Messages in this thread Patch in this message | | | From | Andrew Bresticker <> | Subject | [PATCH] mmc: sdhci: don't read cd-gpio while holding spinlock | Date | Thu, 20 Mar 2014 11:47:12 -0700 |
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mmc_request() reads the cd-gpio via mmc_gpio_get_cd(), which can sleep, while holding host->lock. This may result in the following BUG:
BUG: spinlock wrong CPU on CPU#2, kworker/u8:16/4296 lock: 0xea6b9c80, .magic: dead4ead, .owner: kworker/u8:16/4296, .owner_cpu: 0 CPU: 2 PID: 4296 Comm: kworker/u8:16 Tainted: G C 3.10.18 #137 Workqueue: kmmcd mmc_rescan [<8020cf8c>] (unwind_backtrace+0x0/0x118) from [<8020a0c8>] (show_stack+0x20/0x24) [<8020a0c8>] (show_stack+0x20/0x24) from [<8075e5b8>] (dump_stack+0x20/0x28) [<8075e5b8>] (dump_stack+0x20/0x28) from [<804184a8>] (spin_dump+0x80/0x94) [<804184a8>] (spin_dump+0x80/0x94) from [<804184e8>] (spin_bug+0x2c/0x30) [<804184e8>] (spin_bug+0x2c/0x30) from [<80418790>] (do_raw_spin_unlock+0x94/0xd4) [<80418790>] (do_raw_spin_unlock+0x94/0xd4) from [<80761a44>] (_raw_spin_unlock_irqrestore+0x1c/0x24) [<80761a44>] (_raw_spin_unlock_irqrestore+0x1c/0x24) from [<805ff66c>] (sdhci_request+0x1c8/0x1d0) [<805ff66c>] (sdhci_request+0x1c8/0x1d0) from [<805ebb5c>] (mmc_start_request+0xec/0xf4) [<805ebb5c>] (mmc_start_request+0xec/0xf4) from [<805ebcbc>] (mmc_wait_for_req+0x80/0xf4) ...
Read the cd-gpio before acquiring the spinlock instead.
Signed-off-by: Andrew Bresticker <abrestic@chromium.org> --- drivers/mmc/host/sdhci.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c index 04a5e25..f2ef978 100644 --- a/drivers/mmc/host/sdhci.c +++ b/drivers/mmc/host/sdhci.c @@ -1340,6 +1340,7 @@ static void sdhci_request(struct mmc_host *mmc, struct mmc_request *mrq) u32 tuning_opcode; host = mmc_priv(mmc); + present = mmc_gpio_get_cd(host->mmc); sdhci_runtime_pm_get(host); @@ -1371,7 +1372,6 @@ static void sdhci_request(struct mmc_host *mmc, struct mmc_request *mrq) * zero: cd-gpio is used, and card is removed * one: cd-gpio is used, and card is present */ - present = mmc_gpio_get_cd(host->mmc); if (present < 0) { /* If polling, assume that the card is always present. */ if (host->quirks & SDHCI_QUIRK_BROKEN_CARD_DETECTION) -- 1.9.0.279.gdc9e3eb
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