On Sat, Dec 10, 2016 at 01:32:08PM +0800, Herbert Xu wrote: > On Fri, Dec 09, 2016 at 09:25:38PM -0800, Andy Lutomirski wrote: > > > > > The following crypto drivers initialize a scatterlist to point into an > > > ablkcipher_request, which may have been allocated on the stack with > > > SKCIPHER_REQUEST_ON_STACK(): > > > > > > drivers/crypto/ccp/ccp-crypto-aes-xts.c:162 > > > drivers/crypto/ccp/ccp-crypto-aes.c:94 > > > > These are real, and I wish I'd known about them sooner. > > Are you sure? Any instance of *_ON_STACK must only be used with > sync algorithms and most drivers under drivers/crypto declare > themselves as async. > Why exactly is that? Obviously, it wouldn't work if you returned from the stack frame before the request completed, but does anything stop someone from using an *_ON_STACK() request and then waiting for the request to complete before returning from the stack frame? Eric -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>