user/sven/linux.git/kernel/trace/trace.c, branch v4.10.3

fs: Better permission checking for submounts

2017-03-15T02:20:10Z

commit 93faccbbfa958a9668d3ab4e30f38dd205cee8d8 upstream. To support unprivileged users mounting filesystems two permission checks have to be performed: a test to see if the user allowed to create a mount in the mount namespace, and a test to see if the user is allowed to access the specified filesystem. The automount case is special in that mounting the original filesystem grants permission to mount the sub-filesystems, to any user who happens to stumble across the their mountpoint and satisfies the ordinary filesystem permission checks. Attempting to handle the automount case by using override_creds almost works. It preserves the idea that permission to mount the original filesystem is permission to mount the sub-filesystem. Unfortunately using override_creds messes up the filesystems ordinary permission checks. Solve this by being explicit that a mount is a submount by introducing vfs_submount, and using it where appropriate. vfs_submount uses a new mount internal mount flags MS_SUBMOUNT, to let sget and friends know that a mount is a submount so they can take appropriate action. sget and sget_userns are modified to not perform any permission checks on submounts. follow_automount is modified to stop using override_creds as that has proven problemantic. do_mount is modified to always remove the new MS_SUBMOUNT flag so that we know userspace will never by able to specify it. autofs4 is modified to stop using current_real_cred that was put in there to handle the previous version of submount permission checking. cifs is modified to pass the mountpoint all of the way down to vfs_submount. debugfs is modified to pass the mountpoint all of the way down to trace_automount by adding a new parameter. To make this change easier a new typedef debugfs_automount_t is introduced to capture the type of the debugfs automount function. Fixes: 069d5ac9ae0d ("autofs: Fix automounts by using current_real_cred()->uid") Fixes: aeaa4a79ff6a ("fs: Call d_automount with the filesystems creds") Reviewed-by: Trond Myklebust Reviewed-by: Seth Forshee Signed-off-by: "Eric W. Biederman" Signed-off-by: Greg Kroah-Hartman

clocksource: Use a plain u64 instead of cycle_t

2016-12-25T10:04:12Z

There is no point in having an extra type for extra confusion. u64 is unambiguous. Conversion was done with the following coccinelle script: @rem@ @@ -typedef u64 cycle_t; @fix@ typedef cycle_t; @@ -cycle_t +u64 Signed-off-by: Thomas Gleixner Cc: Peter Zijlstra Cc: John Stultz

Merge tag 'trace-v4.10' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

2016-12-15T21:49:34Z

Pull tracing updates from Steven Rostedt: "This release has a few updates: - STM can hook into the function tracer - Function filtering now supports more advance glob matching - Ftrace selftests updates and added tests - Softirq tag in traces now show only softirqs - ARM nop added to non traced locations at compile time - New trace_marker_raw file that allows for binary input - Optimizations to the ring buffer - Removal of kmap in trace_marker - Wakeup and irqsoff tracers now adhere to the set_graph_notrace file - Other various fixes and clean ups" * tag 'trace-v4.10' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (42 commits) selftests: ftrace: Shift down default message verbosity kprobes/trace: Fix kprobe selftest for newer gcc tracing/kprobes: Add a helper method to return number of probe hits tracing/rb: Init the CPU mask on allocation tracing: Use SOFTIRQ_OFFSET for softirq dectection for more accurate results tracing/fgraph: Have wakeup and irqsoff tracers ignore graph functions too fgraph: Handle a case where a tracer ignores set_graph_notrace tracing: Replace kmap with copy_from_user() in trace_marker writing ftrace/x86_32: Set ftrace_stub to weak to prevent gcc from using short jumps to it tracing: Allow benchmark to be enabled at early_initcall() tracing: Have system enable return error if one of the events fail tracing: Do not start benchmark on boot up tracing: Have the reg function allow to fail ring-buffer: Force rb_end_commit() and rb_set_commit_to_write() inline ring-buffer: Froce rb_update_write_stamp() to be inlined ring-buffer: Force inline of hotpath helper functions tracing: Make __buffer_unlock_commit() always_inline tracing: Make tracepoint_printk a static_key ring-buffer: Always inline rb_event_data() ring-buffer: Make rb_reserve_next_event() always inlined ...

Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2016-12-13T03:56:15Z

Pull timer updates from Thomas Gleixner: "The time/timekeeping/timer folks deliver with this update: - Fix a reintroduced signed/unsigned issue and cleanup the whole signed/unsigned mess in the timekeeping core so this wont happen accidentaly again. - Add a new trace clock based on boot time - Prevent injection of random sleep times when PM tracing abuses the RTC for storage - Make posix timers configurable for real tiny systems - Add tracepoints for the alarm timer subsystem so timer based suspend wakeups can be instrumented - The usual pile of fixes and updates to core and drivers" * 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (23 commits) timekeeping: Use mul_u64_u32_shr() instead of open coding it timekeeping: Get rid of pointless typecasts timekeeping: Make the conversion call chain consistently unsigned timekeeping_Force_unsigned_clocksource_to_nanoseconds_conversion alarmtimer: Add tracepoints for alarm timers trace: Update documentation for mono, mono_raw and boot clock trace: Add an option for boot clock as trace clock timekeeping: Add a fast and NMI safe boot clock timekeeping/clocksource_cyc2ns: Document intended range limitation timekeeping: Ignore the bogus sleep time if pm_trace is enabled selftests/timers: Fix spelling mistake "Asyncrhonous" -> "Asynchronous" clocksource/drivers/bcm2835_timer: Unmap region obtained by of_iomap clocksource/drivers/arm_arch_timer: Map frame with of_io_request_and_map() arm64: dts: rockchip: Arch counter doesn't tick in system suspend clocksource/drivers/arm_arch_timer: Don't assume clock runs in suspend posix-timers: Make them configurable posix_cpu_timers: Move the add_device_randomness() call to a proper place timer: Move sys_alarm from timer.c to itimer.c ptp_clock: Allow for it to be optional Kconfig: Regenerate *.c_shipped files after previous changes ...

