From patchwork Tue Apr 26 14:26:14 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Masami Hiramatsu \(Google\)" X-Patchwork-Id: 567782 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id DFE31C433F5 for ; Tue, 26 Apr 2022 14:26:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237872AbiDZO32 (ORCPT ); Tue, 26 Apr 2022 10:29:28 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60524 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1351430AbiDZO31 (ORCPT ); Tue, 26 Apr 2022 10:29:27 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id ECCC35D5C9; Tue, 26 Apr 2022 07:26:19 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 71671617AE; Tue, 26 Apr 2022 14:26:19 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id EDA6EC385AE; Tue, 26 Apr 2022 14:26:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1650983178; bh=+pviJEHEPY7xSyoldMNeJDLAsyBeQND2yf9wX2ALFiQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=UoJMmo1zksOUlWA6/FrWY0ijxv30NgpVcd+lvd8NsnieGJO1FIn7PksitNelI+6QT yNrkqbD0KoASj73+6V1RRyhVleUyDnqUAXqlKro/jNs/N1O1oTocoVVe9wLsGTO5IJ DPiVJX+reN+gUYtR0YWQ0vcJK3CO09ZHyVxbDnGd3o9JdgA9aG9SJEY7gdXZU08x6e K9XnzlroIhyeFRSgHk6wVWFlinSJXfJzqdTXTOsc3E+eO7G7xejOhCMN+JJY6Zg2iB 9gZ5UMHfymxDJHjNYB4trAMa3cMWlqTQiB7mTHk6xSfUgP1FJi5hODjxH3A3qc+m+1 1zeHl6s/uLQYA== From: Masami Hiramatsu To: stable@vger.kernel.org, Greg Kroah-Hartman Cc: mhiramat@kernel.org, linux-kernel@vger.kernel.org, Ingo Molnar , Sasha Levin Subject: [PATCH 4.19.y 2/3] Revert "ia64: kprobes: Use generic kretprobe trampoline handler" Date: Tue, 26 Apr 2022 23:26:14 +0900 Message-Id: <165098317414.1366179.8363938856817159557.stgit@devnote2> X-Mailer: git-send-email 2.25.1 In-Reply-To: <165098315444.1366179.5950180330185498273.stgit@devnote2> References: <165098315444.1366179.5950180330185498273.stgit@devnote2> User-Agent: StGit/0.19 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.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 Signed-off-by: Masami Hiramatsu --- arch/ia64/kernel/kprobes.c | 77 +++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 75 insertions(+), 2 deletions(-) diff --git a/arch/ia64/kernel/kprobes.c b/arch/ia64/kernel/kprobes.c index 8207b897b49d..aa41bd5cf9b7 100644 --- 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(struct kretprobe_instance *ri, 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;