linux-toradex.git/include/linux/kprobes.h, branch v5.12-rc8

tracing/kprobe: Fix to support kretprobe events on unloaded modules

2021-01-29T20:39:48+00:00

Fix kprobe_on_func_entry() returns error code instead of false so that
register_kretprobe() can return an appropriate error code.

append_trace_kprobe() expects the kprobe registration returns -ENOENT
when the target symbol is not found, and it checks whether the target
module is unloaded or not. If the target module doesn't exist, it
defers to probe the target symbol until the module is loaded.

However, since register_kretprobe() returns -EINVAL instead of -ENOENT
in that case, it always fail on putting the kretprobe event on unloaded
modules. e.g.

Kprobe event:
/sys/kernel/debug/tracing # echo p xfs:xfs_end_io >> kprobe_events
[   16.515574] trace_kprobe: This probe might be able to register after target module is loaded. Continue.

Kretprobe event: (p -> r)
/sys/kernel/debug/tracing # echo r xfs:xfs_end_io >> kprobe_events
sh: write error: Invalid argument
/sys/kernel/debug/tracing # cat error_log
[   41.122514] trace_kprobe: error: Failed to register probe event
  Command: r xfs:xfs_end_io
             ^

To fix this bug, change kprobe_on_func_entry() to detect symbol lookup
failure and return -ENOENT in that case. Otherwise it returns -EINVAL
or 0 (succeeded, given address is on the entry).

Link: https://lkml.kernel.org/r/161176187132.1067016.8118042342894378981.stgit@devnote2

Cc: stable@vger.kernel.org
Fixes: 59158ec4aef7 ("tracing/kprobes: Check the probe on unloaded module correctly")
Reported-by: Jianlin Lv 
Signed-off-by: Masami Hiramatsu 
Signed-off-by: Steven Rostedt (VMware)

Merge tag 'trace-v5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

2020-12-17T21:22:17+00:00

Pull tracing updates from Steven Rostedt:
 "The major update to this release is that there's a new arch config
  option called CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS.

  Currently, only x86_64 enables it. All the ftrace callbacks now take a
  struct ftrace_regs instead of a struct pt_regs. If the architecture
  has HAVE_DYNAMIC_FTRACE_WITH_ARGS enabled, then the ftrace_regs will
  have enough information to read the arguments of the function being
  traced, as well as access to the stack pointer.

  This way, if a user (like live kernel patching) only cares about the
  arguments, then it can avoid using the heavier weight "regs" callback,
  that puts in enough information in the struct ftrace_regs to simulate
  a breakpoint exception (needed for kprobes).

  A new config option that audits the timestamps of the ftrace ring
  buffer at most every event recorded.

  Ftrace recursion protection has been cleaned up to move the protection
  to the callback itself (this saves on an extra function call for those
  callbacks).

  Perf now handles its own RCU protection and does not depend on ftrace
  to do it for it (saving on that extra function call).

  New debug option to add "recursed_functions" file to tracefs that
  lists all the places that triggered the recursion protection of the
  function tracer. This will show where things need to be fixed as
  recursion slows down the function tracer.

  The eval enum mapping updates done at boot up are now offloaded to a
  work queue, as it caused a noticeable pause on slow embedded boards.

  Various clean ups and last minute fixes"

* tag 'trace-v5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (33 commits)
  tracing: Offload eval map updates to a work queue
  Revert: "ring-buffer: Remove HAVE_64BIT_ALIGNED_ACCESS"
  ring-buffer: Add rb_check_bpage in __rb_allocate_pages
  ring-buffer: Fix two typos in comments
  tracing: Drop unneeded assignment in ring_buffer_resize()
  tracing: Disable ftrace selftests when any tracer is running
  seq_buf: Avoid type mismatch for seq_buf_init
  ring-buffer: Fix a typo in function description
  ring-buffer: Remove obsolete rb_event_is_commit()
  ring-buffer: Add test to validate the time stamp deltas
  ftrace/documentation: Fix RST C code blocks
  tracing: Clean up after filter logic rewriting
  tracing: Remove the useless value assignment in test_create_synth_event()
  livepatch: Use the default ftrace_ops instead of REGS when ARGS is available
  ftrace/x86: Allow for arguments to be passed in to ftrace_regs by default
  ftrace: Have the callbacks receive a struct ftrace_regs instead of pt_regs
  MAINTAINERS: assign ./fs/tracefs to TRACING
  tracing: Fix some typos in comments
  ftrace: Remove unused varible 'ret'
  ring-buffer: Add recording of ring buffer recursion into recursed_functions
  ...

ftrace: Have the callbacks receive a struct ftrace_regs instead of pt_regs

2020-11-13T17:14:55+00:00

In preparation to have arguments of a function passed to callbacks attached
to functions as default, change the default callback prototype to receive a
struct ftrace_regs as the forth parameter instead of a pt_regs.

