* [PATCH] percpu: add __percpu to SHIFT_PERCPU_PTR @ 2019-10-15 10:26 Ben Dooks 2019-10-17 18:13 ` Dennis Zhou 0 siblings, 1 reply; 4+ messages in thread From: Ben Dooks @ 2019-10-15 10:26 UTC (permalink / raw) To: linux-kernel Cc: Ben Dooks, Dennis Zhou, Tejun Heo, Christoph Lameter, linux-kernel The SHIFT_PERCPU_PTR() returns a pointer used by a number of functions that expect the pointer to be __percpu annotated (sparse address space 3). Adding __percpu to this makes the following sparse warnings go away. Note, this then creates the problem the __percup is marked as noderef, which may need removing for some of the internal functions, or to remove other warnings. mm/vmstat.c:385:13: warning: incorrect type in initializer (different address spaces) mm/vmstat.c:385:13: expected signed char [noderef] [usertype] <asn:3> *__p mm/vmstat.c:385:13: got signed char * mm/vmstat.c:385:13: warning: incorrect type in initializer (different address spaces) mm/vmstat.c:385:13: expected signed char [noderef] [usertype] <asn:3> *__p mm/vmstat.c:385:13: got signed char * mm/vmstat.c:385:13: warning: incorrect type in initializer (different address spaces) mm/vmstat.c:385:13: expected signed char [noderef] [usertype] <asn:3> *__p mm/vmstat.c:385:13: got signed char * mm/vmstat.c:385:13: warning: incorrect type in initializer (different address spaces) mm/vmstat.c:385:13: expected signed char [noderef] [usertype] <asn:3> *__p mm/vmstat.c:385:13: got signed char * mm/vmstat.c:401:13: warning: incorrect type in initializer (different address spaces) mm/vmstat.c:401:13: expected signed char [noderef] [usertype] <asn:3> *__p mm/vmstat.c:401:13: got signed char * mm/vmstat.c:401:13: warning: incorrect type in initializer (different address spaces) mm/vmstat.c:401:13: expected signed char [noderef] [usertype] <asn:3> *__p mm/vmstat.c:401:13: got signed char * mm/vmstat.c:401:13: warning: incorrect type in initializer (different address spaces) mm/vmstat.c:401:13: expected signed char [noderef] [usertype] <asn:3> *__p mm/vmstat.c:401:13: got signed char * mm/vmstat.c:401:13: warning: incorrect type in initializer (different address spaces) mm/vmstat.c:401:13: expected signed char [noderef] [usertype] <asn:3> *__p mm/vmstat.c:401:13: got signed char * mm/vmstat.c:429:13: warning: incorrect type in initializer (different address spaces) mm/vmstat.c:429:13: expected signed char [noderef] [usertype] <asn:3> *__p mm/vmstat.c:429:13: got signed char * mm/vmstat.c:429:13: warning: incorrect type in initializer (different address spaces) mm/vmstat.c:429:13: expected signed char [noderef] [usertype] <asn:3> *__p mm/vmstat.c:429:13: got signed char * mm/vmstat.c:429:13: warning: incorrect type in initializer (different address spaces) mm/vmstat.c:429:13: expected signed char [noderef] [usertype] <asn:3> *__p mm/vmstat.c:429:13: got signed char * mm/vmstat.c:429:13: warning: incorrect type in initializer (different address spaces) mm/vmstat.c:429:13: expected signed char [noderef] [usertype] <asn:3> *__p mm/vmstat.c:429:13: got signed char * mm/vmstat.c:445:13: warning: incorrect type in initializer (different address spaces) mm/vmstat.c:445:13: expected signed char [noderef] [usertype] <asn:3> *__p mm/vmstat.c:445:13: got signed char * mm/vmstat.c:445:13: warning: incorrect type in initializer (different address