Greetings, The below warning shows up in linux-next and was fine in v3.13-rc4: [ 2.305687] Trying default address 0x9400000 [ 2.306177] SC520 CDP flash device: 0x800000 at 0x8400000 [ 2.306784] ------------[ cut here ]------------ [ 2.307297] WARNING: CPU: 1 PID: 1 at arch/x86/mm/ioremap.c:102 __ioremap_caller+0x28f/0x668() [ 2.308492] Modules linked in: [ 2.308862] CPU: 1 PID: 1 Comm: swapper/0 Not tainted 3.13.0-rc4-next-20131220-06014-gf15b2a3 #1 [ 2.309835] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 [ 2.310466] 0000000000000006 ffff88000ecdfd90 ffffffff8867b58b 0000000000000000 [ 2.311341] ffff88000ecdfdc8 ffffffff87c7df1b ffffffff87c42291 0000000008400000 [ 2.312221] 0000000000000010 0000000000008400 0000000000000001 ffff88000ecdfdd8 [ 2.313112] Call Trace: [ 2.313394] [] dump_stack+0xa1/0xd6 [ 2.313965] [] warn_slowpath_common+0xb0/0xde [ 2.314619] [] ? __ioremap_caller+0x28f/0x668 [ 2.315273] [] warn_slowpath_null+0x28/0x31 [ 2.315927] [] __ioremap_caller+0x28f/0x668 [ 2.316584] [] ? init_sc520cdp+0x17d/0x389 [ 2.317213] [] ioremap_nocache+0x25/0x2e [ 2.317830] [] init_sc520cdp+0x17d/0x389 [ 2.318437] [] ? init_l440gx+0x469/0x469 [ 2.319053] [] do_one_initcall+0xcf/0x1f3 [ 2.319710] [] ? parameq+0x29/0x32 [ 2.320268] [] ? parse_args+0x274/0x3af [ 2.320886] [] kernel_init_freeable+0x1ea/0x2ea [ 2.321557] [] ? do_early_param+0xd7/0xd7 [ 2.322202] [] ? rest_init+0x167/0x167 [ 2.322828] [] kernel_init+0x15/0x186 [ 2.323413] [] ret_from_fork+0x7c/0xb0 [ 2.324018] [] ? rest_init+0x167/0x167 [ 2.324621] ---[ end trace 79acbb3d3c741c0f ]--- [ 2.341477] kworker/u4:1 (78) used greatest stack depth: 6288 bytes left Attached is the full dmesg and kconfig that can trigger this warning. Thanks, Fengguang