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* [PATCH] mm/kasan: Print frame description for stack bugs
@ 2019-05-17 13:10 Marco Elver
  2019-05-18 20:48 ` kbuild test robot
  2019-05-23  9:50 ` kbuild test robot
  0 siblings, 2 replies; 5+ messages in thread
From: Marco Elver @ 2019-05-17 13:10 UTC (permalink / raw)
  To: aryabinin, dvyukov, glider, andreyknvl, akpm
  Cc: linux-kernel, linux-mm, kasan-dev, Marco Elver

This adds support for printing stack frame description on invalid stack
accesses. The frame description is embedded by the compiler, which is
parsed and then pretty-printed.

Currently, we can only print the stack frame info for accesses to the
task's own stack, but not accesses to other tasks' stacks.

Example of what it looks like:

[   17.924050] page dumped because: kasan: bad access detected
[   17.924908]
[   17.925153] addr ffff8880673ef98a is located in stack of task insmod/2008 at offset 106 in frame:
[   17.926542]  kasan_stack_oob+0x0/0xf5 [test_kasan]
[   17.927932]
[   17.928206] this frame has 2 objects:
[   17.928783]  [32, 36) 'i'
[   17.928784]  [96, 106) 'stack_array'
[   17.929216]
[   17.930031] Memory state around the buggy address:

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=198435
Signed-off-by: Marco Elver <elver@google.com>
---
Change-Id: I4836cde103052991ac8871796a45b4c977c9e2e7
---
 mm/kasan/kasan.h  |   5 ++
 mm/kasan/report.c | 160 ++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 165 insertions(+)

diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h
index 3ce956efa0cb..1979db4763e2 100644
--- a/mm/kasan/kasan.h
+++ b/mm/kasan/kasan.h
@@ -43,6 +43,11 @@
 
 #define KASAN_ALLOCA_REDZONE_SIZE	32
 
+/*
+ * Stack frame marker (compiler ABI).
+ */
+#define KASAN_CURRENT_STACK_FRAME_MAGIC 0x41B58AB3
+
 /* Don't break randconfig/all*config builds */
 #ifndef KASAN_ABI_VERSION
 #define KASAN_ABI_VERSION 1
diff --git a/mm/kasan/report.c b/mm/kasan/report.c
index 03a443579386..c6ad8462c0dc 100644
--- a/mm/kasan/report.c
+++ b/mm/kasan/report.c
@@ -28,6 +28,7 @@
 #include <linux/types.h>
 #include <linux/kasan.h>
 #include <linux/module.h>
+#include <linux/sched/task_stack.h>
 
 #include <asm/sections.h>
 
@@ -181,6 +182,163 @@ static inline bool init_task_stack_addr(const void *addr)
 			sizeof(init_thread_union.stack));
 }
 
