user/sven/linux.git/kernel, branch v3.2.58

wait: fix reparent_leader() vs EXIT_DEAD->EXIT_ZOMBIE race

2014-04-30T15:23:26Z

commit dfccbb5e49a621c1b21a62527d61fc4305617aca upstream. wait_task_zombie() first does EXIT_ZOMBIE->EXIT_DEAD transition and drops tasklist_lock. If this task is not the natural child and it is traced, we change its state back to EXIT_ZOMBIE for ->real_parent. The last transition is racy, this is even documented in 50b8d257486a "ptrace: partially fix the do_wait(WEXITED) vs EXIT_DEAD->EXIT_ZOMBIE race". wait_consider_task() tries to detect this transition and clear ->notask_error but we can't rely on ptrace_reparented(), debugger can exit and do ptrace_unlink() before its sub-thread sets EXIT_ZOMBIE. And there is another problem which were missed before: this transition can also race with reparent_leader() which doesn't reset >exit_signal if EXIT_DEAD, assuming that this task must be reaped by someone else. So the tracee can be re-parented with ->exit_signal != SIGCHLD, and if /sbin/init doesn't use __WALL it becomes unreapable. Change reparent_leader() to update ->exit_signal even if EXIT_DEAD. Note: this is the simple temporary hack for -stable, it doesn't try to solve all problems, it will be reverted by the next changes. Signed-off-by: Oleg Nesterov Reported-by: Jan Kratochvil Reported-by: Michal Schmidt Tested-by: Michal Schmidt Cc: Al Viro Cc: Lennart Poettering Cc: Roland McGrath Cc: Tejun Heo Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Ben Hutchings

audit: convert PPIDs to the inital PID namespace.

2014-04-30T15:23:23Z

commit c92cdeb45eea38515e82187f48c2e4f435fb4e25 upstream. sys_getppid() returns the parent pid of the current process in its own pid namespace. Since audit filters are based in the init pid namespace, a process could avoid a filter or trigger an unintended one by being in an alternate pid namespace or log meaningless information. Switch to task_ppid_nr() for PPIDs to anchor all audit filters in the init_pid_ns. (informed by ebiederman's 6c621b7e) Cc: Eric W. Biederman Signed-off-by: Richard Guy Briggs [bwh: Backported to 3.2: sys_getppid() is used by audit_exit() but not audit_log_task_info()] Signed-off-by: Ben Hutchings

blktrace: fix accounting of partially completed requests

2014-04-30T15:23:20Z

commit af5040da01ef980670b3741b3e10733ee3e33566 upstream. trace_block_rq_complete does not take into account that request can be partially completed, so we can get the following incorrect output of blkparser: C R 232 + 240 [0] C R 240 + 232 [0] C R 248 + 224 [0] C R 256 + 216 [0] but should be: C R 232 + 8 [0] C R 240 + 8 [0] C R 248 + 8 [0] C R 256 + 8 [0] Also, the whole output summary statistics of completed requests and final throughput will be incorrect. This patch takes into account real completion size of the request and fixes wrong completion accounting. Signed-off-by: Roman Pen CC: Steven Rostedt CC: Frederic Weisbecker CC: Ingo Molnar CC: linux-kernel@vger.kernel.org Signed-off-by: Jens Axboe [bwh: Backported to 3.2: drop change in blk-mq.c] Signed-off-by: Ben Hutchings

printk: Fix scheduling-while-atomic problem in console_cpu_notify()

2014-04-01T23:59:00Z

commit 85eae82a0855d49852b87deac8653e4ebc8b291f upstream. The console_cpu_notify() function runs with interrupts disabled in the CPU_DYING case. It therefore cannot block, for example, as will happen when it calls console_lock(). Therefore, remove the CPU_DYING leg of the switch statement to avoid this problem. Signed-off-by: Paul E. McKenney Reviewed-by: Srivatsa S. Bhat Signed-off-by: Linus Torvalds Signed-off-by: Ben Hutchings

timekeeping: fix 32-bit overflow in get_monotonic_boottime

2014-04-01T23:59:00Z

fixed upstream in v3.6 by ec145babe754f9ea1079034a108104b6001e001c get_monotonic_boottime adds three nanonsecond values stored in longs, followed by an s64. If the long values are all close to 1e9 the first three additions can overflow and become negative when added to the s64. Cast the first value to s64 so that all additions are 64 bit. Signed-off-by: Colin Cross [jstultz: Fished this out of the AOSP commong.git tree. This was fixed upstream in v3.6 by ec145babe754f9ea1079034a108104b6001e001c] Signed-off-by: John Stultz Signed-off-by: Greg Kroah-Hartman Signed-off-by: Ben Hutchings

