linux/kernel, branch v2.6.30.1

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

async: Fix lack of boot-time console due to insufficient synchronization

2009-06-08T19:31:53Z

Our async work synchronization was broken by "async: make sure independent async domains can't accidentally entangle" (commit d5a877e8dd409d8c702986d06485c374b705d340), because it would report the wrong lowest active async ID when there was both running and pending async work. This caused things like no being able to read the root filesystem, resulting in missing console devices and inability to run 'init', causing a boot-time panic. This fixes it by properly returning the lowest pending async ID: if there is any running async work, that will have a lower ID than any pending work, and we should _not_ look at the pending work list. There were alternative patches from Jaswinder and James, but this one also cleans up the code by removing the pointless 'ret' variable and the unnecesary testing for an empty list around 'for_each_entry()' (if the list is empty, the for_each_entry() thing just won't execute). Fixes-bug: http://bugzilla.kernel.org/show_bug.cgi?id=13474 Reported-and-tested-by: Chris Clayton Cc: Jaswinder Singh Rajput Cc: James Bottomley Cc: Arjan van de Ven Signed-off-by: Linus Torvalds

ptrace: revert "ptrace_detach: the wrong wakeup breaks the ERESTARTxxx logic"

2009-06-05T01:07:40Z

Commit 95a3540da9c81a5987be810e1d9a83640a366bd5 ("ptrace_detach: the wrong wakeup breaks the ERESTARTxxx logic") removed the "extra" wake_up_process() from ptrace_detach(), but as Jan pointed out this breaks the compatibility. I believe the changelog is right and this wake_up() is wrong in many ways, but GDB assumes that ptrace(PTRACE_DETACH, child, 0, 0) always wakes up the tracee. Despite the fact this breaks SIGNAL_STOP_STOPPED/group_stop_count logic, and despite the fact this wake_up_process() can break another assumption: PTRACE_DETACH with SIGSTOP should leave the tracee in TASK_STOPPED case. Because the untraced child can dequeue SIGSTOP and call do_signal_stop() before ptrace_detach() calls wake_up_process(). Revert this change for now. We need some fixes even if we we want to keep the current behaviour, but these fixes are not for 2.6.30. Signed-off-by: Oleg Nesterov Acked-by: Roland McGrath Cc: Jan Kratochvil Cc: Denys Vlasenko Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

ptrace: tracehook_report_clone: fix false positives

2009-06-05T01:07:40Z

The "trace || CLONE_PTRACE" check in tracehook_report_clone() is not right, - If the untraced task does clone(CLONE_PTRACE) the new child is not traced, we must not queue SIGSTOP. - If we forked the traced task, but the tracer exits and untraces both the forking task and the new child (after copy_process() drops tasklist_lock), we should not queue SIGSTOP too. Change the code to check task_ptrace() != 0 instead. This is still racy, but the race is harmless. We can race with another tracer attaching to this child, or the tracer can exit and detach in parallel. But giwen that we didn't do wake_up_new_task() yet, the child must have the pending SIGSTOP anyway. Signed-off-by: Oleg Nesterov Acked-by: Roland McGrath Cc: Christoph Hellwig Cc: Ingo Molnar Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

kmod: Release sub_info on cred allocation failure.

2009-05-26T19:11:19Z

call_usermodehelper_setup() forgot to kfree(sub_info) when prepare_usermodehelper_creds() failed. Signed-off-by: Tetsuo Handa Signed-off-by: David Howells Signed-off-by: Linus Torvalds

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/suspend-2.6

2009-05-25T02:38:25Z

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/suspend-2.6: PM: Do not hold dpm_list_mtx while disabling/enabling nonboot CPUs

async: make sure independent async domains can't accidentally entangle

2009-05-24T20:38:41Z

The problem occurs when async_synchronize_full_domain() is called when the async_pending list is not empty. This will cause lowest_running() to return the cookie of the first entry on the async_pending list, which might be nothing at all to do with the domain being asked for and thus cause the domain synchronization to wait for an unrelated domain. This can cause a deadlock if domain synchronization is used from one domain to wait for another. Fix by running over the async_pending list to see if any pending items actually belong to our domain (and return their cookies if they do). Signed-off-by: James Bottomley Signed-off-by: Arjan van de Ven Signed-off-by: Linus Torvalds

PM: Do not hold dpm_list_mtx while disabling/enabling nonboot CPUs

2009-05-24T19:15:07Z

We shouldn't hold dpm_list_mtx while executing [disable|enable]_nonboot_cpus(), because theoretically this may lead to a deadlock as shown by the following example (provided by Johannes Berg): CPU 3 CPU 2 CPU 1 suspend/hibernate something: rtnl_lock() device_pm_lock() -> mutex_lock(&dpm_list_mtx) mutex_lock(&dpm_list_mtx) linkwatch_work -> rtnl_lock() disable_nonboot_cpus() -> flush CPU 3 workqueue Fortunately, device drivers are supposed to stop any activities that might lead to the registration of new device objects way before disable_nonboot_cpus() is called, so it shouldn't be necessary to hold dpm_list_mtx over the entire late part of device suspend and early part of device resume. Thus, during the late suspend and the early resume of devices acquire dpm_list_mtx only when dpm_list is going to be traversed and release it right after that. This patch is reported to fix the regressions tracked as http://bugzilla.kernel.org/show_bug.cgi?id=13245. Signed-off-by: Rafael J. Wysocki Acked-by: Alan Stern Reported-by: Miles Lane Tested-by: Ming Lei