From: paulmck@kernel.org
To: rcu@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, kernel-team@fb.com,
mingo@kernel.org, jiangshanlai@gmail.com, dipankar@in.ibm.com,
akpm@linux-foundation.org, mathieu.desnoyers@efficios.com,
josh@joshtriplett.org, tglx@linutronix.de, peterz@infradead.org,
rostedt@goodmis.org, dhowells@redhat.com, edumazet@google.com,
fweisbec@gmail.com, oleg@redhat.com, joel@joelfernandes.org,
"Paul E. McKenney" <paulmck@kernel.org>
Subject: [PATCH tip/core/rcu 4/9] rcu: Use WRITE_ONCE() for assignments to ->pprev for hlist_nulls
Date: Mon, 9 Dec 2019 20:19:57 -0800 [thread overview]
Message-ID: <20191210042002.3490-4-paulmck@kernel.org> (raw)
In-Reply-To: <20191210041938.GA3367@paulmck-ThinkPad-P72>
From: "Paul E. McKenney" <paulmck@kernel.org>
Eric Dumazet supplied a KCSAN report of a bug that forces use
of hlist_unhashed_lockless() from sk_unhashed():
------------------------------------------------------------------------
BUG: KCSAN: data-race in inet_unhash / inet_unhash
write to 0xffff8880a69a0170 of 8 bytes by interrupt on cpu 1:
__hlist_nulls_del include/linux/list_nulls.h:88 [inline]
hlist_nulls_del_init_rcu include/linux/rculist_nulls.h:36 [inline]
__sk_nulls_del_node_init_rcu include/net/sock.h:676 [inline]
inet_unhash+0x38f/0x4a0 net/ipv4/inet_hashtables.c:612
tcp_set_state+0xfa/0x3e0 net/ipv4/tcp.c:2249
tcp_done+0x93/0x1e0 net/ipv4/tcp.c:3854
tcp_write_err+0x7e/0xc0 net/ipv4/tcp_timer.c:56
tcp_retransmit_timer+0x9b8/0x16d0 net/ipv4/tcp_timer.c:479
tcp_write_timer_handler+0x42d/0x510 net/ipv4/tcp_timer.c:599
tcp_write_timer+0xd1/0xf0 net/ipv4/tcp_timer.c:619
call_timer_fn+0x5f/0x2f0 kernel/time/timer.c:1404
expire_timers kernel/time/timer.c:1449 [inline]
__run_timers kernel/time/timer.c:1773 [inline]
__run_timers kernel/time/timer.c:1740 [inline]
run_timer_softirq+0xc0c/0xcd0 kernel/time/timer.c:1786
__do_softirq+0x115/0x33f kernel/softirq.c:292
invoke_softirq kernel/softirq.c:373 [inline]
irq_exit+0xbb/0xe0 kernel/softirq.c:413
exiting_irq arch/x86/include/asm/apic.h:536 [inline]
smp_apic_timer_interrupt+0xe6/0x280 arch/x86/kernel/apic/apic.c:1137
apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:830
native_safe_halt+0xe/0x10 arch/x86/kernel/paravirt.c:71
arch_cpu_idle+0x1f/0x30 arch/x86/kernel/process.c:571
default_idle_call+0x1e/0x40 kernel/sched/idle.c:94
cpuidle_idle_call kernel/sched/idle.c:154 [inline]
do_idle+0x1af/0x280 kernel/sched/idle.c:263
cpu_startup_entry+0x1b/0x20 kernel/sched/idle.c:355
start_secondary+0x208/0x260 arch/x86/kernel/smpboot.c:264
secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:241
read to 0xffff8880a69a0170 of 8 bytes by interrupt on cpu 0:
sk_unhashed include/net/sock.h:607 [inline]
inet_unhash+0x3d/0x4a0 net/ipv4/inet_hashtables.c:592
tcp_set_state+0xfa/0x3e0 net/ipv4/tcp.c:2249
tcp_done+0x93/0x1e0 net/ipv4/tcp.c:3854
tcp_write_err+0x7e/0xc0 net/ipv4/tcp_timer.c:56
tcp_retransmit_timer+0x9b8/0x16d0 net/ipv4/tcp_timer.c:479
tcp_write_timer_handler+0x42d/0x510 net/ipv4/tcp_timer.c:599
tcp_write_timer+0xd1/0xf0 net/ipv4/tcp_timer.c:619
call_timer_fn+0x5f/0x2f0 kernel/time/timer.c:1404
expire_timers kernel/time/timer.c:1449 [inline]
__run_timers kernel/time/timer.c:1773 [inline]
__run_timers kernel/time/timer.c:1740 [inline]
run_timer_softirq+0xc0c/0xcd0 kernel/time/timer.c:1786
__do_softirq+0x115/0x33f kernel/softirq.c:292
invoke_softirq kernel/softirq.c:373 [inline]
irq_exit+0xbb/0xe0 kernel/softirq.c:413
exiting_irq arch/x86/include/asm/apic.h:536 [inline]
smp_apic_timer_interrupt+0xe6/0x280 arch/x86/kernel/apic/apic.c:1137
apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:830
native_safe_halt+0xe/0x10 arch/x86/kernel/paravirt.c:71
arch_cpu_idle+0x1f/0x30 arch/x86/kernel/process.c:571
default_idle_call+0x1e/0x40 kernel/sched/idle.c:94
cpuidle_idle_call kernel/sched/idle.c:154 [inline]
do_idle+0x1af/0x280 kernel/sched/idle.c:263
cpu_startup_entry+0x1b/0x20 kernel/sched/idle.c:355
rest_init+0xec/0xf6 init/main.c:452
arch_call_rest_init+0x17/0x37
start_kernel+0x838/0x85e init/main.c:786
x86_64_start_reservations+0x29/0x2b arch/x86/kernel/head64.c:490
x86_64_start_kernel+0x72/0x76 arch/x86/kernel/head64.c:471
secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:241
Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.4.0-rc6+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine,
BIOS Google 01/01/2011
------------------------------------------------------------------------
This commit therefore replaces C-language assignments with WRITE_ONCE()
in include/linux/list_nulls.h and include/linux/rculist_nulls.h.
