linux-toradex.git/arch/arc/kernel/kprobes.c, branch v6.7

kprobes: treewide: Make it harder to refer kretprobe_trampoline directly

2021-10-01T01:24:06+00:00

Since now there is kretprobe_trampoline_addr() for referring the
address of kretprobe trampoline code, we don't need to access
kretprobe_trampoline directly.

Make it harder to refer by renaming it to __kretprobe_trampoline().

Link: https://lkml.kernel.org/r/163163045446.489837.14510577516938803097.stgit@devnote2

Suggested-by: Ingo Molnar 
Signed-off-by: Masami Hiramatsu 
Signed-off-by: Steven Rostedt (VMware)

kprobes: treewide: Remove trampoline_address from kretprobe_trampoline_handler()

2021-10-01T01:24:06+00:00

The __kretprobe_trampoline_handler() callback, called from low level
arch kprobes methods, has the 'trampoline_address' parameter, which is
entirely superfluous as it basically just replicates:

  dereference_kernel_function_descriptor(kretprobe_trampoline)

In fact we had bugs in arch code where it wasn't replicated correctly.

So remove this superfluous parameter and use kretprobe_trampoline_addr()
instead.

Link: https://lkml.kernel.org/r/163163044546.489837.13505751885476015002.stgit@devnote2

Signed-off-by: Masami Hiramatsu 
Tested-by: Andrii Nakryiko 
Signed-off-by: Steven Rostedt (VMware)

kprobes: Do not increment probe miss count in the fault handler

2021-06-03T13:47:26+00:00

Kprobes has a counter 'nmissed', that is used to count the number of
times a probe handler was not called. This generally happens when we hit
a kprobe while handling another kprobe.

However, if one of the probe handlers causes a fault, we are currently
incrementing 'nmissed'. The comment in fault handler indicates that this
can be used to account faults taken by the probe handlers. But, this has
never been the intention as is evident from the comment above 'nmissed'
in 'struct kprobe':

	/*count the number of times this probe was temporarily disarmed */
	unsigned long nmissed;

Signed-off-by: Naveen N. Rao 
Signed-off-by: Peter Zijlstra (Intel) 
Acked-by: Masami Hiramatsu 
Link: https://lkml.kernel.org/r/20210601120150.672652-1-naveen.n.rao@linux.vnet.ibm.com

kprobes: Remove kprobe::fault_handler

2021-06-01T14:00:08+00:00

The reason for kprobe::fault_handler(), as given by their comment:

 * We come here because instructions in the pre/post
 * handler caused the page_fault, this could happen
 * if handler tries to access user space by
 * copy_from_user(), get_user() etc. Let the
 * user-specified handler try to fix it first.

Is just plain bad. Those other handlers are ran from non-preemptible
context and had better use _nofault() functions. Also, there is no
upstream usage of this.

Signed-off-by: Peter Zijlstra (Intel) 
Reviewed-by: Christoph Hellwig 
Acked-by: Masami Hiramatsu 
Link: https://lore.kernel.org/r/20210525073213.561116662@infradead.org

arc: kprobes: Use generic kretprobe trampoline handler

2020-09-08T09:52:32+00:00

Use the generic kretprobe trampoline handler. Don't use
framepointer verification.

Signed-off-by: Masami Hiramatsu 
Signed-off-by: Ingo Molnar 
Link: https://lore.kernel.org/r/159870604671.1229682.13639386820521358456.stgit@devnote2

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500

2019-06-19T15:09:55+00:00

Based on 2 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license version 2 as
  published by the free software foundation

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license version 2 as
  published by the free software foundation #

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-only

has been chosen to replace the boilerplate/reference in 4122 file(s).

Signed-off-by: Thomas Gleixner 
Reviewed-by: Enrico Weigelt 
Reviewed-by: Kate Stewart 
Reviewed-by: Allison Randal 
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de
Signed-off-by: Greg Kroah-Hartman

bpf/error-inject/kprobes: Clear current_kprobe and enable preempt in kprobe

2018-06-21T10:33:19+00:00

Clear current_kprobe and enable preemption in kprobe
even if pre_handler returns !0.

This simplifies function override using kprobes.

Jprobe used to require to keep the preemption disabled and
keep current_kprobe until it returned to original function
entry. For this reason kprobe_int3_handler() and similar
arch dependent kprobe handers checks pre_handler result
and exit without enabling preemption if the result is !0.

After removing the jprobe, Kprobes does not need to
keep preempt disabled even if user handler returns !0
anymore.

