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 <[email protected]> Acked-by: Sascha Hauer <[email protected]> --- v3: - move to first patch in the series as asked by Sascha - add Acked-by v2: - only rebased 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 ff9e496..8ae7cf5 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; -- 1.7.5.4 _______________________________________________ devicetree-discuss mailing list [email protected] https://lists.ozlabs.org/listinfo/devicetree-discuss
