Messages in this thread | | | From | Linus Torvalds <> | Date | Sun, 31 Jan 2021 15:55:54 -0800 | Subject | Re: [REGRESSION] x86/entry: TIF_SINGLESTEP handling is still broken |
| |
On Sun, Jan 31, 2021 at 3:35 PM Linus Torvalds <torvalds@linux-foundation.org> wrote: > > I wonder if the simple solution is to just > > (a) always set one of the SYSCALL_WORK_EXIT bits on the child in > ptrace (exactly to catch the child on system call exit) > > (b) basically revert 299155244770 ("entry: Drop usage of TIF flags in > the generic syscall code") and have the syscall exit code check the > TIF_SINGLESTEP flag
Actually, (b) looks unnecessary - as long as we get to syscall_exit_work(), the current code will work fine.
So maybe just add a dummy SYSCALL_WORK_SYSCALL_EXIT_TRAP, and set that flag whenever a singestep is requested for a process that is currently in a system call?
IOW, make it a very explicit "do TF for system calls", rather than the old code that was doing so implicitly and not very obviously. Hmm?
Linus
| |