On 24.03.2014 03:43, Andrew Bresticker wrote:
> sdhci_request() and sdhci_card_event() read 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 <abres...@chromium.org>
> ---
> drivers/mmc/host/sdhci.c | 7 ++++---
> 1 file changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
> index 04a5e25..328b250 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)
> @@ -2082,15 +2082,16 @@ static void sdhci_card_event(struct mmc_host *mmc)
> {
> struct sdhci_host *host = mmc_priv(mmc);
> unsigned long flags;
> + int present;
>
> /* First check if client has provided their own card event */
> if (host->ops->card_event)
> host->ops->card_event(host);
>
> + present = sdhci_get_cd(mmc);
Shouldn't that be sdhci_do_get_cd(mmc) ?
> spin_lock_irqsave(&host->lock, flags);
>
> - /* Check host->mrq first in case we are runtime suspended */
> - if (host->mrq && !sdhci_do_get_cd(host)) {
> + if (host->mrq && !present) {
> pr_err("%s: Card removed during transfer!\n",
> mmc_hostname(host->mmc));
> pr_err("%s: Resetting controller.\n",
>
--
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