spaces) mm/vmstat.c:445:13: expected signed char [noderef] [usertype] <asn:3> *__p mm/vmstat.c:445:13: got signed char * mm/vmstat.c:445:13: warning: incorrect type in initializer (different address spaces) mm/vmstat.c:445:13: expected signed char [noderef] [usertype] <asn:3> *__p mm/vmstat.c:445:13: got signed char * mm/vmstat.c:445:13: warning: incorrect type in initializer (different address spaces) mm/vmstat.c:445:13: expected signed char [noderef] [usertype] <asn:3> *__p mm/vmstat.c:445:13: got signed char * mm/vmstat.c:763:29: warning: incorrect type in initializer (different address spaces) mm/vmstat.c:763:29: expected signed char [noderef] <asn:3> *__p mm/vmstat.c:763:29: got signed char * mm/vmstat.c:763:29: warning: incorrect type in initializer (different address spaces) mm/vmstat.c:763:29: expected signed char [noderef] <asn:3> *__p mm/vmstat.c:763:29: got signed char * mm/vmstat.c:763:29: warning: incorrect type in initializer (different address spaces) mm/vmstat.c:763:29: expected signed char [noderef] <asn:3> *__p mm/vmstat.c:763:29: got signed char * mm/vmstat.c:763:29: warning: incorrect type in initializer (different address spaces) mm/vmstat.c:763:29: expected signed char [noderef] <asn:3> *__p mm/vmstat.c:763:29: got signed char * mm/vmstat.c:825:29: warning: incorrect type in initializer (different address spaces) mm/vmstat.c:825:29: expected signed char [noderef] <asn:3> *__p mm/vmstat.c:825:29: got signed char * mm/vmstat.c:825:29: warning: incorrect type in initializer (different address spaces) mm/vmstat.c:825:29: expected signed char [noderef] <asn:3> *__p mm/vmstat.c:825:29: got signed char * mm/vmstat.c:825:29: warning: incorrect type in initializer (different address spaces) mm/vmstat.c:825:29: expected signed char [noderef] <asn:3> *__p mm/vmstat.c:825:29: got signed char * mm/vmstat.c:825:29: warning: incorrect type in initializer (different address spaces) mm/vmstat.c:825:29: expected signed char [noderef] <asn:3> *__p mm/vmstat.c:825:29: got signed char * Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk> --- Cc: Dennis Zhou <dennis@kernel.org> Cc: Tejun Heo <tj@kernel.org> Cc: Christoph Lameter <cl@linux.com> Cc: linux-kernel@vger.kernel.org --- include/linux/percpu-defs.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/linux/percpu-defs.h b/include/linux/percpu-defs.h index a6fabd865211..a49b6c702598 100644 --- a/include/linux/percpu-defs.h +++ b/include/linux/percpu-defs.h @@ -229,7 +229,7 @@ do { \ * pointer value. The weird cast keeps both GCC and sparse happy. */ #define SHIFT_PERCPU_PTR(__p, __offset) \ - RELOC_HIDE((typeof(*(__p)) __kernel __force *)(__p), (__offset)) + RELOC_HIDE((typeof(*(__p)) __kernel __percpu __force *)(__p), (__offset)) #define per_cpu_ptr(ptr, cpu) \ ({ \ -- 2.23.0 ^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] percpu: add __percpu to SHIFT_PERCPU_PTR 2019-10-15 10:26 [PATCH] percpu: add __percpu to SHIFT_PERCPU_PTR Ben Dooks @ 2019-10-17 18:13 ` Dennis Zhou 2019-11-25 22:41 ` Dennis Zhou 0 siblings, 1 reply; 4+ messages in thread From: Dennis Zhou @ 2019-10-17 18:13 UTC (permalink / raw) To: Ben Dooks Cc: linux-kernel, Dennis Zhou, Tejun Heo, Christoph Lameter, linux-kernel On Tue, Oct 15, 2019 at 11:26:15AM +0100, Ben Dooks wrote: > The SHIFT_PERCPU_PTR() returns a pointer used by a number > of functions that