From 3e10e716abf3c71bdb5d86b8f507f9e72236c9cd Mon Sep 17 00:00:00 2001 From: Jiri Slaby Date: Thu, 19 Nov 2009 17:16:37 +0100 Subject: resource: add helpers for fetching rlimits We want to be sure that compiler fetches the limit variable only once, so add helpers for fetching current and maximal resource limits which do that. Add them to sched.h (instead of resource.h) due to circular dependency sched.h->resource.h->task_struct Alternative would be to create a separate res_access.h or similar. Signed-off-by: Jiri Slaby Cc: James Morris Cc: Heiko Carstens Cc: Andrew Morton Cc: Ingo Molnar --- include/linux/sched.h | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) (limited to 'include/linux/sched.h') diff --git a/include/linux/sched.h b/include/linux/sched.h index f2f842d..8d4991b 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -2601,6 +2601,28 @@ static inline void mm_init_owner(struct mm_struct *mm, struct task_struct *p) } #endif /* CONFIG_MM_OWNER */ +static inline unsigned long task_rlimit(const struct task_struct *tsk, + unsigned int limit) +{ + return ACCESS_ONCE(tsk->signal->rlim[limit].rlim_cur); +} + +static inline unsigned long task_rlimit_max(const struct task_struct *tsk, + unsigned int limit) +{ + return ACCESS_ONCE(tsk->signal->rlim[limit].rlim_max); +} + +static inline unsigned long rlimit(unsigned int limit) +{ + return task_rlimit(current, limit); +} + +static inline unsigned long rlimit_max(unsigned int limit) +{ + return task_rlimit_max(current, limit); +} + #endif /* __KERNEL__ */ #endif -- cgit v1.1 From efc1a3b16930c41d64ffefde16b87d82f603a8a0 Mon Sep 17 00:00:00 2001 From: David Howells Date: Fri, 15 Jan 2010 17:01:35 -0800 Subject: nommu: don't need get_unmapped_area() for NOMMU get_unmapped_area() is unnecessary for NOMMU as no-one calls it. Signed-off-by: David Howells Acked-by: Al Viro Cc: Greg Ungerer Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/sched.h | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) (limited to 'include/linux/sched.h') diff --git a/include/linux/sched.h b/include/linux/sched.h index 8d4991b..6f7bba9 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -377,6 +377,8 @@ extern int sysctl_max_map_count; #include +#ifdef CONFIG_MMU +extern void arch_pick_mmap_layout(struct mm_struct *mm); extern unsigned long arch_get_unmapped_area(struct file *, unsigned long, unsigned long, unsigned long, unsigned long); @@ -386,6 +388,9 @@ arch_get_unmapped_area_topdown(struct file *filp, unsigned long addr, unsigned long flags); extern void arch_unmap_area(struct mm_struct *, unsigned long); extern void arch_unmap_area_topdown(struct mm_struct *, unsigned long); +#else +static inline void arch_pick_mmap_layout(struct mm_struct *mm) {} +#endif #if USE_SPLIT_PTLOCKS /* @@ -2491,8 +2496,6 @@ static inline void set_task_cpu(struct task_struct *p, unsigned int cpu) #endif /* CONFIG_SMP */ -extern void arch_pick_mmap_layout(struct mm_struct *mm); - #ifdef CONFIG_TRACING extern void __trace_special(void *__tr, void *__data, -- cgit v1.1 From 221af7f87b97431e3ee21ce4b0e77d5411cf1549 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Thu, 28 Jan 2010 22:14:42 -0800 Subject: Split 'flush_old_exec' into two functions 'flush_old_exec()' is the point of no return when doing an execve(), and it is pretty badly misnamed. It doesn't just flush the old executable environment, it also starts up the new one. Which is very inconvenient for things like setting up the new personality, because we want the new personality to affect the starting of the new environment, but at the same time we do _not_ want the new personality to take effect if flushing the old one fails. As a result, the x86-64 '32-bit' personality is actually done using this insane "I'm going to change the ABI, but I haven't done it yet" bit (TIF_ABI_PENDING), with SET_PERSONALITY() not actually setting the personality, but just the "pending" bit, so that "flush_thread()" can do the actual personality magic. This patch in no way changes any of that insanity, but it does split the 'flush_old_exec()' function up into a preparatory part that can fail (still called flush_old_exec()), and a new part that will actually set up the new exec environment (setup_new_exec()). All callers are changed to trivially comply with the new world order. Signed-off-by: H. Peter Anvin Cc: stable@kernel.org Signed-off-by: Linus Torvalds --- include/linux/sched.