Commit da331ba8 authored Jul 03, 2013 by Bartlomiej Zolnierkiewicz Committed by Linus Torvalds Jul 03, 2013

drivers/dma/pl330.c: fix locking in pl330_free_chan_resources()



tasklet_kill() may sleep so call it before taking pch->lock.

Fixes following lockup:

  BUG: scheduling while atomic: cat/2383/0x00000002
  Modules linked in:
    unwind_backtrace+0x0/0xfc
    __schedule_bug+0x4c/0x58
    __schedule+0x690/0x6e0
    sys_sched_yield+0x70/0x78
    tasklet_kill+0x34/0x8c
    pl330_free_chan_resources+0x24/0x88
    dma_chan_put+0x4c/0x50
  [...]
  BUG: spinlock lockup suspected on CPU#0, swapper/0/0
   lock: 0xe52aa04c, .magic: dead4ead, .owner: cat/2383, .owner_cpu: 1
    unwind_backtrace+0x0/0xfc
    do_raw_spin_lock+0x194/0x204
    _raw_spin_lock_irqsave+0x20/0x28
    pl330_tasklet+0x2c/0x5a8
    tasklet_action+0xfc/0x114
    __do_softirq+0xe4/0x19c
    irq_exit+0x98/0x9c
    handle_IPI+0x124/0x16c
    gic_handle_irq+0x64/0x68
    __irq_svc+0x40/0x70
    cpuidle_wrap_enter+0x4c/0xa0
    cpuidle_enter_state+0x18/0x68
    cpuidle_idle_call+0xac/0xe0
    cpu_idle+0xac/0xf0

Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Acked-by: Jassi Brar <jassisinghbrar@gmail.com>
Cc: Vinod Koul <vinod.koul@linux.intel.com>
Cc: Tomasz Figa <t.figa@samsung.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent fe746501

drivers/dma/pl330.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -2485,10 +2485,10 @@ static void pl330_free_chan_resources(struct dma_chan *chan)
		struct dma_pl330_chan *pch = to_pchan(chan);
		unsigned long flags;

		spin_lock_irqsave(&pch->lock, flags);

		tasklet_kill(&pch->task);

		spin_lock_irqsave(&pch->lock, flags);

		pl330_release_channel(pch->pl330_chid);
		pch->pl330_chid = NULL;

Admin message