d0b7213f89
When booting on 32-bit machines (seen on OpenRISC) I saw this warning
with CONFIG_DEBUG_MUTEXES turned on.
------------[ cut here ]------------
WARNING: CPU: 0 PID: 0 at kernel/locking/mutex.c:1242 __mutex_unlock_slowpath+0x328/0x3ec
DEBUG_LOCKS_WARN_ON(__owner_task(owner) != current)
Modules linked in:
CPU: 0 PID: 0 Comm: swapper Not tainted 5.8.0-rc1-simple-smp-00005-g2864e2171db4-dirty #179
Call trace:
[<(ptrval)>] dump_stack+0x34/0x48
[<(ptrval)>] __warn+0x104/0x158
[<(ptrval)>] ? __mutex_unlock_slowpath+0x328/0x3ec
[<(ptrval)>] warn_slowpath_fmt+0x7c/0x94
[<(ptrval)>] __mutex_unlock_slowpath+0x328/0x3ec
[<(ptrval)>] mutex_unlock+0x18/0x28
[<(ptrval)>] __cpuhp_setup_state_cpuslocked.part.0+0x29c/0x2f4
[<(ptrval)>] ? page_alloc_cpu_dead+0x0/0x30
[<(ptrval)>] ? start_kernel+0x0/0x684
[<(ptrval)>] __cpuhp_setup_state+0x4c/0x5c
[<(ptrval)>] page_alloc_init+0x34/0x68
[<(ptrval)>] ? start_kernel+0x1a0/0x684
[<(ptrval)>] ? early_init_dt_scan_nodes+0x60/0x70
irq event stamp: 0
I traced this to kernel/locking/mutex.c storing 3 bits of MUTEX_FLAGS in
the task_struct pointer (mutex.owner). There is a comment saying that
task_structs are always aligned to L1_CACHE_BYTES. This is not true for
the init_task.
On 64-bit machines this is not a problem because symbol addresses are
naturally aligned to 64-bits providing 3 bits for MUTEX_FLAGS. Howerver,
for 32-bit machines the symbol address only has 2 bits available.
Fix this by setting init_task alignment to at least L1_CACHE_BYTES.
Signed-off-by: Stafford Horne <shorne@gmail.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
218 lines
5.9 KiB
C
218 lines
5.9 KiB
C
// SPDX-License-Identifier: GPL-2.0
|
|
#include <linux/init_task.h>
|
|
#include <linux/export.h>
|
|
#include <linux/mqueue.h>
|
|
#include <linux/sched.h>
|
|
#include <linux/sched/sysctl.h>
|
|
#include <linux/sched/rt.h>
|
|
#include <linux/sched/task.h>
|
|
#include <linux/init.h>
|
|
#include <linux/fs.h>
|
|
#include <linux/mm.h>
|
|
#include <linux/audit.h>
|
|
#include <linux/numa.h>
|
|
#include <linux/scs.h>
|
|
|
|
#include <linux/uaccess.h>
|
|
|
|
static struct signal_struct init_signals = {
|
|
.nr_threads = 1,
|
|
.thread_head = LIST_HEAD_INIT(init_task.thread_node),
|
|
.wait_chldexit = __WAIT_QUEUE_HEAD_INITIALIZER(init_signals.wait_chldexit),
|
|
.shared_pending = {
|
|
.list = LIST_HEAD_INIT(init_signals.shared_pending.list),
|
|
.signal = {{0}}
|
|
},
|
|
.multiprocess = HLIST_HEAD_INIT,
|
|
.rlim = INIT_RLIMITS,
|
|
.cred_guard_mutex = __MUTEX_INITIALIZER(init_signals.cred_guard_mutex),
|
|
.exec_update_mutex = __MUTEX_INITIALIZER(init_signals.exec_update_mutex),
|
|
#ifdef CONFIG_POSIX_TIMERS
|
|
.posix_timers = LIST_HEAD_INIT(init_signals.posix_timers),
|
|
.cputimer = {
|
|
.cputime_atomic = INIT_CPUTIME_ATOMIC,
|
|
},
