On Thu, 26 Apr 2018, Michael S. Tsirkin wrote: > On Thu, Apr 26, 2018 at 12:07:25PM -0400, Mikulas Patocka wrote: > > > IIUC debug kernels mainly exist so people who experience e.g. memory > > > corruption can try and debug the failure. In this case, CONFIG_DEBUG_SG > > > will *already* catch a failure early. Nothing special needs to be done. > > > > The patch helps people debug such memory coprruptions (such as using DMA > > API on the result of kvmalloc). > > That's my point. I don't think your patch helps debug any memory > corruptions. With CONFIG_DEBUG_SG using DMA API already causes a > BUG_ON, that's before any memory can get corrupted. The patch turns a hard-to-reproduce bug into an easy-to-reproduce bug. Obviously we don't want this in production kernels, but in the debug kernels it should be done. Mikulas
