hwrng: core - Fix page fault dead lock on mmap-ed hwrng

There is a dead-lock in the hwrng device read path.  This triggers
when the user reads from /dev/hwrng into memory also mmap-ed from
/dev/hwrng.  The resulting page fault triggers a recursive read
which then dead-locks.

Fix this by using a stack buffer when calling copy_to_user.

Reported-by: Edward Adam Davis <[email protected]>
Reported-by: [email protected]
Fixes: 9996508b3353 ("hwrng: core - Replace u32 in driver API with byte array")
Cc: <[email protected]>
Signed-off-by: Herbert Xu <[email protected]>

0 files changed, 0 insertions, 0 deletions