Commit 2d1bcbc6 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'probes-fixes-v6.4-rc1' of... 

Merge tag 'probes-fixes-v6.4-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull probes fixes from Masami Hiramatsu:

 - Initialize 'ret' local variables on fprobe_handler() to fix the
   smatch warning. With this, fprobe function exit handler is not
   working randomly.

 - Fix to use preempt_enable/disable_notrace for rethook handler to
   prevent recursive call of fprobe exit handler (which is based on
   rethook)

 - Fix recursive call issue on fprobe_kprobe_handler()

 - Fix to detect recursive call on fprobe_exit_handler()

 - Fix to make all arch-dependent rethook code notrace (the
   arch-independent code is already notrace)"

* tag 'probes-fixes-v6.4-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  rethook, fprobe: do not trace rethook related functions
  fprobe: add recursion detection in fprobe_exit_handler
  fprobe: make fprobe_kprobe_handler recursion free
  rethook: use preempt_{disable, enable}_notrace in rethook_trampoline_handler
  tracing: fprobe: Initialize ret valiable to fix smatch error
parents 1f594fe7 571a2a50

arch/riscv/kernel/probes/Makefile

+2 −0
Original line number Diff line number Diff line
@@ -4,3 +4,5 @@ obj-$(CONFIG_RETHOOK) += rethook.o rethook_trampoline.o 
obj-$(CONFIG_KPROBES_ON_FTRACE)	+= ftrace.o

obj-$(CONFIG_UPROBES)		+= uprobes.o decode-insn.o simulate-insn.o

CFLAGS_REMOVE_simulate-insn.o = $(CC_FLAGS_FTRACE)

CFLAGS_REMOVE_rethook.o = $(CC_FLAGS_FTRACE)

CFLAGS_REMOVE_rethook_trampoline.o = $(CC_FLAGS_FTRACE)

arch/s390/kernel/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -10,6 +10,7 @@ CFLAGS_REMOVE_ftrace.o = $(CC_FLAGS_FTRACE) 


# Do not trace early setup code

CFLAGS_REMOVE_early.o		= $(CC_FLAGS_FTRACE)

CFLAGS_REMOVE_rethook.o		= $(CC_FLAGS_FTRACE)



endif

arch/x86/kernel/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -17,6 +17,7 @@ CFLAGS_REMOVE_ftrace.o = -pg 
CFLAGS_REMOVE_early_printk.o = -pg

CFLAGS_REMOVE_head64.o = -pg

CFLAGS_REMOVE_sev.o = -pg

CFLAGS_REMOVE_rethook.o = -pg

endif



KASAN_SANITIZE_head$(BITS).o				:= n

kernel/trace/fprobe.c

+58 −15
Original line number Diff line number Diff line
@@ -17,36 +17,30 @@ 
struct fprobe_rethook_node {

	struct rethook_node node;

	unsigned long entry_ip;

	unsigned long entry_parent_ip;

	char data[];

};



static void fprobe_handler(unsigned long ip, unsigned long parent_ip,

static inline void __fprobe_handler(unsigned long ip, unsigned long parent_ip,

			struct ftrace_ops *ops, struct ftrace_regs *fregs)

{

	struct fprobe_rethook_node *fpr;

	struct rethook_node *rh = NULL;

	struct fprobe *fp;

	void *entry_data = NULL;

	int bit, ret;

	int ret = 0;



	fp = container_of(ops, struct fprobe, ops);

	if (fprobe_disabled(fp))

		return;



	bit = ftrace_test_recursion_trylock(ip, parent_ip);

	if (bit < 0) {

		fp->nmissed++;

		return;

	}



	if (fp->exit_handler) {

		rh = rethook_try_get(fp->rethook);

		if (!rh) {

			fp->nmissed++;

			goto out;

			return;

		}

		fpr = container_of(rh, struct fprobe_rethook_node, node);

		fpr->entry_ip = ip;

		fpr->entry_parent_ip = parent_ip;

		if (fp->entry_data_size)

			entry_data = fpr->data;

	}
@@ -61,23 +55,60 @@ static void fprobe_handler(unsigned long ip, unsigned long parent_ip, 
		else

			rethook_hook(rh, ftrace_get_regs(fregs), true);

	}

out:

}



static void fprobe_handler(unsigned long ip, unsigned long parent_ip,

		struct ftrace_ops *ops, struct ftrace_regs *fregs)

{

	struct fprobe *fp;

	int bit;



	fp = container_of(ops, struct fprobe, ops);

	if (fprobe_disabled(fp))

		return;



	/* recursion detection has to go before any traceable function and

	 * all functions before this point should be marked as notrace

	 */

	bit = ftrace_test_recursion_trylock(ip, parent_ip);

	if (bit < 0) {

		fp->nmissed++;

		return;

	}

	__fprobe_handler(ip, parent_ip, ops, fregs);

	ftrace_test_recursion_unlock(bit);



}

NOKPROBE_SYMBOL(fprobe_handler);



static void fprobe_kprobe_handler(unsigned long ip, unsigned long parent_ip,

				  struct ftrace_ops *ops, struct ftrace_regs *fregs)

{

	struct fprobe *fp = container_of(ops, struct fprobe, ops);

	struct fprobe *fp;

	int bit;



	fp = container_of(ops, struct fprobe, ops);

	if (fprobe_disabled(fp))

		return;



	/* recursion detection has to go before any traceable function and

	 * all functions called before this point should be marked as notrace

	 */

	bit = ftrace_test_recursion_trylock(ip, parent_ip);

	if (bit < 0) {

		fp->nmissed++;

		return;

	}



	if (unlikely(kprobe_running())) {

		fp->nmissed++;

		return;

	}



	kprobe_busy_begin();

	fprobe_handler(ip, parent_ip, ops, fregs);

	__fprobe_handler(ip, parent_ip, ops, fregs);

	kprobe_busy_end();

	ftrace_test_recursion_unlock(bit);

}



static void fprobe_exit_handler(struct rethook_node *rh, void *data,
@@ -85,14 +116,26 @@ static void fprobe_exit_handler(struct rethook_node *rh, void *data, 
{

	struct fprobe *fp = (struct fprobe *)data;

	struct fprobe_rethook_node *fpr;

	int bit;



	if (!fp || fprobe_disabled(fp))

		return;



	fpr = container_of(rh, struct fprobe_rethook_node, node);



	/*

	 * we need to assure no calls to traceable functions in-between the

	 * end of fprobe_handler and the beginning of fprobe_exit_handler.

	 */

	bit = ftrace_test_recursion_trylock(fpr->entry_ip, fpr->entry_parent_ip);

	if (bit < 0) {

		fp->nmissed++;

		return;

	}



	fp->exit_handler(fp, fpr->entry_ip, regs,

			 fp->entry_data_size ? (void *)fpr->data : NULL);

	ftrace_test_recursion_unlock(bit);

}

NOKPROBE_SYMBOL(fprobe_exit_handler);

kernel/trace/rethook.c

+2 −2
Original line number Diff line number Diff line
@@ -288,7 +288,7 @@ unsigned long rethook_trampoline_handler(struct pt_regs *regs, 
	 * These loops must be protected from rethook_free_rcu() because those

	 * are accessing 'rhn->rethook'.

	 */

	preempt_disable();

	preempt_disable_notrace();



	/*

	 * Run the handler on the shadow stack. Do not unlink the list here because
@@ -321,7 +321,7 @@ unsigned long rethook_trampoline_handler(struct pt_regs *regs, 
		first = first->next;

		rethook_recycle(rhn);

	}

	preempt_enable();

	preempt_enable_notrace();



	return correct_ret_addr;

}