Hi,
I was able to get deadlock with CONFIG_DEBUG_SPINLOCK enabled. I added
also CONFIG_PROVE_LOCKING to get more verbose output. I got following
error message after SDIO device has been powered.
I'm able to replicate issue with Linux next-20120710. Platform is imx28.
[ 79.660000] =============================================
[ 79.660000] [ INFO: possible recursive locking detected ]
[ 79.660000] 3.4.0-00009-g3e96082-dirty #11 Not tainted
[ 79.660000] ---------------------------------------------
[ 79.660000] swapper/0 is trying to acquire lock:
[ 79.660000] (&(&host->lock)->rlock#2){-.....}, at: [<c026ea3c>]
mxs_mmc_enable_sdio_irq+0x18/0xd4
[ 79.660000]
[ 79.660000] but task is already holding lock:
[ 79.660000] (&(&host->lock)->rlock#2){-.....}, at: [<c026f744>]
mxs_mmc_irq_handler+0x1c/0xe8
[ 79.660000]
[ 79.660000] other info that might help us debug this:
[ 79.660000] Possible unsafe locking scenario:
[ 79.660000]
[ 79.660000] CPU0
[ 79.660000] ----
[ 79.660000] lock(&(&host->lock)->rlock#2);
[ 79.660000] lock(&(&host->lock)->rlock#2);
[ 79.660000]
[ 79.660000] *** DEADLOCK ***
[ 79.660000]
[ 79.660000] May be due to missing lock nesting notation
[ 79.660000]
[ 79.660000] 1 lock held by swapper/0:
[ 79.660000] #0: (&(&host->lock)->rlock#2){-.....}, at: [<c026f744>]
mxs_mmc_irq_handler+0x1c/0xe8
[ 79.660000]
[ 79.660000] stack backtrace:
[ 79.660000] [<c0014bd0>] (unwind_backtrace+0x0/0xf4) from
[<c005f9c0>] (__lock_acquire+0x1948/0x1d48)
[ 79.660000] [<c005f9c0>] (__lock_acquire+0x1948/0x1d48) from
[<c005fea0>] (lock_acquire+0xe0/0xf8)
[ 79.660000] [<c005fea0>] (lock_acquire+0xe0/0xf8) from [<c03a8460>]
(_raw_spin_lock_irqsave+0x44/0x58)
[ 79.660000] [<c03a8460>] (_raw_spin_lock_irqsave+0x44/0x58) from
[<c026ea3c>] (mxs_mmc_enable_sdio_irq+0x18/0xd4)
[ 79.660000] [<c026ea3c>] (mxs_mmc_enable_sdio_irq+0x18/0xd4) from
[<c026f7fc>] (mxs_mmc_irq_handler+0xd4/0xe8)
[ 79.660000] [<c026f7fc>] (mxs_mmc_irq_handler+0xd4/0xe8) from
[<c006bdd8>] (handle_irq_event_percpu+0x70/0x254)
[ 79.660000] [<c006bdd8>] (handle_irq_event_percpu+0x70/0x254) from
[<c006bff8>] (handle_irq_event+0x3c/0x5c)
[ 79.660000] [<c006bff8>] (handle_irq_event+0x3c/0x5c) from
[<c006e6d0>] (handle_level_irq+0x90/0x110)
[ 79.660000] [<c006e6d0>] (handle_level_irq+0x90/0x110) from
[<c006b930>] (generic_handle_irq+0x38/0x50)
[ 79.660000] [<c006b930>] (generic_handle_irq+0x38/0x50) from
[<c00102fc>] (handle_IRQ+0x30/0x84)
[ 79.660000] [<c00102fc>] (handle_IRQ+0x30/0x84) from [<c000f058>]
(__irq_svc+0x38/0x60)
