From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Eric Dumazet <edumazet@google.com>,
Thomas Gleixner <tglx@linutronix.de>,
Sasha Levin <sashal@kernel.org>
Subject: [PATCH AUTOSEL 4.14 21/33] hrtimer: Annotate lockless access to timer->base
Date: Sat, 26 Oct 2019 09:20:58 -0400 [thread overview]
Message-ID: <20191026132110.4026-21-sashal@kernel.org> (raw)
In-Reply-To: <20191026132110.4026-1-sashal@kernel.org>
From: Eric Dumazet <edumazet@google.com>
[ Upstream commit ff229eee3d897f52bd001c841f2d3cce8853ecdc ]
Followup to commit dd2261ed45aa ("hrtimer: Protect lockless access
to timer->base")
lock_hrtimer_base() fetches timer->base without lock exclusion.
Compiler is allowed to read timer->base twice (even if considered dumb)
which could end up trying to lock migration_base and return
&migration_base.
base = timer->base;
if (likely(base != &migration_base)) {
/* compiler reads timer->base again, and now (base == &migration_base)
raw_spin_lock_irqsave(&base->cpu_base->lock, *flags);
if (likely(base == timer->base))
return base; /* == &migration_base ! */
Similarly the write sides must use WRITE_ONCE() to avoid store tearing.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20191008173204.180879-1-edumazet@google.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
kernel/time/hrtimer.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c
index d00e85ac10d66..e7ef0d830c093 100644
--- a/kernel/time/hrtimer.c
+++ b/kernel/time/hrtimer.c
@@ -143,7 +143,7 @@ struct hrtimer_clock_base *lock_hrtimer_base(const struct hrtimer *timer,
struct hrtimer_clock_base *base;
for (;;) {
- base = timer->base;
+ base = READ_ONCE(timer->base);
if (likely(base != &migration_base)) {
raw_spin_lock_irqsave(&base->cpu_base->lock, *flags);
if (likely(base == timer->base))
@@ -235,7 +235,7 @@ switch_hrtimer_base(struct hrtimer *timer, struct hrtimer_clock_base *base,
return base;
/* See the comment in lock_hrtimer_base() */
- timer->base = &migration_base;
+ WRITE_ONCE(timer->base, &migration_base);
raw_spin_unlock(&base->cpu_base->lock);
raw_spin_lock(&new_base->cpu_base->lock);
@@ -244,10 +244,10 @@ switch_hrtimer_base(struct hrtimer *timer, struct hrtimer_clock_base *base,
raw_spin_unlock(&new_base->cpu_base->lock);
raw_spin_lock(&base->cpu_base->lock);
new_cpu_base = this_cpu_base;
- timer->base = base;
+ WRITE_ONCE(timer->base, base);
goto again;
}
- timer->base = new_base;
+ WRITE_ONCE(timer->base, new_base);
} else {
if (new_cpu_base != this_cpu_base &&
hrtimer_check_target(timer, new_base)) {
--
2.20.1
next prev parent reply other threads:[~2019-10-26 13:26 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-26 13:20 [PATCH AUTOSEL 4.14 01/33] iommu/arm-smmu: Free context bitmap in the err path of arm_smmu_init_domain_context Sasha Levin
2019-10-26 13:20 ` [PATCH AUTOSEL 4.14 02/33] mac80211_hwsim: fix incorrect dev_alloc_name failure goto Sasha Levin
2019-10-26 13:20 ` [PATCH AUTOSEL 4.14 03/33] nvme: retain split access workaround for capability reads Sasha Levin
2019-10-26 13:20 ` [PATCH AUTOSEL 4.14 04/33] net: dsa: b53: Do not clear existing mirrored port mask Sasha Levin
2019-10-26 13:20 ` [PATCH AUTOSEL 4.14 05/33] net: stmmac: gmac4+: Not all Unicast addresses may be available Sasha Levin
