On Tue, Jan 12, 2021 at 05:41:46PM +0300, Dan Carpenter wrote:
> Hello Paul E. McKenney,
>
> The patch b3a539cc4d37: "EXP rcuscale: Add crude tests for
> mem_dump_obj()" from Dec 7, 2020, leads to the following static
> checker warning:
>
> kernel/rcu/rcutorture.c:1888 rcu_torture_stats()
> warn: did you mean to pass the address of 'rhp'
>
> kernel/rcu/rcutorture.c
> 1865 {
> 1866 struct rcu_head *rhp;
> 1867 struct kmem_cache *kcp;
> 1868 static int z;
> 1869
> 1870 kcp = kmem_cache_create("rcuscale", 136, 8, SLAB_STORE_USER, NULL);
> 1871 rhp = kmem_cache_alloc(kcp, GFP_KERNEL);
> 1872 pr_alert("mem_dump_obj() slab test: rcu_torture_stats = %px, &rhp = %px, rhp = %px, &z = %px\n", stats_task, &rhp, rhp, &z);
> ^^^^
> Hopefully the address of rhp doesn't change at all in this function 0_0!
One would hope!
The duplication makes it easier to check the output. Without it,
it is necessary to get some information from the immediately preceding
pr_alert() and others of it from the first pr_alert().
Thanx, Paul
> 1873 pr_alert("mem_dump_obj(ZERO_SIZE_PTR):");
> 1874 mem_dump_obj(ZERO_SIZE_PTR);
> 1875 pr_alert("mem_dump_obj(NULL):");
> 1876 mem_dump_obj(NULL);
> 1877 pr_alert("mem_dump_obj(%px):", &rhp);
> 1878 mem_dump_obj(&rhp);
> 1879 pr_alert("mem_dump_obj(%px):", rhp);
> 1880 mem_dump_obj(rhp);
> 1881 pr_alert("mem_dump_obj(%px):", &rhp->func);
> 1882 mem_dump_obj(&rhp->func);
> 1883 pr_alert("mem_dump_obj(%px):", &z);
> 1884 mem_dump_obj(&z);
> 1885 kmem_cache_free(kcp, rhp);
> 1886 kmem_cache_destroy(kcp);
> 1887 rhp = kmalloc(sizeof(*rhp), GFP_KERNEL);
> 1888 pr_alert("mem_dump_obj() kmalloc test: rcu_torture_stats = %px, &rhp = %px, rhp = %px\n", stats_task, &rhp, rhp);
> 1889 pr_alert("mem_dump_obj(kmalloc %px):", rhp);
> 1890 mem_dump_obj(rhp);
> 1891 pr_alert("mem_dump_obj(kmalloc %px):", &rhp->func);
> 1892 mem_dump_obj(&rhp->func);
> 1893 kfree(rhp);
> 1894 rhp = vmalloc(4096);
> 1895 pr_alert("mem_dump_obj() vmalloc test: rcu_torture_stats = %px, &rhp = %px, rhp = %px\n", stats_task, &rhp, rhp);
> 1896 pr_alert("mem_dump_obj(vmalloc %px):", rhp);
> 1897 mem_dump_obj(rhp);
> 1898 pr_alert("mem_dump_obj(vmalloc %px):", &rhp->func);
> 1899 mem_dump_obj(&rhp->func);
> 1900 vfree(rhp);
> 1901 }
>
> regards,
> dan carpenter
