rcu: Use WRITE_ONCE() for assignments to ->pprev for hlist_nulls
[ Upstream commit 860c8802ace14c646864795e057349c9fb2d60ad ]
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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2 files changed