sk_buff *skb)
{
        WRITE_ONCE(NEXT(skb), NULL);
        WRITE_ONCE(NEXT(xchg_release(&queue->head, skb)), skb);
}

The queue->head is 64bit pointer size.

#define __xchg_relaxed(ptr, new, size)                                  \
({                                                                      \
        __typeof__(ptr) __ptr = (ptr);                                  \
        __typeof__(new) __new = (new);                                  \
        __typeof__(*(ptr)) __ret;                                       \
        switch (size) {                                                 \
        case 2: {                                                       \
... Clang shouldn't give warning from here, because code won't enter the path.
                break;                                                  \
        }                                                               \
        case 4:                                                         \
...
                break;                                                  \
        case 8:                                                         \
... The case would enter this path.
                break;                                                  \
        default:                                                        \
                BUILD_BUG();                                            \
        }                                                               \
        __ret;                                                          \
})

On Thu, Jul 28, 2022 at 8:05 AM kernel test robot <lkp at intel.com> wrote:
>
> Hi,
>
> I love your patch! Perhaps something to improve:
>
> [auto build test WARNING on arnd-asm-generic/master]
> [also build test WARNING on linus/master v5.19-rc8 next-20220727]
> [If your patch is applied to the wrong git tree, kindly drop us a note.
> And when submitting patch, we suggest to use '--base' as documented in
> https://git-scm.com/docs/git-format-patch#_base_tree_information]
>
> url:    https://github.com/intel-lab-lkp/linux/commits/guoren-kernel-org/arch-Add-qspinlock-support-with-combo-style/20220724-202743
> base:   https://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic.git master
> config: riscv-randconfig-r026-20220727 (https://download.01.org/0day-ci/archive/20220728/202207280822.VHS6qieH-lkp@intel.com/config)
> compiler: clang version 15.0.0 (https://github.com/llvm/llvm-project 8dfaecc4c24494337933aff9d9166486ca0949f1)
> reproduce (this is a W=1 build):
>         wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
>         chmod +x ~/bin/make.cross
>         # install riscv cross compiling tool for clang build
>         # apt-get install binutils-riscv64-linux-gnu
>         # https://github.com/intel-lab-lkp/linux/commit/980c0acb7f432777e3473ab9a5696044e03b3f3d
>         git remote add linux-review https://github.com/intel-lab-lkp/linux
>         git fetch --no-tags linux-review guoren-kernel-org/arch-Add-qspinlock-support-with-combo-style/20220724-202743
>         git checkout 980c0acb7f432777e3473ab9a5696044e03b3f3d
>         # save the config file
>         mkdir build_dir && cp config build_dir/.config
>         COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=riscv SHELL=/bin/bash drivers/net/wireguard/
>
> If you fix the issue, kindly add following tag where applicable
> Reported-by: kernel test robot <lkp at intel.com>
>
> All warnings (new ones prefixed by >>):
>
>    In file included from drivers/net/wireguard/queueing.c:6:
>    In file included from drivers/net/wireguard/queueing.h:9:
>    In file included from drivers/net/wireguard/peer.h:9:
>    In file included from drivers/net/wireguard/device.h:9:
>    In file included from drivers/net/wireguard/noise.h:8:
>    In file included from drivers/net/wireguard/messages.h:10:
>    In file included from include/crypto/chacha20poly1305.h:10:
>    In file included from include/linux/scatterlist.h:9:
>    In file included from arch/riscv/include/asm/io.h:136:
>    include/asm-generic/io.h:547:31: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            val = __raw_readb(PCI_IOBASE + addr);
>                              ~~~~~~~~~~ ^
>    include/asm-generic/io.h:560:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            val = __le16_to_cpu((__le16 __force)__raw_readw(PCI_IOBASE + addr));
