From: Joel Fernandes <joel@joelfernandes.org>
To: Bjorn Helgaas <helgaas@kernel.org>
Cc: linux-kernel@vger.kernel.org,
Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>,
Borislav Petkov <bp@alien8.de>,
c0d1n61at3@gmail.com, "David S. Miller" <davem@davemloft.net>,
edumazet@google.com,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>,
"H. Peter Anvin" <hpa@zytor.com>, Ingo Molnar <mingo@redhat.com>,
Jonathan Corbet <corbet@lwn.net>,
Josh Triplett <josh@joshtriplett.org>,
keescook@chromium.org, kernel-hardening@lists.openwall.com,
kernel-team@android.com, Lai Jiangshan <jiangshanlai@gmail.com>,
Len Brown <lenb@kernel.org>,
linux-acpi@vger.kernel.org, linux-doc@vger.kernel.org,
linux-pci@vger.kernel.org, linux-pm@vger.kernel.org,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
neilb@suse.com, netdev@vger.kernel.org,
Oleg Nesterov <oleg@redhat.com>,
"Paul E. McKenney" <paulmck@linux.ibm.com>,
Pavel Machek <pavel@ucw.cz>,
peterz@infradead.org, "Rafael J. Wysocki" <rjw@rjwysocki.net>,
Rasmus Villemoes <rasmus.villemoes@prevas.dk>,
rcu@vger.kernel.org, Steven Rostedt <rostedt@goodmis.org>,
Tejun Heo <tj@kernel.org>, Thomas Gleixner <tglx@linutronix.de>,
will@kernel.org,
"maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)"
<x86@kernel.org>
Subject: Re: [PATCH 7/9] x86/pci: Pass lockdep condition to pcm_mmcfg_list iterator (v1)
Date: Tue, 16 Jul 2019 00:03:03 -0400 [thread overview]
Message-ID: <20190716040303.GA73383@google.com> (raw)
In-Reply-To: <20190715200235.GG46935@google.com>
On Mon, Jul 15, 2019 at 03:02:35PM -0500, Bjorn Helgaas wrote:
> On Mon, Jul 15, 2019 at 10:37:03AM -0400, Joel Fernandes (Google) wrote:
> > The pcm_mmcfg_list is traversed with list_for_each_entry_rcu without a
> > reader-lock held, because the pci_mmcfg_lock is already held. Make this
> > known to the list macro so that it fixes new lockdep warnings that
> > trigger due to lockdep checks added to list_for_each_entry_rcu().
> >
> > Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
>
> Ingo takes care of most patches to this file, but FWIW,
>
> Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Thanks.
> I would personally prefer if you capitalized the subject to match the
> "x86/PCI:" convention that's used fairly consistently in
> arch/x86/pci/.
>
> Also, I didn't apply this to be sure, but it looks like this might
> make a line or two wider than 80 columns, which I would rewrap if I
> were applying this.
Updated below is the patch with the nits corrected:
---8<-----------------------
From 73fab09d7e33ca2110c24215f8ed428c12625dbe Mon Sep 17 00:00:00 2001
From: "Joel Fernandes (Google)" <joel@joelfernandes.org>
Date: Sat, 1 Jun 2019 15:05:49 -0400
Subject: [PATCH] x86/PCI: Pass lockdep condition to pcm_mmcfg_list iterator
(v1)
The pcm_mmcfg_list is traversed with list_for_each_entry_rcu without a
reader-lock held, because the pci_mmcfg_lock is already held. Make this
known to the list macro so that it fixes new lockdep warnings that
trigger due to lockdep checks added to list_for_each_entry_rcu().
