Commit 4b4eef57 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'probes-fixes-v6.5-rc1-2' of... 

Merge tag 'probes-fixes-v6.5-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull probe fixes from Masami Hiramatsu:

 - fprobe: Add a comment why fprobe will be skipped if another kprobe is
   running in fprobe_kprobe_handler().

 - probe-events: Fix some issues related to fetch-arguments:

    - Fix double counting of the string length for user-string and
      symstr. This will require longer buffer in the array case.

    - Fix not to count error code (minus value) for the total used
      length in array argument. This makes the total used length
      shorter.

    - Fix to update dynamic used data size counter only if fetcharg uses
      the dynamic size data. This may mis-count the used dynamic data
      size and corrupt data.

    - Revert "tracing: Add "(fault)" name injection to kernel probes"
      because that did not work correctly with a bug, and we agreed the
      current '(fault)' output (instead of '"(fault)"' like a string)
      explains what happened more clearly.

    - Fix to record 0-length (means fault access) data_loc data in fetch
      function itself, instead of store_trace_args(). If we record an
      array of string, this will fix to save fault access data on each
      entry of the array correctly.

* tag 'probes-fixes-v6.5-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  tracing/probes: Fix to record 0-length data_loc in fetch_store_string*() if fails
  Revert "tracing: Add "(fault)" name injection to kernel probes"
  tracing/probes: Fix to update dynamic data counter if fetcharg uses it
  tracing/probes: Fix not to count error code to total length
  tracing/probes: Fix to avoid double count of the string length on the array
  fprobes: Add a comment why fprobe_kprobe_handler exits if kprobe is running
parents 831fe284 797311bc

kernel/trace/fprobe.c

+6 −0
Original line number Diff line number Diff line
@@ -100,6 +100,12 @@ static void fprobe_kprobe_handler(unsigned long ip, unsigned long parent_ip, 
		return;

	}



	/*

	 * This user handler is shared with other kprobes and is not expected to be

	 * called recursively. So if any other kprobe handler is running, this will

	 * exit as kprobe does. See the section 'Share the callbacks with kprobes'

	 * in Documentation/trace/fprobe.rst for more information.

	 */

	if (unlikely(kprobe_running())) {

		fp->nmissed++;

		goto recursion_unlock;

kernel/trace/trace.h

+2 −0
Original line number Diff line number Diff line
@@ -113,6 +113,8 @@ enum trace_type { 
#define MEM_FAIL(condition, fmt, ...)					\

	DO_ONCE_LITE_IF(condition, pr_err, "ERROR: " fmt, ##__VA_ARGS__)



#define FAULT_STRING "(fault)"



#define HIST_STACKTRACE_DEPTH	16

#define HIST_STACKTRACE_SIZE	(HIST_STACKTRACE_DEPTH * sizeof(unsigned long))

#define HIST_STACKTRACE_SKIP	5

kernel/trace/trace_probe.c

+1 −1
Original line number Diff line number Diff line
@@ -67,7 +67,7 @@ int PRINT_TYPE_FUNC_NAME(string)(struct trace_seq *s, void *data, void *ent) 
	int len = *(u32 *)data >> 16;



	if (!len)

		trace_seq_puts(s, "(fault)");

		trace_seq_puts(s, FAULT_STRING);

	else

		trace_seq_printf(s, "\"%s\"",

				 (const char *)get_loc_data(data, ent));

kernel/trace/trace_probe_kernel.h

+8 −22
Original line number Diff line number Diff line
@@ -2,8 +2,6 @@ 
#ifndef __TRACE_PROBE_KERNEL_H_

#define __TRACE_PROBE_KERNEL_H_



#define FAULT_STRING "(fault)"



/*

 * This depends on trace_probe.h, but can not include it due to

 * the way trace_probe_tmpl.h is used by trace_kprobe.c and trace_eprobe.c.
@@ -15,16 +13,8 @@ static nokprobe_inline int 
fetch_store_strlen_user(unsigned long addr)

{

	const void __user *uaddr =  (__force const void __user *)addr;

	int ret;



	ret = strnlen_user_nofault(uaddr, MAX_STRING_SIZE);

	/*

	 * strnlen_user_nofault returns zero on fault, insert the

	 * FAULT_STRING when that occurs.

	 */

	if (ret <= 0)

		return strlen(FAULT_STRING) + 1;

	return ret;

	return strnlen_user_nofault(uaddr, MAX_STRING_SIZE);

}



/* Return the length of string -- including null terminal byte */
@@ -44,18 +34,14 @@ fetch_store_strlen(unsigned long addr) 
		len++;

	} while (c && ret == 0 && len < MAX_STRING_SIZE);



	/* For faults, return enough to hold the FAULT_STRING */

	return (ret < 0) ? strlen(FAULT_STRING) + 1 : len;

	return (ret < 0) ? ret : len;

}



static nokprobe_inline void set_data_loc(int ret, void *dest, void *__dest, void *base, int len)

static nokprobe_inline void set_data_loc(int ret, void *dest, void *__dest, void *base)

{

	if (ret >= 0) {

	if (ret < 0)

		ret = 0;

	*(u32 *)dest = make_data_loc(ret, __dest - base);

	} else {

		strscpy(__dest, FAULT_STRING, len);

		ret = strlen(__dest) + 1;

	}

}



/*
@@ -76,7 +62,7 @@ fetch_store_string_user(unsigned long addr, void *dest, void *base) 
	__dest = get_loc_data(dest, base);



	ret = strncpy_from_user_nofault(__dest, uaddr, maxlen);

	set_data_loc(ret, dest, __dest, base, maxlen);

	set_data_loc(ret, dest, __dest, base);



	return ret;

}
@@ -107,7 +93,7 @@ fetch_store_string(unsigned long addr, void *dest, void *base) 
	 * probing.

	 */

	ret = strncpy_from_kernel_nofault(__dest, (void *)addr, maxlen);

	set_data_loc(ret, dest, __dest, base, maxlen);

	set_data_loc(ret, dest, __dest, base);



	return ret;

}

kernel/trace/trace_probe_tmpl.h

+5 −5
Original line number Diff line number Diff line
@@ -156,11 +156,11 @@ process_fetch_insn_bottom(struct fetch_insn *code, unsigned long val, 
			code++;

			goto array;

		case FETCH_OP_ST_USTRING:

			ret += fetch_store_strlen_user(val + code->offset);

			ret = fetch_store_strlen_user(val + code->offset);

			code++;

			goto array;

		case FETCH_OP_ST_SYMSTR:

			ret += fetch_store_symstrlen(val + code->offset);

			ret = fetch_store_symstrlen(val + code->offset);

			code++;

			goto array;

		default:
@@ -204,6 +204,8 @@ process_fetch_insn_bottom(struct fetch_insn *code, unsigned long val, 
array:

	/* the last stage: Loop on array */

	if (code->op == FETCH_OP_LP_ARRAY) {

		if (ret < 0)

			ret = 0;

		total += ret;

		if (++i < code->param) {

			code = s3;
@@ -265,9 +267,7 @@ store_trace_args(void *data, struct trace_probe *tp, void *rec, 
		if (unlikely(arg->dynamic))

			*dl = make_data_loc(maxlen, dyndata - base);

		ret = process_fetch_insn(arg->code, rec, dl, base);

		if (unlikely(ret < 0 && arg->dynamic)) {

			*dl = make_data_loc(0, dyndata - base);

		} else {

		if (arg->dynamic && likely(ret > 0)) {

			dyndata += ret;

			maxlen -= ret;

		}