>                                                            ~~~~~~~~~~ ^
>    include/uapi/linux/byteorder/little_endian.h:37:51: note: expanded from macro '__le16_to_cpu'
>    #define __le16_to_cpu(x) ((__force __u16)(__le16)(x))
>                                                      ^
>    In file included from drivers/net/wireguard/queueing.c:6:
>    In file included from drivers/net/wireguard/queueing.h:9:
>    In file included from drivers/net/wireguard/peer.h:9:
>    In file included from drivers/net/wireguard/device.h:9:
>    In file included from drivers/net/wireguard/noise.h:8:
>    In file included from drivers/net/wireguard/messages.h:10:
>    In file included from include/crypto/chacha20poly1305.h:10:
>    In file included from include/linux/scatterlist.h:9:
>    In file included from arch/riscv/include/asm/io.h:136:
>    include/asm-generic/io.h:573:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            val = __le32_to_cpu((__le32 __force)__raw_readl(PCI_IOBASE + addr));
>                                                            ~~~~~~~~~~ ^
>    include/uapi/linux/byteorder/little_endian.h:35:51: note: expanded from macro '__le32_to_cpu'
>    #define __le32_to_cpu(x) ((__force __u32)(__le32)(x))
>                                                      ^
>    In file included from drivers/net/wireguard/queueing.c:6:
>    In file included from drivers/net/wireguard/queueing.h:9:
>    In file included from drivers/net/wireguard/peer.h:9:
>    In file included from drivers/net/wireguard/device.h:9:
>    In file included from drivers/net/wireguard/noise.h:8:
>    In file included from drivers/net/wireguard/messages.h:10:
>    In file included from include/crypto/chacha20poly1305.h:10:
>    In file included from include/linux/scatterlist.h:9:
>    In file included from arch/riscv/include/asm/io.h:136:
>    include/asm-generic/io.h:584:33: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            __raw_writeb(value, PCI_IOBASE + addr);
>                                ~~~~~~~~~~ ^
>    include/asm-generic/io.h:594:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            __raw_writew((u16 __force)cpu_to_le16(value), PCI_IOBASE + addr);
>                                                          ~~~~~~~~~~ ^
>    include/asm-generic/io.h:604:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            __raw_writel((u32 __force)cpu_to_le32(value), PCI_IOBASE + addr);
>                                                          ~~~~~~~~~~ ^
>    include/asm-generic/io.h:1107:55: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            return (port > MMIO_UPPER_LIMIT) ? NULL : PCI_IOBASE + port;
>                                                      ~~~~~~~~~~ ^
> >> drivers/net/wireguard/queueing.c:68:18: warning: cast to smaller integer type 'u32' (aka 'unsigned int') from 'typeof (_x_)' (aka 'struct sk_buff *') [-Wpointer-to-int-cast]
>            WRITE_ONCE(NEXT(xchg_release(&queue->head, skb)), skb);
>                            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>    include/linux/atomic/atomic-instrumented.h:1901:2: note: expanded from macro 'xchg_release'
>            arch_xchg_release(__ai_ptr, __VA_ARGS__); \
>            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>    include/linux/atomic/atomic-arch-fallback.h:24:2: note: expanded from macro 'arch_xchg_release'
>            __atomic_op_release(arch_xchg, __VA_ARGS__)
>            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>    include/linux/atomic.h:68:2: note: expanded from macro '__atomic_op_release'
>            op##_relaxed(args);                                             \
>            ^~~~~~~~~~~~~~~~~~
>    note: (skipping 7 expansions in backtrace; use -fmacro-backtrace-limit=0 to see all)
>    include/linux/compiler_types.h:352:22: note: expanded from macro 'compiletime_assert'
>            _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
>                                ^~~~~~~~~
>    include/linux/compiler_types.h:340:23: note: expanded from macro '_compiletime_assert'
>            __compiletime_assert(condition, msg, prefix, suffix)
>                                 ^~~~~~~~~
>    include/linux/compiler_types.h:332:9: note: expanded from macro '__compiletime_assert'
