From: Dmitry Vyukov <dvyukov@google.com>
To: kbuild test robot <fengguang.wu@intel.com>
Cc: kbuild-all@01.org, LKML <linux-kernel@vger.kernel.org>,
tipbuild@zytor.com, Ingo Molnar <mingo@kernel.org>
Subject: Re: [tip:locking/core 9/11] include/asm-generic/atomic-instrumented.h:288:24: sparse: cast truncates bits from constant value (100 becomes 0)
Date: Mon, 12 Mar 2018 18:17:32 +0300 [thread overview]
Message-ID: <CACT4Y+Yscqe6M1jXSkcuvw+5-27YzZn4AXwKzU1oJCNhUrj1Ng@mail.gmail.com> (raw)
In-Reply-To: <201803122219.vHl3IwRo%fengguang.wu@intel.com>
On Mon, Mar 12, 2018 at 5:52 PM, kbuild test robot
<fengguang.wu@intel.com> wrote:
> tree: https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git locking/core
> head: ac605bee0bfab40fd5d11964705e907d2d5a32de
> commit: 8bf705d130396e69c04cd8e6e010244ad2ce71f4 [9/11] locking/atomic/x86: Switch atomic.h to use atomic-instrumented.h
> reproduce:
> # apt-get install sparse
> git checkout 8bf705d130396e69c04cd8e6e010244ad2ce71f4
> make ARCH=x86_64 allmodconfig
> make C=1 CF=-D__CHECK_ENDIAN__
>
>
> sparse warnings: (new ones prefixed by >>)
>
> kernel/locking/qspinlock.c:418:22: sparse: incorrect type in assignment (different modifiers) @@ expected struct mcs_spinlock *prev @@ got struct struct mcs_spinlock *prev @@
> kernel/locking/qspinlock.c:418:22: expected struct mcs_spinlock *prev
> kernel/locking/qspinlock.c:418:22: got struct mcs_spinlock [pure] *
> kernel/locking/qspinlock_paravirt.h:519:1: sparse: symbol '__pv_queued_spin_unlock_slowpath' was not declared. Should it be static?
> kernel/locking/qspinlock.c:418:22: sparse: incorrect type in assignment (different modifiers) @@ expected struct mcs_spinlock *prev @@ got struct struct mcs_spinlock *prev @@
> kernel/locking/qspinlock.c:418:22: expected struct mcs_spinlock *prev
> kernel/locking/qspinlock.c:418:22: got struct mcs_spinlock [pure] *
>>> include/asm-generic/atomic-instrumented.h:288:24: sparse: cast truncates bits from constant value (100 becomes 0)
>
> vim +288 include/asm-generic/atomic-instrumented.h
>
> b06ed71a6 Dmitry Vyukov 2018-01-29 282
> b06ed71a6 Dmitry Vyukov 2018-01-29 283 static __always_inline unsigned long
> b06ed71a6 Dmitry Vyukov 2018-01-29 284 cmpxchg_size(volatile void *ptr, unsigned long old, unsigned long new, int size)
> b06ed71a6 Dmitry Vyukov 2018-01-29 285 {
> b06ed71a6 Dmitry Vyukov 2018-01-29 286 switch (size) {
> b06ed71a6 Dmitry Vyukov 2018-01-29 287 case 1:
> b06ed71a6 Dmitry Vyukov 2018-01-29 @288 return arch_cmpxchg((u8 *)ptr, (u8)old, (u8)new);
> b06ed71a6 Dmitry Vyukov 2018-01-29 289 case 2:
> b06ed71a6 Dmitry Vyukov 2018-01-29 290 return arch_cmpxchg((u16 *)ptr, (u16)old, (u16)new);
> b06ed71a6 Dmitry Vyukov 2018-01-29 291 case 4:
> b06ed71a6 Dmitry Vyukov 2018-01-29 292 return arch_cmpxchg((u32 *)ptr, (u32)old, (u32)new);
> b06ed71a6 Dmitry Vyukov 2018-01-29 293 case 8:
> b06ed71a6 Dmitry Vyukov 2018-01-29 294 BUILD_BUG_ON(sizeof(unsigned long) != 8);
> b06ed71a6 Dmitry Vyukov 2018-01-29 295 return arch_cmpxchg((u64 *)ptr, (u64)old, (u64)new);
> b06ed71a6 Dmitry Vyukov 2018-01-29 296 }
> b06ed71a6 Dmitry Vyukov 2018-01-29 297 BUILD_BUG();
> b06ed71a6 Dmitry Vyukov 2018-01-29 298 return 0;
> b06ed71a6 Dmitry Vyukov 2018-01-29 299 }
> b06ed71a6 Dmitry Vyukov 2018-01-29 300
>
> :::::: The code at line 288 was first introduced by commit
> :::::: b06ed71a624ba088a3e3e3ac7d4185f48c7c1660 locking/atomic, asm-generic: Add asm-generic/atomic-instrumented.h
>
> :::::: TO: Dmitry Vyukov <dvyukov@google.com>
> :::::: CC: Ingo Molnar <mingo@kernel.org>
I will take a look tomorrow.
next prev parent reply other threads:[~2018-03-12 15:17 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-12 14:52 [tip:locking/core 9/11] include/asm-generic/atomic-instrumented.h:288:24: sparse: cast truncates bits from constant value (100 becomes 0) kbuild test robot
2018-03-12 15:17 ` Dmitry Vyukov [this message]
2018-03-13 8:49 ` Dmitry Vyukov
2018-03-13 10:46 ` Peter Zijlstra
2018-03-13 11:08 ` Dmitry Vyukov
2018-03-13 17:29 ` Christopher Li
2018-03-13 18:00 ` Luc Van Oostenryck
2018-03-13 18:08 ` Peter Zijlstra
2018-03-13 20:01 ` Luc Van Oostenryck
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