From: Eric W. Biederman > Sent: 28 November 2017 06:27 > Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> writes: > > > On Mon, Nov 27, 2017 at 4:03 PM, Linus Torvalds > > <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote: > >> > >> So the big remaining ones for me are the /proc/<pid>/stack (stack > >> pointers) and the /proc/net/* ones. > >> > >> I'm a bit disappointed that those haven't been fixed already and > >> aren't even in this series.. > > > > Oh well, I just did /proc/<pid>/stack by making it just print 0 > > unconditionally rather than the hex number. > > Patch? > > I know I have used /proc/<pid>/stack manually many times when looking > at a system where something is hung/weird and I needed to see what is > going on. The backtrace inside the kernel can be invaluable. Ditto - after I spotted it. Also the similar tracebacks from echo t >/proc/sysrq-trigger although they are less useful unless you've a big kernel message buffer. Although they can be requested from a keyboard if everything except the keyboard interrupt is borked. > At the same time I don't know if we actually need the hex address. > But please don't break that interface it is very useful. Definitely need to know which addresses are zero (or near zero). I will have tied the addresses there to ones available elsewhere. (In private trace that won't be affected by whatever kernel printf does with %p.) If you want to hide addresses, then maybe use a write-only sysctl. David
