/* * Created by: Jason Wessel * * Copyright (c) 2009 Wind River Systems, Inc. All Rights Reserved. * * This file is licensed under the terms of the GNU General Public * License version 2. This program is licensed "as is" without any * warranty of any kind, whether express or implied. */ #ifndef _DEBUG_CORE_H_ #define _DEBUG_CORE_H_ /* * These are the private implementation headers between the kernel * debugger core and the debugger front end code. */ /* kernel debug core data structures */ struct kgdb_state { int ex_vector; int signo; int err_code; int cpu; int pass_exception; unsigned long thr_query; unsigned long threadid; long kgdb_usethreadid; struct pt_regs *linux_regs; atomic_t *send_ready; }; /* Exception state values */ #define DCPU_WANT_MASTER 0x1 /* Waiting to become a master kgdb cpu */ #define DCPU_NEXT_MASTER 0x2 /* Transition from one master cpu to another */ #define DCPU_IS_SLAVE 0x4 /* Slave cpu enter exception */ #define DCPU_SSTEP 0x8 /* CPU is single stepping */ struct debuggerinfo_struct { void *debuggerinfo; struct task_struct *task; int exception_state; int ret_state; int irq_depth; int enter_kgdb; }; extern struct debuggerinfo_struct kgdb_info[]; /* kernel debug core break point routines */ extern int dbg_remove_all_break(void); extern int dbg_set_sw_break(unsigned long addr); extern int dbg_remove_sw_break(unsigned long addr); extern int dbg_activate_sw_breakpoints(void); extern int dbg_deactivate_sw_breakpoints(void); /* polled character access to i/o module */ extern int dbg_io_get_char(void); /* stub return value for switching between the gdbstub and kdb */ #define DBG_PASS_EVENT -12345 /* Switch from one cpu to another */ #define DBG_SWITCH_CPU_EVENT -123456 extern int dbg_switch_cpu; /* gdbstub interface functions */ extern int gdb_serial_stub(struct kgdb_state *ks); extern void gdbstub_msg_write(const char *s, int len); /* gdbstub functions used for kdb <-> gdbstub transition */ extern int gdbstub_state(struct kgdb_state *ks, char *cmd); extern int dbg_kdb_mode; #ifdef CONFIG_KGDB_KDB extern int kdb_stub(struct kgdb_state *ks); extern int kdb_parse(const char *cmdstr); extern int kdb_common_init_state(struct kgdb_state *ks); extern int kdb_common_deinit_state(void); #else /* ! CONFIG_KGDB_KDB */ static inline int kdb_stub(struct kgdb_state *ks) { return DBG_PASS_EVENT; } #endif /* CONFIG_KGDB_KDB */ #endif /* _DEBUG_CORE_H_ */ 'h' value='nds-private-remove'/>
path: root/sound/soc/omap/ams-delta.c
diff options
context:
space:
mode:
authorDouglas Miller <dougmill@linux.vnet.ibm.com>2017-01-28 06:42:20 -0600
committerTejun Heo <tj@kernel.org>2017-01-28 07:49:42 -0500
commit966d2b04e070bc040319aaebfec09e0144dc3341 (patch)
tree4b96156e3d1dd4dfd6039b7c219c9dc4616da52d /sound/soc/omap/ams-delta.c
parent1b1bc42c1692e9b62756323c675a44cb1a1f9dbd (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+
Diffstat (limited to 'sound/soc/omap/ams-delta.c')