expect the pointer to be __percpu annotated > (sparse address space 3). Adding __percpu to this makes the > following sparse warnings go away. > > Note, this then creates the problem the __percup is marked > as noderef, which may need removing for some of the internal > functions, or to remove other warnings. > > mm/vmstat.c:385:13: warning: incorrect type in initializer (different address spaces) > mm/vmstat.c:385:13: expected signed char [noderef] [usertype] <asn:3> *__p > mm/vmstat.c:385:13: got signed char * > mm/vmstat.c:385:13: warning: incorrect type in initializer (different address spaces) > mm/vmstat.c:385:13: expected signed char [noderef] [usertype] <asn:3> *__p > mm/vmstat.c:385:13: got signed char * > mm/vmstat.c:385:13: warning: incorrect type in initializer (different address spaces) > mm/vmstat.c:385:13: expected signed char [noderef] [usertype] <asn:3> *__p > mm/vmstat.c:385:13: got signed char * > mm/vmstat.c:385:13: warning: incorrect type in initializer (different address spaces) > mm/vmstat.c:385:13: expected signed char [noderef] [usertype] <asn:3> *__p > mm/vmstat.c:385:13: got signed char * > mm/vmstat.c:401:13: warning: incorrect type in initializer (different address spaces) > mm/vmstat.c:401:13: expected signed char [noderef] [usertype] <asn:3> *__p > mm/vmstat.c:401:13: got signed char * > mm/vmstat.c:401:13: warning: incorrect type in initializer (different address spaces) > mm/vmstat.c:401:13: expected signed char [noderef] [usertype] <asn:3> *__p > mm/vmstat.c:401:13: got signed char * > mm/vmstat.c:401:13: warning: incorrect type in initializer (different address spaces) > mm/vmstat.c:401:13: expected signed char [noderef] [usertype] <asn:3> *__p > mm/vmstat.c:401:13: got signed char * > mm/vmstat.c:401:13: warning: incorrect type in initializer (different address spaces) > mm/vmstat.c:401:13: expected signed char [noderef] [usertype] <asn:3> *__p > mm/vmstat.c:401:13: got signed char * > mm/vmstat.c:429:13: warning: incorrect type in initializer (different address spaces) > mm/vmstat.c:429:13: expected signed char [noderef] [usertype] <asn:3> *__p > mm/vmstat.c:429:13: got signed char * > mm/vmstat.c:429:13: warning: incorrect type in initializer (different address spaces) > mm/vmstat.c:429:13: expected signed char [noderef] [usertype] <asn:3> *__p > mm/vmstat.c:429:13: got signed char * > mm/vmstat.c:429:13: warning: incorrect type in initializer (different address spaces) > mm/vmstat.c:429:13: expected signed char [noderef] [usertype] <asn:3> *__p > mm/vmstat.c:429:13: got signed char * > mm/vmstat.c:429:13: warning: incorrect type in initializer (different address spaces) > mm/vmstat.c:429:13: expected signed char [noderef] [usertype] <asn:3> *__p > mm/vmstat.c:429:13: got signed char * > mm/vmstat.c:445:13: warning: incorrect type in initializer (different address spaces) > mm/vmstat.c:445:13: expected signed char [noderef] [usertype] <asn:3> *__p > mm/vmstat.c:445:13: got signed char * > mm/vmstat.c:445:13: warning: incorrect type in initializer (different address spaces) > mm/vmstat.c:445:13: expected signed char [noderef] [usertype] <asn:3> *__p > mm/vmstat.c:445:13: got signed char * > mm/vmstat.c:445:13: warning: incorrect type in initializer (different address spaces) > mm/vmstat.c:445:13: expected signed char [noderef] [usertype] <asn:3> *__p > mm/vmstat.c:445:13: got signed char * > mm/vmstat.c:445:13: warning: incorrect type in initializer (different address spaces) > mm/vmstat.c:445:13: expected signed char [noderef] [usertype] <asn:3> *__p > mm/vmstat.c:445:13: got signed char * > mm/vmstat.c:763:29: warning: incorrect type in initializer (different address spaces) > mm/vmstat.c:763:29: expected signed char [noderef] <asn:3> *__p > mm/vmstat.c:763:29: got signed char * > mm/vmstat.c:763:29: warning: incorrect type in initializer (different address spaces) > mm/vmstat.c:763:29: expected signed char [noderef] <asn:3> *__p > mm/vmstat.c:763:29: got signed char * > mm/vmstat.c:763:29: warning: incorrect type in initializer (different address spaces) > mm/vmstat.c:763:29: expected signed char [noderef] <asn:3> *__p > mm/vmstat.c:763:29: got signed char * > mm/vmstat.c:763:29: warning: incorrect type in initializer (different address spaces) > mm/vmstat.c:763:29: expected signed char [noderef] <asn:3> *__p > mm/vmstat.c:763:29: got signed char * > mm/vmstat.c:825:29: warning: incorrect type in initializer (different address spaces) > mm/vmstat.c:825:29: expected signed char [noderef] <asn:3> *__p > mm/vmstat.c:825:29: got signed char * > mm/vmstat.c:825:29: warning: incorrect type in initializer (different address spaces) > mm/vmstat.c:825:29: expected signed char [noderef] <asn:3> *__p > mm/vmstat.c:825:29: got signed char * > mm/vmstat.c:825:29: warning: incorrect type in initializer (different address spaces) > mm/vmstat.c:825:29: expected signed char [noderef] <asn:3> *__p > mm/vmstat.c:825:29: got signed char * > mm/vmstat.c:825:29: warning: incorrect type in initializer (different address spaces) > mm/vmstat.c:825:29: expected signed char [noderef] <asn:3> *__p > mm/vmstat.c:825:29: got signed char * > > Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk> > --- > Cc: Dennis Zhou <dennis@kernel.org> > Cc: Tejun Heo <tj@kernel.org> > Cc: Christoph Lameter <cl@linux.com> > Cc: linux-kernel@vger.kernel.org > --- > include/linux/percpu-defs.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/include/linux/percpu-defs.h b/include/linux/percpu-defs.h > index a6fabd865211..a49b6c702598 100644 > --- a/include/linux/percpu-defs.h > +++ b/include/linux/percpu-defs.h > @@ -229,7 +229,7 @@ do { \ > * pointer value. The weird cast keeps both GCC and sparse happy. > */ > #define SHIFT_PERCPU_PTR(__p, __offset) \ > - RELOC_HIDE((typeof(*(__p)) __kernel __force *)(__p), (__offset)) > + RELOC_HIDE((typeof(*(__p)) __kernel __percpu __force *)(__p), (__offset)) > > #define per_cpu_ptr(ptr, cpu) \ > ({ \ > -- > 2.23.0 > Hello, I've applied it for-5.5. Thanks, Dennis ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] percpu: add __percpu to SHIFT_PERCPU_PTR 2019-10-17 18:13 ` Dennis Zhou @ 2019-11-25 22:41 ` Dennis Zhou 2019-11-26 16:37 ` Luc Van Oostenryck 0 siblings, 1 reply; 4+ messages in thread From: Dennis Zhou @ 2019-11-25 22:41 UTC (permalink / raw) To: Dennis Zhou Cc: Ben Dooks, linux-kernel, Tejun Heo, Christoph Lameter, linux-kernel On Thu, Oct 17, 2019 at 02:13:01PM -0400, Dennis Zhou wrote: > On Tue, Oct 15, 2019 at 11:26:15AM +0100, Ben Dooks wrote: > > The SHIFT_PERCPU_PTR() returns a pointer used by a number > > of functions that expect the pointer to be __percpu annotated > > (sparse address space 3). Adding __percpu to this makes the > > following sparse warnings go away. > > > > Note, this then creates the problem the __percup is marked > > as noderef, which may need removing for some of the internal > > functions, or to remove other warnings. > > > > mm/vmstat.c:385:13: warning: incorrect type in initializer (different address spaces) > > mm/vmstat.c:385:13: expected signed char [noderef] [usertype] <asn:3> *__p > > mm/vmstat.c:385:13: got signed char * > > mm/vmstat.c:385:13: warning: incorrect type in initializer (different address spaces) > > mm/vmstat.c:385:13: expected signed char [noderef] [usertype] <asn:3> *__p > > mm/vmstat.c:385:13: got signed char * > > mm/vmstat.c:385:13: warning: incorrect type in initializer (different address spaces) > > mm/vmstat.c:385:13: expected signed char [noderef] [usertype] <asn:3> *__p > > mm/vmstat.c:385:13: got signed char * > > mm/vmstat.c:385:13: warning: incorrect type in initializer (different address spaces) > > mm/vmstat.c:385:13: expected signed char [noderef] [usertype] <asn:3> *__p > > mm/vmstat.c:385:13: got signed char * > > mm/vmstat.c:401:13: warning: incorrect type in initializer (different address spaces) > > mm/vmstat.c:401:13: expected signed char [noderef] [usertype] <asn:3> *__p > > mm/vmstat.c:401:13: got signed char * > > mm/vmstat.c:401:13: warning: incorrect type in initializer (different address spaces) > > mm/vmstat.c:401:13: expected signed char [noderef] [usertype] <asn:3> *__p > > mm/vmstat.c:401:13: got signed char * > > mm/vmstat.c:401:13: warning: incorrect type in initializer (different address spaces) > > mm/vmstat.c:401:13: expected signed char [noderef] [usertype] <asn:3> *__p > > mm/vmstat.c:401:13: got signed char * > > mm/vmstat.c:401:13: warning: incorrect type in initializer (different address spaces) > > mm/vmstat.c:401:13: expected signed char [noderef] [usertype] <asn:3> *__p > > mm/vmstat.c:401:13: got signed char * > > mm/vmstat.c:429:13: warning: incorrect type in initializer (different address spaces) > > mm/vmstat.c:429:13: expected signed char [noderef] [usertype] <asn:3> *__p > > mm/vmstat.c:429:13: got signed char * > > mm/vmstat.c:429:13: warning: incorrect type in initializer (different address spaces) > > mm/vmstat.c:429:13: expected signed char [noderef] [usertype] <asn:3> *__p > > mm/vmstat.c:429:13: got signed char * > > mm/vmstat.c:429:13: warning: incorrect type in initializer (different address spaces) > > mm/vmstat.c:429:13: expected signed char [noderef] [usertype] <asn:3> *__p > > mm/vmstat.c:429:13: got signed char * > > mm/vmstat.c:429:13: warning: incorrect type in initializer (different address spaces) > > mm/vmstat.c:429:13: expected signed char [noderef] [usertype] <asn:3> *__p > > mm/vmstat.c:429:13: got signed char * > > mm/vmstat.c:445:13: warning: incorrect type in initializer (different address spaces) > > mm/vmstat.c:445:13: expected signed char [noderef] [usertype] <asn:3> *__p > > mm/vmstat.c:445:13: got signed char * > > mm/vmstat.c:445:13: warning: incorrect type in initializer (different address spaces) > > mm/vmstat.c:445:13: expected signed char [noderef] [usertype] <asn:3> *__p > > mm/vmstat.c:445:13: got signed char * > > mm/vmstat.c:445:13: warning: incorrect type in initializer (different address spaces) > > mm/vmstat.c:445:13: expected signed char [noderef] [usertype] <asn:3> *__p > > mm/vmstat.c:445:13: got signed char * > > mm/vmstat.c:445:13: warning: incorrect type in initializer (different address spaces) > > mm/vmstat.c:445:13: expected signed char [noderef] [usertype] <asn:3> *__p > > mm/vmstat.c:445:13: got signed char * > > mm/vmstat.c:763:29: warning: incorrect type in initializer (different address spaces) > > mm/vmstat.c:763:29: expected signed char [noderef] <asn:3> *__p > > mm/vmstat.c:763:29: got signed char * > > mm/vmstat.c:763:29: warning: incorrect type in initializer (different address spaces) > > mm/vmstat.c:763:29: expected signed char [noderef] <asn:3> *__p > > mm/vmstat.c:763:29: got signed char * > > mm/vmstat.c:763:29: warning: incorrect type in initializer (different address spaces) > > mm/vmstat.c:763:29: expected signed char [noderef] <asn:3> *__p > > mm/vmstat.c:763:29: got signed char * > > mm/vmstat.c:763:29: warning: incorrect type in initializer (different address spaces) > > mm/vmstat.c:763:29: expected signed char [noderef] <asn:3> *__p > > mm/vmstat.c:763:29: got signed char * > > mm/vmstat.c:825:29: warning: incorrect type in initializer (different address spaces) > > mm/vmstat.c:825:29: expected signed char [noderef] <asn:3> *__p > > mm/vmstat.c:825:29: got signed char * > > mm/vmstat.c:825:29: warning: incorrect type in initializer (different address spaces) > > mm/vmstat.c:825:29: expected signed char [noderef] <asn:3> *__p > > mm/vmstat.c:825:29: got signed char * > > mm/vmstat.c:825:29: warning: incorrect type in initializer (different address spaces) > > mm/vmstat.c:825:29: expected signed char [noderef] <asn:3> *__p > > mm/vmstat.c:825:29: got signed char * > > mm/vmstat.c:825:29: warning: incorrect type in initializer (different address spaces) > > mm/vmstat.c:825:29: expected signed char [noderef] <asn:3> *__p > > mm/vmstat.c:825:29: got signed char * > > > > Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk> > > --- > > Cc: Dennis Zhou <dennis@kernel.org> > > Cc: Tejun Heo <tj@kernel.org> > > Cc: Christoph Lameter <cl@linux.com> > > Cc: linux-kernel@vger.kernel.org > > --- > > include/linux/percpu-defs.h | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/include/linux/percpu-defs.h b/include/linux/percpu-defs.h > > index a6fabd865211..a49b6c702598 100644 > > --- a/include/linux/percpu-defs.h > > +++ b/include/linux/percpu-defs.h > > @@ -229,7 +229,7 @@ do { \ > > * pointer value. The weird cast keeps both GCC and sparse happy. > > */ > > #define SHIFT_PERCPU_PTR(__p, __offset) \ > > - RELOC_HIDE((typeof(*(__p)) __kernel __force *)(__p), (__offset)) > > + RELOC_HIDE((typeof(*(__p)) __kernel __percpu __force *)(__p), (__offset)) > > > > #define per_cpu_ptr(ptr, cpu) \ > > ({ \ > > -- > > 2.23.0 > > > > Hello, > > I've applied it for-5.5. > > Thanks, > Dennis Hi Ben, I've reverted this commit. After spending a little more time on it, I don't think this is the fix we want because after we call RELOC_HIDE, we are shifting from __percpu to __kernel address spaces as we're adding the offset here. Thanks, Dennis ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] percpu: add __percpu to SHIFT_PERCPU_PTR 2019-11-25 22:41 ` Dennis Zhou @ 2019-11-26 16:37 ` Luc Van Oostenryck 0 siblings, 0 replies; 4+ messages in thread From: Luc Van Oostenryck @ 2019-11-26 16:37 UTC (permalink / raw) To: