diff options
| author | Masami Hiramatsu (Google) <mhiramat@kernel.org> | 2023-12-01 14:53:56 +0900 |
|---|---|---|
| committer | Masami Hiramatsu (Google) <mhiramat@kernel.org> | 2023-12-01 14:53:56 +0900 |
| commit | a1461f1fd6cfdc4b8917c9d4a91e92605d1f28dc (patch) | |
| tree | caed8315567be58b912560043e4dde9fe3214940 /include | |
| parent | d839a656d0f3caca9f96e9bf912fd394ac6a11bc (diff) | |
rethook: Use __rcu pointer for rethook::handler
Since the rethook::handler is an RCU-maganged pointer so that it will
notice readers the rethook is stopped (unregistered) or not, it should
be an __rcu pointer and use appropriate functions to be accessed. This
will use appropriate memory barrier when accessing it. OTOH,
rethook::data is never changed, so we don't need to check it in
get_kretprobe().
NOTE: To avoid sparse warning, rethook::handler is defined by a raw
function pointer type with __rcu instead of rethook_handler_t.
Link: https://lore.kernel.org/all/170126066201.398836.837498688669005979.stgit@devnote2/
Fixes: 54ecbe6f1ed5 ("rethook: Add a generic return hook")
Cc: stable@vger.kernel.org
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202311241808.rv9ceuAh-lkp@intel.com/
Tested-by: JP Kobryn <inwardvessel@gmail.com>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/kprobes.h | 6 | ||||
| -rw-r--r-- | include/linux/rethook.h | 7 |
2 files changed, 8 insertions, 5 deletions
diff --git a/include/linux/kprobes.h b/include/linux/kprobes.h index 64672bace560..0ff44d6633e3 100644 --- a/include/linux/kprobes.h +++ b/include/linux/kprobes.h @@ -197,10 +197,8 @@ extern int arch_trampoline_kprobe(struct kprobe *p); #ifdef CONFIG_KRETPROBE_ON_RETHOOK static nokprobe_inline struct kretprobe *get_kretprobe(struct kretprobe_instance *ri) { - RCU_LOCKDEP_WARN(!rcu_read_lock_any_held(), - "Kretprobe is accessed from instance under preemptive context"); - - return (struct kretprobe *)READ_ONCE(ri->node.rethook->data); + /* rethook::data is non-changed field, so that you can access it freely. */ + return (struct kretprobe *)ri->node.rethook->data; } static nokprobe_inline unsigned long get_kretprobe_retaddr(struct kretprobe_instance *ri) { diff --git a/include/linux/rethook.h b/include/linux/rethook.h index ce69b2b7bc35..ba60962805f6 100644 --- a/include/linux/rethook.h +++ b/include/linux/rethook.h @@ -28,7 +28,12 @@ typedef void (*rethook_handler_t) (struct rethook_node *, void *, unsigned long, */ struct rethook { void *data; - rethook_handler_t handler; + /* + * To avoid sparse warnings, this uses a raw function pointer with + * __rcu, instead of rethook_handler_t. But this must be same as + * rethook_handler_t. + */ + void (__rcu *handler) (struct rethook_node *, void *, unsigned long, struct pt_regs *); struct objpool_head pool; struct rcu_head rcu; }; |