Sergey Bugaev, le mar. 28 févr. 2023 22:44:08 +0300, a ecrit:
> @@ -430,23 +429,11 @@ _hurdsig_abort_rpcs (struct hurd_sigstate *ss, int
> signo, int sigthread,
> receive completes immediately or aborts. */
> abort_thread (ss, state, reply);
>
> - if (state->basic.PC >= (uintptr_t) &_hurd_intr_rpc_msg_about_to
> - && state->basic.PC < (uintptr_t) &_hurd_intr_rpc_msg_in_trap)
> - {
> - /* The thread is about to do the RPC, but hasn't yet entered
> - mach_msg. Mutate the thread's state so it knows not to try
> - the RPC. */
> - INTR_MSG_BACK_OUT (&state->basic);
> - MACHINE_THREAD_STATE_SET_PC (&state->basic,
> - &_hurd_intr_rpc_msg_in_trap);
> - state->basic.SYSRETURN = MACH_SEND_INTERRUPTED;
> - *state_change = 1;
> - }
> - else if (state->basic.PC == (uintptr_t) &_hurd_intr_rpc_msg_in_trap
> - /* The thread was blocked in the system call. After thread_abort,
> - the return value register indicates what state the RPC was in
> - when interrupted. */
> - && state->basic.SYSRETURN == MACH_RCV_INTERRUPTED)
> + if (state->basic.PC == (uintptr_t) &_hurd_intr_rpc_msg_in_trap
> + /* The thread was blocked in the system call. After thread_abort, the
> + return value register indicates what state the RPC was in when
> + interrupted. */
> + && state->basic.SYSRETURN == MACH_RCV_INTERRUPTED)
> {
> /* The RPC request message was sent and the thread was waiting for
> the reply message; now the message receive has been aborted, so
No, that's not enough, it's racy: if cancellation/interrupt
happens between the last C check and actually running lcall, the
cancellation/interrupt will be lost.
We do need to properly check for the eip case between the last check for
these, and lcall.
Samuel
