I'm doing some test on qihoo 360t7, after some time all system stuck. Fortunately, I can ping the device.
I add some test code in icmp_echo to show status for each task, and I also showed the stack for the task which status is D. The debug message shows that all tasks are stuck in squashfs_cache_get+0x2f4/0x3a0 and two worker task stuck in spinand_mtd_read+0x54/0x2fc.
I also changed the "spi-max-frequency = <52000000>;" to "spi-max-frequency = <40000000>;", but it dose not works.
I'm confuse if there can be 2 pending spinand_mtd_read for one spi nand device?
[ 254.915765] PID: 18, Comm: kworker/1:0, State: D (disk sleep)
[ 254.921506] [<0>] __switch_to+0xb4/0xf0
[ 254.925337] [<0>] spinand_mtd_read+0x54/0x2fc
[ 254.929690] [<0>] mtd_read_oob_std+0x58/0x80
[ 254.933950] [<0>] mtd_read_oob+0x8c/0x150
[ 254.937954] [<0>] mtd_read+0x50/0x70
[ 254.941519] [<0>] ubi_io_read+0xb8/0x36c
[ 254.945432] [<0>] ubi_eba_read_leb+0xac/0x4e0
[ 254.949783] [<0>] ubi_eba_read_leb_sg+0xbc/0x150
[ 254.954390] [<0>] ubi_leb_read_sg+0xe0/0x120
[ 254.958653] [<0>] ubiblock_do_work+0xc4/0x110
[ 254.962999] [<0>] process_one_work+0x210/0x3b0
[ 254.967432] [<0>] worker_thread+0x170/0x4d0
[ 254.971608] [<0>] kthread+0x110/0x120
[ 254.975261] [<0>] ret_from_fork+0x10/0x20
[ 254.979264] PID: 19, Comm: kworker/1:0H, State: I (idle)
[ 254.984563] PID: 20, Comm: inet_frag_wq, State: I (idle)
[ 254.989865] PID: 21, Comm: kworker/0:1, State: D (disk sleep)
[ 254.995601] [<0>] __switch_to+0xb4/0xf0
[ 254.999431] [<0>] spinand_mtd_read+0x54/0x2fc
[ 255.003778] [<0>] mtd_read_oob_std+0x58/0x80
[ 255.008041] [<0>] mtd_read_oob+0x8c/0x150
[ 255.012040] [<0>] mtd_read+0x50/0x70
[ 255.015606] [<0>] ubi_io_read+0xb8/0x36c
[ 255.019522] [<0>] ubi_eba_read_leb+0xac/0x4e0
[ 255.023869] [<0>] ubi_eba_read_leb_sg+0xbc/0x150
[ 255.028480] [<0>] ubi_leb_read_sg+0xe0/0x120
[ 255.032739] [<0>] ubiblock_do_work+0xc4/0x110
[ 255.037084] [<0>] process_one_work+0x210/0x3b0
[ 255.041521] [<0>] worker_thread+0x170/0x4d0
[ 255.045694] [<0>] kthread+0x110/0x120
[ 255.049350] [<0>] ret_from_fork+0x10/0x20