Messages in this thread Patch in this message | | | From | Anton Arapov <> | Subject | [RFC PATCH v2 4/4] uretprobes: invoke return probe handlers | Date | Wed, 9 Jan 2013 12:24:52 +0100 |
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uretprobe handlers are invoked when the trampoline is hit, on completion the trampoline is replaced with the saved return address and the uretprobe instance deleted.
v2: get rid of ->return_consumers use rp_handler()
Signed-off-by: Anton Arapov <anton@redhat.com> --- arch/x86/include/asm/uprobes.h | 5 ++++ include/linux/uprobes.h | 4 +++ kernel/events/uprobes.c | 61 +++++++++++++++++++++++++++++++++++++++++- 3 files changed, 69 insertions(+), 1 deletion(-)
diff --git a/arch/x86/include/asm/uprobes.h b/arch/x86/include/asm/uprobes.h index c353555..9a605b8 100644 --- a/arch/x86/include/asm/uprobes.h +++ b/arch/x86/include/asm/uprobes.h @@ -56,4 +56,9 @@ extern bool arch_uprobe_xol_was_trapped(struct task_struct *tsk); extern int arch_uprobe_exception_notify(struct notifier_block *self, unsigned long val, void *data); extern void arch_uprobe_abort_xol(struct arch_uprobe *aup, struct pt_regs *regs); extern unsigned long arch_uretprobe_hijack_return_addr(unsigned long rp_trampoline_vaddr, struct pt_regs *regs); + +static inline unsigned long arch_uretprobe_get_sp(struct pt_regs *regs) +{ + return (unsigned long)regs->sp; +} #endif /* _ASM_UPROBES_H */ diff --git a/include/linux/uprobes.h b/include/linux/uprobes.h index cdc4d53..1a229db 100644 --- a/include/linux/uprobes.h +++ b/include/linux/uprobes.h @@ -45,7 +45,11 @@ enum uprobe_filter_ctx { }; struct uprobe_consumer { + /* probe handler */ int (*handler)(struct uprobe_consumer *self, struct pt_regs *regs); + /* return probe handler */ + int (*rp_handler)(struct uprobe_consumer *self, struct pt_regs *regs); + bool (*filter)(struct uprobe_consumer *self, enum uprobe_filter_ctx ctx, struct mm_struct *mm); diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index d6fa497..8232c29 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -1548,6 +1548,57 @@ static void handler_chain(struct uprobe *uprobe, struct pt_regs *regs) up_read(&uprobe->register_rwsem); } +static void handler_rp_chain(struct uprobe *uprobe, struct pt_regs *regs) +{ + struct uprobe_consumer *uc; + + down_read(&uprobe->register_rwsem); + for (uc = uprobe->consumers; uc; uc = uc->next) { + if (uc->rp_handler) + uc->rp_handler(uc, regs); + } + up_read(&uprobe->register_rwsem); +} + +static void handle_rp_swbp(struct pt_regs *regs) +{ + struct hlist_head *head; + struct hlist_node *r1, *r2; + + struct return_uprobe_i *ri; + struct uprobe_task *utask; + + struct xol_area *area; + unsigned long rp_trampoline_vaddr; + unsigned long orig_ret_vaddr, cur_sp; + + cur_sp = arch_uretprobe_get_sp(regs); + utask = current->utask; + head = &utask->return_uprobes; + + area = get_xol_area(); + rp_trampoline_vaddr = area->vaddr; + + hlist_for_each_entry_safe(ri, r1, r2, head, hlist) { + orig_ret_vaddr = ri->orig_ret_vaddr; + + if (ri->uprobe->consumers) { + instruction_pointer_set(regs, orig_ret_vaddr); + handler_rp_chain(ri->uprobe, regs); + } + + hlist_del(&ri->hlist); + kfree(ri); + + if (orig_ret_vaddr != rp_trampoline_vaddr) + return; + } + + printk(KERN_ERR "uretprobe: no instance with original return address!" + " pid/tgid=%d/%d", current->pid, current->tgid); + send_sig(SIGSEGV, current, 0); +} + /* * Run handler and ask thread to singlestep. * Ensure all non-fatal signals cannot interrupt thread while it singlesteps. @@ -1555,12 +1606,20 @@ static void handler_chain(struct uprobe *uprobe, struct pt_regs *regs) static void handle_swbp(struct pt_regs *regs) { struct uprobe *uprobe; + struct xol_area *area; unsigned long bp_vaddr; int uninitialized_var(is_swbp); bp_vaddr = uprobe_get_swbp_addr(regs); - uprobe = find_active_uprobe(bp_vaddr, &is_swbp); + area = get_xol_area(); + if (area) { + if (bp_vaddr == area->vaddr) { + handle_rp_swbp(regs); + return; + } + } + uprobe = find_active_uprobe(bp_vaddr, &is_swbp); if (!uprobe) { if (is_swbp > 0) { /* No matching uprobe; signal SIGTRAP. */ -- 1.8.0.2
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