>                    if (!(condition))                                       \
>                          ^~~~~~~~~
> >> drivers/net/wireguard/queueing.c:68:18: warning: cast to 'typeof (*((__ai_ptr)))' (aka 'struct sk_buff *') from smaller integer type 'unsigned int' [-Wint-to-pointer-cast]
>            WRITE_ONCE(NEXT(xchg_release(&queue->head, skb)), skb);
>            ~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>    include/linux/atomic/atomic-instrumented.h:1901:2: note: expanded from macro 'xchg_release'
>            arch_xchg_release(__ai_ptr, __VA_ARGS__); \
>            ^
>    include/linux/atomic/atomic-arch-fallback.h:24:2: note: expanded from macro 'arch_xchg_release'
>            __atomic_op_release(arch_xchg, __VA_ARGS__)
>            ^
>    include/linux/atomic.h:68:2: note: expanded from macro '__atomic_op_release'
>            op##_relaxed(args);                                             \
>            ^
>    note: (skipping 7 expansions in backtrace; use -fmacro-backtrace-limit=0 to see all)
>    include/linux/compiler_types.h:352:22: note: expanded from macro 'compiletime_assert'
>            _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
>            ~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>    include/linux/compiler_types.h:340:23: note: expanded from macro '_compiletime_assert'
>            __compiletime_assert(condition, msg, prefix, suffix)
>            ~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>    include/linux/compiler_types.h:332:9: note: expanded from macro '__compiletime_assert'
>                    if (!(condition))                                       \
>                          ^~~~~~~~~
> >> drivers/net/wireguard/queueing.c:68:18: warning: cast to smaller integer type 'u32' (aka 'unsigned int') from 'typeof (_x_)' (aka 'struct sk_buff *') [-Wpointer-to-int-cast]
>            WRITE_ONCE(NEXT(xchg_release(&queue->head, skb)), skb);
>                            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>    include/linux/atomic/atomic-instrumented.h:1901:2: note: expanded from macro 'xchg_release'
>            arch_xchg_release(__ai_ptr, __VA_ARGS__); \
>            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>    include/linux/atomic/atomic-arch-fallback.h:24:2: note: expanded from macro 'arch_xchg_release'
>            __atomic_op_release(arch_xchg, __VA_ARGS__)
>            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>    include/linux/atomic.h:68:2: note: expanded from macro '__atomic_op_release'
>            op##_relaxed(args);                                             \
>            ^~~~~~~~~~~~~~~~~~
>    note: (skipping 7 expansions in backtrace; use -fmacro-backtrace-limit=0 to see all)
>    include/linux/compiler_types.h:352:22: note: expanded from macro 'compiletime_assert'
>            _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
>                                ^~~~~~~~~
>    include/linux/compiler_types.h:340:23: note: expanded from macro '_compiletime_assert'
>            __compiletime_assert(condition, msg, prefix, suffix)
>                                 ^~~~~~~~~
>    include/linux/compiler_types.h:332:9: note: expanded from macro '__compiletime_assert'
>                    if (!(condition))                                       \
>                          ^~~~~~~~~
> >> drivers/net/wireguard/queueing.c:68:18: warning: cast to 'typeof (*((__ai_ptr)))' (aka 'struct sk_buff *') from smaller integer type 'unsigned int' [-Wint-to-pointer-cast]
>            WRITE_ONCE(NEXT(xchg_release(&queue->head, skb)), skb);
>            ~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>    include/linux/atomic/atomic-instrumented.h:1901:2: note: expanded from macro 'xchg_release'
>            arch_xchg_release(__ai_ptr, __VA_ARGS__); \
>            ^
>    include/linux/atomic/atomic-arch-fallback.h:24:2: note: expanded from macro 'arch_xchg_release'
>            __atomic_op_release(arch_xchg, __VA_ARGS__)
>            ^
>    include/linux/atomic.h:68:2: note: expanded from macro '__atomic_op_release'
>            op##_relaxed(args);                                             \
>            ^
>    note: (skipping 7 expansions in backtrace; use -fmacro-backtrace-limit=0 to see all)
