From 8c6a98b22b750c9eb52653ba643faa17db8d3881 Mon Sep 17 00:00:00 2001 From: Andy Whitcroft Date: Mon, 24 Jan 2011 09:31:38 -0800 Subject: Input: sysrq - ensure sysrq_enabled and __sysrq_enabled are consistent Currently sysrq_enabled and __sysrq_enabled are initialised separately and inconsistently, leading to sysrq being actually enabled by reported as not enabled in sysfs. The first change to the sysfs configurable synchronises these two: static int __read_mostly sysrq_enabled = 1; static int __sysrq_enabled; Add a common define to carry the default for these preventing them becoming out of sync again. Default this to 1 to mirror previous behaviour. Signed-off-by: Andy Whitcroft Cc: stable@kernel.org Signed-off-by: Dmitry Torokhov --- kernel/sysctl.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/sysctl.c b/kernel/sysctl.c index c33a1edb799f..3afce4dc9ba5 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -169,7 +169,8 @@ static int proc_taint(struct ctl_table *table, int write, #endif #ifdef CONFIG_MAGIC_SYSRQ -static int __sysrq_enabled; /* Note: sysrq code ises it's own private copy */ +/* Note: sysrq code uses it's own private copy */ +static int __sysrq_enabled = SYSRQ_DEFAULT_ENABLE; static int sysrq_sysctl_handler(ctl_table *table, int write, void __user *buffer, size_t *lenp, -- cgit v1.2.3 From ac751efa6a0d70f2c9daef5c7e3a92270f5c2dff Mon Sep 17 00:00:00 2001 From: Torben Hohn Date: Tue, 25 Jan 2011 15:07:35 -0800 Subject: console: rename acquire/release_console_sem() to console_lock/unlock() The -rt patches change the console_semaphore to console_mutex. As a result, a quite large chunk of the patches changes all acquire/release_console_sem() to acquire/release_console_mutex() This commit makes things use more neutral function names which dont make implications about the underlying lock. The only real change is the return value of console_trylock which is inverted from try_acquire_console_sem() This patch also paves the way to switching console_sem from a semaphore to a mutex. [akpm@linux-foundation.org: coding-style fixes] [akpm@linux-foundation.org: make console_trylock return 1 on success, per Geert] Signed-off-by: Torben Hohn Cc: Thomas Gleixner Cc: Greg KH Cc: Ingo Molnar Cc: Geert Uytterhoeven Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/printk.c | 100 ++++++++++++++++++++++++++++++-------------------------- 1 file changed, 54 insertions(+), 46 deletions(-) (limited to 'kernel') diff --git a/kernel/printk.c b/kernel/printk.c index 53d9a9ec88e6..2ddbdc73aade 100644 --- a/kernel/printk.c +++ b/kernel/printk.c @@ -97,7 +97,7 @@ static int console_locked, console_suspended; /* * logbuf_lock protects log_buf, log_start, log_end, con_start and logged_chars * It is also used in interesting ways to provide interlocking in - * release_console_sem(). + * console_unlock();. */ static DEFINE_SPINLOCK(logbuf_lock); @@ -501,7 +501,7 @@ static void _call_console_drivers(unsigned start, /* * Call the console drivers, asking them to write out * log_buf[start] to log_buf[end - 1]. - * The console_sem must be held. + * The console_lock must be held. */ static void call_console_drivers(unsigned start, unsigned end) { @@ -604,11 +604,11 @@ static int have_callable_console(void) * * This is printk(). It can be called from any context. We want it to work. * - * We try to grab the console_sem. If we succeed, it's easy - we log the output and + * We try to grab the console_lock. If we succeed, it's easy - we log the output and * call the console drivers. If we fail to get the semaphore we place the output * into the log buffer and return. The current holder of the console_sem will - * notice the new output in release_console_sem() and will send it to the - * consoles before releasing the semaphore. + * notice the new output in console_unlock(); and will send it to the + * consoles before releasing the lock. * * One effect of this deferred printing is that code which calls