On Mon, Dec 09, 2024 at 11:12:52AM -0500, Liam R. Howlett wrote: > +Cc maintainers listed of kernel/events/uprobe.c > > TL;DR: > dup_mmap() fails, but uprobe thinks it's fine and keeps trying to use an > incomplete mm_struct. > > We're looking for a way to signal to uprobe to abort, cleanly. > > Looking at kernel/fork.c, dup_mmap(): > > fail_uprobe_end: > uprobe_end_dup_mmap(); > return retval; > > So uprobe is aware it could fail, but releases the semaphore and then > doesn't check if the mm struct is okay to use. > > What should happen in the failed mm_struct case? > > Thanks, > Liam > (As discussed on IRC) how about moving up the dup_mmap_sem lock one level, we can put the mm before the rmap lookup in build_map_info() is able to find it, which should avoid the whole issue? Untested patch attached. ----8<----