>    include/linux/compiler_types.h:352:22: note: expanded from macro 'compiletime_assert'
>            _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
>            ~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>    include/linux/compiler_types.h:340:23: note: expanded from macro '_compiletime_assert'
>            __compiletime_assert(condition, msg, prefix, suffix)
>            ~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>    include/linux/compiler_types.h:332:9: note: expanded from macro '__compiletime_assert'
>                    if (!(condition))                                       \
>                          ^~~~~~~~~
> >> drivers/net/wireguard/queueing.c:68:18: warning: cast to smaller integer type 'u32' (aka 'unsigned int') from 'typeof (_x_)' (aka 'struct sk_buff *') [-Wpointer-to-int-cast]
>            WRITE_ONCE(NEXT(xchg_release(&queue->head, skb)), skb);
>                            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>    include/linux/atomic/atomic-instrumented.h:1901:2: note: expanded from macro 'xchg_release'
>            arch_xchg_release(__ai_ptr, __VA_ARGS__); \
>            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>    include/linux/atomic/atomic-arch-fallback.h:24:2: note: expanded from macro 'arch_xchg_release'
>            __atomic_op_release(arch_xchg, __VA_ARGS__)
>            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>    include/linux/atomic.h:68:2: note: expanded from macro '__atomic_op_release'
>            op##_relaxed(args);                                             \
>            ^~~~~~~~~~~~~~~~~~
>    note: (skipping 7 expansions in backtrace; use -fmacro-backtrace-limit=0 to see all)
>    include/linux/compiler_types.h:352:22: note: expanded from macro 'compiletime_assert'
>            _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
>                                ^~~~~~~~~
>    include/linux/compiler_types.h:340:23: note: expanded from macro '_compiletime_assert'
>            __compiletime_assert(condition, msg, prefix, suffix)
>                                 ^~~~~~~~~
>    include/linux/compiler_types.h:332:9: note: expanded from macro '__compiletime_assert'
>                    if (!(condition))                                       \
>                          ^~~~~~~~~
> >> drivers/net/wireguard/queueing.c:68:18: warning: cast to 'typeof (*((__ai_ptr)))' (aka 'struct sk_buff *') from smaller integer type 'unsigned int' [-Wint-to-pointer-cast]
>            WRITE_ONCE(NEXT(xchg_release(&queue->head, skb)), skb);
>            ~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>    include/linux/atomic/atomic-instrumented.h:1901:2: note: expanded from macro 'xchg_release'
>            arch_xchg_release(__ai_ptr, __VA_ARGS__); \
>            ^
>    include/linux/atomic/atomic-arch-fallback.h:24:2: note: expanded from macro 'arch_xchg_release'
>            __atomic_op_release(arch_xchg, __VA_ARGS__)
>            ^
>    include/linux/atomic.h:68:2: note: expanded from macro '__atomic_op_release'
>            op##_relaxed(args);                                             \
>            ^
>    note: (skipping 7 expansions in backtrace; use -fmacro-backtrace-limit=0 to see all)
>    include/linux/compiler_types.h:352:22: note: expanded from macro 'compiletime_assert'
>            _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
>            ~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>    include/linux/compiler_types.h:340:23: note: expanded from macro '_compiletime_assert'
>            __compiletime_assert(condition, msg, prefix, suffix)
>            ~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>    include/linux/compiler_types.h:332:9: note: expanded from macro '__compiletime_assert'
>                    if (!(condition))                                       \
>                          ^~~~~~~~~
> >> drivers/net/wireguard/queueing.c:68:18: warning: cast to smaller integer type 'u32' (aka 'unsigned int') from 'typeof (_x_)' (aka 'struct sk_buff *') [-Wpointer-to-int-cast]
>            WRITE_ONCE(NEXT(xchg_release(&queue->head, skb)), skb);
>                            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>    include/linux/atomic/atomic-instrumented.h:1901:2: note: expanded from macro 'xchg_release'
