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-rw-r--r--arch/um/kernel/tt/process_kern.c10
1 files changed, 8 insertions, 2 deletions
diff --git a/arch/um/kernel/tt/process_kern.c b/arch/um/kernel/tt/process_kern.c
index 295c1ac817b3..a9c1443fc548 100644
--- a/arch/um/kernel/tt/process_kern.c
+++ b/arch/um/kernel/tt/process_kern.c
@@ -51,6 +51,13 @@ void switch_to_tt(void *prev, void *next)
c = 0;
+ /* Notice that here we "up" the semaphore on which "to" is waiting, and
+ * below (the read) we wait on this semaphore (which is implemented by
+ * switch_pipe) and go sleeping. Thus, after that, we have resumed in
+ * "to", and can't use any more the value of "from" (which is outdated),
+ * nor the value in "to" (since it was the task which stole us the CPU,
+ * which we don't care about). */
+
err = os_write_file(to->thread.mode.tt.switch_pipe[1], &c, sizeof(c));
if(err != sizeof(c))
panic("write of switch_pipe failed, err = %d", -err);
@@ -77,7 +84,7 @@ void switch_to_tt(void *prev, void *next)
change_sig(SIGALRM, alrm);
change_sig(SIGPROF, prof);
- arch_switch();
+ arch_switch_to_tt(prev_sched, current);
flush_tlb_all();
local_irq_restore(flags);
@@ -141,7 +148,6 @@ static void new_thread_handler(int sig)
set_cmdline("(kernel thread)");
change_sig(SIGUSR1, 1);
- change_sig(SIGVTALRM, 1);
change_sig(SIGPROF, 1);
local_irq_enable();
if(!run_kernel_thread(fn, arg, &current->thread.exec_buf))