It was reported that a bug on arm64 caused a bad ip address to be used for
updating into a nop in ftrace_init(), but the error path (rightfully)
returned -EINVAL and not -EFAULT, as the bug caused more than one error to
occur. But because -EINVAL was returned, the ftrace_bug() tried to report
what was at the location of the ip address, and read it directly. This
caused the machine to panic, as the ip was not pointing to a valid memory
address.

Instead, read the ip address with copy_from_kernel_nofault() to safely
access the memory, and if it faults, report that the address faulted,
otherwise report what was in that location.

Link: https://lore.kernel.org/lkml/20210607032329.28671-1-mark-pk.tsai@mediatek.com/

Cc: stable@vger.kernel.org
Fixes: 05736a427f7e1 ("ftrace: warn on failure to disable mcount callers")
Reported-by: Mark-PK Tsai <mark-pk.tsai@mediatek.com>
Tested-by: Mark-PK Tsai <mark-pk.tsai@mediatek.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

Pull tracing fix from Steven Rostedt:
 "Fix probes written to the set_ftrace_filter file

  Now that there's a library that accesses the tracefs file system
  (libtracefs), the way the files are interacted with is slightly
  different than the command line. For instance, the write() system call
  is used directly instead of an echo. This exposes some old bugs.

  If a probe is written to "set_ftrace_filter" without any white space
  after it, it will be ignored. This is because the write expects that a
  string written to it that does not end with white spaces thinks there
  is more to come. But if the file is closed, the release function needs
  to finish it. The "set_ftrace_filter" release function handles the
  filter part of the "set_ftrace_filter" file, but did not handle the
  probe part"

* tag 'trace-v5.13-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  ftrace: Handle commands when closing set_ftrace_filter file

 # echo switch_mm:traceoff > /sys/kernel/tracing/set_ftrace_filter

will cause switch_mm to stop tracing by the traceoff command.

 # echo -n switch_mm:traceoff > /sys/kernel/tracing/set_ftrace_filter

does nothing.

The reason is that the parsing in the write function only processes
commands if it finished parsing (there is white space written after the
command). That's to handle:

 write(fd, "switch_mm:", 10);
 write(fd, "traceoff", 8);

cases, where the command is broken over multiple writes.

The problem is if the file descriptor is closed, then the write call is
not processed, and the command needs to be processed in the release code.
The release code can handle matching of functions, but does not handle
commands.

Cc: stable@vger.kernel.org
Fixes: eda1e32855656 ("tracing: handle broken names in ftrace filter")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

Pull tracing updates from Steven Rostedt:
 "New feature:

   - A new "func-no-repeats" option in tracefs/options directory.

     When set the function tracer will detect if the current function
     being traced is the same as the previous one, and instead of
     recording it, it will keep track of the number of times that the
     function is repeated in a row. And when another function is
     recorded, it will write a new event that shows the function that
     repeated, the number of times it repeated and the time stamp of
     when the last repeated function occurred.

  Enhancements:

   - In order to implement the above "func-no-repeats" option, the ring
     buffer timestamp can now give the accurate timestamp of the event
     as it is being recorded, instead of having to record an absolute
     timestamp for all events. This helps the histogram code which no
     longer needs to waste ring buffer space.

   - New validation logic to make sure all trace events that access
     dereferenced pointers do so in a safe way, and will warn otherwise.

  Fixes:

   - No longer limit the PIDs of tasks that are recorded for
     "saved_cmdlines" to PID_MAX_DEFAULT (32768), as systemd now allows
     for a much larger range. This caused the mapping of PIDs to the
     task names to be dropped for all tasks with a PID greater than
     32768.

   - Change trace_clock_global() to never block. This caused a deadlock.

  Clean ups:

   - Typos, prototype fixes, and removing of duplicate or unused code.

   - Better management of ftrace_page allocations"

* tag 'trace-v5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (32 commits)
  tracing: Restructure trace_clock_global() to never block
  tracing: Map all PIDs to command lines
  ftrace: Reuse the output of the function tracer for func_repeats
  tracing: Add "func_no_repeats" option for function tracing
  tracing: Unify the logic for function tracing options
  tracing: Add method for recording "func_repeats" events
  tracing: Add "last_func_repeats" to struct trace_array
  tracing: Define new ftrace event "func_repeats"
  tracing: Define static void trace_print_time()
  ftrace: Simplify the calculation of page number for ftrace_page->records some more
  ftrace: Store the order of pages allocated in ftrace_page
  tracing: Remove unused argument from "ring_buffer_time_stamp()
  tracing: Remove duplicate struct declaration in trace_events.h
  tracing: Update create_system_filter() kernel-doc comment
  tracing: A minor cleanup for create_system_filter()
  kernel: trace: Mundane typo fixes in the file trace_events_filter.c
  tracing: Fix various typos in comments
  scripts/recordmcount.pl: Make vim and emacs indent the same
  scripts/recordmcount.pl: Make indent spacing consistent
  tracing: Add a verifier to check string pointers for trace events
  ...

Commit b40c6eabfcd40 ("ftrace: Simplify the calculation of page number for
ftrace_page->records") simplified the calculation of the number of pages
needed for each page group without having any empty pages, but it can be
simplified even further.

Link: https://lore.kernel.org/lkml/CAHk-=wjt9b7kxQ2J=aDNKbR1QBMB3Hiqb_hYcZbKsxGRSEb+gQ@mail.gmail.com/

Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

Instead of saving the size of the records field of the ftrace_page, store
the order it uses to allocate the pages, as that is what is needed to know
in order to free the pages. This simplifies the code.

Link: https://lore.kernel.org/lkml/CAHk-=whyMxheOqXAORt9a7JK9gc9eHTgCJ55Pgs4p=X3RrQubQ@mail.gmail.com/

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[ change log written by Steven Rostedt ]
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

Needed to merge trace/ftrace/urgent to get:

  Commit 59300b36f85 ("ftrace: Check if pages were allocated before calling free_pages()")

To clean up the code that is affected by it as well.

Pull ftrace fix from Steven Rostedt:
 "Add check of order < 0 before calling free_pages()

  The function addresses that are traced by ftrace are stored in pages,
  and the size is held in a variable. If there's some error in creating
  them, the allocate ones will be freed. In this case, it is possible
  that the order of pages to be freed may end up being negative due to a
  size of zero passed to get_count_order(), and then that negative
  number will cause free_pages() to free a very large section.

  Make sure that does not happen"

* tag 'trace-v5.12-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  ftrace: Check if pages were allocated before calling free_pages()

It is possible that on error pg->size can be zero when getting its order,
which would return a -1 value. It is dangerous to pass in an order of -1
to free_pages(). Check if order is greater than or equal to zero before
calling free_pages().

Link: https://lore.kernel.org/lkml/20210330093916.432697c7@gandalf.local.home/

Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

Fix ~59 single-word typos in the tracing code comments, and fix
the grammar in a handful of places.

Link: https://lore.kernel.org/r/20210322224546.GA1981273@gmail.com
Link: https://lkml.kernel.org/r/20210323174935.GA4176821@gmail.com

Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>