lkml.org 
[lkml]   [2020]   [Aug]   [20]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 5.4 138/152] mfd: dln2: Run event handler loop under spinlock
    Date
    From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

    [ Upstream commit 3d858942250820b9adc35f963a257481d6d4c81d ]

    The event handler loop must be run with interrupts disabled.
    Otherwise we will have a warning:

    [ 1970.785649] irq 31 handler lineevent_irq_handler+0x0/0x20 enabled interrupts
    [ 1970.792739] WARNING: CPU: 0 PID: 0 at kernel/irq/handle.c:159 __handle_irq_event_percpu+0x162/0x170
    [ 1970.860732] RIP: 0010:__handle_irq_event_percpu+0x162/0x170
    ...
    [ 1970.946994] Call Trace:
    [ 1970.949446] <IRQ>
    [ 1970.951471] handle_irq_event_percpu+0x2c/0x80
    [ 1970.955921] handle_irq_event+0x23/0x43
    [ 1970.959766] handle_simple_irq+0x57/0x70
    [ 1970.963695] generic_handle_irq+0x42/0x50
    [ 1970.967717] dln2_rx+0xc1/0x210 [dln2]
    [ 1970.971479] ? usb_hcd_unmap_urb_for_dma+0xa6/0x1c0
    [ 1970.976362] __usb_hcd_giveback_urb+0x77/0xe0
    [ 1970.980727] usb_giveback_urb_bh+0x8e/0xe0
    [ 1970.984837] tasklet_action_common.isra.0+0x4a/0xe0
    ...

    Recently xHCI driver switched to tasklets in the commit 36dc01657b49
    ("usb: host: xhci: Support running urb giveback in tasklet context").

    The handle_irq_event_* functions are expected to be called with interrupts
    disabled and they rightfully complain here because we run in tasklet context
    with interrupts enabled.

    Use a event spinlock to protect event handler from being interrupted.

    Note, that there are only two users of this GPIO and ADC drivers and both of
    them are using generic_handle_irq() which makes above happen.

    Fixes: 338a12814297 ("mfd: Add support for Diolan DLN-2 devices")
    Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
    Signed-off-by: Lee Jones <lee.jones@linaro.org>
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    drivers/mfd/dln2.c | 4 ++++
    1 file changed, 4 insertions(+)

    diff --git a/drivers/mfd/dln2.c b/drivers/mfd/dln2.c
    index 4faa8d2e5d045..707f4287ab4a0 100644
    --- a/drivers/mfd/dln2.c
    +++ b/drivers/mfd/dln2.c
    @@ -287,7 +287,11 @@ static void dln2_rx(struct urb *urb)
    len = urb->actual_length - sizeof(struct dln2_header);

    if (handle == DLN2_HANDLE_EVENT) {
    + unsigned long flags;
    +
    + spin_lock_irqsave(&dln2->event_cb_lock, flags);
    dln2_run_event_callbacks(dln2, id, echo, data, len);
    + spin_unlock_irqrestore(&dln2->event_cb_lock, flags);
    } else {
    /* URB will be re-submitted in _dln2_transfer (free_rx_slot) */
    if (dln2_transfer_complete(dln2, urb, handle, echo))
    --
    2.25.1


    \
     
     \ /
      Last update: 2020-08-20 14:31    [W:4.196 / U:0.252 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site