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spi: dw: fix possible race condition

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It is possible to get an interrupt as soon as it is requested.  dw_spi_irq
does spi_controller_get_devdata(master) and expects it to be different than
NULL. However, spi_controller_set_devdata() is called after request_irq(),
resulting in the following crash:

CPU 0 Unable to handle kernel paging request at virtual address 00000030, epc == 8058e09c, ra == 8018ff90
[...]
Call Trace:
[<8058e09c>] dw_spi_irq+0x8/0x64
[<8018ff90>] __handle_irq_event_percpu+0x70/0x1d4
[<80190128>] handle_irq_event_percpu+0x34/0x8c
[<801901c4>] handle_irq_event+0x44/0x80
[<801951a8>] handle_level_irq+0xdc/0x194
[<8018f580>] generic_handle_irq+0x38/0x50
[<804c6924>] ocelot_irq_handler+0x104/0x1c0

Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Alexandre Belloni 2018-07-17 16:23:10 +02:00 committed by Mark Brown
parent 2ba87a9bcc
commit 66b19d7623
No known key found for this signature in database
GPG key ID: 24D68B725D5487D0
1 changed files with 2 additions and 1 deletions
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3
drivers/spi/spi-dw.c
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@ -485,6 +485,8 @@ int dw_spi_add_host(struct device *dev, struct dw_spi *dws)
dws->dma_inited = 0;
dws->dma_addr = (dma_addr_t)(dws->paddr + DW_SPI_DR);
spi_controller_set_devdata(master, dws);
ret = request_irq(dws->irq, dw_spi_irq, IRQF_SHARED, dev_name(dev),
master);
if (ret < 0) {
@ -518,7 +520,6 @@ int dw_spi_add_host(struct device *dev, struct dw_spi *dws)
}
}
spi_controller_set_devdata(master, dws);
ret = devm_spi_register_controller(dev, master);
if (ret) {
dev_err(&master->dev, "problem registering spi master\n");