From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from e23smtp06.au.ibm.com (e23smtp06.au.ibm.com [202.81.31.148]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "e23smtp06.au.ibm.com", Issuer "Equifax" (verified OK)) by ozlabs.org (Postfix) with ESMTPS id DDC4EB7EF1 for ; Thu, 13 May 2010 17:44:03 +1000 (EST) Received: from d23relay05.au.ibm.com (d23relay05.au.ibm.com [202.81.31.247]) by e23smtp06.au.ibm.com (8.14.3/8.13.1) with ESMTP id o4D7hsgT014388 for ; Thu, 13 May 2010 17:43:54 +1000 Received: from d23av03.au.ibm.com (d23av03.au.ibm.com [9.190.234.97]) by d23relay05.au.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id o4D7atl31405030 for ; Thu, 13 May 2010 17:36:55 +1000 Received: from d23av03.au.ibm.com (loopback [127.0.0.1]) by d23av03.au.ibm.com (8.14.3/8.13.1/NCO v10.0 AVout) with ESMTP id o4D7i2xR024822 for ; Thu, 13 May 2010 17:44:03 +1000 From: "Ian Munsie" To: linux-kernel@vger.kernel.org Subject: [PATCH 1/4] ftrace syscalls: don't add events for unmapped syscalls Date: Thu, 13 May 2010 17:43:11 +1000 Message-Id: <1273736594-19320-2-git-send-email-imunsie@au1.ibm.com> In-Reply-To: <1273736594-19320-1-git-send-email-imunsie@au1.ibm.com> References: <1273736594-19320-1-git-send-email-imunsie@au1.ibm.com> Cc: Frederic Weisbecker , Jason Baron , Steven Rostedt , Ingo Molnar , Paul Mackerras , Ian Munsie , linuxppc-dev@lists.ozlabs.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , From: Ian Munsie FTRACE_SYSCALLS would create events for each and every system call, even if it had failed to map the system call's name with it's number. This resulted in a number of events being created that would not behave as expected. This could happen, for example, on architectures who's symbol names are unusual and will not match the system call name. It could also happen with system calls which were mapped to sys_ni_syscall. This patch changes the default system call number in the metadata to -1. If the system call name from the metadata is not successfully mapped to a system call number during boot, than the event initialisation routine will now return an error, preventing the event from being created. Signed-off-by: Ian Munsie --- include/linux/syscalls.h | 2 ++ kernel/trace/trace_syscalls.c | 8 ++++++++ 2 files changed, 10 insertions(+), 0 deletions(-) diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h index 057929b..a970c24 100644 --- a/include/linux/syscalls.h +++ b/include/linux/syscalls.h @@ -186,6 +186,7 @@ struct perf_event_attr; __attribute__((section("__syscalls_metadata"))) \ __syscall_meta_##sname = { \ .name = "sys"#sname, \ + .syscall_nr = -1, /* Filled in at boot */ \ .nb_args = nb, \ .types = types_##sname, \ .args = args_##sname, \ @@ -201,6 +202,7 @@ struct perf_event_attr; __attribute__((section("__syscalls_metadata"))) \ __syscall_meta__##sname = { \ .name = "sys_"#sname, \ + .syscall_nr = -1, /* Filled in at boot */ \ .nb_args = 0, \ .enter_event = &event_enter__##sname, \ .exit_event = &event_exit__##sname, \ diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c index 4d6d711..732f021 100644 --- a/kernel/trace/trace_syscalls.c +++ b/kernel/trace/trace_syscalls.c @@ -381,6 +381,14 @@ void unreg_event_syscall_exit(struct ftrace_event_call *call) int init_syscall_trace(struct ftrace_event_call *call) { int id; + int num; + + num = ((struct syscall_metadata *)call->data)->syscall_nr; + if (num < 0 || num >= NR_syscalls) { + pr_debug("syscall %s metadata not mapped, disabling ftrace event\n", + ((struct syscall_metadata *)call->data)->name); + return -ENOSYS; + } if (set_syscall_print_fmt(call) < 0) return -ENOMEM; -- 1.7.1