>            arch_xchg_release(__ai_ptr, __VA_ARGS__); \
>            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>    include/linux/atomic/atomic-arch-fallback.h:24:2: note: expanded from macro 'arch_xchg_release'
>            __atomic_op_release(arch_xchg, __VA_ARGS__)
>            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>    include/linux/atomic.h:68:2: note: expanded from macro '__atomic_op_release'
>            op##_relaxed(args);                                             \
>            ^~~~~~~~~~~~~~~~~~
>    note: (skipping 7 expansions in backtrace; use -fmacro-backtrace-limit=0 to see all)
>    include/linux/compiler_types.h:352:22: note: expanded from macro 'compiletime_assert'
>            _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
>                                ^~~~~~~~~
>    include/linux/compiler_types.h:340:23: note: expanded from macro '_compiletime_assert'
>            __compiletime_assert(condition, msg, prefix, suffix)
>                                 ^~~~~~~~~
>    include/linux/compiler_types.h:332:9: note: expanded from macro '__compiletime_assert'
>                    if (!(condition))                                       \
>                          ^~~~~~~~~
> >> drivers/net/wireguard/queueing.c:68:18: warning: cast to 'typeof (*((__ai_ptr)))' (aka 'struct sk_buff *') from smaller integer type 'unsigned int' [-Wint-to-pointer-cast]
>            WRITE_ONCE(NEXT(xchg_release(&queue->head, skb)), skb);
>            ~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>    include/linux/atomic/atomic-instrumented.h:1901:2: note: expanded from macro 'xchg_release'
>            arch_xchg_release(__ai_ptr, __VA_ARGS__); \
>            ^
>    include/linux/atomic/atomic-arch-fallback.h:24:2: note: expanded from macro 'arch_xchg_release'
>            __atomic_op_release(arch_xchg, __VA_ARGS__)
>            ^
>    include/linux/atomic.h:68:2: note: expanded from macro '__atomic_op_release'
>            op##_relaxed(args);                                             \
>            ^
>    note: (skipping 7 expansions in backtrace; use -fmacro-backtrace-limit=0 to see all)
>    include/linux/compiler_types.h:352:22: note: expanded from macro 'compiletime_assert'
>            _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
>            ~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>    include/linux/compiler_types.h:340:23: note: expanded from macro '_compiletime_assert'
>            __compiletime_assert(condition, msg, prefix, suffix)
>            ~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>    include/linux/compiler_types.h:332:9: note: expanded from macro '__compiletime_assert'
>                    if (!(condition))                                       \
>                          ^~~~~~~~~
> >> drivers/net/wireguard/queueing.c:68:18: warning: cast to smaller integer type 'u32' (aka 'unsigned int') from 'typeof (_x_)' (aka 'struct sk_buff *') [-Wpointer-to-int-cast]
>            WRITE_ONCE(NEXT(xchg_release(&queue->head, skb)), skb);
>                            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>    include/linux/atomic/atomic-instrumented.h:1901:2: note: expanded from macro 'xchg_release'
>            arch_xchg_release(__ai_ptr, __VA_ARGS__); \
>            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>    include/linux/atomic/atomic-arch-fallback.h:24:2: note: expanded from macro 'arch_xchg_release'
>            __atomic_op_release(arch_xchg, __VA_ARGS__)
>            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>    include/linux/atomic.h:68:2: note: expanded from macro '__atomic_op_release'
>            op##_relaxed(args);                                             \
>            ^~~~~~~~~~~~~~~~~~
>    note: (skipping 6 expansions in backtrace; use -fmacro-backtrace-limit=0 to see all)
>    include/linux/compiler_types.h:352:22: note: expanded from macro 'compiletime_assert'
>            _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
>                                ^~~~~~~~~
>    include/linux/compiler_types.h:340:23: note: expanded from macro '_compiletime_assert'
>            __compiletime_assert(condition, msg, prefix, suffix)
>                                 ^~~~~~~~~
