diff options
| author | Anatolij Gustschin <agust@denx.de> | 2013-04-08 23:28:05 +0200 |
|---|---|---|
| committer | Chris Ball <cjb@laptop.org> | 2013-04-12 15:13:13 -0400 |
| commit | 70aa6109597ea6955a93f16430b588b5ee5ba547 (patch) | |
| tree | e56a0940ff8fb9f27878466b6ed2d8692f93ca95 /drivers/mmc | |
| parent | 7ff747c45908abb4fb894b21a8752a3e48acf02b (diff) | |
mmc: mxcmmc: fix race conditions for host->req and host->data access
mxcmci_dma_callback() is invoked by DMA drivers in soft-irq
context and can be interrupted by the mxcmci_irq() interrupt
which can finish the mmc request or data transfer and set
host->req or host->data pointers to NULL. Then mxcmci_data_done()
crashes with a null pointer dereferences. Protect all accesses
to host->req and host->data by spin locks.
Also check host->data pointer in mxcmci_watchdog() before
dereferencing it.
Signed-off-by: Anatolij Gustschin <agust@denx.de>
Acked-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Chris Ball <cjb@laptop.org>
Diffstat (limited to 'drivers/mmc')
| -rw-r--r-- | drivers/mmc/host/mxcmmc.c | 31 |
1 files changed, 24 insertions, 7 deletions
diff --git a/drivers/mmc/host/mxcmmc.c b/drivers/mmc/host/mxcmmc.c index 848ab2c2ff0..b82e37af316 100644 --- a/drivers/mmc/host/mxcmmc.c +++ b/drivers/mmc/host/mxcmmc.c @@ -623,24 +623,40 @@ static void mxcmci_datawork(struct work_struct *work) static void mxcmci_data_done(struct mxcmci_host *host, unsigned int stat) { - struct mmc_data *data = host->data; + struct mmc_request *req; int data_error; + unsigned long flags; + + spin_lock_irqsave(&host->lock, flags); - if (!data) + if (!host->data) { + spin_unlock_irqrestore(&host->lock, flags); return; + } + + if (!host->req) { + spin_unlock_irqrestore(&host->lock, flags); + return; + } + + req = host->req; + if (!req->stop) + host->req = NULL; /* we will handle finish req below */ data_error = mxcmci_finish_data(host, stat); + spin_unlock_irqrestore(&host->lock, flags); + mxcmci_read_response(host, stat); host->cmd = NULL; - if (host->req->stop) { - if (mxcmci_start_cmd(host, host->req->stop, 0)) { - mxcmci_finish_request(host, host->req); + if (req->stop) { + if (mxcmci_start_cmd(host, req->stop, 0)) { + mxcmci_finish_request(host, req); return; } } else { - mxcmci_finish_request(host, host->req); + mxcmci_finish_request(host, req); } } @@ -931,7 +947,8 @@ static void mxcmci_watchdog(unsigned long data) /* Mark transfer as erroneus and inform the upper layers */ - host->data->error = -ETIMEDOUT; + if (host->data) + host->data->error = -ETIMEDOUT; host->req = NULL; host->cmd = NULL; host->data = NULL; |