On Thu, Dec 7, 2023 at 9:14 PM Munehisa Kamata <kamatam@xxxxxxxxxx> wrote: > On Tue, 2023-12-05 14:21:51 -0800, Paul Moore wrote: ... > > I think my thoughts are neatly summarized by Andrew's "yuk!" comment > > at the top. However, before we go too much further on this, can we > > get clarification that Casey was able to reproduce this on a stock > > upstream kernel? Last I read in the other thread Casey wasn't seeing > > this problem on Linux v6.5. > > > > However, for the moment I'm going to assume this is a real problem, is > > there some reason why the existing pid_revalidate() code is not being > > called in the bind mount case? From what I can see in the original > > problem report, the path walk seems to work okay when the file is > > accessed directly from /proc, but fails when done on the bind mount. > > Is there some problem with revalidating dentrys on bind mounts? > > Hi Paul, > > https://lkml.kernel.org/linux-fsdevel/20090608201745.GO8633@xxxxxxxxxxxxxxxxxx/ > > After reading this thread, I have doubt about solving this in VFS. > Honestly, however, I'm not sure if it's entirely relevant today. Have you tried simply mounting proc a second time instead of using a bind mount? % mount -t proc non /new/location/for/proc I ask because from your description it appears that proc does the right thing with respect to revalidation, it only becomes an issue when accessing proc through a bind mount. Or did I misunderstand the problem? -- paul-moore.com
