> -----Original Message----- > From: Tobin C. Harding [mailto:m...@tobin.cc] > Sent: Thursday, November 2, 2017 3:15 AM > To: Sergey Senozhatsky <sergey.senozhatsky.w...@gmail.com> > Cc: Sergey Senozhatsky <sergey.senozhat...@gmail.com>; kernel- > harden...@lists.openwall.com; Jason A. Donenfeld <ja...@zx2c4.com>; > Theodore Ts'o <ty...@mit.edu>; Linus Torvalds <torvalds@linux- > foundation.org>; Kees Cook <keesc...@chromium.org>; Paolo Bonzini > <pbonz...@redhat.com>; Tycho Andersen <ty...@docker.com>; Roberts, > William C <william.c.robe...@intel.com>; Tejun Heo <t...@kernel.org>; Jordan > Glover <golden_mille...@protonmail.ch>; Greg KH > <gre...@linuxfoundation.org>; Petr Mladek <pmla...@suse.com>; Joe > Perches <j...@perches.com>; Ian Campbell <i...@hellion.org.uk>; Catalin > Marinas > <catalin.mari...@arm.com>; Will Deacon <wilal.dea...@arm.com>; Steven > Rostedt <rost...@goodmis.org>; Chris Fries <cfr...@google.com>; Dave > Weinstein <olo...@google.com>; Daniel Micay <danielmi...@gmail.com>; Djalal > Harouni <tix...@gmail.com>; linux-kernel@vger.kernel.org > Subject: Re: [PATCH V8 0/2] printk: hash addresses printed with %p > > On Thu, Nov 02, 2017 at 05:23:44PM +0900, Sergey Senozhatsky wrote: > > On (11/01/17 10:35), Tobin C. Harding wrote: > > [..] > > > Yes. The question has been raised will we be here again in 6 years > > > time trying to fix all the uses of %x. And there are already 29K > > > uses of %[xX] in tree, which of these are leaking addresses? This is why > > > Linus' > > > has commented that really effort should be directed at finding the > > > leaks as they happen (in procfs, sysfs, dmesg) instead of fixing > > > this in the code. > > > > got it. thanks. > > > > > So far I haven't been able to come up with any meaningful way to do > > > this on 32 bit machines. There is a patch adding a script to catch > > > leaks on 64 bit machines in flight. > > > > who is expected to run that script? > > If one person runs it and finds one leaking address, I'd say it wast worth > writing. If > a bunch of people with different set ups run it and we find a bunch of leaking > addresses, WIN!
I wonder if the 0 day testing robot could run it.... > > Your comment did give me the idea of adding some output to the command > offering an email address to send suspicious output for those who do not wish > to > investigate it further. I can put my email address if there is not a better > option. > > > BTW, can BPF/eBPF printk addresses? > > I know absolutely zero about BPF/eBPF. I guess now is a good time to learn. > > > > This patch needs to be a small part of a continued effort to stop > > > the leaks if we want to have any hope of stopping them. > > > > > > If you have any suggestions on dealing with %x please do say. We > > > have code changes, compiler warnings, and checkpatch - none of which > > > immediately seem great. > > > > hm... just a huge pile of if's > > > > if (is_vmalloc_addr(addr)) > > do_hashing(addr); > > else if (__module_address(addr)) > > do_hashing(addr); > > else if (is_kernel(addr) || is_kernel_inittext(addr)) > > ... > > > > but that's going to be really messy and "iffy". > > This is the only suggestion we have so far. > > thanks, > Tobin.
