On Fri, Feb 27, 2026 at 10:10:02AM -0500, Steven Rostedt wrote: > On Fri, 27 Feb 2026 10:41:17 +0000 > Vincent Donnefort <[email protected]> wrote: > > > > Hum, not sure this is entirely correct. We do set VM_DONTCOPY when > > > creating the > > > mapping (see __rb_map_vma). So AFAICT ->open() is not called in this > > > situation (see > > > dup_mmap()) > > > > Ah right, Syzkaller is using madvise(MADVISE_DOFORK) which resets > > VM_DONTCOPY. > > Hmm, > > So this means user space can override the DONTCOPY? Can this cause bugs > elsewhere that DONTCOPY is used?
Indeed, user space can clear DONTCOPY... unless we also set VM_IO. > > -- Steve
