Messages in this thread Patch in this message |  | | Date | Fri, 6 Sep 2002 17:57:13 +0200 (CEST) | From | Ingo Molnar <> | Subject | Re: [patch] ptrace-fix-2.5.33-A1 |
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On Fri, 6 Sep 2002, Daniel Jacobowitz wrote:
> Because it's also needed for non-CLONE_DETACH processes. I added it > earlier down by the release_task, remember? I deleted it in this patch > originally, and the change got lost somewhere; my intent is to check for > this only in release_task and nowhere else. When I have a clear point > to resync with Linus again then I'll make sure this is right.
Linus' tree is at http://linux.bkbits.net/linux-2.5/, and i've done the attached patch to collect & clean up all the things that happened since yesterday. It's basically what was your tree this morning - i'd suggest for you to base subsequent patches on BK-curr + this patch. (To reduce confusion i wont send any new patches for this area from now on.)
Ingo
diff -rNu linux.orig/kernel/exit.c linux/kernel/exit.c --- linux.orig/kernel/exit.c Fri Sep 6 11:37:53 2002 +++ linux/kernel/exit.c Fri Sep 6 11:39:47 2002 @@ -66,8 +66,12 @@ atomic_dec(&p->user->processes); security_ops->task_free_security(p); free_uid(p->user); - BUG_ON(p->ptrace || !list_empty(&p->ptrace_list) || - !list_empty(&p->ptrace_children)); + if (unlikely(p->ptrace)) { + write_lock_irq(&tasklist_lock); + __ptrace_unlink(p); + write_unlock_irq(&tasklist_lock); + } + BUG_ON(!list_empty(&p->ptrace_list) || !list_empty(&p->ptrace_children)); unhash_process(p); release_thread(p); @@ -428,7 +432,7 @@ * There are only two places where our children can be: * * - in our child list - * - in the global ptrace list + * - in our ptraced child list * * Search them and reparent children. */ @@ -443,14 +447,22 @@ read_unlock(&tasklist_lock); } -static inline void zap_thread(task_t *p, task_t *father) +static inline void zap_thread(task_t *p, task_t *father, int traced) { - ptrace_unlink(p); - list_del_init(&p->sibling); - p->ptrace = 0; + /* If we were tracing the thread, release it; otherwise preserve the + ptrace links. */ + if (unlikely(traced)) { + task_t *trace_task = p->parent; + __ptrace_unlink(p); + p->ptrace = 1; + __ptrace_link(p, trace_task); + } else { + p->ptrace = 0; + list_del_init(&p->sibling); + p->parent = p->real_parent; + list_add_tail(&p->sibling, &p->parent->children); + } - p->parent = p->real_parent; - list_add_tail(&p->sibling, &p->parent->children); if (p->state == TASK_ZOMBIE && p->exit_signal != -1) do_notify_parent(p, p->exit_signal); /* @@ -541,11 +553,11 @@ zap_again: list_for_each_safe(_p, _n, ¤t->children) - zap_thread(list_entry(_p,struct task_struct,sibling), current); + zap_thread(list_entry(_p,struct task_struct,sibling), current, 0); list_for_each_safe(_p, _n, ¤t->ptrace_children) - zap_thread(list_entry(_p,struct task_struct,ptrace_list), current); + zap_thread(list_entry(_p,struct task_struct,ptrace_list), current, 1); /* - * reparent_thread might drop the tasklist lock, thus we could + * zap_thread might drop the tasklist lock, thus we could * have new children queued back from the ptrace list into the * child list: */ @@ -716,17 +728,11 @@ retval = p->pid; if (p->real_parent != p->parent) { write_lock_irq(&tasklist_lock); - ptrace_unlink(p); + __ptrace_unlink(p); do_notify_parent(p, SIGCHLD); write_unlock_irq(&tasklist_lock); - } else { - if (p->ptrace) { - write_lock_irq(&tasklist_lock); - ptrace_unlink(p); - write_unlock_irq(&tasklist_lock); - } + } else release_task(p); - } goto end_wait4; default: continue;
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