From 5a276fa6bdf82fd442046969603968c83626ce0b Mon Sep 17 00:00:00 2001 From: Michael Grzeschik Date: Tue, 17 Sep 2013 15:56:07 +0200 Subject: [PATCH] dmaengine: imx-dma: fix lockdep issue between irqhandler and tasklet The tasklet and irqhandler are using spin_lock while other routines are using spin_lock_irqsave/restore. This leads to lockdep issues as described bellow. This patch is changing the code to use spinlock_irq_save/restore in both code pathes. As imxdma_xfer_desc always gets called with spin_lock_irqsave lock held, this patch also removes the spare call inside the routine to avoid double locking. [ 403.358162] ================================= [ 403.362549] [ INFO: inconsistent lock state ] [ 403.366945] 3.10.0-20130823+ #904 Not tainted [ 403.371331] --------------------------------- [ 403.375721] inconsistent {IN-HARDIRQ-W} -> {HARDIRQ-ON-W} usage. [ 403.381769] swapper/0 [HC0[0]:SC1[1]:HE1:SE0] takes: [ 403.386762] (&(&imxdma->lock)->rlock){?.-...}, at: [] imxdma_tasklet+0x20/0x134 [ 403.395201] {IN-HARDIRQ-W} state was registered at: [ 403.400108] [] mark_lock+0x2a0/0x6b4 [ 403.404798] [] __lock_acquire+0x650/0x1a64 [ 403.410004] [] lock_acquire+0x94/0xa8 [ 403.414773] [] _raw_spin_lock+0x54/0x8c [ 403.419720] [] dma_irq_handler+0x78/0x254 [ 403.424845] [] handle_irq_event_percpu+0x38/0x1b4 [ 403.430670] [] handle_irq_event+0x44/0x64 [ 403.435789] [] handle_level_irq+0xd8/0xf0 [ 403.440903] [] generic_handle_irq+0x28/0x38 [ 403.446194] [] handle_IRQ+0x68/0x8c [ 403.450789] [] avic_handle_irq+0x3c/0x48 [ 403.455811] [] __irq_svc+0x44/0x74 [ 403.460314] [] cpu_startup_entry+0x88/0xf4 [ 403.465525] [] rest_init+0xb8/0xe0 [ 403.470045] [] start_kernel+0x28c/0x2d4 [ 403.474986] [] 0xa0008040 [ 403.478709] irq event stamp: 50854 [ 403.482140] hardirqs last enabled at (50854): [] tasklet_action+0x38/0xdc [ 403.489954] hardirqs last disabled at (50853): [] tasklet_action+0x20/0xdc [ 403.497761] softirqs last enabled at (50850): [] _local_bh_enable+0x14/0x18 [ 403.505741] softirqs last disabled at (50851): [] irq_exit+0x88/0xdc [ 403.513026] [ 403.513026] other info that might help us debug this: [ 403.519593] Possible unsafe locking scenario: [ 403.519593] [ 403.525548] CPU0 [ 403.528020] ---- [ 403.530491] lock(&(&imxdma->lock)->rlock); [ 403.534828] [ 403.537474] lock(&(&imxdma->lock)->rlock); [ 403.541983] [ 403.541983] *** DEADLOCK *** [ 403.541983] [ 403.547951] no locks held by swapper/0. [ 403.551813] [ 403.551813] stack backtrace: [ 403.556222] CPU: 0 PID: 0 Comm: swapper Not tainted 3.10.0-20130823+ #904 [ 403.563039] Backtrace: [ 403.565581] [] (dump_backtrace+0x0/0x10c) from [] (show_stack+0x18/0x1c) [ 403.574054] r6:00000000 r5:c05c51d8 r4:c040bd58 r3:00200000 [ 403.579872] [] (show_stack+0x0/0x1c) from [] (dump_stack+0x20/0x28) [ 403.587955] [] (dump_stack+0x0/0x28) from [] (print_usage_bug.part.28+0x224/0x28c) [ 403.597340] [] (print_usage_bug.part.28+0x0/0x28c) from [] (mark_lock+0x440/0x6b4) [ 403.606682] r8:c004a41c r7:00000000 r6:c040bd58 r5:c040c040 r4:00000002 [ 403.613566] [] (mark_lock+0x0/0x6b4) from [] (__lock_acquire+0x6cc/0x1a64) [ 403.622244] [] (__lock_acquire+0x0/0x1a64) from [] (lock_acquire+0x94/0xa8) [ 403.631010] [] (lock_acquire+0x0/0xa8) from [] (_raw_spin_lock+0x54/0x8c) [ 403.639614] [] (_raw_spin_lock+0x0/0x8c) from [] (imxdma_tasklet+0x20/0x134) [ 403.648434] r6:c3847010 r5:c040e890 r4:c38470d4 [ 403.653194] [] (imxdma_tasklet+0x0/0x134) from [] (tasklet_action+0x8c/0xdc) [ 403.662013] r8:c0599160 r7:00000000 r6:00000000 r5:c040e890 r4:c3847114 r3:c019d75c [ 403.670042] [] (tasklet_action+0x0/0xdc) from [] (__do_softirq+0xe4/0x1f0) [ 