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!
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