For callbacks that set the FL_SAVE_REGS flag in their ftrace_ops flags, they
will now need to get the pt_regs via a ftrace_get_regs() helper call. If
this is called by a callback that their ftrace_ops did not have a
FL_SAVE_REGS flag set, it that helper function will return NULL.

This will allow the ftrace_regs to hold enough just to get the parameters
and stack pointer, but without the worry that callbacks may have a pt_regs
that is not completely filled.

Acked-by: Peter Zijlstra (Intel) 
Reviewed-by: Masami Hiramatsu 
Signed-off-by: Steven Rostedt (VMware)

Merge branch 'linus' into perf/kprobes

2020-11-07T12:18:49+00:00

Merge recent kprobes updates into perf/kprobes that came from -mm.

Signed-off-by: Ingo Molnar

Merge tag 'perf-kprobes-2020-10-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2020-10-12T21:21:15+00:00

Pull perf/kprobes updates from Ingo Molnar:
 "This prepares to unify the kretprobe trampoline handler and make
  kretprobe lockless (those patches are still work in progress)"

* tag 'perf-kprobes-2020-10-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  kprobes: Fix to check probe enabled before disarm_kprobe_ftrace()
  kprobes: Make local functions static
  kprobes: Free kretprobe_instance with RCU callback
  kprobes: Remove NMI context check
  sparc: kprobes: Use generic kretprobe trampoline handler
  sh: kprobes: Use generic kretprobe trampoline handler
  s390: kprobes: Use generic kretprobe trampoline handler
  powerpc: kprobes: Use generic kretprobe trampoline handler
  parisc: kprobes: Use generic kretprobe trampoline handler
  mips: kprobes: Use generic kretprobe trampoline handler
  ia64: kprobes: Use generic kretprobe trampoline handler
  csky: kprobes: Use generic kretprobe trampoline handler
  arc: kprobes: Use generic kretprobe trampoline handler
  arm64: kprobes: Use generic kretprobe trampoline handler
  arm: kprobes: Use generic kretprobe trampoline handler
  x86/kprobes: Use generic kretprobe trampoline handler
  kprobes: Add generic kretprobe trampoline handler

kprobes: Replace rp->free_instance with freelist

2020-10-12T16:27:28+00:00

Gets rid of rp->lock, and as a result kretprobes are now fully
lockless.

Signed-off-by: Peter Zijlstra (Intel) 
Signed-off-by: Masami Hiramatsu 
Signed-off-by: Ingo Molnar 
Link: https://lore.kernel.org/r/159870623583.1229682.17472357584134058687.stgit@devnote2

kprobes: Remove kretprobe hash

2020-10-12T16:27:27+00:00

The kretprobe hash is mostly superfluous, replace it with a per-task
variable.

This gets rid of the task hash and it's related locking.

Note that this may change the kprobes module-exported API for kretprobe
handlers. If any out-of-tree kretprobe user uses ri->rp, use
get_kretprobe(ri) instead.

Signed-off-by: Peter Zijlstra (Intel) 
Signed-off-by: Masami Hiramatsu 
Signed-off-by: Ingo Molnar 
Link: https://lore.kernel.org/r/159870620431.1229682.16325792502413731312.stgit@devnote2

kprobes: tracing/kprobes: Fix to kill kprobes on initmem after boot

2020-09-18T18:27:24+00:00

Since kprobe_event= cmdline option allows user to put kprobes on the
functions in initmem, kprobe has to make such probes gone after boot.
Currently the probes on the init functions in modules will be handled
by module callback, but the kernel init text isn't handled.
Without this, kprobes may access non-exist text area to disable or
remove it.

Link: https://lkml.kernel.org/r/159972810544.428528.1839307531600646955.stgit@devnote2

Fixes: 970988e19eb0 ("tracing/kprobe: Add kprobe_event= boot parameter")
Cc: Jonathan Corbet 
Cc: Shuah Khan 
Cc: Randy Dunlap 
Cc: Ingo Molnar 
Cc: stable@vger.kernel.org
Signed-off-by: Masami Hiramatsu 
Signed-off-by: Steven Rostedt (VMware)

kprobes: Make local functions static

2020-09-08T09:52:42+00:00

Since we unified the kretprobe trampoline handler from arch/* code,
some functions and objects do not need to be exported anymore.

Signed-off-by: Masami Hiramatsu 
Signed-off-by: Ingo Molnar 
Link: https://lore.kernel.org/r/159870618256.1229682.8692046612635810882.stgit@devnote2

kprobes: Free kretprobe_instance with RCU callback

2020-09-08T09:52:35+00:00

Free kretprobe_instance with RCU callback instead of directly
freeing the object in the kretprobe handler context.

This will make kretprobe run safer in NMI context.

Signed-off-by: Masami Hiramatsu 
Signed-off-by: Ingo Molnar 
Link: https://lore.kernel.org/r/159870616685.1229682.11978742048709542226.stgit@devnote2