From: Eugene Teo tsk->exit_state can only be 0, EXIT_ZOMBIE, or EXIT_DEAD. A non-zero test is the same as tsk->exit_state & (EXIT_ZOMBIE | EXIT_DEAD), so just testing tsk->exit_state is sufficient. Signed-off-by: Eugene Teo Cc: Roland McGrath Cc: Oleg Nesterov Signed-off-by: Andrew Morton --- fs/proc/array.c | 3 +-- kernel/fork.c | 2 +- kernel/sched.c | 2 +- 3 files changed, 3 insertions(+), 4 deletions(-) diff -puN fs/proc/array.c~fix-tsk-exit_state-usage-resend fs/proc/array.c --- a/fs/proc/array.c~fix-tsk-exit_state-usage-resend +++ a/fs/proc/array.c @@ -146,8 +146,7 @@ static inline const char *get_task_state TASK_UNINTERRUPTIBLE | TASK_STOPPED | TASK_TRACED)) | - (tsk->exit_state & (EXIT_ZOMBIE | - EXIT_DEAD)); + tsk->exit_state; const char **p = &task_state_array[0]; while (state) { diff -puN kernel/fork.c~fix-tsk-exit_state-usage-resend kernel/fork.c --- a/kernel/fork.c~fix-tsk-exit_state-usage-resend +++ a/kernel/fork.c @@ -118,7 +118,7 @@ EXPORT_SYMBOL(free_task); void __put_task_struct(struct task_struct *tsk) { - WARN_ON(!(tsk->exit_state & (EXIT_DEAD | EXIT_ZOMBIE))); + WARN_ON(!tsk->exit_state); WARN_ON(atomic_read(&tsk->usage)); WARN_ON(tsk == current); diff -puN kernel/sched.c~fix-tsk-exit_state-usage-resend kernel/sched.c --- a/kernel/sched.c~fix-tsk-exit_state-usage-resend +++ a/kernel/sched.c @@ -5265,7 +5265,7 @@ static void migrate_dead(unsigned int de struct rq *rq = cpu_rq(dead_cpu); /* Must be exiting, otherwise would be on tasklist. */ - BUG_ON(p->exit_state != EXIT_ZOMBIE && p->exit_state != EXIT_DEAD); + BUG_ON(!p->exit_state); /* Cannot have done final schedule yet: would have vanished. */ BUG_ON(p->state == TASK_DEAD); _