>    include/linux/compiler_types.h:332:9: note: expanded from macro '__compiletime_assert'
>                    if (!(condition))                                       \
>                          ^~~~~~~~~
> >> drivers/net/wireguard/queueing.c:68:18: warning: cast to 'typeof (*((__ai_ptr)))' (aka 'struct sk_buff *') from smaller integer type 'unsigned int' [-Wint-to-pointer-cast]
>            WRITE_ONCE(NEXT(xchg_release(&queue->head, skb)), skb);
>            ~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>    include/linux/atomic/atomic-instrumented.h:1901:2: note: expanded from macro 'xchg_release'
>            arch_xchg_release(__ai_ptr, __VA_ARGS__); \
>            ^
>    include/linux/atomic/atomic-arch-fallback.h:24:2: note: expanded from macro 'arch_xchg_release'
>            __atomic_op_release(arch_xchg, __VA_ARGS__)
>            ^
>    include/linux/atomic.h:68:2: note: expanded from macro '__atomic_op_release'
>            op##_relaxed(args);                                             \
>            ^
>    note: (skipping 6 expansions in backtrace; use -fmacro-backtrace-limit=0 to see all)
>    include/linux/compiler_types.h:352:22: note: expanded from macro 'compiletime_assert'
>            _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
>            ~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>    include/linux/compiler_types.h:340:23: note: expanded from macro '_compiletime_assert'
>            __compiletime_assert(condition, msg, prefix, suffix)
>            ~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>    include/linux/compiler_types.h:332:9: note: expanded from macro '__compiletime_assert'
>                    if (!(condition))                                       \
>                          ^~~~~~~~~
> >> drivers/net/wireguard/queueing.c:68:18: warning: cast to smaller integer type 'u32' (aka 'unsigned int') from 'typeof (_x_)' (aka 'struct sk_buff *') [-Wpointer-to-int-cast]
>            WRITE_ONCE(NEXT(xchg_release(&queue->head, skb)), skb);
>                            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>    include/linux/atomic/atomic-instrumented.h:1901:2: note: expanded from macro 'xchg_release'
>            arch_xchg_release(__ai_ptr, __VA_ARGS__); \
>            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>    include/linux/atomic/atomic-arch-fallback.h:24:2: note: expanded from macro 'arch_xchg_release'
>            __atomic_op_release(arch_xchg, __VA_ARGS__)
>            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>    include/linux/atomic.h:68:2: note: expanded from macro '__atomic_op_release'
>            op##_relaxed(args);                                             \
>            ^~~~~~~~~~~~~~~~~~
>    note: (skipping 3 expansions in backtrace; use -fmacro-backtrace-limit=0 to see all)
>    drivers/net/wireguard/queueing.c:49:21: note: expanded from macro 'NEXT'
>    #define NEXT(skb) ((skb)->prev)
>                        ^~~
>    include/asm-generic/rwonce.h:61:15: note: expanded from macro 'WRITE_ONCE'
>            __WRITE_ONCE(x, val);                                           \
>                         ^
>    include/asm-generic/rwonce.h:55:20: note: expanded from macro '__WRITE_ONCE'
>            *(volatile typeof(x) *)&(x) = (val);                            \
>                              ^
> >> drivers/net/wireguard/queueing.c:68:18: warning: cast to 'typeof (*((__ai_ptr)))' (aka 'struct sk_buff *') from smaller integer type 'unsigned int' [-Wint-to-pointer-cast]
>            WRITE_ONCE(NEXT(xchg_release(&queue->head, skb)), skb);
>            ~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>    include/linux/atomic/atomic-instrumented.h:1901:2: note: expanded from macro 'xchg_release'
>            arch_xchg_release(__ai_ptr, __VA_ARGS__); \
>            ^
>    include/linux/atomic/atomic-arch-fallback.h:24:2: note: expanded from macro 'arch_xchg_release'
>            __atomic_op_release(arch_xchg, __VA_ARGS__)
>            ^
>    include/linux/atomic.h:68:2: note: expanded from macro '__atomic_op_release'
>            op##_relaxed(args);                                             \
>            ^
>    note: (skipping 3 expansions in backtrace; use -fmacro-backtrace-limit=0 to see all)
