klog: ------------[ cut here ]------------
klog: WARNING: CPU: 0 PID: 307 at kernel/dma/mapping.c:335 dma_free_attrs+0xc4/0xc8
klog: Modules linked in: nf_defrag_ipv4
klog: CPU: 0 PID: 307 Comm: gina Not tainted 5.4.22 #4
klog: Hardware name: Freescale i.MX6 Quad/DualLite (Device Tree)
klog: [<c0110328>] (unwind_backtrace) from [<c010b7ec>] (show_stack+0x10/0x14)
klog: [<c010b7ec>] (show_stack) from [<c08dd7f8>] (dump_stack+0x90/0xa4)
klog: [<c08dd7f8>] (dump_stack) from [<c012bea0>] (__warn+0xbc/0xd8)
klog: [<c012bea0>] (__warn) from [<c012bf20>] (warn_slowpath_fmt+0x64/0xc4)
klog: [<c012bf20>] (warn_slowpath_fmt) from [<c0181a68>] (dma_free_attrs+0xc4/0xc8)
klog: [<c0181a68>] (dma_free_attrs) from [<c04631c8>] (sdma_free_bd+0x30/0x38)
klog: [<c04631c8>] (sdma_free_bd) from [<c04631dc>] (sdma_desc_free+0xc/0x18)
klog: [<c04631dc>] (sdma_desc_free) from [<c0464f70>] (sdma_channel_synchronize+0x48/0x88)
klog: [<c0464f70>] (sdma_channel_synchronize) from [<c0495fac>] (imx_uart_shutdown+0x16c/0x2a8)
klog: [<c0495fac>] (imx_uart_shutdown) from [<c04857b8>] (uart_port_shutdown+0x34/0x40)
klog: [<c04857b8>] (uart_port_shutdown) from [<c0485814>] (uart_tty_port_shutdown+0x50/0xb8)
klog: [<c0485814>] (uart_tty_port_shutdown) from [<c048144c>] (tty_port_shutdown+0x90/0x9c)
klog: [<c048144c>] (tty_port_shutdown) from [<c0481c2c>] (tty_port_close+0x3c/0x74)
klog: [<c0481c2c>] (tty_port_close) from [<c0478458>] (tty_release+0xf0/0x48c)
klog: [<c0478458>] (tty_release) from [<c02425ec>] (__fput+0x88/0x218)
klog: [<c02425ec>] (__fput) from [<c0147798>] (task_work_run+0xa4/0xc4)
klog: [<c0147798>] (task_work_run) from [<c010b310>] (do_work_pending+0x550/0x55c)
klog: [<c010b310>] (do_work_pending) from [<c010106c>] (slow_work_pending+0xc/0x20)
klog: Exception stack(0xee723fb0 to 0xee723ff8)
klog: 3fa0:                                     00000000 00005402 bea6ab64 00000000
klog: 3fc0: 00000000 b6f124d0 bea6aba4 00000006 0000000d 00000001 00084ff8 00000000
klog: 3fe0: 0004822c bea6ab88 00034780 b6d08c34 600b0010 00000006
klog: ---[ end trace 86fea4e74a267f57 ]---