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    SubjectRe: uart_startup: GFP_KERNEL allocation with IRQs disabled
    On 08/03/2012 03:46 AM, Fengguang Wu wrote:
    > Hi all,

    Hi,

    > The IRQ should be disabled somewhere in the path walk, which makes
    > the GFP_KERNEL allocation in uart_startup() no longer valid..
    >
    > [ 0.499537] kworker/u:1 (29) used greatest stack depth: 7156 bytes left
    > [ 0.500947] ------------[ cut here ]------------
    > [ 0.501445] WARNING: at /c/kernel-tests/src/stable/kernel/lockdep.c:2739 lockdep_trace_alloc+0x86/0xb2()
    > [ 0.502413] Modules linked in:
    > [ 0.502766] Pid: 1, comm: init Not tainted 3.5.0-01258-g1ade992 #182
    > [ 0.503419] Call Trace:
    ...
    > [ 0.504381] [<c1079e7d>] get_zeroed_page+0xd/0xf
    > [ 0.504381] [<c10f976f>] uart_startup.part.8+0x46/0x152
    > [ 0.504381] [<c10f745f>] ? tty_port_tty_set+0x37/0x3c
    > [ 0.504381] [<c10fa175>] uart_open+0xc9/0x10b
    > [ 0.504381] [<c10fa0ac>] ? uart_suspend_port+0x229/0x229
    > [ 0.504381] [<c10f1bc2>] tty_open+0x26b/0x3d3
    > [ 0.504381] [<c109872a>] chrdev_open+0xf7/0x117

    This does not make sense to me. I would not blame TTY/serial for this.
    There is somebody who forgot to enable interrupts somewhere. Could you
    enable DEBUG_ATOMIC_SLEEP? It might trigger earlier revealing us the
    culprit.

    thanks,
    --
    js
    suse labs


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