linux.git/arch/parisc/kernel/ftrace.c, branch for-next

Merge tag 'parisc-for-6.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux

2024-11-26T22:49:20+00:00

Pull parisc architecture update from Helge Deller:

 - Fix function graph tracing disablement on parisc

* tag 'parisc-for-6.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux:
  parisc/ftrace: Fix function graph tracing disablement

parisc/ftrace: Fix function graph tracing disablement

2024-11-16T21:55:56+00:00

Due to an apparent copy-paste bug, the parisc implementation of
ftrace_disable_ftrace_graph_caller() doesn't actually do anything.
It enables the (already-enabled) static key rather than disabling it.

The result is that after function graph tracing has been "disabled", any
subsequent (non-graph) function tracing will inadvertently also enable
the slow fgraph return address hijacking.

Fixes: 98f2926171ae ("parisc/ftrace: use static key to enable/disable function graph tracer")
Cc: stable@vger.kernel.org # 5.16+
Signed-off-by: Josh Poimboeuf 
Signed-off-by: Helge Deller

asm-generic: introduce text-patching.h

2024-11-07T22:25:15+00:00

Several architectures support text patching, but they name the header
files that declare patching functions differently.

Make all such headers consistently named text-patching.h and add an empty
header in asm-generic for architectures that do not support text patching.

Link: https://lkml.kernel.org/r/20241023162711.2579610-4-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) 
Reviewed-by: Christoph Hellwig 
Acked-by: Geert Uytterhoeven  # m68k
Acked-by: Arnd Bergmann 
Reviewed-by: Luis Chamberlain 
Tested-by: kdevops 
Cc: Andreas Larsson 
Cc: Andy Lutomirski 
Cc: Ard Biesheuvel 
Cc: Borislav Petkov (AMD) 
Cc: Brian Cain 
Cc: Catalin Marinas 
Cc: Christophe Leroy 
Cc: Dave Hansen 
Cc: Dinh Nguyen 
Cc: Guo Ren 
Cc: Helge Deller 
Cc: Huacai Chen 
Cc: Ingo Molnar 
Cc: Johannes Berg 
Cc: John Paul Adrian Glaubitz 
Cc: Kent Overstreet 
Cc: Liam R. Howlett 
Cc: Mark Rutland 
Cc: Masami Hiramatsu (Google) 
Cc: Matt Turner 
Cc: Max Filippov 
Cc: Michael Ellerman 
Cc: Michal Simek 
Cc: Oleg Nesterov 
Cc: Palmer Dabbelt 
Cc: Peter Zijlstra 
Cc: Richard Weinberger 
Cc: Russell King 
Cc: Song Liu 
Cc: Stafford Horne 
Cc: Steven Rostedt (Google) 
Cc: Suren Baghdasaryan 
Cc: Thomas Bogendoerfer 
Cc: Thomas Gleixner 
Cc: Uladzislau Rezki (Sony) 
Cc: Vineet Gupta 
Cc: Will Deacon 
Signed-off-by: Andrew Morton

kprobe/ftrace: bail out if ftrace was killed

2024-05-15T22:23:30+00:00

If an error happens in ftrace, ftrace_kill() will prevent disarming
kprobes. Eventually, the ftrace_ops associated with the kprobes will be
freed, yet the kprobes will still be active, and when triggered, they
will use the freed memory, likely resulting in a page fault and panic.

This behavior can be reproduced quite easily, by creating a kprobe and
then triggering a ftrace_kill(). For simplicity, we can simulate an
ftrace error with a kernel module like [1]:

[1]: https://github.com/brenns10/kernel_stuff/tree/master/ftrace_killer

  sudo perf probe --add commit_creds
  sudo perf trace -e probe:commit_creds
  # In another terminal
  make
  sudo insmod ftrace_killer.ko  # calls ftrace_kill(), simulating bug
  # Back to perf terminal
  # ctrl-c
  sudo perf probe --del commit_creds

After a short period, a page fault and panic would occur as the kprobe
continues to execute and uses the freed ftrace_ops. While ftrace_kill()
is supposed to be used only in extreme circumstances, it is invoked in
FTRACE_WARN_ON() and so there are many places where an unexpected bug
could be triggered, yet the system may continue operating, possibly
without the administrator noticing. If ftrace_kill() does not panic the
system, then we should do everything we can to continue operating,
rather than leave a ticking time bomb.

Link: https://lore.kernel.org/all/20240501162956.229427-1-stephen.s.brennan@oracle.com/

Signed-off-by: Stephen Brennan 
Acked-by: Masami Hiramatsu (Google) 
Acked-by: Guo Ren 
Reviewed-by: Steven Rostedt (Google) 
Signed-off-by: Masami Hiramatsu (Google)

parisc/ftrace: add missing CONFIG_DYNAMIC_FTRACE check

2024-02-16T19:18:03+00:00

Fixes a bug revealed by -Wmissing-prototypes when
CONFIG_FUNCTION_GRAPH_TRACER is enabled but not CONFIG_DYNAMIC_FTRACE:

 arch/parisc/kernel/ftrace.c:82:5: error: no previous prototype for 'ftrace_enable_ftrace_graph_caller' [-Werror=missing-prototypes]
    82 | int ftrace_enable_ftrace_graph_caller(void)
       |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 arch/parisc/kernel/ftrace.c:88:5: error: no previous prototype for 'ftrace_disable_ftrace_graph_caller' [-Werror=missing-prototypes]
    88 | int ftrace_disable_ftrace_graph_caller(void)
       |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Signed-off-by: Max Kellermann 
Signed-off-by: Helge Deller

parisc: ftrace: Add declaration for ftrace_function_trampoline()

2023-08-10T20:51:54+00:00

Make sparse happy by adding declaration for
ftrace_function_trampoline().

