diff options
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/acct.c | 23 | ||||
| -rw-r--r-- | kernel/marker.c | 31 | ||||
| -rw-r--r-- | kernel/printk.c | 83 | ||||
| -rw-r--r-- | kernel/time/timekeeping.c | 4 |
4 files changed, 83 insertions, 58 deletions
diff --git a/kernel/acct.c b/kernel/acct.c index 521dfa53cb9..91e1cfd734d 100644 --- a/kernel/acct.c +++ b/kernel/acct.c @@ -58,6 +58,7 @@ #include <asm/uaccess.h> #include <asm/div64.h> #include <linux/blkdev.h> /* sector_div */ +#include <linux/pid_namespace.h> /* * These constants control the amount of freespace that suspend and @@ -74,7 +75,7 @@ int acct_parm[3] = {4, 2, 30}; /* * External references and all of the globals. */ -static void do_acct_process(struct file *); +static void do_acct_process(struct pid_namespace *ns, struct file *); /* * This structure is used so that all the data protected by lock @@ -86,6 +87,7 @@ struct acct_glbs { volatile int active; volatile int needcheck; struct file *file; + struct pid_namespace *ns; struct timer_list timer; }; @@ -175,9 +177,11 @@ out: static void acct_file_reopen(struct file *file) { struct file *old_acct = NULL; + struct pid_namespace *old_ns = NULL; if (acct_globals.file) { old_acct = acct_globals.file; + old_ns = acct_globals.ns; del_timer(&acct_globals.timer); acct_globals.active = 0; acct_globals.needcheck = 0; @@ -185,6 +189,7 @@ static void acct_file_reopen(struct file *file) } if (file) { acct_globals.file = file; + acct_globals.ns = get_pid_ns(task_active_pid_ns(current)); acct_globals.needcheck = 0; acct_globals.active = 1; /* It's been deleted if it was used before so this is safe */ @@ -196,8 +201,9 @@ static void acct_file_reopen(struct file *file) if (old_acct) { mnt_unpin(old_acct->f_path.mnt); spin_unlock(&acct_globals.lock); - do_acct_process(old_acct); + do_acct_process(old_ns, old_acct); filp_close(old_acct, NULL); + put_pid_ns(old_ns); spin_lock(&acct_globals.lock); } } @@ -419,7 +425,7 @@ static u32 encode_float(u64 value) /* * do_acct_process does all actual work. Caller holds the reference to file. */ -static void do_acct_process(struct file *file) +static void do_acct_process(struct pid_namespace *ns, struct file *file) { struct pacct_struct *pacct = ¤t->signal->pacct; acct_t ac; @@ -481,8 +487,10 @@ static void do_acct_process(struct file *file) ac.ac_gid16 = current->gid; #endif #if ACCT_VERSION==3 - ac.ac_pid = current->tgid; - ac.ac_ppid = current->real_parent->tgid; + ac.ac_pid = task_tgid_nr_ns(current, ns); + rcu_read_lock(); + ac.ac_ppid = task_tgid_nr_ns(rcu_dereference(current->real_parent), ns); + rcu_read_unlock(); #endif spin_lock_irq(¤t->sighand->siglock); @@ -578,6 +586,7 @@ void acct_collect(long exitcode, int group_dead) void acct_process(void) { struct file *file = NULL; + struct pid_namespace *ns; /* * accelerate the common fastpath: @@ -592,8 +601,10 @@ void acct_process(void) return; } get_file(file); + ns = get_pid_ns(acct_globals.ns); spin_unlock(&acct_globals.lock); - do_acct_process(file); + do_acct_process(ns, file); fput(file); + put_pid_ns(ns); } diff --git a/kernel/marker.c b/kernel/marker.c index 48a4ea5afff..041c33e3e95 100644 --- a/kernel/marker.c +++ b/kernel/marker.c @@ -104,18 +104,18 @@ void marker_probe_cb(const struct marker *mdata, void *call_private, char ptype; /* - * disabling preemption to make sure the teardown of the callbacks can - * be done correctly when they are in modules and they insure RCU read - * coherency. + * preempt_disable does two things : disabling preemption to make sure + * the teardown of the callbacks can be done correctly when they are in + * modules and they insure RCU read coherency. */ preempt_disable(); - ptype = ACCESS_ONCE(mdata->ptype); + ptype = mdata->ptype; if (likely(!ptype)) { marker_probe_func *func; /* Must read the ptype before ptr. They are not data dependant, * so we put an explicit smp_rmb() here. */ smp_rmb(); - func = ACCESS_ONCE(mdata->single.func); + func = mdata->single.func; /* Must read the ptr before private data. They are not data * dependant, so we put an explicit smp_rmb() here. */ smp_rmb(); @@ -133,7 +133,7 @@ void marker_probe_cb(const struct marker *mdata, void *call_private, * in the fast path, so put the explicit barrier here. */ smp_read_barrier_depends(); - multi = ACCESS_ONCE(mdata->multi); + multi = mdata->multi; for (i = 0; multi[i].func; i++) { va_start(args, fmt); multi[i].func(multi[i].probe_private, call_private, fmt, @@ -161,13 +161,13 @@ void marker_probe_cb_noarg(const struct marker *mdata, char ptype; preempt_disable(); - ptype = ACCESS_ONCE(mdata->ptype); + ptype = mdata->ptype; if (likely(!ptype)) { marker_probe_func *func; /* Must read the ptype before ptr. They are not data dependant, * so we put an explicit smp_rmb() here. */ smp_rmb(); - func = ACCESS_ONCE(mdata->single.func); + func = mdata->single.func; /* Must read the ptr before private data. They are not data * dependant, so we put an explicit smp_rmb() here. */ smp_rmb(); @@ -183,7 +183,7 @@ void marker_probe_cb_noarg(const struct marker *mdata, * in the fast path, so put the explicit barrier here. */ smp_read_barrier_depends(); - multi = ACCESS_ONCE(mdata->multi); + multi = mdata->multi; for (i = 0; multi[i].func; i++) multi[i].func(multi[i].probe_private, call_private, fmt, &args); @@ -551,9 +551,9 @@ static int set_marker(struct marker_entry **entry, struct marker *elem, /* * Disable a marker and its probe callback. - * Note: only after a synchronize_sched() issued after setting elem->call to the - * empty function insures that the original callback is not used anymore. This - * insured by preemption disabling around the call site. + * Note: only waiting an RCU period after setting elem->call to the empty + * function insures that the original callback is not used anymore. This insured + * by preempt_disable around the call site. */ static void disable_marker(struct marker *elem) { @@ -565,8 +565,8 @@ static void disable_marker(struct marker *elem) elem->ptype = 0; /* single probe */ /* * Leave the private data and id there, because removal is racy and - * should be done only after a synchronize_sched(). These are never used - * until the next initialization anyway. + * should be done only after an RCU period. These are never used until + * the next initialization anyway. */ } @@ -601,9 +601,6 @@ void marker_update_probe_range(struct marker *begin, /* * Update probes, removing the faulty probes. - * Issues a synchronize_sched() when no reference to the module passed - * as parameter is found in the probes so the probe module can be - * safely unloaded from now on. * * Internal callback only changed before the first probe is connected to it. * Single probe private data can only be changed on 0 -> 1 and 2 -> 1 diff --git a/kernel/printk.c b/kernel/printk.c index 9adc2a473e6..c46a20a19a1 100644 --- a/kernel/printk.c +++ b/kernel/printk.c @@ -616,6 +616,40 @@ asmlinkage int printk(const char *fmt, ...) /* cpu currently holding logbuf_lock */ static volatile unsigned int printk_cpu = UINT_MAX; +/* + * Can we actually use the console at this time on this cpu? + * + * Console drivers may assume that per-cpu resources have + * been allocated. So unless they're explicitly marked as + * being able to cope (CON_ANYTIME) don't call them until + * this CPU is officially up. + */ +static inline int can_use_console(unsigned int cpu) +{ + return cpu_online(cpu) || have_callable_console(); +} + +/* + * Try to get console ownership to actually show the kernel + * messages from a 'printk'. Return true (and with the + * console_semaphore held, and 'console_locked' set) if it + * is successful, false otherwise. + * + * This gets called with the 'logbuf_lock' spinlock held and + * interrupts disabled. It should return with 'lockbuf_lock' + * released but interrupts still disabled. + */ +static int acquire_console_semaphore_for_printk(unsigned int cpu) +{ + int retval = 0; + + if (can_use_console(cpu)) + retval = !try_acquire_console_sem(); + printk_cpu = UINT_MAX; + spin_unlock(&logbuf_lock); + return retval; +} + const char printk_recursion_bug_msg [] = KERN_CRIT "BUG: recent printk recursion!\n"; static int printk_recursion_bug; @@ -725,43 +759,22 @@ asmlinkage int vprintk(const char *fmt, va_list args) log_level_unknown = 1; } - if (!down_trylock(&console_sem)) { - /* - * We own the drivers. We can drop the spinlock and - * let release_console_sem() print the text, maybe ... - */ - console_locked = 1; - printk_cpu = UINT_MAX; - spin_unlock(&logbuf_lock); + /* + * Try to acquire and then immediately release the + * console semaphore. The release will do all the + * actual magic (print out buffers, wake up klogd, + * etc). + * + * The acquire_console_semaphore_for_printk() function + * will release 'logbuf_lock' regardless of whether it + * actually gets the semaphore or not. + */ + if (acquire_console_semaphore_for_printk(this_cpu)) + release_console_sem(); - /* - * Console drivers may assume that per-cpu resources have - * been allocated. So unless they're explicitly marked as - * being able to cope (CON_ANYTIME) don't call them until - * this CPU is officially up. - */ - if (cpu_online(smp_processor_id()) || have_callable_console()) { - console_may_schedule = 0; - release_console_sem(); - } else { - /* Release by hand to avoid flushing the buffer. */ - console_locked = 0; - up(&console_sem); - } - lockdep_on(); - raw_local_irq_restore(flags); - } else { - /* - * Someone else owns the drivers. We drop the spinlock, which - * allows the semaphore holder to proceed and to call the - * console drivers with the output which we just produced. - */ - printk_cpu = UINT_MAX; - spin_unlock(&logbuf_lock); - lockdep_on(); + lockdep_on(); out_restore_irqs: - raw_local_irq_restore(flags); - } + raw_local_irq_restore(flags); preempt_enable(); return printed_len; diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c index 671af612b76..a3fa587c350 100644 --- a/kernel/time/timekeeping.c +++ b/kernel/time/timekeeping.c @@ -191,8 +191,12 @@ static void change_clocksource(void) tick_clock_notify(); + /* + * We're holding xtime lock and waking up klogd would deadlock + * us on enqueue. So no printing! printk(KERN_INFO "Time: %s clocksource has been installed.\n", clock->name); + */ } #else static inline void change_clocksource(void) { } |