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| author | Stefan Wahren <stefan.wahren@i2se.com> | 2017-02-16 21:20:45 +0000 |
|---|---|---|
| committer | Wolfram Sang <wsa@the-dreams.de> | 2017-02-20 19:19:54 +0100 |
| commit | ababb08938df7ac245d30a58b95b94ecf8dc04fc (patch) | |
| tree | d744a8bfbef3892fbd494beb7c879f5d2110cd19 /drivers/i2c | |
| parent | 0297ffa69cab614f508ef5d9abdb4c0ffd709795 (diff) | |
| download | linux-ababb08938df7ac245d30a58b95b94ecf8dc04fc.tar.gz linux-ababb08938df7ac245d30a58b95b94ecf8dc04fc.tar.bz2 linux-ababb08938df7ac245d30a58b95b94ecf8dc04fc.zip | |
i2c: bcm2835: Avoid possible NULL ptr dereference
Since commit e2474541032d ("bcm2835: Fix hang for writing messages
larger than 16 bytes") the interrupt handler is prone to a possible
NULL pointer dereference. This could happen if an interrupt fires
before curr_msg is set by bcm2835_i2c_xfer_msg() and randomly occurs
on the RPi 3. Even this is an unexpected behavior the driver must
handle that with an error instead of a crash.
Reported-by: Peter Robinson <pbrobinson@gmail.com>
Fixes: e2474541032d ("bcm2835: Fix hang for writing messages larger than 16 bytes")
Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
Acked-by: Noralf Trønnes <noralf@tronnes.org>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Diffstat (limited to 'drivers/i2c')
| -rw-r--r-- | drivers/i2c/busses/i2c-bcm2835.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/drivers/i2c/busses/i2c-bcm2835.c b/drivers/i2c/busses/i2c-bcm2835.c index c3436f627028..cd07a69e2e93 100644 --- a/drivers/i2c/busses/i2c-bcm2835.c +++ b/drivers/i2c/busses/i2c-bcm2835.c @@ -195,7 +195,9 @@ static irqreturn_t bcm2835_i2c_isr(int this_irq, void *data) } if (val & BCM2835_I2C_S_DONE) { - if (i2c_dev->curr_msg->flags & I2C_M_RD) { + if (!i2c_dev->curr_msg) { + dev_err(i2c_dev->dev, "Got unexpected interrupt (from firmware?)\n"); + } else if (i2c_dev->curr_msg->flags & I2C_M_RD) { bcm2835_drain_rxfifo(i2c_dev); val = bcm2835_i2c_readl(i2c_dev, BCM2835_I2C_S); } |