lib: crc32: conditionally resched when running testcases

Fengguang reports that when crc32 selftests are running on startup, on
some e.g. 32bit systems, we can get a CPU stall like "INFO: rcu_sched
self-detected stall on CPU { 0} (t=2101 jiffies g=4294967081 c=4294967080
q=41)". As this is not intended, add a cond_resched() at the end of a
test case to fix it. Introduced by efba721f63 ("lib: crc32: add test cases
for crc32{, c}_combine routines").

Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

lib/crc32.c

@@ -29,6 +29,7 @@
 #include <linux/crc32.h>
 #include <linux/module.h>
 #include <linux/types.h>
+#include <linux/sched.h>
 #include "crc32defs.h"
 
 #if CRC_LE_BITS > 8
@@ -1054,6 +1055,7 @@ static int __init crc32c_combine_test(void)
 			      crc_full == test[i].crc32c_le))
 				errors++;
 			runs++;
+			cond_resched();
 		}
 	}
 
@@ -1147,6 +1149,7 @@ static int __init crc32_combine_test(void)
 			      crc_full == test[i].crc_le))
 				errors++;
 			runs++;
+			cond_resched();
 		}
 	}