lkml.org 
[lkml]   [2017]   [Feb]   [15]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [RFC] kasan stack overflow warnings again: READ_ONCE(), typecheck()
From
Date
On 02/15/2017 05:18 PM, Christian Borntraeger wrote:
> On 02/15/2017 12:03 AM, Arnd Bergmann wrote:
>>
>> -#define WRITE_ONCE(x, val) \
>> -({ \
>> - union { typeof(x) __val; char __c[1]; } __u = \
>> - { .__val = (__force typeof(x)) (val) }; \
>> - __write_once_size(&(x), __u.__c, sizeof(x)); \
>> - __u.__val; \
>> -})
>> +#define WRITE_ONCE(x, val) \
>> +( \
>> + __builtin_choose_expr(sizeof(x) == 1, *(volatile typeof(&(x)))&(x) = (val), \
>> + __builtin_choose_expr(sizeof(x) == 2, *(volatile typeof(&(x)))&(x) = (val), \
>> + __builtin_choose_expr(sizeof(x) == 4, *(volatile typeof(&(x)))&(x) = (val), \
>> + __builtin_choose_expr(sizeof(x) == sizeof(long), *(volatile typeof(&(x)))&(x) = (val), \
>
> Have you run sparse on those changes?
> IIRC we had to add the __force to get rid of address space annotations
> in that macro above. Cannot tell if we need something like that here.
>

The original warning was
fs/afs/inode.c:448:9: sparse: incorrect type in initializer (different address spaces)
fs/afs/inode.c:448:9: expected struct afs_permits *__val
fs/afs/inode.c:448:9: got void [noderef] <asn:4>*<noident>


\
 
 \ /
  Last update: 2017-02-15 17:20    [W:0.081 / U:0.040 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site