Hi

I  hit the following issue by runing /proc/vmallocinfo.  The kernel is 4.1 stable and
32 bit to be used.  after I expand the vamlloc area,  the issue is not occur again.
it is related to the overflow. but I do not see any problem so far.

cat /proc/vmallocinfo
0xf1580000-0xf1600000  524288 raw_dump_mem_write+0x10c/0x188 phys=8b901000 ioremap
0xf1638000-0xf163a000    8192 mcss_pou_queue_init+0xa0/0x13c [mcss] phys=fc614000 ioremap
0xf528e000-0xf5292000   16384 n_tty_open+0x10/0xd0 pages=3 vmalloc
0xf5000000-0xf9001000 67112960 devm_ioremap+0x38/0x70 phys=40000000 ioremap
0xfe001000-0xfe002000    4096 iotable_init+0x0/0xc phys=20001000 ioremap
0xfe200000-0xfe201000    4096 iotable_init+0x0/0xc phys=1a000000 ioremap
0xff100000-0xff101000    4096 iotable_init+0x0/0xc phys=2000a000 ioremap

n_tty_open allocate the vmap area is surrounded by the devm_ioremap ioremap by above info.
I do not see also the race in the condition.

I have no idea to the issue.  Anyone has any suggestions will be appreicated.
The related config is attatched.

Thanks
zhongjiang