But since the function override handler in error-inject
and bpf is also returns !0 if it overrides a function,
to balancing the preempt count, it enables preemption
and reset current kprobe by itself.

That is a bad design that is very buggy. This fixes
such unbalanced preempt-count and current_kprobes setting
in kprobes, bpf and error-inject.

Note: for powerpc and x86, this removes all preempt_disable
from kprobe_ftrace_handler because ftrace callbacks are
called under preempt disabled.

Signed-off-by: Masami Hiramatsu 
Acked-by: Thomas Gleixner 
Acked-by: Naveen N. Rao 
Cc: Alexei Starovoitov 
Cc: Ananth N Mavinakayanahalli 
Cc: Andrew Morton 
Cc: Benjamin Herrenschmidt 
Cc: Catalin Marinas 
Cc: David S. Miller 
Cc: Fenghua Yu 
Cc: Heiko Carstens 
Cc: James Hogan 
Cc: Josef Bacik 
Cc: Linus Torvalds 
Cc: Martin Schwidefsky 
Cc: Michael Ellerman 
Cc: Paul Mackerras 
Cc: Peter Zijlstra 
Cc: Ralf Baechle 
Cc: Rich Felker 
Cc: Russell King 
Cc: Steven Rostedt 
Cc: Tony Luck 
Cc: Vineet Gupta 
Cc: Will Deacon 
Cc: Yoshinori Sato 
Cc: linux-arch@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-ia64@vger.kernel.org
Cc: linux-mips@linux-mips.org
Cc: linux-s390@vger.kernel.org
Cc: linux-sh@vger.kernel.org
Cc: linux-snps-arc@lists.infradead.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: sparclinux@vger.kernel.org
Link: https://lore.kernel.org/lkml/152942494574.15209.12323837825873032258.stgit@devbox
Signed-off-by: Ingo Molnar

ARC/kprobes: Don't call the ->break_handler() in ARC kprobes code

2018-06-21T10:33:13+00:00

Don't call the ->break_handler() from the ARC kprobes code,
because it was only used by jprobes which got removed.

Signed-off-by: Masami Hiramatsu 
Acked-by: Thomas Gleixner 
Cc: Ananth N Mavinakayanahalli 
Cc: Andrew Morton 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Steven Rostedt 
Cc: Vineet Gupta 
Cc: linux-arch@vger.kernel.org
Cc: linux-snps-arc@lists.infradead.org
Link: https://lore.kernel.org/lkml/152942468446.15209.13773902741600803798.stgit@devbox
Signed-off-by: Ingo Molnar

ARC/kprobes: Remove jprobe implementation

2018-06-21T10:33:06+00:00

Remove arch dependent setjump/longjump functions
and unused fields in kprobe_ctlblk for jprobes
from arch/arc.

Signed-off-by: Masami Hiramatsu 
Acked-by: Thomas Gleixner 
Cc: Ananth N Mavinakayanahalli 
Cc: Andrew Morton 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Steven Rostedt 
Cc: Vineet Gupta 
Cc: linux-arch@vger.kernel.org
Cc: linux-snps-arc@lists.infradead.org
Link: https://lore.kernel.org/lkml/152942436460.15209.3038881268172249579.stgit@devbox
Signed-off-by: Ingo Molnar

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial

2013-11-16T00:47:22+00:00

Pull trivial tree updates from Jiri Kosina:
 "Usual earth-shaking, news-breaking, rocket science pile from
  trivial.git"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (23 commits)
  doc: usb: Fix typo in Documentation/usb/gadget_configs.txt
  doc: add missing files to timers/00-INDEX
  timekeeping: Fix some trivial typos in comments
  mm: Fix some trivial typos in comments
  irq: Fix some trivial typos in comments
  NUMA: fix typos in Kconfig help text
  mm: update 00-INDEX
  doc: Documentation/DMA-attributes.txt fix typo
  DRM: comment: `halve' -> `half'
  Docs: Kconfig: `devlopers' -> `developers'
  doc: typo on word accounting in kprobes.c in mutliple architectures
  treewide: fix "usefull" typo
  treewide: fix "distingush" typo
  mm/Kconfig: Grammar s/an/a/
  kexec: Typo s/the/then/
  Documentation/kvm: Update cpuid documentation for steal time and pv eoi
  treewide: Fix common typo in "identify"
  __page_to_pfn: Fix typo in comment
  Correct some typos for word frequency
  clk: fixed-factor: Fix a trivial typo
  ...