From: Nicolas Boichat > Sent: 24 August 2020 03:59 > > trace_printk is meant as a debugging tool, and should not be > compiled into production code without specific debug Kconfig > options enabled, or source code changes, as indicated by the > warning that shows up on boot if any trace_printk is called: > ** NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE ** > ** ** > ** trace_printk() being used. Allocating extra memory. ** > ** ** > ** This means that this is a DEBUG kernel and it is ** > ** unsafe for production use. ** > > If DISALLOW_TRACE_PRINTK=1 is passed on the make command > line, the kernel will generate a build-time error if > trace_printk is used. We expect distributors to set this > option for their production kernels. > > Note that the code to handle trace_printk is still present, > so this does not prevent people from compiling out-of-tree > kernel modules, or BPF programs. > > Also, we are not making this a kernel config option as we > want the developer convenience of being able to reuse a > production kernel config, add trace_printk for debugging, > and rebuild, without any config changes. Since the objective seems to be to ensure there are no calls to trace_printk() in the git tree, but to allow them in uncommitted sources. Why not use a config option and rely on rand-config builds to detect any 'accidental' commits? David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)
