Messages in this thread Patch in this message | | | Date | Fri, 7 Apr 2006 02:06:31 +0400 | From | Oleg Nesterov <> | Subject | [PATCH 3/4] coredump: kill ptrace related stuff |
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With this patch zap_process() sets SIGNAL_GROUP_EXIT while sending SIGKILL to the thread group. This means that a TASK_TRACED task
1. Will be awakened by signal_wake_up(1)
2. Can't sleep again via ptrace_notify()
3. Can't go to do_signal_stop() after return from ptrace_stop() in get_signal_to_deliver()
So we can remove all ptrace related stuff from coredump path.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
--- rc1/fs/exec.c~3_PTRACE 2006-04-06 15:19:33.000000000 +0400 +++ rc1/fs/exec.c 2006-04-06 19:56:36.000000000 +0400 @@ -1384,12 +1384,14 @@ static void format_corename(char *corena *out_ptr = 0; } -static void zap_process(struct task_struct *start, int *ptraced) +static void zap_process(struct task_struct *start) { struct task_struct *t; unsigned long flags; spin_lock_irqsave(&start->sighand->siglock, flags); + start->signal->flags = SIGNAL_GROUP_EXIT; + start->signal->group_stop_count = 0; t = start; do { @@ -1397,22 +1399,17 @@ static void zap_process(struct task_stru t->mm->core_waiters++; sigaddset(&t->pending.signal, SIGKILL); signal_wake_up(t, 1); - - if (unlikely(t->ptrace) && - unlikely(t->parent->mm == t->mm)) - *ptraced = 1; } } while ((t = next_thread(t)) != start); spin_unlock_irqrestore(&start->sighand->siglock, flags); } -static void zap_threads (struct mm_struct *mm) +static void zap_threads(struct mm_struct *mm) { struct task_struct *g, *p; struct task_struct *tsk = current; struct completion *vfork_done = tsk->vfork_done; - int traced = 0; /* * Make sure nobody is waiting for us to release the VM, @@ -1429,29 +1426,12 @@ static void zap_threads (struct mm_struc do { if (p->mm) { if (p->mm == mm) - zap_process(p, &traced); + zap_process(p); break; } } while ((p = next_thread(p)) != g); } read_unlock(&tasklist_lock); - - if (unlikely(traced)) { - /* - * We are zapping a thread and the thread it ptraces. - * If the tracee went into a ptrace stop for exit tracing, - * we could deadlock since the tracer is waiting for this - * coredump to finish. Detach them so they can both die. - */ - write_lock_irq(&tasklist_lock); - do_each_thread(g,p) { - if (mm == p->mm && p != tsk && - p->ptrace && p->parent->mm == mm) { - __ptrace_detach(p, 0); - } - } while_each_thread(g,p); - write_unlock_irq(&tasklist_lock); - } } static void coredump_wait(struct mm_struct *mm) --- rc1/include/linux/ptrace.h~3_PTRACE 2006-03-01 21:57:22.000000000 +0300 +++ rc1/include/linux/ptrace.h 2006-04-06 16:37:54.000000000 +0400 @@ -84,7 +84,6 @@ extern int ptrace_readdata(struct task_s extern int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len); extern int ptrace_attach(struct task_struct *tsk); extern int ptrace_detach(struct task_struct *, unsigned int); -extern void __ptrace_detach(struct task_struct *, unsigned int); extern void ptrace_disable(struct task_struct *); extern int ptrace_check_attach(struct task_struct *task, int kill); extern int ptrace_request(struct task_struct *child, long request, long addr, long data); --- rc1/kernel/ptrace.c~3_PTRACE 2006-04-03 16:21:26.000000000 +0400 +++ rc1/kernel/ptrace.c 2006-04-06 16:41:41.000000000 +0400 @@ -183,7 +183,7 @@ bad: return retval; } -void __ptrace_detach(struct task_struct *child, unsigned int data) +static inline void __ptrace_detach(struct task_struct *child, unsigned int data) { child->exit_code = data; /* .. re-parent .. */ @@ -202,8 +202,7 @@ int ptrace_detach(struct task_struct *ch ptrace_disable(child); write_lock_irq(&tasklist_lock); - if (child->ptrace) - __ptrace_detach(child, data); + __ptrace_detach(child, data); write_unlock_irq(&tasklist_lock); return 0; - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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