From: Jiri Kosina <jkosina@suse.cz>
To: Andi Kleen <andi@firstfloor.org>
Cc: Jiri Slaby <jslaby@suse.cz>,
linux-kernel@vger.kernel.org, jirislaby@gmail.com,
Vojtech Pavlik <vojtech@suse.cz>, Michael Matz <matz@suse.de>,
Steven Rostedt <rostedt@goodmis.org>,
Frederic Weisbecker <fweisbec@gmail.com>,
Ingo Molnar <mingo@redhat.com>
Subject: Re: [RFC 03/16] kgr: initial code
Date: Thu, 1 May 2014 22:37:47 +0200 (CEST) [thread overview]
Message-ID: <alpine.LNX.2.00.1405012233510.29834@pobox.suse.cz> (raw)
In-Reply-To: <87tx99ckuh.fsf@tassilo.jf.intel.com>
On Thu, 1 May 2014, Andi Kleen wrote:
> > diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
> > index 1e96c3628bf2..a03b1e9d2de3 100644
> > --- a/arch/x86/kernel/entry_64.S
> > +++ b/arch/x86/kernel/entry_64.S
> > @@ -615,6 +615,7 @@ GLOBAL(system_call_after_swapgs)
> > movq %rax,ORIG_RAX-ARGOFFSET(%rsp)
> > movq %rcx,RIP-ARGOFFSET(%rsp)
> > CFI_REL_OFFSET rip,RIP-ARGOFFSET
> > + movw $0, TI_kgr_in_progress+THREAD_INFO(%rsp,RIP-ARGOFFSET)
>
> Better use 4 bytes. This has the potential to cause an expensive
> Length Changing Prefixes Stall on Intel CPUs.
Patch 16/16 converts this to a single bit within TI_flags.
> > +static int kgr_init_ftrace_ops(const struct kgr_patch_fun *patch_fun)
> > +{
> > + struct kgr_loc_caches *caches;
> > + unsigned long fentry_loc;
> > +
> > + /*
> > + * Initialize the ftrace_ops->private with pointers to the fentry
> > + * sites of both old and new functions. This is used as a
> > + * redirection target in the per-arch stubs.
> > + *
> > + * Beware! -- freeing (once unloading will be implemented)
> > + * will require synchronize_sched() etc.
> > + */
> > +
> > + caches = kmalloc(sizeof(*caches), GFP_KERNEL);
> > + if (!caches) {
> > + kgr_debug("kgr: unable to allocate fentry caches\n");
> > + return -ENOMEM;
> > + }
>
> All the error paths in this function leak memory.
Gah, good catch, thanks a lot.
--
Jiri Kosina
SUSE Labs
next prev parent reply other threads:[~2014-05-01 20:37 UTC|newest]
Thread overview: 59+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-04-30 14:30 [RFC 00/16] kGraft Jiri Slaby
2014-04-30 14:30 ` [RFC 01/16] ftrace: Add function to find fentry of function Jiri Slaby
2014-04-30 14:48 ` Steven Rostedt
2014-04-30 14:58 ` Jiri Slaby
2014-04-30 14:30 ` [RFC 02/16] ftrace: Make ftrace_is_dead available globally Jiri Slaby
2014-04-30 14:30 ` [RFC 03/16] kgr: initial code Jiri Slaby
2014-04-30 14:56 ` Steven Rostedt
2014-04-30 14:57 ` Jiri Slaby
2014-05-01 20:20 ` Andi Kleen
2014-05-01 20:37 ` Jiri Kosina [this message]
2014-05-14 9:28 ` Aravinda Prasad
2014-05-14 10:12 ` Jiri Slaby
2014-05-14 10:41 ` Aravinda Prasad
2014-05-14 10:44 ` Jiri Slaby
2014-05-14 11:19 ` Aravinda Prasad
2014-05-20 11:36 ` Jiri Slaby
2014-05-21 18:28 ` Aravinda Prasad
2014-05-26 8:50 ` Jiri Kosina
2014-04-30 14:30 ` [RFC 04/16] kgr: add testing kgraft patch Jiri Slaby
2014-05-06 11:03 ` Pavel Machek
2014-05-12 12:50 ` Jiri Slaby
2014-04-30 14:30 ` [RFC 05/16] kgr: update Kconfig documentation Jiri Slaby
2014-05-03 14:32 ` Randy Dunlap
2014-04-30 14:30 ` [RFC 06/16] kgr: add Documentation Jiri Slaby
2014-05-06 11:03 ` Pavel Machek
2014-05-09 9:31 ` kgr: dealing with optimalizations? (was Re: [RFC 06/16] kgr: add Documentat)ion Pavel Machek
2014-05-09 12:22 ` Michael Matz
2014-04-30 14:30 ` [RFC 07/16] kgr: trigger the first check earlier Jiri Slaby
2014-04-30 14:30 ` [RFC 08/16] kgr: sched.h, introduce kgr_task_safe helper Jiri Slaby
2014-04-30 14:30 ` [RFC 09/16] kgr: mark task_safe in some kthreads Jiri Slaby
2014-04-30 15:49 ` Greg Kroah-Hartman
2014-04-30 16:55 ` Paul E. McKenney
2014-04-30 18:33 ` Vojtech Pavlik
2014-04-30 19:07 ` Paul E. McKenney
2014-05-01 14:24 ` Tejun Heo
2014-05-01 20:17 ` Jiri Kosina
2014-05-01 21:02 ` Tejun Heo
2014-05-01 21:09 ` Tejun Heo
2014-05-14 14:59 ` Jiri Slaby
2014-05-14 15:15 ` Vojtech Pavlik
2014-05-14 15:30 ` Paul E. McKenney
2014-05-14 16:32 ` Tejun Heo
2014-05-15 3:53 ` Mike Galbraith
2014-05-15 4:06 ` Tejun Heo
2014-05-15 4:46 ` Mike Galbraith
2014-05-15 4:50 ` Tejun Heo
2014-05-15 5:04 ` Mike Galbraith
2014-05-15 5:09 ` Tejun Heo
2014-05-15 5:32 ` Mike Galbraith
2014-05-15 6:05 ` Tejun Heo
2014-05-15 6:32 ` Mike Galbraith
2014-04-30 14:30 ` [RFC 10/16] kgr: kthreads support Jiri Slaby
2014-04-30 14:30 ` [RFC 11/16] kgr: handle irqs Jiri Slaby
2014-04-30 14:30 ` [RFC 12/16] kgr: add tools Jiri Slaby
2014-05-06 11:03 ` Pavel Machek
2014-04-30 14:30 ` [RFC 13/16] kgr: add MAINTAINERS entry Jiri Slaby
2014-04-30 14:30 ` [RFC 14/16] kgr: x86: refuse to build without fentry support Jiri Slaby
2014-04-30 14:30 ` [RFC 15/16] kgr: add procfs interface for per-process 'kgr_in_progress' Jiri Slaby
2014-04-30 14:30 ` [RFC 16/16] kgr: make a per-process 'in progress' flag a single bit Jiri Slaby
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