diff options
| author | Peter Zijlstra <peterz@infradead.org> | 2020-08-29 22:03:24 +0900 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2020-10-12 18:27:27 +0200 |
| commit | d741bf41d7c7db4898bacfcb020353cddc032fd8 (patch) | |
| tree | 9944b2c314717793ebd6be0982dab4bd4f82b2a1 /include | |
| parent | 476c5818c37a7828d558f34ae01f0c32f8bfadde (diff) | |
kprobes: Remove kretprobe hash
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) <peterz@infradead.org>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/159870620431.1229682.16325792502413731312.stgit@devnote2
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/kprobes.h | 19 | ||||
| -rw-r--r-- | include/linux/sched.h | 4 |
2 files changed, 21 insertions, 2 deletions
diff --git a/include/linux/kprobes.h b/include/linux/kprobes.h index 5c8c271fa1e9..00cf4421efd5 100644 --- a/include/linux/kprobes.h +++ b/include/linux/kprobes.h @@ -27,6 +27,7 @@ #include <linux/rcupdate.h> #include <linux/mutex.h> #include <linux/ftrace.h> +#include <linux/refcount.h> #include <asm/kprobes.h> #ifdef CONFIG_KPROBES @@ -144,6 +145,11 @@ static inline int kprobe_ftrace(struct kprobe *p) * ignored, due to maxactive being too low. * */ +struct kretprobe_holder { + struct kretprobe *rp; + refcount_t ref; +}; + struct kretprobe { struct kprobe kp; kretprobe_handler_t handler; @@ -152,17 +158,18 @@ struct kretprobe { int nmissed; size_t data_size; struct hlist_head free_instances; + struct kretprobe_holder *rph; raw_spinlock_t lock; }; struct kretprobe_instance { union { + struct llist_node llist; struct hlist_node hlist; struct rcu_head rcu; }; - struct kretprobe *rp; + struct kretprobe_holder *rph; kprobe_opcode_t *ret_addr; - struct task_struct *task; void *fp; char data[]; }; @@ -221,6 +228,14 @@ unsigned long kretprobe_trampoline_handler(struct pt_regs *regs, return ret; } +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 READ_ONCE(ri->rph->rp); +} + #else /* CONFIG_KRETPROBES */ static inline void arch_prepare_kretprobe(struct kretprobe *rp, struct pt_regs *regs) diff --git a/include/linux/sched.h b/include/linux/sched.h index afe01e232935..5911805cafde 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1315,6 +1315,10 @@ struct task_struct { struct callback_head mce_kill_me; #endif +#ifdef CONFIG_KRETPROBES + struct llist_head kretprobe_instances; +#endif + /* * New fields for task_struct should be added above here, so that * they are included in the randomized portion of task_struct. |