403.678687] r7:00000101 r6:c0402000 r5:c059919c r4:00000001 [ 403.684498] [] (__do_softirq+0x0/0x1f0) from [] (irq_exit+0x88/0xdc) [ 403.692652] [] (irq_exit+0x0/0xdc) from [] (handle_IRQ+0x6c/0x8c) [ 403.700514] r4:00000030 r3:00000110 [ 403.704192] [] (handle_IRQ+0x0/0x8c) from [] (avic_handle_irq+0x3c/0x48) [ 403.712664] r5:c0403f28 r4:c0593ebc [ 403.716343] [] (avic_handle_irq+0x0/0x48) from [] (__irq_svc+0x44/0x74) [ 403.724733] Exception stack(0xc0403f28 to 0xc0403f70) [ 403.729841] 3f20: 00000001 00000004 00000000 20000013 c0402000 c04104a8 [ 403.738078] 3f40: 00000002 c0b69620 a0004000 41069264 a03fb5f4 c0403f7c c0403f40 c0403f70 [ 403.746301] 3f60: c004b92c c0009e74 20000013 ffffffff [ 403.751383] r6:ffffffff r5:20000013 r4:c0009e74 r3:c004b92c [ 403.757210] [] (arch_cpu_idle+0x0/0x4c) from [] (cpu_startup_entry+0x88/0xf4) [ 403.766161] [] (cpu_startup_entry+0x0/0xf4) from [] (rest_init+0xb8/0xe0) [ 403.774753] [] (rest_init+0x0/0xe0) from [] (start_kernel+0x28c/0x2d4) [ 403.783051] r6:c03fc484 r5:ffffffff r4:c040a0e0 [ 403.787797] [] (start_kernel+0x0/0x2d4) from [] (0xa0008040) Signed-off-by: Michael Grzeschik Signed-off-by: Vinod Koul --- drivers/dma/imx-dma.c | 19 ++++++++----------- 1 file changed, 8 insertions(+), 11 deletions(-) diff --git a/drivers/dma/imx-dma.c b/drivers/dma/imx-dma.c index 442af61..247aa7c 100644 --- a/drivers/dma/imx-dma.c +++ b/drivers/dma/imx-dma.c @@ -437,17 +437,18 @@ static void dma_irq_handle_channel(struct imxdma_channel *imxdmac) struct imxdma_engine *imxdma = imxdmac->imxdma; int chno = imxdmac->channel; struct imxdma_desc *desc; + unsigned long flags; - spin_lock(&imxdma->lock); + spin_lock_irqsave(&imxdma->lock, flags); if (list_empty(&imxdmac->ld_active)) { - spin_unlock(&imxdma->lock); + spin_unlock_irqrestore(&imxdma->lock, flags); goto out; } desc = list_first_entry(&imxdmac->ld_active, struct imxdma_desc, node); - spin_unlock(&imxdma->lock); + spin_unlock_irqrestore(&imxdma->lock, flags); if (desc->sg) { u32 tmp; @@ -519,7 +520,6 @@ static int imxdma_xfer_desc(struct imxdma_desc *d) { struct imxdma_channel *imxdmac = to_imxdma_chan(d->desc.chan); struct imxdma_engine *imxdma = imxdmac->imxdma; - unsigned long flags; int slot = -1; int i; @@ -527,7 +527,6 @@ static int imxdma_xfer_desc(struct imxdma_desc *d) switch (d->type) { case IMXDMA_DESC_INTERLEAVED: /* Try to get a free 2D slot */ - spin_lock_irqsave(&imxdma->lock, flags); for (i = 0; i < IMX_DMA_2D_SLOTS; i++) { if ((imxdma->slots_2d[i].count > 0) && ((imxdma->slots_2d[i].xsr != d->x) || @@ -537,10 +536,8 @@ static int imxdma_xfer_desc(struct imxdma_desc *d) slot = i; break; } - if (slot < 0) { - spin_unlock_irqrestore(&imxdma->lock, flags); + if (slot < 0) return -EBUSY; - } imxdma->slots_2d[slot].xsr = d->x; imxdma->slots_2d[slot].ysr = d->y; @@ -549,7 +546,6 @@ static int imxdma_xfer_desc(struct imxdma_desc *d) imxdmac->slot_2d = slot; imxdmac->enabled_2d = true; - spin_unlock_irqrestore(&imxdma->lock, flags); if (slot == IMX_DMA_2D_SLOT_A) { d->config_mem &= ~CCR_MSEL_B; @@ -625,8 +621,9 @@ static void imxdma_tasklet(unsigned long data) struct imxdma_channel *imxdmac = (void *)data; struct imxdma_engine *imxdma = imxdmac->imxdma; struct imxdma_desc *desc; + unsigned long flags; - spin_lock(&imxdma->lock); + spin_lock_irqsave(&imxdma->lock, flags); if (list_empty(&imxdmac->ld_active)) { /* Someone might have called terminate all */ @@ -663,7 +660,7 @@ static void imxdma_tasklet(unsigned long data) __func__, imxdmac->channel); } out: - spin_unlock(&imxdma->lock); + spin_unlock_irqrestore(&imxdma->lock, flags); } static int imxdma_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd, -- 2.7.4