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authorOleg Nesterov <oleg@redhat.com>2009-09-23 18:56:44 -0400
committerLinus Torvalds <torvalds@linux-foundation.org>2009-09-24 10:20:59 -0400
commita7f0765edfd53aed09cb7b0e15863688b39447de (patch)
treec89adfe418f9988ad4044e0f22827458bdf6b155 /include/linux/sched.h
parent1dd3a27326d307952f8ad2499478c84dc7311517 (diff)
ptrace: __ptrace_detach: do __wake_up_parent() if we reap the tracee
The bug is old, it wasn't cause by recent changes. Test case: static void *tfunc(void *arg) { int pid = (long)arg; assert(ptrace(PTRACE_ATTACH, pid, NULL, NULL) == 0); kill(pid, SIGKILL); sleep(1); return NULL; } int main(void) { pthread_t th; long pid = fork(); if (!pid) pause(); signal(SIGCHLD, SIG_IGN); assert(pthread_create(&th, NULL, tfunc, (void*)pid) == 0); int r = waitpid(-1, NULL, __WNOTHREAD); printf("waitpid: %d %m\n", r); return 0; } Before the patch this program hangs, after this patch waitpid() correctly fails with errno == -ECHILD. The problem is, __ptrace_detach() reaps the EXIT_ZOMBIE tracee if its ->real_parent is our sub-thread and we ignore SIGCHLD. But in this case we should wake up other threads which can sleep in do_wait(). Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Roland McGrath <roland@redhat.com> Cc: Vitaly Mayatskikh <vmayatsk@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/sched.h')
-rw-r--r--include/linux/sched.h1
1 files changed, 1 insertions, 0 deletions
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 848d1f20086e..9e5a88afe6be 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -2059,6 +2059,7 @@ extern int kill_pgrp(struct pid *pid, int sig, int priv);
2059extern int kill_pid(struct pid *pid, int sig, int priv); 2059extern int kill_pid(struct pid *pid, int sig, int priv);
2060extern int kill_proc_info(int, struct siginfo *, pid_t); 2060extern int kill_proc_info(int, struct siginfo *, pid_t);
2061extern int do_notify_parent(struct task_struct *, int); 2061extern int do_notify_parent(struct task_struct *, int);
2062extern void __wake_up_parent(struct task_struct *p, struct task_struct *parent);
2062extern void force_sig(int, struct task_struct *); 2063extern void force_sig(int, struct task_struct *);
2063extern void force_sig_specific(int, struct task_struct *); 2064extern void force_sig_specific(int, struct task_struct *);
2064extern int send_sig(int, struct task_struct *, int); 2065extern int send_sig(int, struct task_struct *, int);