mmc: mxs-mmc: fix deadlock caused by recursion loop

Lauri Hintsala · gregkh · commit 3dd2bf1c4b2f · 2012-10-02T10:39:08.000-07:00
commit fc108d2 upstream. Release the lock before mmc_signal_sdio_irq is called by mxs_mmc_enable_sdio_irq. Backtrace: [ 65.470000] ============================================= [ 65.470000] [ INFO: possible recursive locking detected ] [ 65.470000] 3.5.0-rc5 #2 Not tainted [ 65.470000] --------------------------------------------- [ 65.470000] ksdioirqd/mmc0/73 is trying to acquire lock: [ 65.470000] (&(&host->lock)->rlock#2){-.-...}, at: [<bf054120>] mxs_mmc_enable_sdio_irq+0x18/0xdc [mxs_mmc] [ 65.470000] [ 65.470000] but task is already holding lock: [ 65.470000] (&(&host->lock)->rlock#2){-.-...}, at: [<bf054120>] mxs_mmc_enable_sdio_irq+0x18/0xdc [mxs_mmc] [ 65.470000] [ 65.470000] other info that might help us debug this: [ 65.470000] Possible unsafe locking scenario: [ 65.470000] [ 65.470000] CPU0 [ 65.470000] ---- [ 65.470000] lock(&(&host->lock)->rlock#2); [ 65.470000] lock(&(&host->lock)->rlock#2); [ 65.470000] [ 65.470000] *** DEADLOCK *** [ 65.470000] [ 65.470000] May be due to missing lock nesting notation [ 65.470000] [ 65.470000] 1 lock held by ksdioirqd/mmc0/73: [ 65.470000] #0: (&(&host->lock)->rlock#2){-.-...}, at: [<bf054120>] mxs_mmc_enable_sdio_irq+0x18/0xdc [mxs_mmc] [ 65.470000] [ 65.470000] stack backtrace: [ 65.470000] [<c0014990>] (unwind_backtrace+0x0/0xf4) from [<c005ccb8>] (__lock_acquire+0x14f8/0x1b98) [ 65.470000] [<c005ccb8>] (__lock_acquire+0x14f8/0x1b98) from [<c005d3f8>] (lock_acquire+0xa0/0x108) [ 65.470000] [<c005d3f8>] (lock_acquire+0xa0/0x108) from [<c02f671c>] (_raw_spin_lock_irqsave+0x48/0x5c) [ 65.470000] [<c02f671c>] (_raw_spin_lock_irqsave+0x48/0x5c) from [<bf054120>] (mxs_mmc_enable_sdio_irq+0x18/0xdc [mxs_mmc]) [ 65.470000] [<bf054120>] (mxs_mmc_enable_sdio_irq+0x18/0xdc [mxs_mmc]) from [<bf0541d0>] (mxs_mmc_enable_sdio_irq+0xc8/0xdc [mxs_mmc]) [ 65.470000] [<bf0541d0>] (mxs_mmc_enable_sdio_irq+0xc8/0xdc [mxs_mmc]) from [<c0219b38>] (sdio_irq_thread+0x1bc/0x274) [ 65.470000] [<c0219b38>] (sdio_irq_thread+0x1bc/0x274) from [<c003c324>] (kthread+0x8c/0x98) [ 65.470000] [<c003c324>] (kthread+0x8c/0x98) from [<c00101ac>] (kernel_thread_exit+0x0/0x8) [ 65.470000] BUG: spinlock lockup suspected on CPU#0, ksdioirqd/mmc0/73 [ 65.470000] lock: 0xc3358724, .magic: dead4ead, .owner: ksdioirqd/mmc0/73, .owner_cpu: 0 [ 65.470000] [<c0014990>] (unwind_backtrace+0x0/0xf4) from [<c01b46b0>] (do_raw_spin_lock+0x100/0x144) [ 65.470000] [<c01b46b0>] (do_raw_spin_lock+0x100/0x144) from [<c02f6724>] (_raw_spin_lock_irqsave+0x50/0x5c) [ 65.470000] [<c02f6724>] (_raw_spin_lock_irqsave+0x50/0x5c) from [<bf054120>] (mxs_mmc_enable_sdio_irq+0x18/0xdc [mxs_mmc]) [ 65.470000] [<bf054120>] (mxs_mmc_enable_sdio_irq+0x18/0xdc [mxs_mmc]) from [<bf0541d0>] (mxs_mmc_enable_sdio_irq+0xc8/0xdc [mxs_mmc]) [ 65.470000] [<bf0541d0>] (mxs_mmc_enable_sdio_irq+0xc8/0xdc [mxs_mmc]) from [<c0219b38>] (sdio_irq_thread+0x1bc/0x274) [ 65.470000] [<c0219b38>] (sdio_irq_thread+0x1bc/0x274) from [<c003c324>] (kthread+0x8c/0x98) [ 65.470000] [<c003c324>] (kthread+0x8c/0x98) from [<c00101ac>] (kernel_thread_exit+0x0/0x8) Reported-by: Attila Kinali <attila@kinali.ch> Signed-off-by: Lauri Hintsala <lauri.hintsala@bluegiga.com> Acked-by: Shawn Guo <shawn.guo@linaro.org> Signed-off-by: Chris Ball <cjb@laptop.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/mmc/host/mxs-mmc.c b/drivers/mmc/host/mxs-mmc.c
@@ -637,11 +637,6 @@ static void mxs_mmc_enable_sdio_irq(struct mmc_host *mmc, int enable)
 		       host->base + HW_SSP_CTRL0 + STMP_OFFSET_REG_SET);
 		writel(BM_SSP_CTRL1_SDIO_IRQ_EN,
 		       host->base + HW_SSP_CTRL1(host) + STMP_OFFSET_REG_SET);
-
-		if (readl(host->base + HW_SSP_STATUS(host)) &
-				BM_SSP_STATUS_SDIO_IRQ)
-			mmc_signal_sdio_irq(host->mmc);
-
 	} else {
 		writel(BM_SSP_CTRL0_SDIO_IRQ_CHECK,
 		       host->base + HW_SSP_CTRL0 + STMP_OFFSET_REG_CLR);
@@ -650,6 +645,11 @@ static void mxs_mmc_enable_sdio_irq(struct mmc_host *mmc, int enable)
 	}
 
 	spin_unlock_irqrestore(&host->lock, flags);
+
+	if (enable && readl(host->base + HW_SSP_STATUS(host)) &
+			BM_SSP_STATUS_SDIO_IRQ)
+		mmc_signal_sdio_irq(host->mmc);
+
 }
 
 static const struct mmc_host_ops mxs_mmc_ops = {
