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mgrzeschikVinod Koul
mgrzeschik
authored and
Vinod Koul
committed
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+ torvalds#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: [<c019d77c>] imxdma_tasklet+0x20/0x134 [ 403.395201] {IN-HARDIRQ-W} state was registered at: [ 403.400108] [<c004b264>] mark_lock+0x2a0/0x6b4 [ 403.404798] [<c004d7c8>] __lock_acquire+0x650/0x1a64 [ 403.410004] [<c004f15c>] lock_acquire+0x94/0xa8 [ 403.414773] [<c02f74e4>] _raw_spin_lock+0x54/0x8c [ 403.419720] [<c019d094>] dma_irq_handler+0x78/0x254 [ 403.424845] [<c0061124>] handle_irq_event_percpu+0x38/0x1b4 [ 403.430670] [<c00612e4>] handle_irq_event+0x44/0x64 [ 403.435789] [<c0063a70>] handle_level_irq+0xd8/0xf0 [ 403.440903] [<c0060a20>] generic_handle_irq+0x28/0x38 [ 403.446194] [<c0009cc4>] handle_IRQ+0x68/0x8c [ 403.450789] [<c0008714>] avic_handle_irq+0x3c/0x48 [ 403.455811] [<c0008f84>] __irq_svc+0x44/0x74 [ 403.460314] [<c0040b04>] cpu_startup_entry+0x88/0xf4 [ 403.465525] [<c02f00d0>] rest_init+0xb8/0xe0 [ 403.470045] [<c03e07dc>] start_kernel+0x28c/0x2d4 [ 403.474986] [<a0008040>] 0xa0008040 [ 403.478709] irq event stamp: 50854 [ 403.482140] hardirqs last enabled at (50854): [<c001c6b8>] tasklet_action+0x38/0xdc [ 403.489954] hardirqs last disabled at (50853): [<c001c6a0>] tasklet_action+0x20/0xdc [ 403.497761] softirqs last enabled at (50850): [<c001bc64>] _local_bh_enable+0x14/0x18 [ 403.505741] softirqs last disabled at (50851): [<c001c268>] 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] <Interrupt> [ 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+ torvalds#904 [ 403.563039] Backtrace: [ 403.565581] [<c000b98c>] (dump_backtrace+0x0/0x10c) from [<c000bb28>] (show_stack+0x18/0x1c) [ 403.574054] r6:00000000 r5:c05c51d8 r4:c040bd58 r3:00200000 [ 403.579872] [<c000bb10>] (show_stack+0x0/0x1c) from [<c02f398c>] (dump_stack+0x20/0x28) [ 403.587955] [<c02f396c>] (dump_stack+0x0/0x28) from [<c02f29c8>] (print_usage_bug.part.28+0x224/0x28c) [ 403.597340] [<c02f27a4>] (print_usage_bug.part.28+0x0/0x28c) from [<c004b404>] (mark_lock+0x440/0x6b4) [ 403.606682] r8:c004a41c r7:00000000 r6:c040bd58 r5:c040c040 r4:00000002 [ 403.613566] [<c004afc4>] (mark_lock+0x0/0x6b4) from [<c004d844>] (__lock_acquire+0x6cc/0x1a64) [ 403.622244] [<c004d178>] (__lock_acquire+0x0/0x1a64) from [<c004f15c>] (lock_acquire+0x94/0xa8) [ 403.631010] [<c004f0c8>] (lock_acquire+0x0/0xa8) from [<c02f74e4>] (_raw_spin_lock+0x54/0x8c) [ 403.639614] [<c02f7490>] (_raw_spin_lock+0x0/0x8c) from [<c019d77c>] (imxdma_tasklet+0x20/0x134) [ 403.648434] r6:c3847010 r5:c040e890 r4:c38470d4 [ 403.653194] [<c019d75c>] (imxdma_tasklet+0x0/0x134) from [<c001c70c>] (tasklet_action+0x8c/0xdc) [ 403.662013] r8:c0599160 r7:00000000 r6:00000000 r5:c040e890 r4:c3847114 r3:c019d75c [ 403.670042] [<c001c680>] (tasklet_action+0x0/0xdc) from [<c001bd4c>] (__do_softirq+0xe4/0x1f0) [ 403.678687] r7:00000101 r6:c0402000 r5:c059919c r4:00000001 [ 403.684498] [<c001bc68>] (__do_softirq+0x0/0x1f0) from [<c001c268>] (irq_exit+0x88/0xdc) [ 403.692652] [<c001c1e0>] (irq_exit+0x0/0xdc) from [<c0009cc8>] (handle_IRQ+0x6c/0x8c) [ 403.700514] r4:00000030 r3:00000110 [ 403.704192] [<c0009c5c>] (handle_IRQ+0x0/0x8c) from [<c0008714>] (avic_handle_irq+0x3c/0x48) [ 403.712664] r5:c0403f28 r4:c0593ebc [ 403.716343] [<c00086d8>] (avic_handle_irq+0x0/0x48) from [<c0008f84>] (__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 4106926 a03fb5f4 c0403f7c c0403f40 c0403f70 [ 403.746301] 3f60: c004b92c c0009e74 20000013 ffffffff [ 403.751383] r6:ffffffff r5:20000013 r4:c0009e74 r3:c004b92c [ 403.757210] [<c0009e30>] (arch_cpu_idle+0x0/0x4c) from [<c0040b04>] (cpu_startup_entry+0x88/0xf4) [ 403.766161] [<c0040a7c>] (cpu_startup_entry+0x0/0xf4) from [<c02f00d0>] (rest_init+0xb8/0xe0) [ 403.774753] [<c02f0018>] (rest_init+0x0/0xe0) from [<c03e07dc>] (start_kernel+0x28c/0x2d4) [ 403.783051] r6:c03fc484 r5:ffffffff r4:c040a0e0 [ 403.787797] [<c03e0550>] (start_kernel+0x0/0x2d4) from [<a0008040>] (0xa0008040) Signed-off-by: Michael Grzeschik <m.grzeschik@pengutronix.de> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
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‎drivers/dma/imx-dma.c