Dennis Zhou Cc: Ben Dooks, linux-kernel, Tejun Heo, Christoph Lameter, linux-kernel On Mon, Nov 25, 2019 at 05:41:19PM -0500, Dennis Zhou wrote: > On Thu, Oct 17, 2019 at 02:13:01PM -0400, Dennis Zhou wrote: > > On Tue, Oct 15, 2019 at 11:26:15AM +0100, Ben Dooks wrote: > > > The SHIFT_PERCPU_PTR() returns a pointer used by a number > > > of functions that expect the pointer to be __percpu annotated > > > (sparse address space 3). Adding __percpu to this makes the > > > following sparse warnings go away. > > > > > > Note, this then creates the problem the __percup is marked > > > as noderef, which may need removing for some of the internal > > > functions, or to remove other warnings. > > > > > > diff --git a/include/linux/percpu-defs.h b/include/linux/percpu-defs.h > > > index a6fabd865211..a49b6c702598 100644 > > > --- a/include/linux/percpu-defs.h > > > +++ b/include/linux/percpu-defs.h > > > @@ -229,7 +229,7 @@ do { \ > > > * pointer value. The weird cast keeps both GCC and sparse happy. > > > */ > > > #define SHIFT_PERCPU_PTR(__p, __offset) \ > > > - RELOC_HIDE((typeof(*(__p)) __kernel __force *)(__p), (__offset)) > > > + RELOC_HIDE((typeof(*(__p)) __kernel __percpu __force *)(__p), (__offset)) > > > > > > #define per_cpu_ptr(ptr, cpu) \ > > > ({ \ > > > -- > > > 2.23.0 > > > > > Hi Ben, > > I've reverted this commit. After spending a little more time on it, I > don't think this is the fix we want because after we call RELOC_HIDE, > we are shifting from __percpu to __kernel address spaces as we're adding > the offset here. I agree. SHIFT_PERCPU_PTR()'s type is as designed. Also, it should be noted that this warning doesn't exist on x86. The problem lies in include/asm-generic/percpu.h, in this case within: #define raw_cpu_generic_add_return(pcp, val) \ ({ \ typeof(&(pcp)) __p = raw_cpu_ptr(&(pcp)); \ \ *__p += val; \ *__p; \ }) There, the variable __p is declared as a __percpu pointer but: 1) the value assigned to it, the return value of raw_cpu_ptr(), is not a plain (__kernel) pointer. 2) the variable is dereferenced just after when a __percpu pointer is implicitly __noderef. It's thus not SHIFT_PERCPU_PTR() or raw_cpu_ptr() that must have their return type changed but the declaration of __p. Here is a quick patch, only compile & sparse tested on mm/vmstat.c: diff --git a/include/asm-generic/percpu.h b/include/asm-generic/percpu.h index c2de013b2..757b667ca 100644 --- a/include/asm-generic/percpu.h +++ b/include/asm-generic/percpu.h @@ -74,7 +74,7 @@ do { \ #define raw_cpu_generic_add_return(pcp, val) \ ({ \ - typeof(&(pcp)) __p = raw_cpu_ptr(&(pcp)); \ + typeof(pcp) __kernel __force *__p = raw_cpu_ptr(&(pcp)); \ \ *__p += val; \ *__p; \ Note: the same problem is present in raw_cpu_generic_xchg(), raw_cpu_generic_cmpxchg() & raw_cpu_generic_cmpxchg_double() I need more testing and to evaluate possible side-effects before sending a proper patch. Best regards, -- Luc Van Oostenryck ^ permalink raw reply related [flat|nested] 4+ messages in thread
end of thread, other threads:[~2019-11-26 16:37 UTC | newest] Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2019-10-15 10:26 [PATCH] percpu: add __percpu to SHIFT_PERCPU_PTR Ben Dooks 2019-10-17 18:13 ` Dennis Zhou 2019-11-25 22:41 ` Dennis Zhou 2019-11-26 16:37 ` Luc Van Oostenryck
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