On 02/27, Will Drewry wrote: > On Mon, Feb 27, 2012 at 11:54 AM, Oleg Nesterov <oleg@xxxxxxxxxx> wrote: > > On 02/24, Will Drewry wrote: > >> > >> arch/Kconfig | 1 + > >> include/linux/ptrace.h | 7 +++++-- > >> include/linux/seccomp.h | 4 +++- > >> include/linux/tracehook.h | 6 ++++++ > >> kernel/ptrace.c | 4 ++++ > >> kernel/seccomp.c | 18 ++++++++++++++++++ > > > > FYI, this conflicts with the changes -mm tree. > > > > The changes in ptrace.* confict with Denys's > > "ptrace: simplify PTRACE_foo constants and PTRACE_SETOPTIONS code" > > > > The change in tracehook.h conflicts with > > "ptrace: the killed tracee should not enter the syscall" > > What's the best way to reconcile this in this day and age? Of course I'd prefer if you make this change on top of Denys's patch ;) Besides, if you agree with PTRACE_EVENT_SECCOMP/PTRACE_O_SECCOMP you need only one trivial change in ptrace.h. > I don't see > these in kernel-next yet and I can't tell if there is a public -mm > anywhere anymore. Strange... I didn't check, but every patch in http://marc.info/?l=linux-mm-commits has this note: The -mm tree is included into linux-next and is updated there every 3-4 working days > >> --- a/kernel/seccomp.c > >> +++ b/kernel/seccomp.c > >> @@ -354,6 +354,24 @@ int __secure_computing_int(int this_syscall) > >> seccomp_send_sigsys(this_syscall, reason_code); > >> return -1; > >> } > >> + case SECCOMP_RET_TRACE: { > >> + int ret; > >> + struct pt_regs *regs = task_pt_regs(current); > >> + if (!(test_tsk_thread_flag(current, TIF_SYSCALL_TRACE)) || > >> + !(current->ptrace & PT_TRACE_SECCOMP)) > >> + return -1; > >> + /* > >> + * PT_TRACE_SECCOMP and seccomp.trace indicate whether > >> + * tracehook_report_syscall_entry needs to signal the > >> + * tracer. This avoids race conditions in hand off and > >> + * the requirement for TIF_SYSCALL_TRACE ensures that > >> + * we are in the syscall slow path. > >> + */ > >> + current->seccomp.trace = 1; > >> + ret = tracehook_report_syscall_entry(regs); > >> + current->seccomp.trace = 0; > >> + return ret; > > > > To be honest, this interface looks a bit strange to me... > > > > Once again, sorry if this was already discussed. But perhaps it would > > be better to introduce PTRACE_EVENT_SECCOMP/PTRACE_O_SECCOMP instead? > > > > SECCOMP_RET_TRACE: could simply do ptrace_event(PTRACE_EVENT_SECCOMP) > > unconditionaly. The tracer can set the option and do PTRACE_CONT if it > > doesn't want the system call notifications. > > Works for me - this also gets rid of the extra int for brief state > tracking. I'll switch over to that in the next rev. Great. In this case this patch becomes really trivial. Just 2 defines in ptrace.h and the unconditional ptrace_event() under SECCOMP_RET_TRACE. But probably you should check fatal_signal_pending(current) after ptrace_event() returns, ptrace_event() returns void. Oleg. -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
