/*
* Copyright (c) 2012, NVIDIA CORPORATION. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope 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 __SOC_TEGRA_FUSE_H__
#define __SOC_TEGRA_FUSE_H__
#define TEGRA20 0x20
#define TEGRA30 0x30
#define TEGRA114 0x35
#define TEGRA124 0x40
#define TEGRA132 0x13
#define TEGRA210 0x21
#define TEGRA_FUSE_SKU_CALIB_0 0xf0
#define TEGRA30_FUSE_SATA_CALIB 0x124
#define TEGRA_FUSE_USB_CALIB_EXT_0 0x250
#ifndef __ASSEMBLY__
u32 tegra_read_chipid(void);
u8 tegra_get_chip_id(void);
enum tegra_revision {
TEGRA_REVISION_UNKNOWN = 0,
TEGRA_REVISION_A01,
TEGRA_REVISION_A02,
TEGRA_REVISION_A03,
TEGRA_REVISION_A03p,
TEGRA_REVISION_A04,
TEGRA_REVISION_MAX,
};
struct tegra_sku_info {
int sku_id;
int cpu_process_id;
int cpu_speedo_id;
int cpu_speedo_value;
int cpu_iddq_value;
int soc_process_id;
int soc_speedo_id;
int soc_speedo_value;
int gpu_process_id;
int gpu_speedo_id;
int gpu_speedo_value;
enum tegra_revision revision;
};
u32 tegra_read_straps(void);
u32 tegra_read_ram_code(void);
u32 tegra_read_chipid(void);
int tegra_fuse_readl(unsigned long offset, u32 *value);
extern struct tegra_sku_info tegra_sku_info;
#endif /* __ASSEMBLY__ */
#endif /* __SOC_TEGRA_FUSE_H__ */
t.cgi/linux/net-next.git/log/include/sound/gus.h?h=nds-private-remove'>logtreecommitdiff
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+