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
---
arch/x86/pci/mmconfig-shared.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/arch/x86/pci/mmconfig-shared.c b/arch/x86/pci/mmconfig-shared.c
index 7389db538c30..9e3250ec5a37 100644
--- a/arch/x86/pci/mmconfig-shared.c
+++ b/arch/x86/pci/mmconfig-shared.c
@@ -29,6 +29,7 @@
static bool pci_mmcfg_running_state;
static bool pci_mmcfg_arch_init_failed;
static DEFINE_MUTEX(pci_mmcfg_lock);
+#define pci_mmcfg_lock_held() lock_is_held(&(pci_mmcfg_lock).dep_map)
LIST_HEAD(pci_mmcfg_list);
@@ -54,7 +55,8 @@ static void list_add_sorted(struct pci_mmcfg_region *new)
struct pci_mmcfg_region *cfg;
/* keep list sorted by segment and starting bus number */
- list_for_each_entry_rcu(cfg, &pci_mmcfg_list, list) {
+ list_for_each_entry_rcu(cfg, &pci_mmcfg_list, list,
+ pci_mmcfg_lock_held()) {
if (cfg->segment > new->segment ||
(cfg->segment == new->segment &&
cfg->start_bus >= new->start_bus)) {
@@ -118,7 +120,8 @@ struct pci_mmcfg_region *pci_mmconfig_lookup(int segment, int bus)
{
struct pci_mmcfg_region *cfg;
- list_for_each_entry_rcu(cfg, &pci_mmcfg_list, list)
+ list_for_each_entry_rcu(cfg, &pci_mmcfg_list, list
+ pci_mmcfg_lock_held())
if (cfg->segment == segment &&
cfg->start_bus <= bus && bus <= cfg->end_bus)
return cfg;
--
2.22.0.510.g264f2c817a-goog
next prev parent reply other threads:[~2019-07-16 4:03 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-15 14:36 [PATCH 0/9] Harden list_for_each_entry_rcu() and family Joel Fernandes (Google)
2019-07-15 14:36 ` [PATCH 1/9] rcu/update: Remove useless check for debug_locks (v1) Joel Fernandes (Google)
2019-07-15 14:36 ` [PATCH 2/9] rcu: Add support for consolidated-RCU reader checking (v3) Joel Fernandes (Google)
2019-07-16 18:38 ` Paul E. McKenney
2019-07-16 18:46 ` Joel Fernandes
2019-07-16 18:53 ` Paul E. McKenney
2019-07-16 22:02 ` Joel Fernandes
2019-07-17 0:07 ` Paul E. McKenney
2019-07-15 14:36 ` [PATCH 3/9] rcu/sync: Remove custom check for reader-section (v2) Joel Fernandes (Google)
2019-07-16 18:39 ` Paul E. McKenney
2019-07-15 14:37 ` [PATCH 4/9] ipv4: add lockdep condition to fix for_each_entry (v1) Joel Fernandes (Google)
2019-07-16 18:39 ` Paul E. McKenney
2019-07-16 21:12 ` David Miller
2019-07-15 14:37 ` [PATCH 5/9] driver/core: Convert to use built-in RCU list checking (v1) Joel Fernandes (Google)
2019-07-16 18:40 ` Paul E. McKenney
2019-07-15 14:37 ` [PATCH 6/9] workqueue: Convert for_each_wq to use built-in list check (v2) Joel Fernandes (Google)
2019-07-16 18:41 ` Paul E. McKenney
2019-07-15 14:37 ` [PATCH 7/9] x86/pci: Pass lockdep condition to pcm_mmcfg_list iterator (v1) Joel Fernandes (Google)
2019-07-15 20:02 ` Bjorn Helgaas
2019-07-16 4:03 ` Joel Fernandes [this message]
2019-07-16 18:42 ` Paul E. McKenney
2019-07-15 14:37 ` [PATCH 8/9] acpi: Use built-in RCU list checking for acpi_ioremaps list (v1) Joel Fernandes (Google)
2019-07-15 21:44 ` Rafael J. Wysocki
2019-07-16 18:43 ` Paul E. McKenney
2019-07-15 14:37 ` [PATCH 9/9] doc: Update documentation about list_for_each_entry_rcu (v1) Joel Fernandes (Google)
2019-07-16 18:46 ` [PATCH 0/9] Harden list_for_each_entry_rcu() and family Paul E. McKenney
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