On Mon, Aug 05, 2019 at 04:32:41PM -0700, Stephen Boyd wrote: > The hwrng_fill() function can run while devices are suspending and > resuming. If the hwrng is behind a bus such as i2c or SPI and that bus > is suspended, the hwrng may hang the bus while attempting to add some > randomness. It's been observed on ChromeOS devices with suspend-to-idle > (s2idle) and an i2c based hwrng that this kthread may run and ask the > hwrng device for randomness before the i2c bus has been resumed. > > Let's make this kthread freezable so that we don't try to touch the > hwrng during suspend/resume. This ensures that we can't cause the hwrng > backing driver to get into a bad state because the device is guaranteed > to be resumed before the hwrng kthread is thawed. > > Cc: Andrey Pronin <apronin@xxxxxxxxxxxx> > Cc: Duncan Laurie <dlaurie@xxxxxxxxxxxx> > Cc: Jason Gunthorpe <jgg@xxxxxxxx> > Cc: Arnd Bergmann <arnd@xxxxxxxx> > Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> > Cc: Guenter Roeck <groeck@xxxxxxxxxxxx> > Cc: Alexander Steffen <Alexander.Steffen@xxxxxxxxxxxx> > Signed-off-by: Stephen Boyd <swboyd@xxxxxxxxxxxx> > --- > > I'm splitting this patch off of the larger series so it can > go through the crypto tree. See [1] for the prevoius round. > Nothing has changed in this patch since then. > > [1] https://lkml.kernel.org/r/20190716224518.62556-2-swboyd@xxxxxxxxxxxx > > drivers/char/hw_random/core.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) Patch applied. Thanks. -- Email: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx> Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