|
|
#endif
|
|
INIT_CPU_TIMERS(init_signals)
|
|
.pids = {
|
|
[PIDTYPE_PID] = &init_struct_pid,
|
|
[PIDTYPE_TGID] = &init_struct_pid,
|
|
[PIDTYPE_PGID] = &init_struct_pid,
|
|
[PIDTYPE_SID] = &init_struct_pid,
|
|
},
|
|
INIT_PREV_CPUTIME(init_signals)
|
|
};
|
|
|
|
static struct sighand_struct init_sighand = {
|
|
.count = REFCOUNT_INIT(1),
|
|
.action = { { { .sa_handler = SIG_DFL, } }, },
|
|
.siglock = __SPIN_LOCK_UNLOCKED(init_sighand.siglock),
|
|
.signalfd_wqh = __WAIT_QUEUE_HEAD_INITIALIZER(init_sighand.signalfd_wqh),
|
|
};
|
|
|
|
#ifdef CONFIG_SHADOW_CALL_STACK
|
|
unsigned long init_shadow_call_stack[SCS_SIZE / sizeof(long)]
|
|
__init_task_data = {
|
|
[(SCS_SIZE / sizeof(long)) - 1] = SCS_END_MAGIC
|
|
};
|
|
#endif
|
|
|
|
/*
|
|
* Set up the first task table, touch at your own risk!. Base=0,
|
|
* limit=0x1fffff (=2MB)
|
|
*/
|
|
struct task_struct init_task
|
|
#ifdef CONFIG_ARCH_TASK_STRUCT_ON_STACK
|
|
__init_task_data
|
|
#endif
|
|
__aligned(L1_CACHE_BYTES)
|
|
= {
|
|
#ifdef CONFIG_THREAD_INFO_IN_TASK
|
|
.thread_info = INIT_THREAD_INFO(init_task),
|
|
.stack_refcount = REFCOUNT_INIT(1),
|
|
#endif
|
|
.state = 0,
|
|
.stack = init_stack,
|
|
.usage = REFCOUNT_INIT(2),
|
|
.flags = PF_KTHREAD,
|
|
.prio = MAX_PRIO - 20,
|
|
.static_prio = MAX_PRIO - 20,
|
|
.normal_prio = MAX_PRIO - 20,
|
|
.policy = SCHED_NORMAL,
|
|
.cpus_ptr = &init_task.cpus_mask,
|
|
.cpus_mask = CPU_MASK_ALL,
|
|
.nr_cpus_allowed= NR_CPUS,
|
|
.mm = NULL,
|
|
.active_mm = &init_mm,
|
|
.restart_block = {
|
|
.fn = do_no_restart_syscall,
|
|
},
|
|
.se = {
|
|
.group_node = LIST_HEAD_INIT(init_task.se.group_node),
|
|
},
|
|
.rt = {
|
|
.run_list = LIST_HEAD_INIT(init_task.rt.run_list),
|
|
.time_slice = RR_TIMESLICE,
|
|
},
|
|
.tasks = LIST_HEAD_INIT(init_task.tasks),
|
|
#ifdef CONFIG_SMP
|
|
.pushable_tasks = PLIST_NODE_INIT(init_task.pushable_tasks, MAX_PRIO),
|
|
#endif
|
|
#ifdef CONFIG_CGROUP_SCHED
|
|
.sched_task_group = &root_task_group,
|
|
#endif
|
|
.ptraced = LIST_HEAD_INIT(init_task.ptraced),
|
|
.ptrace_entry = LIST_HEAD_INIT(init_task.ptrace_entry),
|
|
.real_parent = &init_task,
|
|
.parent = &init_task,
|
|
.children = LIST_HEAD_INIT(init_task.children),
|
|
.sibling = LIST_HEAD_INIT(init_task.sibling),
|
|
.group_leader = &init_task,
|
|
RCU_POINTER_INITIALIZER(real_cred, &init_cred),
|
|
RCU_POINTER_INITIALIZER(cred, &init_cred),
|
|
.comm = INIT_TASK_COMM,
|
|
.thread = INIT_THREAD,
|
|
.fs = &init_fs,
|
|
.files = &init_files,
|
|
.signal = &init_signals,
|
|
.sighand = &init_sighand,
|
|
.nsproxy = &init_nsproxy,
|
|
.pending = {
|
|
.list = LIST_HEAD_INIT(init_task.pending.list),
|
|
.signal = {{0}}
|
|
},
|
|
.blocked = {{0}},
|
|
.alloc_lock = __SPIN_LOCK_UNLOCKED(init_task.alloc_lock),
|
|
.journal_info = NULL,
|
|
INIT_CPU_TIMERS(init_task)