Lines changed: 8 additions & 11 deletions
Original file line numberDiff line numberDiff line change
@@ -437,17 +437,18 @@ static void dma_irq_handle_channel(struct imxdma_channel *imxdmac)
437437
struct imxdma_engine *imxdma = imxdmac->imxdma;
438438
int chno = imxdmac->channel;
439439
struct imxdma_desc *desc;
440+
unsigned long flags;
440441

441-
spin_lock(&imxdma->lock);
442+
spin_lock_irqsave(&imxdma->lock, flags);
442443
if (list_empty(&imxdmac->ld_active)) {
443-
spin_unlock(&imxdma->lock);
444+
spin_unlock_irqrestore(&imxdma->lock, flags);
444445
goto out;
445446
}
446447

447448
desc = list_first_entry(&imxdmac->ld_active,
448449
struct imxdma_desc,
449450
node);
450-
spin_unlock(&imxdma->lock);
451+
spin_unlock_irqrestore(&imxdma->lock, flags);
451452

452453
if (desc->sg) {
453454
u32 tmp;
@@ -519,15 +520,13 @@ static int imxdma_xfer_desc(struct imxdma_desc *d)
519520
{
520521
struct imxdma_channel *imxdmac = to_imxdma_chan(d->desc.chan);
521522
struct imxdma_engine *imxdma = imxdmac->imxdma;
522-
unsigned long flags;
523523
int slot = -1;
524524
int i;
525525

526526
/* Configure and enable */
527527
switch (d->type) {
528528
case IMXDMA_DESC_INTERLEAVED:
529529
/* Try to get a free 2D slot */
530-
spin_lock_irqsave(&imxdma->lock, flags);
531530
for (i = 0; i < IMX_DMA_2D_SLOTS; i++) {
532531
if ((imxdma->slots_2d[i].count > 0) &&
533532
((imxdma->slots_2d[i].xsr != d->x) ||
@@ -537,10 +536,8 @@ static int imxdma_xfer_desc(struct imxdma_desc *d)
537536
slot = i;
538537
break;
539538
}
540-
if (slot < 0) {
541-
spin_unlock_irqrestore(&imxdma->lock, flags);
539+
if (slot < 0)
542540
return -EBUSY;
543-
}
544541

545542
imxdma->slots_2d[slot].xsr = d->x;
546543
imxdma->slots_2d[slot].ysr = d->y;
@@ -549,7 +546,6 @@ static int imxdma_xfer_desc(struct imxdma_desc *d)
549546

550547
imxdmac->slot_2d = slot;
551548
imxdmac->enabled_2d = true;
552-
spin_unlock_irqrestore(&imxdma->lock, flags);
553549

554550
if (slot == IMX_DMA_2D_SLOT_A) {
555551
d->config_mem &= ~CCR_MSEL_B;
@@ -625,8 +621,9 @@ static void imxdma_tasklet(unsigned long data)
625621
struct imxdma_channel *imxdmac = (void *)data;
626622
struct imxdma_engine *imxdma = imxdmac->imxdma;
627623
struct imxdma_desc *desc;
624+
unsigned long flags;
628625

629-
spin_lock(&imxdma->lock);
626+
spin_lock_irqsave(&imxdma->lock, flags);
630627

631628
if (list_empty(&imxdmac->ld_active)) {
632629
/* Someone might have called terminate all */
@@ -663,7 +660,7 @@ static void imxdma_tasklet(unsigned long data)
663660
__func__, imxdmac->channel);
664661
}
665662
out:
666-
spin_unlock(&imxdma->lock);
663+
spin_unlock_irqrestore(&imxdma->lock, flags);
667664
}
668665

669666
static int imxdma_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd,

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