From mboxrd@z Thu Jan 1 00:00:00 1970 From: b.zolnierkie@samsung.com (Bartlomiej Zolnierkiewicz) Date: Fri, 30 Nov 2012 11:59:30 +0100 Subject: [PATCH 1/4] DMA: PL330: fix locking in pl330_free_chan_resources() In-Reply-To: References: <1351504796-24788-1-git-send-email-b.zolnierkie@samsung.com> <1351504796-24788-2-git-send-email-b.zolnierkie@samsung.com> Message-ID: <201211301159.31098.b.zolnierkie@samsung.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Monday 29 October 2012 22:48:05 Jassi Brar wrote: > On Mon, Oct 29, 2012 at 10:59 AM, Bartlomiej Zolnierkiewicz > wrote: > > tasklet_kill() may sleep so call it before taking pch->lock. > > > > Fixes following lockup: > > > > [ 345.470000] BUG: scheduling while atomic: cat/2383/0x00000002 > > [ 345.470000] Modules linked in: > > [ 345.470000] [] (unwind_backtrace+0x0/0xfc) from [] (__schedule_bug+0x4c/0x58) > > [ 345.470000] [] (__schedule_bug+0x4c/0x58) from [] (__schedule+0x690/0x6e0) > > [ 345.470000] [] (__schedule+0x690/0x6e0) from [] (sys_sched_yield+0x70/0x78) > > [ 345.470000] [] (sys_sched_yield+0x70/0x78) from [] (tasklet_kill+0x34/0x8c) > > [ 345.470000] [] (tasklet_kill+0x34/0x8c) from [] (pl330_free_chan_resources+0x24/0x88) > > [ 345.470000] [] (pl330_free_chan_resources+0x24/0x88) from [] (dma_chan_put+0x4c/0x50) > > [ 345.470000] [] (dma_chan_put+0x4c/0x50) from [] (dma_release_channel+0x28/0x98) > > [...] > > [ 368.335000] BUG: spinlock lockup suspected on CPU#0, swapper/0/0 > > [ 368.340000] lock: 0xe52aa04c, .magic: dead4ead, .owner: cat/2383, .owner_cpu: 1 > > [ 368.350000] [] (unwind_backtrace+0x0/0xfc) from [] (do_raw_spin_lock+0x194/0x204) > > [ 368.360000] [] (do_raw_spin_lock+0x194/0x204) from [] (_raw_spin_lock_irqsave+0x20/0x28) > > [ 368.365000] [] (_raw_spin_lock_irqsave+0x20/0x28) from [] (pl330_tasklet+0x2c/0x5a8) > > [ 368.375000] [] (pl330_tasklet+0x2c/0x5a8) from [] (tasklet_action+0xfc/0x114) > > [ 368.385000] [] (tasklet_action+0xfc/0x114) from [] (__do_softirq+0xe4/0x19c) > > [ 368.395000] [] (__do_softirq+0xe4/0x19c) from [] (irq_exit+0x98/0x9c) > > [ 368.405000] [] (irq_exit+0x98/0x9c) from [] (handle_IPI+0x124/0x16c) > > [ 368.410000] [] (handle_IPI+0x124/0x16c) from [] (gic_handle_irq+0x64/0x68) > > [ 368.420000] [] (gic_handle_irq+0x64/0x68) from [] (__irq_svc+0x40/0x70) > > [ 368.430000] Exception stack(0xc04a3f00 to 0xc04a3f48) > > [ 368.435000] 3f00: c04a3f48 00000000 6f9e23e8 00000050 c07492c8 c04a3f48 00000000 c04ccc88 > > [ 368.440000] 3f20: 6f9dbac3 00000050 6f9e23e8 00000050 3b9aca00 c04a3f48 c005cfa4 c02946d4 > > [ 368.450000] 3f40: 60000013 ffffffff > > [ 368.455000] [] (__irq_svc+0x40/0x70) from [] (cpuidle_wrap_enter+0x4c/0xa0) > > [ 368.460000] [] (cpuidle_wrap_enter+0x4c/0xa0) from [] (cpuidle_enter_state+0x18/0x68) > > [ 368.470000] [] (cpuidle_enter_state+0x18/0x68) from [] (cpuidle_idle_call+0xac/0xe0) > > [ 368.480000] [] (cpuidle_idle_call+0xac/0xe0) from [] (cpu_idle+0xac/0xf0) > > [ 368.490000] [] (cpu_idle+0xac/0xf0) from [] (start_kernel+0x28c/0x294) > > > > Cc: Jassi Brar > > Cc: Vinod Koul > > Cc: Tomasz Figa > > Signed-off-by: Bartlomiej Zolnierkiewicz > > Signed-off-by: Kyungmin Park > > --- > > drivers/dma/pl330.c | 4 ++-- > > 1 file changed, 2 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/dma/pl330.c b/drivers/dma/pl330.c > > index 665668b..db7574b 100644 > > --- a/drivers/dma/pl330.c > > +++ b/drivers/dma/pl330.c > > @@ -2459,10 +2459,10 @@ 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; > > > Thanks. > > Acked-by: Jassi Brar Vinod/Dan could you please pick this patch for 3.8? Thanks! Best regards, -- Bartlomiej Zolnierkiewicz Samsung Poland R&D Center