From: Masami Hiramatsu mhiramat@kernel.org
This reverts commit d3380de483d55d904fb94a241406b34ed2fada7d.
Since this commit is a part of generic kretprobe trampoline handler series, without the other patches in that series, this causes a build error on ia64.
Reported-by: kernel test robot lkp@intel.com Signed-off-by: Masami Hiramatsu mhiramat@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/ia64/kernel/kprobes.c | 77 +++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 75 insertions(+), 2 deletions(-)
--- a/arch/ia64/kernel/kprobes.c +++ b/arch/ia64/kernel/kprobes.c @@ -409,9 +409,83 @@ static void kretprobe_trampoline(void) { }
+/* + * At this point the target function has been tricked into + * returning into our trampoline. Lookup the associated instance + * and then: + * - call the handler function + * - cleanup by marking the instance as unused + * - long jump back to the original return address + */ int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs) { - regs->cr_iip = __kretprobe_trampoline_handler(regs, kretprobe_trampoline, NULL); + struct kretprobe_instance *ri = NULL; + struct hlist_head *head, empty_rp; + struct hlist_node *tmp; + unsigned long flags, orig_ret_address = 0; + unsigned long trampoline_address = + ((struct fnptr *)kretprobe_trampoline)->ip; + + INIT_HLIST_HEAD(&empty_rp); + kretprobe_hash_lock(current, &head, &flags); + + /* + * It is possible to have multiple instances associated with a given + * task either because an multiple functions in the call path + * have a return probe installed on them, and/or more than one return + * return probe was registered for a target function. + * + * We can handle this because: + * - instances are always inserted at the head of the list + * - when multiple return probes are registered for the same + * function, the first instance's ret_addr will point to the + * real return address, and all the rest will point to + * kretprobe_trampoline + */ + hlist_for_each_entry_safe(ri, tmp, head, hlist) { + if (ri->task != current) + /* another task is sharing our hash bucket */ + continue; + + orig_ret_address = (unsigned long)ri->ret_addr; + if (orig_ret_address != trampoline_address) + /* + * This is the real return address. Any other + * instances associated with this task are for + * other calls deeper on the call stack + */ + break; + } + + regs->cr_iip = orig_ret_address; + + hlist_for_each_entry_safe(ri, tmp, head, hlist) { + if (ri->task != current) + /* another task is sharing our hash bucket */ + continue; + + if (ri->rp && ri->rp->handler) + ri->rp->handler(ri, regs); + + orig_ret_address = (unsigned long)ri->ret_addr; + recycle_rp_inst(ri, &empty_rp); + + if (orig_ret_address != trampoline_address) + /* + * This is the real return address. Any other + * instances associated with this task are for + * other calls deeper on the call stack + */ + break; + } + kretprobe_assert(ri, orig_ret_address, trampoline_address); + + kretprobe_hash_unlock(current, &flags); + + hlist_for_each_entry_safe(ri, tmp, &empty_rp, hlist) { + hlist_del(&ri->hlist); + kfree(ri); + } /* * By returning a non-zero value, we are telling * kprobe_handler() that we don't want the post_handler @@ -424,7 +498,6 @@ void __kprobes arch_prepare_kretprobe(st struct pt_regs *regs) { ri->ret_addr = (kprobe_opcode_t *)regs->b0; - ri->fp = NULL;
/* Replace the return addr with trampoline addr */ regs->b0 = ((struct fnptr *)kretprobe_trampoline)->ip;