From mboxrd@z Thu Jan 1 00:00:00 1970 From: Shaohua Li Date: Tue, 13 Nov 2007 06:55:20 +0000 Subject: [PATCH] kprobe: make kreturn probe handler stack unwind correct Message-Id: <1194936920.27851.5.camel@sli10-conroe.sh.intel.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-ia64@vger.kernel.org Restore regs->ccr_iip before kreturn probe handler runs. In this way, if probe handler does unwind, unwind can correctly get the stack trace. http://sourceware.org/bugzilla/show_bug.cgi?idP51 Signed-off-by: Shaohua Li Index: linux/arch/ia64/kernel/kprobes.c =================================--- linux.orig/arch/ia64/kernel/kprobes.c 2007-10-17 10:33:45.000000000 +0800 +++ linux/arch/ia64/kernel/kprobes.c 2007-11-13 14:39:50.000000000 +0800 @@ -435,6 +435,23 @@ int __kprobes trampoline_probe_handler(s /* 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, node, 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); @@ -452,8 +469,6 @@ int __kprobes trampoline_probe_handler(s kretprobe_assert(ri, orig_ret_address, trampoline_address); - regs->cr_iip = orig_ret_address; - reset_current_kprobe(); spin_unlock_irqrestore(&kretprobe_lock, flags); preempt_enable_no_resched();