[ 79.660000] [<c000f058>] (__irq_svc+0x38/0x60) from [<c0010520>]
(default_idle+0x2c/0x40)
[ 79.660000] [<c0010520>] (default_idle+0x2c/0x40) from [<c0010a90>]
(cpu_idle+0x64/0xcc)
[ 79.660000] [<c0010a90>] (cpu_idle+0x64/0xcc) from [<c04ff858>]
(start_kernel+0x244/0x2c8)
[ 79.660000] BUG: spinlock lockup on CPU#0, swapper/0
[ 79.660000] lock: c398cb2c, .magic: dead4ead, .owner: swapper/0,
.owner_cpu: 0
[ 79.660000] [<c0014bd0>] (unwind_backtrace+0x0/0xf4) from
[<c01ddb1c>] (do_raw_spin_lock+0xf0/0x144)
[ 79.660000] [<c01ddb1c>] (do_raw_spin_lock+0xf0/0x144) from
[<c03a8468>] (_raw_spin_lock_irqsave+0x4c/0x58)
[ 79.660000] [<c03a8468>] (_raw_spin_lock_irqsave+0x4c/0x58) from
[<c026ea3c>] (mxs_mmc_enable_sdio_irq+0x18/0xd4)
[ 79.660000] [<c026ea3c>] (mxs_mmc_enable_sdio_irq+0x18/0xd4) from
[<c026f7fc>] (mxs_mmc_irq_handler+0xd4/0xe8)
[ 79.660000] [<c026f7fc>] (mxs_mmc_irq_handler+0xd4/0xe8) from
[<c006bdd8>] (handle_irq_event_percpu+0x70/0x254)
[ 79.660000] [<c006bdd8>] (handle_irq_event_percpu+0x70/0x254) from
[<c006bff8>] (handle_irq_event+0x3c/0x5c)
[ 79.660000] [<c006bff8>] (handle_irq_event+0x3c/0x5c) from
[<c006e6d0>] (handle_level_irq+0x90/0x110)
[ 79.660000] [<c006e6d0>] (handle_level_irq+0x90/0x110) from
[<c006b930>] (generic_handle_irq+0x38/0x50)
[ 79.660000] [<c006b930>] (generic_handle_irq+0x38/0x50) from
[<c00102fc>] (handle_IRQ+0x30/0x84)
[ 79.660000] [<c00102fc>] (handle_IRQ+0x30/0x84) from [<c000f058>]
(__irq_svc+0x38/0x60)
[ 79.660000] [<c000f058>] (__irq_svc+0x38/0x60) from [<c0010520>]
(default_idle+0x2c/0x40)
[ 79.660000] [<c0010520>] (default_idle+0x2c/0x40) from [<c0010a90>]
(cpu_idle+0x64/0xcc)
[ 79.660000] [<c0010a90>] (cpu_idle+0x64/0xcc) from [<c04ff858>]
(start_kernel+0x244/0x2c8)
I found a way to fix this issue:
--- a/drivers/mmc/host/mxs-mmc.c
+++ b/drivers/mmc/host/mxs-mmc.c
@@ -278,11 +278,11 @@ static irqreturn_t mxs_mmc_irq_handler(int irq,
void *dev_id)
writel(stat & MXS_MMC_IRQ_BITS,
host->base + HW_SSP_CTRL1(host) + STMP_OFFSET_REG_CLR);
+ spin_unlock(&host->lock);
+
if ((stat & BM_SSP_CTRL1_SDIO_IRQ) && (stat & BM_SSP_CTRL1_SDIO_IRQ_EN))
mmc_signal_sdio_irq(host->mmc);
- spin_unlock(&host->lock);
-
if (stat & BM_SSP_CTRL1_RESP_TIMEOUT_IRQ)
cmd->error = -ETIMEDOUT;
else if (stat & BM_SSP_CTRL1_RESP_ERR_IRQ)
Is there any reason to keep mmc_signal_sdio_irq inside the spinlock?
mmc_signal_sdio_irq calls mxs_mmc_enable_sdio_irq and it tries to
acquire lock while it is already acquired.
Best regards,
Lauri Hintsala
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