From: Andrew Bresticker <abrestic@chromium.org>
To: Chris Ball <chris@printf.net>
Cc: Ulf Hansson <ulf.hansson@linaro.org>,
linux-mmc@vger.kernel.org, linux-kernel@vger.kernel.org,
Andrew Bresticker <abrestic@chromium.org>
Subject: [PATCH] mmc: sdhci: don't read cd-gpio while holding spinlock
Date: Thu, 20 Mar 2014 11:47:12 -0700 [thread overview]
Message-ID: <1395341232-14490-1-git-send-email-abrestic@chromium.org> (raw)
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
next reply other threads:[~2014-03-20 18:47 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-03-20 18:47 Andrew Bresticker [this message]
2014-03-21 6:45 ` Adrian Hunter
2014-03-22 1:38 ` Andrew Bresticker
2014-03-24 1:43 ` [PATCH V2] " Andrew Bresticker
2014-03-24 6:19 ` Adrian Hunter
2014-03-24 16:18 ` Andrew Bresticker
2014-03-25 8:25 ` Adrian Hunter
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