>    drivers/net/wireguard/queueing.c:49:21: note: expanded from macro 'NEXT'
>    #define NEXT(skb) ((skb)->prev)
>                        ^
>    include/asm-generic/rwonce.h:61:15: note: expanded from macro 'WRITE_ONCE'
>            __WRITE_ONCE(x, val);                                           \
>            ~~~~~~~~~~~~~^~~~~~~
>    include/asm-generic/rwonce.h:55:20: note: expanded from macro '__WRITE_ONCE'
>            *(volatile typeof(x) *)&(x) = (val);                            \
>                              ^
> >> drivers/net/wireguard/queueing.c:68:18: warning: cast to smaller integer type 'u32' (aka 'unsigned int') from 'typeof (_x_)' (aka 'struct sk_buff *') [-Wpointer-to-int-cast]
>            WRITE_ONCE(NEXT(xchg_release(&queue->head, skb)), skb);
>                            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>    include/linux/atomic/atomic-instrumented.h:1901:2: note: expanded from macro 'xchg_release'
>            arch_xchg_release(__ai_ptr, __VA_ARGS__); \
>            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>    include/linux/atomic/atomic-arch-fallback.h:24:2: note: expanded from macro 'arch_xchg_release'
>            __atomic_op_release(arch_xchg, __VA_ARGS__)
>            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>    include/linux/atomic.h:68:2: note: expanded from macro '__atomic_op_release'
>            op##_relaxed(args);                                             \
>            ^~~~~~~~~~~~~~~~~~
>    note: (skipping 3 expansions in backtrace; use -fmacro-backtrace-limit=0 to see all)
>    drivers/net/wireguard/queueing.c:49:21: note: expanded from macro 'NEXT'
>    #define NEXT(skb) ((skb)->prev)
>                        ^~~
>    include/asm-generic/rwonce.h:61:15: note: expanded from macro 'WRITE_ONCE'
>            __WRITE_ONCE(x, val);                                           \
>                         ^
>    include/asm-generic/rwonce.h:55:27: note: expanded from macro '__WRITE_ONCE'
>            *(volatile typeof(x) *)&(x) = (val);                            \
>                                     ^
> >> drivers/net/wireguard/queueing.c:68:18: warning: cast to 'typeof (*((__ai_ptr)))' (aka 'struct sk_buff *') from smaller integer type 'unsigned int' [-Wint-to-pointer-cast]
>            WRITE_ONCE(NEXT(xchg_release(&queue->head, skb)), skb);
>            ~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>    include/linux/atomic/atomic-instrumented.h:1901:2: note: expanded from macro 'xchg_release'
>            arch_xchg_release(__ai_ptr, __VA_ARGS__); \
>            ^
>    include/linux/atomic/atomic-arch-fallback.h:24:2: note: expanded from macro 'arch_xchg_release'
>            __atomic_op_release(arch_xchg, __VA_ARGS__)
>            ^
>    include/linux/atomic.h:68:2: note: expanded from macro '__atomic_op_release'
>            op##_relaxed(args);                                             \
>            ^
>    note: (skipping 3 expansions in backtrace; use -fmacro-backtrace-limit=0 to see all)
>    drivers/net/wireguard/queueing.c:49:21: note: expanded from macro 'NEXT'
>    #define NEXT(skb) ((skb)->prev)
>                        ^
>    include/asm-generic/rwonce.h:61:15: note: expanded from macro 'WRITE_ONCE'
>            __WRITE_ONCE(x, val);                                           \
>            ~~~~~~~~~~~~~^~~~~~~
>    include/asm-generic/rwonce.h:55:27: note: expanded from macro '__WRITE_ONCE'
>            *(volatile typeof(x) *)&(x) = (val);                            \
>                                     ^
>    21 warnings generated.
>
>
> vim +68 drivers/net/wireguard/queueing.c
>
> 8b5553ace83cced7 Jason A. Donenfeld 2021-02-22  64
> 8b5553ace83cced7 Jason A. Donenfeld 2021-02-22  65  static void __wg_prev_queue_enqueue(struct prev_queue *queue, struct sk_buff *skb)
> 8b5553ace83cced7 Jason A. Donenfeld 2021-02-22  66  {
> 8b5553ace83cced7 Jason A. Donenfeld 2021-02-22  67      WRITE_ONCE(NEXT(skb), NULL);
> 8b5553ace83cced7 Jason A. Donenfeld 2021-02-22 @68      WRITE_ONCE(NEXT(xchg_release(&queue->head, skb)), skb);
> 8b5553ace83cced7 Jason A. Donenfeld 2021-02-22  69  }
> 8b5553ace83cced7 Jason A. Donenfeld 2021-02-22  70
>
> --
> 0-DAY CI Kernel Test Service
> https://01.org/lkp



-- 
Best Regards
 Guo Ren



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