printk() and * then changes console_loglevel may break. This is because console_loglevel @@ -659,19 +659,19 @@ static inline int can_use_console(unsigned int cpu) /* * 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 + * console_lock 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) +static int console_trylock_for_printk(unsigned int cpu) __releases(&logbuf_lock) { int retval = 0; - if (!try_acquire_console_sem()) { + if (console_trylock()) { retval = 1; /* @@ -827,12 +827,12 @@ asmlinkage int vprintk(const char *fmt, va_list args) * actual magic (print out buffers, wake up klogd, * etc). * - * The acquire_console_semaphore_for_printk() function + * The console_trylock_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(); + if (console_trylock_for_printk(this_cpu)) + console_unlock(); lockdep_on(); out_restore_irqs: @@ -993,7 +993,7 @@ void suspend_console(void) if (!console_suspend_enabled) return; printk("Suspending console(s) (use no_console_suspend to debug)\n"); - acquire_console_sem(); + console_lock(); console_suspended = 1; up(&console_sem); } @@ -1004,7 +1004,7 @@ void resume_console(void) return; down(&console_sem); console_suspended = 0; - release_console_sem(); + console_unlock(); } /** @@ -1027,21 +1027,21 @@ static int __cpuinit console_cpu_notify(struct notifier_block *self, case CPU_DYING: case CPU_DOWN_FAILED: case CPU_UP_CANCELED: - acquire_console_sem(); - release_console_sem(); + console_lock(); + console_unlock(); } return NOTIFY_OK; } /** - * acquire_console_sem - lock the console system for exclusive use. + * console_lock - lock the console system for exclusive use. * - * Acquires a semaphore which guarantees that the caller has + * Acquires a lock which guarantees that the caller has * exclusive access to the console system and the console_drivers list. * * Can sleep, returns nothing. */ -void acquire_console_sem(void) +void console_lock(void) { BUG_ON(in_interrupt()); down(&console_sem); @@ -1050,21 +1050,29 @@ void acquire_console_sem(void) console_locked = 1; console_may_schedule = 1; } -EXPORT_SYMBOL(acquire_console_sem); +EXPORT_SYMBOL(console_lock); -int try_acquire_console_sem(void) +/** + * console_trylock - try to lock the console system for exclusive use. + * + * Tried to acquire a lock which guarantees that the caller has + * exclusive access to the console system and the console_drivers list. + * + * returns 1 on success, and 0 on failure to acquire the lock. + */ +int console_trylock(void) { if (down_trylock(&console_sem)) - return -1; + return 0; if (console_suspended) { up(&console_sem); - return -1; + return 0; } console_locked = 1; console_may_schedule = 0; - return 0; + return 1; } -EXPORT_SYMBOL(try_acquire_console_sem); +EXPORT_SYMBOL(console_trylock); int is_console_locked(void) { @@ -1095,20 +1103,20 @@ void wake_up_klogd(void) } /** - * release_console_sem - unlock the console system + * console_unlock - unlock the console system * - * Releases the semaphore which the caller holds on the console system + * Releases the console_lock which the caller holds on the console system * and the console driver list. * - * While the semaphore was held, console output may have been buffered - * by printk(). If this is the case, release_console_sem() emits - * the output prior to releasing the semaphore. + * While the console_lock was held, console output may have been buffered + * by printk(). If this is the case, console_unlock(); emits + * the output prior to releasing the lock. * * If there is output waiting for klogd, we wake it up. * - * release_console_sem() may be called from any context. + * console_unlock(); may be called from any context. */ -void release_console_sem(void) +void console_unlock(void) { unsigned long flags; unsigned _con_start, _log_end; @@ -1141,7 +1149,7 @@ void release_console_sem(void) if (wake_klogd) wake_up_klogd(); } -EXPORT_SYMBOL(release_console_sem); +EXPORT_SYMBOL(console_unlock); /** * console_conditional_schedule - yield the CPU if required @@ -1150,7 +1158,7 @@ EXPORT_SYMBOL(release_console_sem); * if this CPU should yield the CPU to another task, do * so here. * - * Must be called within acquire_console_sem(). + * Must be called within console_lock();. */ void __sched console_conditional_schedule(void) { @@ -1171,14 +1179,14 @@ void console_unblank(void) if (down_trylock(&console_sem) != 0) return; } else - acquire_console_sem(); + console_lock(); console_locked = 1; console_may_schedule = 0; for_each_console(c) if ((c->flags & CON_ENABLED) && c->unblank) c->unblank(); - release_console_sem(); + console_unlock(); } /* @@ -1189,7 +1197,7 @@ struct tty_driver *console_device(int *index) struct console *c; struct tty_driver *driver = NULL; - acquire_console_sem(); + console_lock(); for_each_console(c) { if (!c->device) continue; @@ -1197,7 +1205,7 @@ struct tty_driver *console_device(int *index) if (driver) break; } - release_console_sem(); + console_unlock(); return driver; } @@ -1208,17 +1216,17 @@ struct tty_driver *console_device(int *index) */ void console_stop(struct console *console) { - acquire_console_sem(); + console_lock(); console->flags &= ~CON_ENABLED; - release_console_sem(); + console_unlock(); } EXPORT_SYMBOL(console_stop); void console_start(struct console *console) { - acquire_console_sem(); + console_lock(); console->flags |= CON_ENABLED; - release_console_sem(); + console_unlock(); } EXPORT_SYMBOL(console_start); @@ -1340,7 +1348,7 @@ void register_console(struct console *newcon) * Put this console in the list - keep the * preferred driver at the head of the list. */ - acquire_console_sem(); + console_lock(); if ((newcon->flags & CON_CONSDEV) || console_drivers == NULL) { newcon->next = console_drivers; console_drivers = newcon; @@ -1352,14 +1360,14 @@ void register_console(struct console *newcon) } if (newcon->flags & CON_PRINTBUFFER) { /* - * release_console_sem() will print out the buffered messages + * console_unlock(); will print out the buffered messages * for us. */ spin_lock_irqsave(&logbuf_lock, flags); con_start = log_start; spin_unlock_irqrestore(&logbuf_lock, flags); } - release_console_sem(); + console_unlock(); console_sysfs_notify(); /* @@ -1396,7 +1404,7 @@ int unregister_console(struct console *console) return braille_unregister_console(console); #endif - acquire_console_sem(); + console_lock(); if (console_drivers == console) { console_drivers=console->next; res = 0; @@ -1418,7 +1426,7 @@ int unregister_console(struct console *console) if (console_drivers != NULL && console->flags & CON_CONSDEV) console_drivers->flags |= CON_CONSDEV; - release_console_sem(); + console_unlock(); console_sysfs_notify(); return res; } -- cgit v1.2.3 From e37b6a7b27b400c3aa488db8c6629a05095bc79c Mon Sep 17 00:00:00 2001 From: Paul Turner Date: Fri, 21 Jan 2011 20:44:59 -0800 Subject: sched: Fix sign under-flows in wake_affine While care is taken around the zero-point in effective_load to not exceed the instantaneous rq->weight, it's still possible (e.g. using wake_idx != 0) for (load + effective_load) to underflow. In this case the comparing the unsigned values can result in incorrect balanced decisions. Signed-off-by: Paul Turner Signed-off-by: Peter Zijlstra LKML-Reference: <20110122044851.734245014@google.com> Signed-off-by: Ingo Molnar --- kernel/sched_fair.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'kernel') diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index 354769979c02..ccecfec02a70 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -1432,7 +1432,7 @@ static inline unsigned long effective_load(struct task_group *tg, int cpu, static int wake_affine(struct sched_domain *sd, struct task_struct *p, int sync) { - unsigned long this_load, load; + s64 this_load, load; int idx, this_cpu, prev_cpu; unsigned long tl_per_task; struct task_group *tg; @@ -1471,8 +1471,8 @@ static int wake_affine(struct sched_domain *sd, struct task_struct *p, int sync) * Otherwise check if either cpus are near enough in load to allow this * task to be woken on this_cpu. */ - if (this_load) { - unsigned long this_eff_load, prev_eff_load; + if (this_load > 0) { + s64 this_eff_load, prev_eff_load; this_eff_load = 100; this_eff_load *= power_of(prev_cpu); -- cgit v1.2.3 From b815f1963e47b9b69bb17e0588bd5af5b1114ae0 Mon Sep 17 00:00:00 2001 From: Paul Turner Date: Fri, 21 Jan 2011 20:45:00 -0800 Subject: sched: Fix/remove redundant cfs_rq checks Since updates are against an entity's queuing cfs_rq it's not possible to enter update_cfs_{shares,load} with a NULL cfs_rq. (Indeed, update_cfs_load would crash prior to the check if we did anyway since we load is examined during the initializers). Also, in the update_cfs_load case there's no point in maintaining averages for rq->cfs_rq since we don't perform shares distribution at that level -- NULL check is replaced accordingly. Thanks to Dan Carpenter for pointing out the deference before NULL check. Signed-off-by: Paul Turner Signed-off-by: Peter Zijlstra LKML-Reference: <20110122044851.825284940@google.com> Signed-off-by: Ingo Molnar --- kernel/sched_fair.c | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-) (limited to 'kernel') diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index ccecfec02a70..1997383ba4d6 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -722,7 +722,7 @@ static void update_cfs_load(struct cfs_rq *cfs_rq, int global_update) u64 now, delta; unsigned long load = cfs_rq->load.weight; - if (!cfs_rq) + if (cfs_rq->tg == &root_task_group) return; now = rq_of(cfs_rq)->clock; @@ -830,9 +830,6 @@ static void update_cfs_shares(struct cfs_rq *cfs_rq, long weight_delta) struct sched_entity *se; long shares; - if (!cfs_rq) - return; - tg = cfs_rq->tg; se = tg->se[cpu_of(rq_of(cfs_rq))]; if (!se) -- cgit v1.2.3 From 05ca62c6ca17f39b88fa956d5ebc1fa6e93ad5e3 Mon Sep 17 00:00:00 2001 From: Paul Turner Date: Fri, 21 Jan 2011 20:45:02 -0800 Subject: sched: Use rq->clock_task instead of rq->clock for correctly maintaining load averages The delta in clock_task is a more fair attribution of how much time a tg has been contributing load to the current cpu. While not really important it also means we're more in sync (by magnitude) with respect to periodic updates (since __update_curr deltas are clock_task based). Signed-off-by: Paul Turner Signed-off-by: Peter Zijlstra LKML-Reference: <20110122044852.007092349@google.com> Signed-off-by: Ingo Molnar --- kernel/sched_fair.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index 1997383ba4d6..0c26e2df450e 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -725,7 +725,7 @@ static void update_cfs_load(struct cfs_rq *cfs_rq, int global_update) if (cfs_rq->tg == &root_task_group) return; - now = rq_of(cfs_rq)->clock; + now = rq_of(cfs_rq)->clock_task; delta = now - cfs_rq->load_stamp; /* truncate load history at 4 idle periods */ -- cgit v1.2.3 From aa5bd67dcfdf9af34c7fa36ebc87d4e1f7e91873 Mon Sep 17 00:00:00 2001 From: Kacper Kornet Date: Sat, 29 Jan 2011 00:21:04 +0100 Subject: Fix prlimit64 for suid/sgid processes Since check_prlimit_permission always fails in the case of SUID/GUID processes, such processes are not able to read or set their own limits. This commit changes this by assuming that process can always read/change its own limits. Signed-off-by: Kacper Kornet Acked-by: Jiri Slaby Signed-off-by: Linus Torvalds --- kernel/sys.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/sys.c b/kernel/sys.c index 31b71a276b40..18da702ec813 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -1385,7 +1385,8 @@ static int check_prlimit_permission(struct task_struct *task) const struct cred *cred = current_cred(), *tcred; tcred = __task_cred(task); - if ((cred->uid != tcred->euid || + if (current != task && + (cred->uid != tcred->euid || cred->uid != tcred->suid || cred->uid != tcred->uid || cred->gid != tcred->egid || -- cgit v1.2.3