From: Jeff Dike From: Bodo Stroesser In most cases reboot failed on my system. After "Restarting system.", UML exited without further messages. I found an SIGIO being processed by sig_handler() resp. sig_handler_common_skas(). Don't know, why this exits, maybe the context is no longer valid at this time. So, I changed the sequence in the reboot part of main() to stop the timers and disable the fds before unblocking the signals. Since this wasn't enough, I also added set_handler(SIGXXX, SIG_IGN) calls to disable_timer() and deactivate_all_fds(). Now reboot works fine in SKAS and it still works in TT. Signed-off-by: Bodo Stroesser Signed-off-by: Jeff Dike Signed-off-by: Andrew Morton --- 25-akpm/arch/um/kernel/irq_user.c | 2 ++ 25-akpm/arch/um/kernel/main.c | 14 ++++++++------ 25-akpm/arch/um/kernel/time.c | 3 +++ 3 files changed, 13 insertions(+), 6 deletions(-) diff -puN arch/um/kernel/irq_user.c~uml-unregister-signal-handlers-at-reboot arch/um/kernel/irq_user.c --- 25/arch/um/kernel/irq_user.c~uml-unregister-signal-handlers-at-reboot 2004-11-28 01:17:29.616586000 -0800 +++ 25-akpm/arch/um/kernel/irq_user.c 2004-11-28 01:17:29.622585088 -0800 @@ -377,6 +377,8 @@ int deactivate_all_fds(void) if(err) return(err); } + /* If there is a signal already queued, after unblocking ignore it */ + set_handler(SIGIO, SIG_IGN, 0, -1); return(0); } diff -puN arch/um/kernel/main.c~uml-unregister-signal-handlers-at-reboot arch/um/kernel/main.c --- 25/arch/um/kernel/main.c~uml-unregister-signal-handlers-at-reboot 2004-11-28 01:17:29.617585848 -0800 +++ 25-akpm/arch/um/kernel/main.c 2004-11-28 01:17:29.623584936 -0800 @@ -155,18 +155,20 @@ int main(int argc, char **argv, char **e int err; printf("\n"); - - /* Let any pending signals fire, then disable them. This - * ensures that they won't be delivered after the exec, when - * they are definitely not expected. - */ - unblock_signals(); + /* stop timers and set SIG*ALRM to be ignored */ disable_timer(); + /* disable SIGIO for the fds and set SIGIO to be ignored */ err = deactivate_all_fds(); if(err) printf("deactivate_all_fds failed, errno = %d\n", -err); + /* Let any pending signals fire now. This ensures + * that they won't be delivered after the exec, when + * they are definitely not expected. + */ + unblock_signals(); + execvp(new_argv[0], new_argv); perror("Failed to exec kernel"); ret = 1; diff -puN arch/um/kernel/time.c~uml-unregister-signal-handlers-at-reboot arch/um/kernel/time.c --- 25/arch/um/kernel/time.c~uml-unregister-signal-handlers-at-reboot 2004-11-28 01:17:29.619585544 -0800 +++ 25-akpm/arch/um/kernel/time.c 2004-11-28 01:17:29.624584784 -0800 @@ -60,6 +60,9 @@ void disable_timer(void) (setitimer(ITIMER_REAL, &disable, NULL) < 0)) printk("disnable_timer - setitimer failed, errno = %d\n", errno); + /* If there are signals already queued, after unblocking ignore them */ + set_handler(SIGALRM, SIG_IGN, 0, -1); + set_handler(SIGVTALRM, SIG_IGN, 0, -1); } void switch_timers(int to_real) _