On 02/28, Will Drewry wrote: > > On Tue, Feb 28, 2012 at 11:04 AM, Will Drewry <wad@xxxxxxxxxxxx> wrote: > > On Tue, Feb 28, 2012 at 10:43 AM, Oleg Nesterov <oleg@xxxxxxxxxx> wrote: > >> > >> Great. In this case this patch becomes really trivial. Just 2 defines > >> in ptrace.h and the unconditional ptrace_event() under SECCOMP_RET_TRACE. > > hrm the only snag is that I can't then rely on TIF_SYSCALL_TRACE to > ensure seccomp is in the slow-path. Right now, on x86, seccomp is > slow-path, but it doesn't have to be to have the syscall and args. > However, for ptrace to behavior properly, I believed it did need to be > in the slow path. If SECCOMP_RET_TRACE doesn't rely on > PTRACE_SYSCALL, then it introduces a need for seccomp to always be in > the slow path or to flag (somehow) when it needs slow path. My understanding of this magic is very limited, and I'm afraid I misunderstood... So please correct me. But what is the problem? system_call checks _TIF_WORK_SYSCALL_ENTRY which includes _TIF_SECCOMP | _TIF_SYSCALL_TRACE, and jumps to tracesys which does SAVE_REST. Anyway. secure_computing() is called by syscall_trace_enter() which also calls tracehook_report_syscall_entry(). If SECCOMP_RET_TRACE can't do ptrace_event() then why tracehook_report_syscall_entry() is fine? Oleg. -- To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
