Nice catch, Queued for v19-rc2. Nathan Lynch wrote: > 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; > } > _______________________________________________ Containers mailing list Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/containers
