Messages in this thread | | | Subject | Re: [PATCH] remove BUG_ON(p->ptrace) in release_task() | From | OGAWA Hirofumi <> | Date | Mon, 02 Sep 2002 22:33:16 +0900 |
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Daniel Jacobowitz <dan@debian.org> writes:
> On Mon, Sep 02, 2002 at 02:38:03AM +0900, OGAWA Hirofumi wrote: > > Hi, > > > > I think, BUG_ON(p->ptrace) will be called if the CLONE_DETACH process > > is traced. This patch removes BUG_ON(p->ptrace), and also removes > > BUG_ON(p->ptrace) workaround in sys_wait4(). > > The BUG_ON is correct, and that isn't a workaround - if the list is not > empty, then it will be garbage after the task struct is freed. Your > patch breaks tracing of normal processes again, because the ptrace_list > will not be empty.
Whoops, yes, I'm wrong. Sorry. My fixes wasn't enough. However, looks like your case called the following BUG().
sys_ptrace() -> ptrace_attach() -> __ptrace_link()
void __ptrace_link(task_t *child, task_t *new_parent) { if (!list_empty(&child->ptrace_list)) BUG(); if (child->parent == new_parent) BUG(); <--- this list_add(&child->ptrace_list, &child->parent->ptrace_children); REMOVE_LINKS(child);
So, I need to look source more. Thanks. -- OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> - 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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