lkml.org 
[lkml]   [2013]   [Jan]   [9]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [RFC PATCH v2 3/4] uretprobes: return probe entry, prepare uretprobe
    On 01/09, Anton Arapov wrote:
    >
    > todo:
    > protect uprobe

    Yep ;)

    > static struct uprobe_task *get_utask(void)
    > {
    > - if (!current->utask)
    > + if (!current->utask) {
    > current->utask = kzalloc(sizeof(struct uprobe_task), GFP_KERNEL);
    > + INIT_HLIST_HEAD(&current->utask->return_uprobes);

    What if kzalloc() fails?

    > +static void prepare_uretprobe(struct uprobe *uprobe, struct pt_regs *regs)
    > +{
    > + struct return_uprobe_i *ri;
    > + struct uprobe_task *utask;
    > + struct xol_area *area;
    > + unsigned long rp_trampoline_vaddr = 0;
    > +
    > + area = get_xol_area();
    > + if (area)
    > + rp_trampoline_vaddr = area->rp_trampoline_vaddr;
    > + if (!rp_trampoline_vaddr) {
    > + rp_trampoline_vaddr = xol_get_trampoline_slot();

    This is obviously racy. But again, so far I think we can simply remove
    this.

    > static void handler_chain(struct uprobe *uprobe, struct pt_regs *regs)
    > {
    > + int rc = 0;
    > struct uprobe_consumer *uc;
    > int remove = UPROBE_HANDLER_REMOVE;
    >
    > down_read(&uprobe->register_rwsem);
    > for (uc = uprobe->consumers; uc; uc = uc->next) {
    > - int rc = uc->handler(uc, regs);
    > + if (uc->handler)
    > + rc = uc->handler(uc, regs);
    > +
    > + if (uc->rp_handler)
    > + prepare_uretprobe(uprobe, regs); /* put bp at return */

    This doesn't look right. prepare_uretprobe() should not be called
    multiple times.

    Oleg.



    \
     
     \ /
      Last update: 2013-01-09 17:42    [W:2.595 / U:0.372 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site