Signed-off-by: Helge Deller

Merge tag 'trace-v5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

2021-11-02T03:05:19+00:00

Pull tracing updates from Steven Rostedt:

 - kprobes: Restructured stack unwinder to show properly on x86 when a
   stack dump happens from a kretprobe callback.

 - Fix to bootconfig parsing

 - Have tracefs allow owner and group permissions by default (only
   denying others). There's been pressure to allow non root to tracefs
   in a controlled fashion, and using groups is probably the safest.

 - Bootconfig memory managament updates.

 - Bootconfig clean up to have the tools directory be less dependent on
   changes in the kernel tree.

 - Allow perf to be traced by function tracer.

 - Rewrite of function graph tracer to be a callback from the function
   tracer instead of having its own trampoline (this change will happen
   on an arch by arch basis, and currently only x86_64 implements it).

 - Allow multiple direct trampolines (bpf hooks to functions) be batched
   together in one synchronization.

 - Allow histogram triggers to add variables that can perform
   calculations against the event's fields.

 - Use the linker to determine architecture callbacks from the ftrace
   trampoline to allow for proper parameter prototypes and prevent
   warnings from the compiler.

 - Extend histogram triggers to key off of variables.

 - Have trace recursion use bit magic to determine preempt context over
   if branches.

 - Have trace recursion disable preemption as all use cases do anyway.

 - Added testing for verification of tracing utilities.

 - Various small clean ups and fixes.

* tag 'trace-v5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (101 commits)
  tracing/histogram: Fix semicolon.cocci warnings
  tracing/histogram: Fix documentation inline emphasis warning
  tracing: Increase PERF_MAX_TRACE_SIZE to handle Sentinel1 and docker together
  tracing: Show size of requested perf buffer
  bootconfig: Initialize ret in xbc_parse_tree()
  ftrace: do CPU checking after preemption disabled
  ftrace: disable preemption when recursion locked
  tracing/histogram: Document expression arithmetic and constants
  tracing/histogram: Optimize division by a power of 2
  tracing/histogram: Covert expr to const if both operands are constants
  tracing/histogram: Simplify handling of .sym-offset in expressions
  tracing: Fix operator precedence for hist triggers expression
  tracing: Add division and multiplication support for hist triggers
  tracing: Add support for creating hist trigger variables from literal
  selftests/ftrace: Stop tracing while reading the trace file by default
  MAINTAINERS: Update KPROBES and TRACING entries
  test_kprobes: Move it from kernel/ to lib/
  docs, kprobes: Remove invalid URL and add new reference
  samples/kretprobes: Fix return value if register_kretprobe() failed
  lib/bootconfig: Fix the xbc_get_info kerneldoc
  ...

parisc/ftrace: use static key to enable/disable function graph tracer

2021-11-01T06:36:01+00:00

This avoids using dereference_function_descriptor in the ftrace code
path, and it's also faster.

Signed-off-by: Sven Schnelle 
Signed-off-by: Helge Deller

parisc/ftrace: set function trace function

2021-11-01T06:36:01+00:00

With DYNAMIC_FTRACE, we need to implement ftrace_update_trace_func
and not call ftrace_trace_function() directly, as ftrace doesn't
expect calls to this function during code patching.

Signed-off-by: Sven Schnelle 
Signed-off-by: Helge Deller

ftrace: disable preemption when recursion locked

2021-10-27T15:21:49+00:00

As the documentation explained, ftrace_test_recursion_trylock()
and ftrace_test_recursion_unlock() were supposed to disable and
enable preemption properly, however currently this work is done
outside of the function, which could be missing by mistake.

And since the internal using of trace_test_and_set_recursion()
and trace_clear_recursion() also require preemption disabled, we
can just merge the logical.

This patch will make sure the preemption has been disabled when
trace_test_and_set_recursion() return bit >= 0, and
trace_clear_recursion() will enable the preemption if previously
enabled.

Link: https://lkml.kernel.org/r/13bde807-779c-aa4c-0672-20515ae365ea@linux.alibaba.com

CC: Petr Mladek 
Cc: Guo Ren 
Cc: Ingo Molnar 
Cc: "James E.J. Bottomley" 
Cc: Helge Deller 
Cc: Michael Ellerman 
Cc: Benjamin Herrenschmidt 
Cc: Paul Mackerras 
Cc: Paul Walmsley 
Cc: Palmer Dabbelt 
Cc: Albert Ou 
Cc: Thomas Gleixner 
Cc: Borislav Petkov 
Cc: "H. Peter Anvin" 
Cc: Josh Poimboeuf 
Cc: Jiri Kosina 
Cc: Joe Lawrence 
Cc: Masami Hiramatsu 
Cc: Nicholas Piggin 
Cc: Jisheng Zhang 
CC: Steven Rostedt 
CC: Miroslav Benes 
Reported-by: Abaci 
Suggested-by: Peter Zijlstra 
Signed-off-by: Michael Wang 
[ Removed extra line in comment - SDR ]
Signed-off-by: Steven Rostedt (VMware)