linux/kernel, branch v2.6.30.4

sched: fix nr_uninterruptible accounting of frozen tasks really

2009-07-30T21:39:56Z

commit 6301cb95c119ebf324bb96ee226fa9ddffad80a7 upstream. commit e3c8ca8336 (sched: do not count frozen tasks toward load) broke the nr_uninterruptible accounting on freeze/thaw. On freeze the task is excluded from accounting with a check for (task->flags & PF_FROZEN), but that flag is cleared before the task is thawed. So while we prevent that the task with state TASK_UNINTERRUPTIBLE is accounted to nr_uninterruptible on freeze we decrement nr_uninterruptible on thaw. Use a separate flag which is handled by the freezing task itself. Set it before calling the scheduler with TASK_UNINTERRUPTIBLE state and clear it after we return from frozen state. Signed-off-by: Thomas Gleixner Signed-off-by: Greg Kroah-Hartman

tracing/function: Fix the return value of ftrace_trace_onoff_callback()

2009-07-30T21:39:53Z

commit 04aef32d39cc4ef80087c0ce8ed113c6d64f1a6b upstream. ftrace_trace_onoff_callback() will return an error even if we do the right operation, for example: # echo _spin_*:traceon:10 > set_ftrace_filter -bash: echo: write error: Invalid argument # cat set_ftrace_filter #### all functions enabled #### _spin_trylock_bh:traceon:count=10 _spin_unlock_irq:traceon:count=10 _spin_unlock_bh:traceon:count=10 _spin_lock_irq:traceon:count=10 _spin_unlock:traceon:count=10 _spin_trylock:traceon:count=10 _spin_unlock_irqrestore:traceon:count=10 _spin_lock_irqsave:traceon:count=10 _spin_lock_bh:traceon:count=10 _spin_lock:traceon:count=10 We want to set _spin_*:traceon:10 to set_ftrace_filter, it complains with "Invalid argument", but the operation is successful. This is because ftrace_process_regex() returns the number of functions that matched the pattern. If the number is not 0, this value is returned by ftrace_regex_write() whereas we want to return the number of bytes virtually written. Also the file offset pointer is not updated in this case. If the number of matched functions is lower than the number of bytes written by the user, this results to a reprocessing of the string given by the user with a lower size, leading to a malformed ftrace regex and then a -EINVAL returned. So, this patch fixes it by returning 0 if no error occured. The fix also applies on 2.6.30 Signed-off-by: Xiao Guangrong Reviewed-by: Li Zefan Signed-off-by: Frederic Weisbecker Signed-off-by: Greg Kroah-Hartman

sched_rt: Fix overload bug on rt group scheduling

2009-07-30T21:39:52Z

commit a1ba4d8ba9f06a397e97cbd67a93ee306860b40a upstream. Fixes an easily triggerable BUG() when setting process affinities. Make sure to count the number of migratable tasks in the same place: the root rt_rq. Otherwise the number doesn't make sense and we'll hit the BUG in set_cpus_allowed_rt(). Also, make sure we only count tasks, not groups (this is probably already taken care of by the fact that rt_se->nr_cpus_allowed will be 0 for groups, but be more explicit) Tested-by: Thomas Gleixner Signed-off-by: Peter Zijlstra Acked-by: Gregory Haskins LKML-Reference: <1247067476.9777.57.camel@twins> Signed-off-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman

kernel/resource.c: fix sign extension in reserve_setup()

2009-07-20T03:38:50Z

commit 8bc1ad7dd301b7ca7454013519fa92e8c53655ff upstream. When the 32-bit signed quantities get assigned to the u64 resource_size_t, they are incorrectly sign-extended. Addresses http://bugzilla.kernel.org/show_bug.cgi?id=13253 Addresses http://bugzilla.kernel.org/show_bug.cgi?id=9905 Signed-off-by: Zhang Rui Reported-by: Leann Ogasawara Cc: Pierre Ossman Reported-by: Tested-by: Cc: Jesse Barnes Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

futexes: Fix infinite loop in get_futex_key() on huge page

2009-07-20T03:38:50Z

commit ce2ae53b750abfaa012ce408e93da131a5b5649b upstream. get_futex_key() can infinitely loop if it is called on a virtual address that is within a huge page but not aligned to the beginning of that page. The call to get_user_pages_fast will return the struct page for a sub-page within the huge page and the check for page->mapping will always fail. The fix is to call compound_head on the page before checking that it's mapped. Signed-off-by: Sonny Rao Acked-by: Thomas Gleixner Cc: anton@samba.org Cc: rajamony@us.ibm.com Cc: speight@us.ibm.com Cc: mstephen@us.ibm.com Cc: grimm@us.ibm.com Cc: mikey@ozlabs.au.ibm.com LKML-Reference: <20090710231313.GA23572@us.ibm.com> Signed-off-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman

futex: Fix the write access fault problem for real

2009-07-20T03:38:50Z

commit d0725992c8a6fb63a16bc9e8b2a50094cc4db3cd and aa715284b4d28cabde6c25c568d769a6be712bc8 upstream commit 64d1304a64 (futex: setup writeable mapping for futex ops which modify user space data) did address only half of the problem of write access faults. The patch was made on two wrong assumptions: 1) access_ok(VERIFY_WRITE,...) would actually check write access. On x86 it does _NOT_. It's a pure address range check. 2) a RW mapped region can not go away under us. That's wrong as well. Nobody can prevent another thread to call mprotect(PROT_READ) on that region where the futex resides. If that call hits between the get_user_pages_fast() verification and the actual write access in the atomic region we are toast again. The solution is to not rely on access_ok and get_user() for any write access related fault on private and shared futexes. Instead we need to fault it in with verification of write access. There is no generic non destructive write mechanism which would fault the user page in trough a #PF, but as we already know that we will fault we can as well call get_user_pages() directly and avoid the #PF overhead. If get_user_pages() returns -EFAULT we know that we can not fix it anymore and need to bail out to user space. Remove a bunch of confusing comments on this issue as well. Signed-off-by: Thomas Gleixner Signed-off-by: Greg Kroah-Hartman

security: use mmap_min_addr indepedently of security models

2009-07-20T03:38:46Z

commit e0a94c2a63f2644826069044649669b5e7ca75d3 upstream. This patch removes the dependency of mmap_min_addr on CONFIG_SECURITY. It also sets a default mmap_min_addr of 4096. mmapping of addresses below 4096 will only be possible for processes with CAP_SYS_RAWIO. Signed-off-by: Christoph Lameter Acked-by: Eric Paris Looks-ok-by: Linus Torvalds Signed-off-by: James Morris Signed-off-by: Greg Kroah-Hartman

bsdacct: fix access to invalid filp in acct_on()

2009-07-02T23:51:07Z

commit df279ca8966c3de83105428e3391ab17690802a9 upstream. The file opened in acct_on and freshly stored in the ns->bacct struct can be closed in acct_file_reopen by a concurrent call after we release acct_lock and before we call mntput(file->f_path.mnt). Record file->f_path.mnt in a local variable and use this variable only. Signed-off-by: Renaud Lottiaux Signed-off-by: Louis Rilling Cc: Al Viro Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

tracing/urgent: fix unbalanced ftrace_start_up

2009-07-02T23:50:22Z

commit c85a17e22695969aa24a7ffa40cf26d6e6fcfd50 upstream. Perfcounter reports the following stats for a wide system profiling: # # (2364 samples) # # Overhead Symbol # ........ ...... # 15.40% [k] mwait_idle_with_hints 8.29% [k] read_hpet 5.75% [k] ftrace_caller 3.60% [k] ftrace_call [...] This snapshot has been taken while neither the function tracer nor the function graph tracer was running. With dynamic ftrace, such results show a wrong ftrace behaviour because all calls to ftrace_caller or ftrace_graph_caller (the patched calls to mcount) are supposed to be patched into nop if none of those tracers are running. The problem occurs after the first run of the function tracer. Once we launch it a second time, the callsites will never be nopped back, unless you set custom filters. For example it happens during the self tests at boot time. The function tracer selftest runs, and then the dynamic tracing is tested too. After that, the callsites are left un-nopped. This is because the reset callback of the function tracer tries to unregister two ftrace callbacks in once: the common function tracer and the function tracer with stack backtrace, regardless of which one is currently in use. It then creates an unbalance on ftrace_start_up value which is expected to be zero when the last ftrace callback is unregistered. When it reaches zero, the FTRACE_DISABLE_CALLS is set on the next ftrace command, triggering the patching into nop. But since it becomes unbalanced, ie becomes lower than zero, if the kernel functions are patched again (as in every further function tracer runs), they won't ever be nopped back. Note that ftrace_call and ftrace_graph_call are still patched back to ftrace_stub in the off case, but not the callers of ftrace_call and ftrace_graph_caller. It means that the tracing is well deactivated but we waste a useless call into every kernel function. This patch just unregisters the right ftrace_ops for the function tracer on its reset callback and ignores the other one which is not registered, fixing the unbalance. The problem also happens is .30 Signed-off-by: Frederic Weisbecker Cc: Steven Rostedt Signed-off-by: Greg Kroah-Hartman

cpumask: alloc zeroed cpumask for static cpumask_var_ts

2009-06-09T13:00:27Z

These are defined as static cpumask_var_t so if MAXSMP is not used, they are cleared already. Avoid surprises when MAXSMP is enabled. Signed-off-by: Yinghai Lu Signed-off-by: Rusty Russell