Reported-by: Eric Dumazet <edumazet@google.com> # For KCSAN
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
---
include/linux/list_nulls.h | 8 ++++----
include/linux/rculist_nulls.h | 8 ++++----
2 files changed, 8 insertions(+), 8 deletions(-)
diff --git a/include/linux/list_nulls.h b/include/linux/list_nulls.h
index 3ef9674..1ecd356 100644
--- a/include/linux/list_nulls.h
+++ b/include/linux/list_nulls.h
@@ -72,10 +72,10 @@ static inline void hlist_nulls_add_head(struct hlist_nulls_node *n,
struct hlist_nulls_node *first = h->first;
n->next = first;
- n->pprev = &h->first;
+ WRITE_ONCE(n->pprev, &h->first);
h->first = n;
if (!is_a_nulls(first))
- first->pprev = &n->next;
+ WRITE_ONCE(first->pprev, &n->next);
}
static inline void __hlist_nulls_del(struct hlist_nulls_node *n)
@@ -85,13 +85,13 @@ static inline void __hlist_nulls_del(struct hlist_nulls_node *n)
WRITE_ONCE(*pprev, next);
if (!is_a_nulls(next))
- next->pprev = pprev;
+ WRITE_ONCE(next->pprev, pprev);
}
static inline void hlist_nulls_del(struct hlist_nulls_node *n)
{
__hlist_nulls_del(n);
- n->pprev = LIST_POISON2;
+ WRITE_ONCE(n->pprev, LIST_POISON2);
}
/**
diff --git a/include/linux/rculist_nulls.h b/include/linux/rculist_nulls.h
index bc8206a..517a06f 100644
--- a/include/linux/rculist_nulls.h
+++ b/include/linux/rculist_nulls.h
@@ -34,7 +34,7 @@ static inline void hlist_nulls_del_init_rcu(struct hlist_nulls_node *n)
{
if (!hlist_nulls_unhashed(n)) {
__hlist_nulls_del(n);
- n->pprev = NULL;
+ WRITE_ONCE(n->pprev, NULL);
}
}
@@ -66,7 +66,7 @@ static inline void hlist_nulls_del_init_rcu(struct hlist_nulls_node *n)
static inline void hlist_nulls_del_rcu(struct hlist_nulls_node *n)
{
__hlist_nulls_del(n);
- n->pprev = LIST_POISON2;
+ WRITE_ONCE(n->pprev, LIST_POISON2);
}
/**
@@ -94,10 +94,10 @@ static inline void hlist_nulls_add_head_rcu(struct hlist_nulls_node *n,
struct hlist_nulls_node *first = h->first;
n->next = first;
- n->pprev = &h->first;
+ WRITE_ONCE(n->pprev, &h->first);
rcu_assign_pointer(hlist_nulls_first_rcu(h), n);
if (!is_a_nulls(first))
- first->pprev = &n->next;
+ WRITE_ONCE(first->pprev, &n->next);
}
/**
--
2.9.5
next prev parent reply other threads:[~2019-12-10 4:20 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-10 4:19 [PATCH tip/core/rcu 0/9] RCU list updates for v5.6 Paul E. McKenney
2019-12-10 4:19 ` [PATCH tip/core/rcu 1/9] rculist: Describe variadic macro argument in a Sphinx-compatible way paulmck
2019-12-10 4:19 ` [PATCH tip/core/rcu 2/9] list: Add hlist_unhashed_lockless() paulmck
2019-12-10 4:19 ` [PATCH tip/core/rcu 3/9] timer: Use hlist_unhashed_lockless() in timer_pending() paulmck
2019-12-10 4:19 ` paulmck [this message]
2019-12-10 4:19 ` [PATCH tip/core/rcu 5/9] rcu: Add and update docbook header comments in list.h paulmck
2019-12-10 4:19 ` [PATCH tip/core/rcu 6/9] rcu: Add a hlist_nulls_unhashed_lockless() function paulmck
2019-12-10 4:20 ` [PATCH tip/core/rcu 7/9] rculist_nulls: Add docbook comments paulmck
2019-12-10 4:20 ` [PATCH tip/core/rcu 8/9] rculist_nulls: Change docbook comment headers paulmck
2019-12-10 4:20 ` [PATCH tip/core/rcu 9/9] rculist.h: Add list_tail_rcu() paulmck
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