|
|
.pi_lock = __RAW_SPIN_LOCK_UNLOCKED(init_task.pi_lock),
|
|
.timer_slack_ns = 50000, /* 50 usec default slack */
|
|
.thread_pid = &init_struct_pid,
|
|
.thread_group = LIST_HEAD_INIT(init_task.thread_group),
|
|
.thread_node = LIST_HEAD_INIT(init_signals.thread_head),
|
|
#ifdef CONFIG_AUDIT
|
|
.loginuid = INVALID_UID,
|
|
.sessionid = AUDIT_SID_UNSET,
|
|
#endif
|
|
#ifdef CONFIG_PERF_EVENTS
|
|
.perf_event_mutex = __MUTEX_INITIALIZER(init_task.perf_event_mutex),
|
|
.perf_event_list = LIST_HEAD_INIT(init_task.perf_event_list),
|
|
#endif
|
|
#ifdef CONFIG_PREEMPT_RCU
|
|
.rcu_read_lock_nesting = 0,
|
|
.rcu_read_unlock_special.s = 0,
|
|
.rcu_node_entry = LIST_HEAD_INIT(init_task.rcu_node_entry),
|
|
.rcu_blocked_node = NULL,
|
|
#endif
|
|
#ifdef CONFIG_TASKS_RCU
|
|
.rcu_tasks_holdout = false,
|
|
.rcu_tasks_holdout_list = LIST_HEAD_INIT(init_task.rcu_tasks_holdout_list),
|
|
.rcu_tasks_idle_cpu = -1,
|
|
#endif
|
|
#ifdef CONFIG_TASKS_TRACE_RCU
|
|
.trc_reader_nesting = 0,
|
|
.trc_reader_special.s = 0,
|
|
.trc_holdout_list = LIST_HEAD_INIT(init_task.trc_holdout_list),
|
|
#endif
|
|
#ifdef CONFIG_CPUSETS
|
|
.mems_allowed_seq = SEQCNT_ZERO(init_task.mems_allowed_seq),
|
|
#endif
|
|
#ifdef CONFIG_RT_MUTEXES
|
|
.pi_waiters = RB_ROOT_CACHED,
|
|
.pi_top_task = NULL,
|
|
#endif
|
|
INIT_PREV_CPUTIME(init_task)
|
|
#ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN
|
|
.vtime.seqcount = SEQCNT_ZERO(init_task.vtime_seqcount),
|
|
.vtime.starttime = 0,
|
|
.vtime.state = VTIME_SYS,
|
|
#endif
|
|
#ifdef CONFIG_NUMA_BALANCING
|
|
.numa_preferred_nid = NUMA_NO_NODE,
|
|
.numa_group = NULL,
|
|
.numa_faults = NULL,
|
|
#endif
|
|
#ifdef CONFIG_KASAN
|
|
.kasan_depth = 1,
|
|
#endif
|
|
#ifdef CONFIG_KCSAN
|
|
.kcsan_ctx = {
|
|
.disable_count = 0,
|
|
.atomic_next = 0,
|
|
.atomic_nest_count = 0,
|
|
.in_flat_atomic = false,
|
|
.access_mask = 0,
|
|
.scoped_accesses = {LIST_POISON1, NULL},
|
|
},
|
|
#endif
|
|
#ifdef CONFIG_TRACE_IRQFLAGS
|
|
.softirqs_enabled = 1,
|
|
#endif
|
|
#ifdef CONFIG_LOCKDEP
|
|
.lockdep_depth = 0, /* no locks held yet */
|
|
.curr_chain_key = INITIAL_CHAIN_KEY,
|
|
.lockdep_recursion = 0,
|
|
#endif
|
|
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
|
|
.ret_stack = NULL,
|
|
#endif
|
|
#if defined(CONFIG_TRACING) && defined(CONFIG_PREEMPTION)
|
|
.trace_recursion = 0,
|
|
#endif
|
|
#ifdef CONFIG_LIVEPATCH
|
|
.patch_state = KLP_UNDEFINED,
|
|
#endif
|
|
#ifdef CONFIG_SECURITY
|
|
.security = NULL,
|
|
#endif
|
|
};
|
|
EXPORT_SYMBOL(init_task);
|
|
|
|
/*
|
|
* Initial thread structure. Alignment of this is handled by a special
|
|
* linker map entry.
|
|
*/
|
|
#ifndef CONFIG_THREAD_INFO_IN_TASK
|
|
struct thread_info init_thread_info __init_thread_info = INIT_THREAD_INFO(init_task);
|
|
#endif
|