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/linux/sched.h') diff --git a/include/linux/sched.h b/include/linux/sched.h index 6f7bba9..abdfacc 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1369,7 +1369,7 @@ struct task_struct { char comm[TASK_COMM_LEN]; /* executable name excluding path - access with [gs]et_task_comm (which lock it with task_lock()) - - initialized normally by flush_old_exec */ + - initialized normally by setup_new_exec */ /* file system info */ int link_count, total_link_count; #ifdef CONFIG_SYSVIPC -- cgit v1.1 From d6ad3e286d2c075a60b9f11075a2c55aeeeca2ad Mon Sep 17 00:00:00 2001 From: Jason Wessel Date: Wed, 27 Jan 2010 16:25:22 -0600 Subject: softlockup: Add sched_clock_tick() to avoid kernel warning on kgdb resume When CONFIG_HAVE_UNSTABLE_SCHED_CLOCK is set, sched_clock() gets the time from hardware such as the TSC on x86. In this configuration kgdb will report a softlock warning message on resuming or detaching from a debug session. Sequence of events in the problem case: 1) "cpu sched clock" and "hardware time" are at 100 sec prior to a call to kgdb_handle_exception() 2) Debugger waits in kgdb_handle_exception() for 80 sec and on exit the following is called ... touch_softlockup_watchdog() --> __raw_get_cpu_var(touch_timestamp) = 0; 3) "cpu sched clock" = 100s (it was not updated, because the interrupt was disabled in kgdb) but the "hardware time" = 180 sec 4) The first timer interrupt after resuming from kgdb_handle_exception updates the watchdog from the "cpu sched clock" update_process_times() { ... run_local_timers() --> softlockup_tick() --> check (touch_timestamp == 0) (it is "YES" here, we have set "touch_timestamp = 0" at kgdb) --> __touch_softlockup_watchdog() ***(A)--> reset "touch_timestamp" to "get_timestamp()" (Here, the "touch_timestamp" will still be set to 100s.) ... scheduler_tick() ***(B)--> sched_clock_tick() (update "cpu sched clock" to "hardware time" = 180s) ... } 5) The Second timer interrupt handler appears to have a large jump and trips the softlockup warning. update_process_times() { ... run_local_timers() --> softlockup_tick() --> "cpu sched clock" - "touch_timestamp" = 180s-100s > 60s --> printk "soft lockup error messages" ... } note: ***(A) reset "touch_timestamp" to "get_timestamp(this_cpu)" Why is "touch_timestamp" 100 sec, instead of 180 sec? When CONFIG_HAVE_UNSTABLE_SCHED_CLOCK is set, the call trace of get_timestamp() is: get_timestamp(this_cpu) -->cpu_clock(this_cpu) -->sched_clock_cpu(this_cpu) -->__update_sched_clock(sched_clock_data, now) The __update_sched_clock() function uses the GTOD tick value to create a window to normalize the "now" values. So if "now" value is too big for sched_clock_data, it will be ignored. The fix is to invoke sched_clock_tick() to update "cpu sched clock" in order to recover from this state. This is done by introducing the function touch_softlockup_watchdog_sync(). This allows kgdb to request that the sched clock is updated when the watchdog thread runs the first time after a resume from kgdb. [yong.zhang0@gmail.com: Use per cpu instead of an array] Signed-off-by: Jason Wessel Signed-off-by: Dongdong Deng Cc: kgdb-bugreport@lists.sourceforge.net Cc: peterz@infradead.org LKML-Reference: <1264631124-4837-2-git-send-email-jason.wessel@windriver.com> Signed-off-by: Ingo Molnar --- include/linux/sched.h | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'include/linux/sched.h') diff --git a/include/linux/sched.h b/include/linux/sched.h index 6f7bba9..8923215 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -310,6 +310,7 @@ extern void sched_show_task(struct task_struct *p); #ifdef CONFIG_DETECT_SOFTLOCKUP extern void softlockup_tick(void); extern void touch_softlockup_watchdog(void); +extern void touch_softlockup_watchdog_sync(void); extern void touch_all_softlockup_watchdogs(void); extern int proc_dosoftlockup_thresh(struct ctl_table *table, int write, void __user *buffer, @@ -323,6 +324,9 @@ static inline void softlockup_tick(void) static inline void touch_softlockup_watchdog(void) { } +static inline void touch_softlockup_watchdog_sync(void) +{ +} static inline void touch_all_softlockup_watchdogs(void) { } -- cgit v1.1