/*
* Copyright (c) 2014 MediaTek Inc.
* Author: Flora Fu, MediaTek
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* 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.
*/
#ifndef _DT_BINDINGS_RESET_CONTROLLER_MT8173
#define _DT_BINDINGS_RESET_CONTROLLER_MT8173
/* INFRACFG resets */
#define MT8173_INFRA_EMI_REG_RST 0
#define MT8173_INFRA_DRAMC0_A0_RST 1
#define MT8173_INFRA_APCIRQ_EINT_RST 3
#define MT8173_INFRA_APXGPT_RST 4
#define MT8173_INFRA_SCPSYS_RST 5
#define MT8173_INFRA_KP_RST 6
#define MT8173_INFRA_PMIC_WRAP_RST 7
#define MT8173_INFRA_MPIP_RST 8
#define MT8173_INFRA_CEC_RST 9
#define MT8173_INFRA_EMI_RST 32
#define MT8173_INFRA_DRAMC0_RST 34
#define MT8173_INFRA_APMIXEDSYS_RST 35
#define MT8173_INFRA_MIPI_DSI_RST 36
#define MT8173_INFRA_TRNG_RST 37
#define MT8173_INFRA_SYSIRQ_RST 38
#define MT8173_INFRA_MIPI_CSI_RST 39
#define MT8173_INFRA_GCE_FAXI_RST 40
#define MT8173_INFRA_MMIOMMURST 47
/* PERICFG resets */
#define MT8173_PERI_UART0_SW_RST 0
#define MT8173_PERI_UART1_SW_RST 1
#define MT8173_PERI_UART2_SW_RST 2
#define MT8173_PERI_UART3_SW_RST 3
#define MT8173_PERI_IRRX_SW_RST 4
#define MT8173_PERI_PWM_SW_RST 8
#define MT8173_PERI_AUXADC_SW_RST 10
#define MT8173_PERI_DMA_SW_RST 11
#define MT8173_PERI_I2C6_SW_RST 13
#define MT8173_PERI_NFI_SW_RST 14
#define MT8173_PERI_THERM_SW_RST 16
#define MT8173_PERI_MSDC2_SW_RST 17
#define MT8173_PERI_MSDC3_SW_RST 18
#define MT8173_PERI_MSDC0_SW_RST 19
#define MT8173_PERI_MSDC1_SW_RST 20
#define MT8173_PERI_I2C0_SW_RST 22
#define MT8173_PERI_I2C1_SW_RST 23
#define MT8173_PERI_I2C2_SW_RST 24
#define MT8173_PERI_I2C3_SW_RST 25
#define MT8173_PERI_I2C4_SW_RST 26
#define MT8173_PERI_HDMI_SW_RST 29
#define MT8173_PERI_SPI0_SW_RST 33
#endif /* _DT_BINDINGS_RESET_CONTROLLER_MT8173 */
or
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+