kprobes: allow to specify custom allocator for insn caches (af96397d) · Commits · 戴 / test

include/linux/kprobes.h

+2 −0

Original line number	Diff line number	Diff line
		@@ -268,6 +268,8 @@ extern void kprobes_inc_nmissed_count(struct kprobe *p);

		struct kprobe_insn_cache {
		struct mutex mutex;
		void (alloc)(void); /* allocate insn page */
		void (free)(void ); /* free insn page */
		struct list_head pages; /* list of kprobe_insn_page */
		size_t insn_size; /* size of instruction slot */
		int nr_garbage;

kernel/kprobes.c

+18 −2

Original line number	Diff line number	Diff line
		@@ -112,6 +112,7 @@ static struct kprobe_blackpoint kprobe_blacklist[] = {
		struct kprobe_insn_page {
		struct list_head list;
		kprobe_opcode_t insns; / Page of instruction slots */
		struct kprobe_insn_cache *cache;
		int nused;
		int ngarbage;
		char slot_used[];
		@@ -132,8 +133,20 @@ enum kprobe_slot_state {
		SLOT_USED = 2,
		};

		static void *alloc_insn_page(void)
		{
		return module_alloc(PAGE_SIZE);
		}

		static void free_insn_page(void *page)
		{
		module_free(NULL, page);
		}

		struct kprobe_insn_cache kprobe_insn_slots = {
		.mutex = __MUTEX_INITIALIZER(kprobe_insn_slots.mutex),
		.alloc = alloc_insn_page,
		.free = free_insn_page,
		.pages = LIST_HEAD_INIT(kprobe_insn_slots.pages),
		.insn_size = MAX_INSN_SIZE,
		.nr_garbage = 0,
		@@ -182,7 +195,7 @@ kprobe_opcode_t __kprobes __get_insn_slot(struct kprobe_insn_cache c)
		* kernel image and loaded module images reside. This is required
		* so x86_64 can correctly handle the %rip-relative fixups.
		*/
		kip->insns = module_alloc(PAGE_SIZE);
		kip->insns = c->alloc();
		if (!kip->insns) {
		kfree(kip);
		goto out;
		@@ -192,6 +205,7 @@ kprobe_opcode_t __kprobes __get_insn_slot(struct kprobe_insn_cache c)
		kip->slot_used[0] = SLOT_USED;
		kip->nused = 1;
		kip->ngarbage = 0;
		kip->cache = c;
		list_add(&kip->list, &c->pages);
		slot = kip->insns;
		out:
		@@ -213,7 +227,7 @@ static int __kprobes collect_one_slot(struct kprobe_insn_page *kip, int idx)
		*/
		if (!list_is_singular(&kip->list)) {
		list_del(&kip->list);
		module_free(NULL, kip->insns);
		kip->cache->free(kip->insns);
		kfree(kip);
		}
		return 1;
		@@ -274,6 +288,8 @@ out:
		/* For optimized_kprobe buffer */
		struct kprobe_insn_cache kprobe_optinsn_slots = {
		.mutex = __MUTEX_INITIALIZER(kprobe_optinsn_slots.mutex),
		.alloc = alloc_insn_page,
		.free = free_insn_page,
		.pages = LIST_HEAD_INIT(kprobe_optinsn_slots.pages),
		/* .insn_size is initialized later */
		.nr_garbage = 0,

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