ftrace: Have function graph only trace based on global_ops filters

2014-04-01T23:59:00Z

commit 23a8e8441a0a74dd612edf81dc89d1600bc0a3d1 upstream. Doing some different tests, I discovered that function graph tracing, when filtered via the set_ftrace_filter and set_ftrace_notrace files, does not always keep with them if another function ftrace_ops is registered to trace functions. The reason is that function graph just happens to trace all functions that the function tracer enables. When there was only one user of function tracing, the function graph tracer did not need to worry about being called by functions that it did not want to trace. But now that there are other users, this becomes a problem. For example, one just needs to do the following: # cd /sys/kernel/debug/tracing # echo schedule > set_ftrace_filter # echo function_graph > current_tracer # cat trace [..] 0) | schedule() { ------------------------------------------ 0) -0 => rcu_pre-7 ------------------------------------------ 0) ! 2980.314 us | } 0) | schedule() { ------------------------------------------ 0) rcu_pre-7 => -0 ------------------------------------------ 0) + 20.701 us | } # echo 1 > /proc/sys/kernel/stack_tracer_enabled # cat trace [..] 1) + 20.825 us | } 1) + 21.651 us | } 1) + 30.924 us | } /* SyS_ioctl */ 1) | do_page_fault() { 1) | __do_page_fault() { 1) 0.274 us | down_read_trylock(); 1) 0.098 us | find_vma(); 1) | handle_mm_fault() { 1) | _raw_spin_lock() { 1) 0.102 us | preempt_count_add(); 1) 0.097 us | do_raw_spin_lock(); 1) 2.173 us | } 1) | do_wp_page() { 1) 0.079 us | vm_normal_page(); 1) 0.086 us | reuse_swap_page(); 1) 0.076 us | page_move_anon_rmap(); 1) | unlock_page() { 1) 0.082 us | page_waitqueue(); 1) 0.086 us | __wake_up_bit(); 1) 1.801 us | } 1) 0.075 us | ptep_set_access_flags(); 1) | _raw_spin_unlock() { 1) 0.098 us | do_raw_spin_unlock(); 1) 0.105 us | preempt_count_sub(); 1) 1.884 us | } 1) 9.149 us | } 1) + 13.083 us | } 1) 0.146 us | up_read(); When the stack tracer was enabled, it enabled all functions to be traced, which now the function graph tracer also traces. This is a side effect that should not occur. To fix this a test is added when the function tracing is changed, as well as when the graph tracer is enabled, to see if anything other than the ftrace global_ops function tracer is enabled. If so, then the graph tracer calls a test trampoline that will look at the function that is being traced and compare it with the filters defined by the global_ops. As an optimization, if there's no other function tracers registered, or if the only registered function tracers also use the global ops, the function graph infrastructure will call the registered function graph callback directly and not go through the test trampoline. Fixes: d2d45c7a03a2 "tracing: Have stack_tracer use a separate list of functions" Signed-off-by: Steven Rostedt Signed-off-by: Greg Kroah-Hartman Signed-off-by: Ben Hutchings

tracing: Do not add event files for modules that fail tracepoints

2014-04-01T23:58:57Z

commit 45ab2813d40d88fc575e753c38478de242d03f88 upstream. If a module fails to add its tracepoints due to module tainting, do not create the module event infrastructure in the debugfs directory. As the events will not work and worse yet, they will silently fail, making the user wonder why the events they enable do not display anything. Having a warning on module load and the events not visible to the users will make the cause of the problem much clearer. Link: http://lkml.kernel.org/r/20140227154923.265882695@goodmis.org Fixes: 6d723736e472 "tracing/events: add support for modules to TRACE_EVENT" Acked-by: Mathieu Desnoyers Cc: Rusty Russell Signed-off-by: Steven Rostedt Signed-off-by: Ben Hutchings

cpuset: fix a race condition in __cpuset_node_allowed_softwall()

2014-04-01T23:58:56Z

commit 99afb0fd5f05aac467ffa85c36778fec4396209b upstream. It's not safe to access task's cpuset after releasing task_lock(). Holding callback_mutex won't help. Signed-off-by: Li Zefan Signed-off-by: Tejun Heo Signed-off-by: Ben Hutchings

perf: Fix hotplug splat

2014-04-01T23:58:56Z

commit e3703f8cdfcf39c25c4338c3ad8e68891cca3731 upstream. Drew Richardson reported that he could make the kernel go *boom* when hotplugging while having perf events active. It turned out that when you have a group event, the code in __perf_event_exit_context() fails to remove the group siblings from the context. We then proceed with destroying and freeing the event, and when you re-plug the CPU and try and add another event to that CPU, things go *boom* because you've still got dead entries there. Reported-by: Drew Richardson Signed-off-by: Peter Zijlstra Cc: Will Deacon Link: http://lkml.kernel.org/n/tip-k6v5wundvusvcseqj1si0oz0@git.kernel.org Signed-off-by: Ingo Molnar Signed-off-by: Ben Hutchings

sched: Fix double normalization of vruntime

2014-04-01T23:58:56Z

commit 791c9e0292671a3bfa95286bb5c08129d8605618 upstream. dequeue_entity() is called when p->on_rq and sets se->on_rq = 0 which appears to guarentee that the !se->on_rq condition is met. If the task has done set_current_state(TASK_INTERRUPTIBLE) without schedule() the second condition will be met and vruntime will be incorrectly adjusted twice. In certain cases this can result in the task's vruntime never increasing past the vruntime of other tasks on the CFS' run queue, starving them of CPU time. This patch changes switched_from_fair() to use !p->on_rq instead of !se->on_rq. I'm able to cause a task with a priority of 120 to starve all other tasks with the same priority on an ARM platform running 3.2.51-rt72 PREEMPT RT by writing one character at time to a serial tty (16550 UART) in a tight loop. I'm also able to verify making this change corrects the problem on that platform and kernel version. Signed-off-by: George McCollister Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/r/1392767811-28916-1-git-send-email-george.mccollister@gmail.com Signed-off-by: Ingo Molnar [bwh: Backported to 3.2: adjust filename] Signed-off-by: Ben Hutchings