/*
* Copyright (c) 2016 HiSilicon Technologies Co., Ltd.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see .
*/
#ifndef __DTS_HISTB_CLOCK_H
#define __DTS_HISTB_CLOCK_H
/* clocks provided by core CRG */
#define HISTB_OSC_CLK 0
#define HISTB_APB_CLK 1
#define HISTB_AHB_CLK 2
#define HISTB_UART1_CLK 3
#define HISTB_UART2_CLK 4
#define HISTB_UART3_CLK 5
#define HISTB_I2C0_CLK 6
#define HISTB_I2C1_CLK 7
#define HISTB_I2C2_CLK 8
#define HISTB_I2C3_CLK 9
#define HISTB_I2C4_CLK 10
#define HISTB_I2C5_CLK 11
#define HISTB_SPI0_CLK 12
#define HISTB_SPI1_CLK 13
#define HISTB_SPI2_CLK 14
#define HISTB_SCI_CLK 15
#define HISTB_FMC_CLK 16
#define HISTB_MMC_BIU_CLK 17
#define HISTB_MMC_CIU_CLK 18
#define HISTB_MMC_DRV_CLK 19
#define HISTB_MMC_SAMPLE_CLK 20
#define HISTB_SDIO0_BIU_CLK 21
#define HISTB_SDIO0_CIU_CLK 22
#define HISTB_SDIO0_DRV_CLK 23
#define HISTB_SDIO0_SAMPLE_CLK 24
#define HISTB_PCIE_AUX_CLK 25
#define HISTB_PCIE_PIPE_CLK 26
#define HISTB_PCIE_SYS_CLK 27
#define HISTB_PCIE_BUS_CLK 28
#define HISTB_ETH0_MAC_CLK 29
#define HISTB_ETH0_MACIF_CLK 30
#define HISTB_ETH1_MAC_CLK 31
#define HISTB_ETH1_MACIF_CLK 32
#define HISTB_COMBPHY1_CLK 33
/* clocks provided by mcu CRG */
#define HISTB_MCE_CLK 1
#define HISTB_IR_CLK 2
#define HISTB_TIMER01_CLK 3
#define HISTB_LEDC_CLK 4
#define HISTB_UART0_CLK 5
#define HISTB_LSADC_CLK 6
#endif /* __DTS_HISTB_CLOCK_H */
t/sched/act_tunnel_key.c?id=fd76d9105b8e5b80bee58311a5c88d6594622c00'>diff|
|
percpu-refcount: fix reference leak during percpu-atomic transition
percpu_ref_tryget() and percpu_ref_tryget_live() should return
"true" IFF they acquire a reference. But the return value from
atomic_long_inc_not_zero() is a long and may have high bits set,
e.g. PERCPU_COUNT_BIAS, and the return value of the tryget routines
is bool so the reference may actually be acquired but the routines
return "false" which results in a reference leak since the caller
assumes it does not need to do a corresponding percpu_ref_put().
This was seen when performing CPU hotplug during I/O, as hangs in
blk_mq_freeze_queue_wait where percpu_ref_kill (blk_mq_freeze_queue_start)
raced with percpu_ref_tryget (blk_mq_timeout_work).
Sample stack trace:
__switch_to+0x2c0/0x450
__schedule+0x2f8/0x970
schedule+0x48/0xc0
blk_mq_freeze_queue_wait+0x94/0x120
blk_mq_queue_reinit_work+0xb8/0x180
blk_mq_queue_reinit_prepare+0x84/0xa0
cpuhp_invoke_callback+0x17c/0x600
cpuhp_up_callbacks+0x58/0x150
_cpu_up+0xf0/0x1c0
do_cpu_up+0x120/0x150
cpu_subsys_online+0x64/0xe0
device_online+0xb4/0x120
online_store+0xb4/0xc0
dev_attr_store+0x68/0xa0
sysfs_kf_write+0x80/0xb0
kernfs_fop_write+0x17c/0x250
__vfs_write+0x6c/0x1e0
vfs_write+0xd0/0x270
SyS_write+0x6c/0x110
system_call+0x38/0xe0
Examination of the queue showed a single reference (no PERCPU_COUNT_BIAS,
and __PERCPU_REF_DEAD, __PERCPU_REF_ATOMIC set) and no requests.
However, conditions at the time of the race are count of PERCPU_COUNT_BIAS + 0
and __PERCPU_REF_DEAD and __PERCPU_REF_ATOMIC set.
The fix is to make the tryget routines use an actual boolean internally instead
of the atomic long result truncated to a int.
Fixes: e625305b3907 percpu-refcount: make percpu_ref based on longs instead of ints
Link: https://bugzilla.kernel.org/show_bug.cgi?id=190751
Signed-off-by: Douglas Miller <dougmill@linux.vnet.ibm.com>
Reviewed-by: Jens Axboe <axboe@fb.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Fixes: e625305b3907 ("percpu-refcount: make percpu_ref based on longs instead of ints")
Cc: stable@vger.kernel.org # v3.18+