Le 25/10/2019 à 07:52, Qian Cai a écrit :
On Oct 24, 2019, at 11:45 PM, Anshuman Khandual <Anshuman.Khandual@xxxxxxx> wrote:
Nothing specific. But just tested this with x86 defconfig with relevant configs
which are required for this test. Not sure if it involved W=1.
No, it will not. It needs to run like,
make W=1 -j 64 2>/tmp/warns
Are we talking about this peace of code ?
+static unsigned long __init get_random_vaddr(void)
+{
+ unsigned long random_vaddr, random_pages, total_user_pages;
+
+ total_user_pages = (TASK_SIZE - FIRST_USER_ADDRESS) / PAGE_SIZE;
+
+ random_pages = get_random_long() % total_user_pages;
+ random_vaddr = FIRST_USER_ADDRESS + random_pages * PAGE_SIZE;
+
+ WARN_ON((random_vaddr > TASK_SIZE) ||
+ (random_vaddr < FIRST_USER_ADDRESS));
+ return random_vaddr;
+}
+
ramdom_vaddr is unsigned,
random_pages is unsigned and lower than total_user_pages
So the max value random_vaddr can get is FIRST_USER_ADDRESS +
((TASK_SIZE - FIRST_USER_ADDRESS - 1) / PAGE_SIZE) * PAGE_SIZE =
TASK_SIZE - 1
And the min value random_vaddr can get is FIRST_USER_ADDRESS (that's
when random_pages = 0)
So the WARN_ON() is just unneeded, isn't it ?
Christophe
