Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757192Ab0HQPKP (ORCPT ); Tue, 17 Aug 2010 11:10:15 -0400 Received: from mail4.hitachi.co.jp ([133.145.228.5]:49823 "EHLO mail4.hitachi.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750837Ab0HQPKM (ORCPT ); Tue, 17 Aug 2010 11:10:12 -0400 X-AuditID: b753bd60-a5cd7ba000000a18-6a-4c6aa65070ce Message-ID: <4C6AA64E.2050600@hitachi.com> Date: Wed, 18 Aug 2010 00:10:06 +0900 From: Masami Hiramatsu Organization: Systems Development Lab., Hitachi, Ltd., Japan User-Agent: Thunderbird 2.0.0.24 (Windows/20100228) MIME-Version: 1.0 To: KUMANO Syuhei , Ingo Molnar Cc: linux-kernel@vger.kernel.org, Thomas Gleixner , "H. Peter Anvin" , x86@kernel.org, Frederic Weisbecker , Ananth N Mavinakayanahalli , Peter Zijlstra , YOSHIFUJI Hideaki , 2nddept-manager@sdl.hitachi.co.jp Subject: Re: [PATCH] kprobes/x86: Fix the return address of multiple kretprobes References: <1281853084.3254.11.camel@camp10-laptop> In-Reply-To: <1281853084.3254.11.camel@camp10-laptop> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Brightmail-Tracker: AAAAAA== X-FMFTCR: RANGEB Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3898 Lines: 106 KUMANO Syuhei wrote: > Fix the return address of subsequent kretprobes when multiple > kretprobes are set on the same function. > > For example: > # cd /sys/kernel/debug/tracing > # echo "r:event1 sys_symlink" > kprobe_events > # echo "r:event2 sys_symlink" >> kprobe_events > # echo 1 > events/kprobes/enable > # ln -s /tmp/foo /tmp/bar > (without this patch) > # cat trace > ln-897 [000] 20404.133727: event1: (kretprobe_trampoline+0x0/0x4c <- sys_symlink) > ln-897 [000] 20404.133747: event2: (system_call_fastpath+0x16/0x1b <- sys_symlink) > (with this patch) > # cat trace > ln-740 [000] 13799.491076: event1: (system_call_fastpath+0x16/0x1b <- sys_symlink) > ln-740 [000] 13799.491096: event2: (system_call_fastpath+0x16/0x1b <- sys_symlink) > Yeah, I'm OK for this fix. Acked-by: Masami Hiramatsu Ingo, could you pull this on your x86/bugfix tree? Thank you, > Cc: Thomas Gleixner > Cc: Ingo Molnar > Cc: "H. Peter Anvin" > Cc: x86@kernel.org > Cc: Frederic Weisbecker > Cc: Ananth N Mavinakayanahalli > Cc: Peter Zijlstra > Cc: linux-kernel@vger.kernel.org > Cc: YOSHIFUJI Hideaki > Reviewed-by: Masami Hiramatsu > Signed-off-by: KUMANO Syuhei > --- > arch/x86/kernel/kprobes.c | 25 ++++++++++++++++++++++--- > 1 files changed, 22 insertions(+), 3 deletions(-) > > diff --git a/arch/x86/kernel/kprobes.c b/arch/x86/kernel/kprobes.c > index 675879b..5220e14 100644 > --- a/arch/x86/kernel/kprobes.c > +++ b/arch/x86/kernel/kprobes.c > @@ -707,6 +707,7 @@ static __used __kprobes void *trampoline_handler(struct pt_regs *regs) > struct hlist_node *node, *tmp; > unsigned long flags, orig_ret_address = 0; > unsigned long trampoline_address = (unsigned long)&kretprobe_trampoline; > + kprobe_opcode_t *correct_ret_addr = NULL; > > INIT_HLIST_HEAD(&empty_rp); > kretprobe_hash_lock(current, &head, &flags); > @@ -738,14 +739,34 @@ static __used __kprobes void *trampoline_handler(struct pt_regs *regs) > /* 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; > + } > + > + kretprobe_assert(ri, orig_ret_address, trampoline_address); > + > + correct_ret_addr = ri->ret_addr; > + hlist_for_each_entry_safe(ri, node, tmp, head, hlist) { > + if (ri->task != current) > + /* another task is sharing our hash bucket */ > + continue; > + > + orig_ret_address = (unsigned long)ri->ret_addr; > if (ri->rp && ri->rp->handler) { > __get_cpu_var(current_kprobe) = &ri->rp->kp; > get_kprobe_ctlblk()->kprobe_status = KPROBE_HIT_ACTIVE; > + ri->ret_addr = correct_ret_addr; > ri->rp->handler(ri, regs); > __get_cpu_var(current_kprobe) = NULL; > } > > - orig_ret_address = (unsigned long)ri->ret_addr; > recycle_rp_inst(ri, &empty_rp); > > if (orig_ret_address != trampoline_address) > @@ -757,8 +778,6 @@ static __used __kprobes void *trampoline_handler(struct pt_regs *regs) > break; > } > > - kretprobe_assert(ri, orig_ret_address, trampoline_address); > - > kretprobe_hash_unlock(current, &flags); > > hlist_for_each_entry_safe(ri, node, tmp, &empty_rp, hlist) { -- 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/