tracing: Use SOFTIRQ_OFFSET for softirq dectection for more accurate results

2016-12-12T18:51:02Z

The 's' flag is supposed to indicate that a softirq is running. This can be detected by testing the preempt_count with SOFTIRQ_OFFSET. The current code tests the preempt_count with SOFTIRQ_MASK, which would be true even when softirqs are disabled but not serving a softirq. Link: http://lkml.kernel.org/r/1481300417-3564-1-git-send-email-pkondeti@codeaurora.org Signed-off-by: Pavankumar Kondeti Signed-off-by: Steven Rostedt

tracing: Replace kmap with copy_from_user() in trace_marker writing

2016-12-09T14:18:14Z

Instead of using get_user_pages_fast() and kmap_atomic() when writing to the trace_marker file, just allocate enough space on the ring buffer directly, and write into it via copy_from_user(). Writing into the trace_marker file use to allocate a temporary buffer to perform the copy_from_user(), as we didn't want to write into the ring buffer if the copy failed. But as a trace_marker write is suppose to be extremely fast, and allocating memory causes other tracepoints to trigger, Peter Zijlstra suggested using get_user_pages_fast() and kmap_atomic() to keep the user space pages in memory and reading it directly. But Henrik Austad had issues with this because it required taking the mm->mmap_sem and causing long delays with the write. Instead, just allocate the space in the ring buffer and use copy_from_user() directly. If it faults, return -EFAULT and write "" into the ring buffer. Link: http://lkml.kernel.org/r/20161208124018.72dd0f86@gandalf.local.home Cc: Ingo Molnar Cc: Henrik Austad Cc: Peter Zijlstra Updates: d696b58ca2c3ca "tracing: Do not allocate buffer for trace_marker" Suggested-by: Thomas Gleixner Signed-off-by: Steven Rostedt

tracing/rb: Convert to hotplug state machine

2016-12-01T23:52:34Z

Install the callbacks via the state machine. The notifier in struct ring_buffer is replaced by the multi instance interface. Upon __ring_buffer_alloc() invocation, cpuhp_state_add_instance() will invoke the trace_rb_cpu_prepare() on each CPU. This callback may now fail. This means __ring_buffer_alloc() will fail and cleanup (like previously) and during a CPU up event this failure will not allow the CPU to come up. Signed-off-by: Sebastian Andrzej Siewior Cc: Steven Rostedt Cc: rt@linutronix.de Link: http://lkml.kernel.org/r/20161126231350.10321-7-bigeasy@linutronix.de Signed-off-by: Thomas Gleixner

trace: Add an option for boot clock as trace clock

2016-11-29T17:02:59Z

Unlike monotonic clock, boot clock as a trace clock will account for time spent in suspend useful for tracing suspend/resume. This uses earlier introduced infrastructure for using the fast boot clock. Signed-off-by: Joel Fernandes Signed-off-by: John Stultz Reviewed-by: Thomas Gleixner Acked-by: Steven Rostedt Cc: Prarit Bhargava Cc: Richard Cochran Link: http://lkml.kernel.org/r/1480372524-15181-7-git-send-email-john.stultz@linaro.org Signed-off-by: Thomas Gleixner

tracing: Make __buffer_unlock_commit() always_inline

2016-11-24T01:30:51Z

The function __buffer_unlock_commit() is called in a few places outside of trace.c. But for the most part, it should really be inlined, as it is in the hot path of the trace_events. For the callers outside of trace.c, create a new function trace_buffer_unlock_commit_nostack(), as the reason it was used was to avoid the stack tracing that trace_buffer_unlock_commit() could do. Link: http://lkml.kernel.org/r/20161121183700.GW26852@two.firstfloor.org Reported-by: Andi Kleen Signed-off-by: Steven Rostedt

tracing: Make tracepoint_printk a static_key

2016-11-23T20:52:45Z

Currently, when tracepoint_printk is set (enabled by the "tp_printk" kernel command line), it causes trace events to print via printk(). This is a very dangerous operation, but is useful for debugging. The issue is, it's seldom used, but it is always checked even if it's not enabled by the kernel command line. Instead of having this feature called by a branch against a variable, turn that variable into a static key, and this will remove the test and jump. To simplify things, the functions output_printk() and trace_event_buffer_commit() were moved from trace_events.c to trace.c. Signed-off-by: Steven Rostedt