The feeder thread can cause the restart process to fail by indirectly calling exit_group, which sends SIGKILL to all other threads in the process. If the feeder thread "wins" the race, the restart is disrupted. A common symptom of this race is the coordinator task returning from the wait_for_completion_interruptible in wait_all_tasks_finish with a signal (the SIGKILL) pending. Calling _exit isn't enough; see http://www.kernel.org/doc/man-pages/online/pages/man2/exit.2.html#NOTES Exit the feeder thread by using the syscall() macro. Signed-off-by: Nathan Lynch <ntl@xxxxxxxxx> --- restart.c | 12 ++++++++++-- 1 files changed, 10 insertions(+), 2 deletions(-) diff --git a/restart.c b/restart.c index d5d069a..ed4268c 100644 --- a/restart.c +++ b/restart.c @@ -2079,8 +2079,16 @@ static int ckpt_do_feeder(void *data) ckpt_read_write_inspect(ctx); else ckpt_read_write_blind(ctx); - - /* all is well: feeder thread is done */ + + /* All is well: feeder thread is done. However, we must + * invoke the exit system call directly. Otherwise, upon + * return from this function, glibc's clone wrapper will call + * _exit, which calls exit_group, which will terminate the + * whole process, which is not what we want. + */ + syscall(SYS_exit, 0); + + /* not reached */ return 0; } -- 1.6.0.6 _______________________________________________ Containers mailing list Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/containers