2019-10-26 13:20 ` [PATCH AUTOSEL 4.14 06/33] rxrpc: Fix call ref leak Sasha Levin
2019-10-26 13:20 ` [PATCH AUTOSEL 4.14 07/33] mac80211: accept deauth frames in IBSS mode Sasha Levin
2019-10-26 13:20 ` [PATCH AUTOSEL 4.14 08/33] llc: fix sk_buff leak in llc_sap_state_process() Sasha Levin
2019-10-26 13:20 ` [PATCH AUTOSEL 4.14 09/33] llc: fix sk_buff leak in llc_conn_service() Sasha Levin
2019-10-26 13:20 ` [PATCH AUTOSEL 4.14 10/33] llc: fix another potential sk_buff leak in llc_ui_sendmsg() Sasha Levin
2019-10-26 13:20 ` [PATCH AUTOSEL 4.14 11/33] llc: fix sk_buff refcounting in llc_conn_state_process() Sasha Levin
2019-10-26 13:20 ` [PATCH AUTOSEL 4.14 12/33] NFC: pn533: fix use-after-free and memleaks Sasha Levin
2019-10-26 13:20 ` [PATCH AUTOSEL 4.14 13/33] iwlwifi: dbg_ini: fix memory leak in alloc_sgtable Sasha Levin
2019-10-26 13:20 ` [PATCH AUTOSEL 4.14 14/33] net: stmmac: fix length of PTP clock's name string Sasha Levin
2019-10-26 13:20 ` [PATCH AUTOSEL 4.14 15/33] bonding: fix potential NULL deref in bond_update_slave_arr Sasha Levin
2019-10-26 13:20 ` [PATCH AUTOSEL 4.14 16/33] act_mirred: Fix mirred_init_module error handling Sasha Levin
2019-10-26 13:20 ` [PATCH AUTOSEL 4.14 17/33] net: usb: qmi_wwan: add Telit 0x1050 composition Sasha Levin
2020-09-07 9:36 ` Kristian Evensen
2020-09-07 18:15 ` Sasha Levin
2020-09-08 0:33 ` Lars Melin
2020-09-08 12:12 ` Sasha Levin
2019-10-26 13:20 ` [PATCH AUTOSEL 4.14 18/33] net: avoid possible false sharing in sk_leave_memory_pressure() Sasha Levin
2019-10-26 13:20 ` [PATCH AUTOSEL 4.14 19/33] net: add {READ|WRITE}_ONCE() annotations on ->rskq_accept_head Sasha Levin
2019-10-26 13:20 ` [PATCH AUTOSEL 4.14 20/33] drm/msm/dsi: Implement reset correctly Sasha Levin
2019-10-26 13:20 ` Sasha Levin [this message]
2019-10-26 13:20 ` [PATCH AUTOSEL 4.14 22/33] xtensa: fix {get,put}_user() for 64bit values Sasha Levin
2019-10-26 13:21 ` [PATCH AUTOSEL 4.14 23/33] net: i82596: fix dma_alloc_attr for sni_82596 Sasha Levin
2019-10-26 13:21 ` [PATCH AUTOSEL 4.14 24/33] net: bcmgenet: Fix RGMII_MODE_EN value for GENET v1/2/3 Sasha Levin
2019-10-26 13:21 ` [PATCH AUTOSEL 4.14 25/33] net: usb: sr9800: fix uninitialized local variable Sasha Levin
2019-10-26 13:21 ` [PATCH AUTOSEL 4.14 26/33] md/raid0: fix warning message for parameter default_layout Sasha Levin
2019-10-26 13:21 ` [PATCH AUTOSEL 4.14 27/33] net: stmmac: disable/enable ptp_ref_clk in suspend/resume flow Sasha Levin
2019-10-26 13:21 ` [PATCH AUTOSEL 4.14 28/33] usb: hso: obey DMA rules in tiocmget Sasha Levin
2019-10-26 13:21 ` [PATCH AUTOSEL 4.14 29/33] x86/hyperv: Set pv_info.name to "Hyper-V" Sasha Levin
2019-10-26 13:21 ` [PATCH AUTOSEL 4.14 30/33] net: usb: lan78xx: Connect PHY before registering MAC Sasha Levin
2019-10-26 13:21 ` [PATCH AUTOSEL 4.14 31/33] scripts/gdb: fix lx-dmesg when CONFIG_PRINTK_CALLER is set Sasha Levin
2019-10-26 13:21 ` [PATCH AUTOSEL 4.14 32/33] ocfs2: fix error handling in ocfs2_setattr() Sasha Levin
2019-10-26 13:21 ` [PATCH AUTOSEL 4.14 33/33] scripts/gdb: fix debugging modules on s390 Sasha Levin
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