On Thu, Mar 20, 2014 at 11:45 PM, Adrian Hunter <adrian.hunter@xxxxxxxxx> wrote:
> On 20.03.2014 20:47, Andrew Bresticker wrote:
>> 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.
>
> The same problem appears to be in sdhci_card_event() which calls
> sdhci_do_get_cd() under spinlock which then calls mmc_gpio_get_cd()
>
> Will you fix that too?
Yes, will do.
Thanks,
Andrew
>
>
>>
>> Signed-off-by: Andrew Bresticker <abrestic@xxxxxxxxxxxx>
>> ---
>> 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)
>>
>
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