+static bool __must_check tokenize_frame_descr(const char **frame_descr,
+					      char *token, size_t max_tok_len,
+					      unsigned long *value)
+{
+	const char *sep = strchr(*frame_descr, ' ');
+	const ptrdiff_t tok_len = sep - *frame_descr;
+
+	if (sep == NULL)
+		sep = *frame_descr + strlen(*frame_descr);
+
+	if (token != NULL) {
+		if (tok_len + 1 > max_tok_len) {
+			pr_err("KASAN internal error: frame description too long: %s\n",
+			       *frame_descr);
+			return false;
+		}
+		/* Copy token (+ 1 byte for '\0'). */
+		strlcpy(token, *frame_descr, tok_len + 1);
+	}
+	/* Advance frame_descr past separator. */
+	*frame_descr = sep + 1;
+
+	if (value != NULL && kstrtoul(token, 10, value)) {
+		pr_err("KASAN internal error: not a valid number: %s\n", token);
+		return false;
+	}
+
+	return true;
+}
+
+static void print_decoded_frame_descr(const char *frame_descr)
+{
+	/*
+	 * We need to parse the following string:
+	 *    "n alloc_1 alloc_2 ... alloc_n"
+	 * where alloc_i looks like
+	 *    "offset size len name"
+	 * or "offset size len name:line".
+	 */
+
+	char token[64];
+	unsigned long num_objects;
+
+	if (!tokenize_frame_descr(&frame_descr, token, sizeof(token),
+				  &num_objects))
+		return;
+
+	pr_err("\n");
+	pr_err("this frame has %zu %s:\n", num_objects,
+	       num_objects == 1 ? "object" : "objects");
+
+	while (num_objects--) {
+		unsigned long offset;
+		unsigned long size;
+
+		/* access offset */
+		if (!tokenize_frame_descr(&frame_descr, token, sizeof(token),
+					  &offset))
+			return;
+		/* access size */
+		if (!tokenize_frame_descr(&frame_descr, token, sizeof(token),
+					  &size))
+			return;
+		/* name length (unused) */
+		if (!tokenize_frame_descr(&frame_descr, NULL, 0, NULL))
+			return;
+		/* object name */
+		if (!tokenize_frame_descr(&frame_descr, token, sizeof(token),
+					  NULL))
+			return;
+
+		/* Strip line number, if it exists. */
+		strreplace(token, ':', '\0');
+
+		/* Finally, print object information. */
+		pr_err(" [%zu, %zu) '%s'", offset, offset + size, token);
+	}
+}
+
+static bool __must_check get_address_stack_frame_info(const void *addr,
+						      size_t *offset,
+						      const char **frame_descr,
+						      const void **frame_pc)
+{
+	size_t aligned_addr;
+	size_t mem_ptr;
+	const u8 *shadow_bottom;
+	const u8 *shadow_ptr;
+	const size_t *frame;
+
+	/*
+	 * NOTE: We currently only support printing frame information for
+	 * accesses to the task's own stack.
+	 */
+	if (!object_is_on_stack(addr))
+		return false;
+
+	aligned_addr = round_down((size_t)addr, sizeof(long));
+	mem_ptr = round_down(aligned_addr, KASAN_SHADOW_SCALE_SIZE);
+	shadow_ptr = kasan_mem_to_shadow((void *)aligned_addr);
+	shadow_bottom = kasan_mem_to_shadow(end_of_stack(current));
+
+	while (shadow_ptr >= shadow_bottom && *shadow_ptr != KASAN_STACK_LEFT) {
+		shadow_ptr--;
+		mem_ptr -= KASAN_SHADOW_SCALE_SIZE;
+	}
+
+	while (shadow_ptr >= shadow_bottom && *shadow_ptr == KASAN_STACK_LEFT) {
+		shadow_ptr--;
+		mem_ptr -= KASAN_SHADOW_SCALE_SIZE;
+	}
+
+	if (shadow_ptr < shadow_bottom)
+		return false;
+
+	frame = (const size_t *)(mem_ptr + KASAN_SHADOW_SCALE_SIZE);
+	if (frame[0] != KASAN_CURRENT_STACK_FRAME_MAGIC) {
+		pr_err("KASAN internal error: frame info validation failed; invalid marker: %zu\n",
+		       frame[0]);
+		return false;
+	}
+
+	*offset = (size_t)addr - (size_t)frame;
+	*frame_descr = (const char *)frame[1];
+	*frame_pc = (void *)frame[2];
+
+	return true;
+}
+
+static void print_address_stack_frame(const void *addr)
+{
+	size_t offset;
+	const char *frame_descr;
+	const void *frame_pc;
+
+	if (IS_ENABLED(CONFIG_KASAN_SW_TAGS))
+		return;
+
+	if (!get_address_stack_frame_info(addr, &offset, &frame_descr,
+					  &frame_pc))
+		return;
+
+	/*
+	 * get_address_stack_frame_info only returns true if the given addr is
+	 * on the current task's stack.
+	 */
+	pr_err("\n");
+	pr_err("addr %px is located in stack of task %s/%d at offset %zu in frame:\n",
+	       addr, current->comm, task_pid_nr(current), offset);
+	pr_err(" %pS\n", frame_pc);
+
+	if (!frame_descr)
+		return;
+
+	print_decoded_frame_descr(frame_descr);
+}
+
 static void print_address_description(void *addr)
 {
 	struct page *page = addr_to_page(addr);
@@ -204,6 +362,8 @@ static void print_address_description(void *addr)
 		pr_err("The buggy address belongs to the page:\n");
 		dump_page(page, "kasan: bad access detected");
 	}
+
+	print_address_stack_frame(addr);
 }
 
 static bool row_is_guilty(const void *row, const void *guilty)
-- 
2.21.0.1020.gf2820cf01a-goog


^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: [PATCH] mm/kasan: Print frame description for stack bugs
  2019-05-17 13:10 [PATCH] mm/kasan: Print frame description for stack bugs Marco Elver
@ 2019-05-18 20:48 ` kbuild test robot
  2019-05-22  2:10   ` Andrew Morton
  2019-05-23  9:50 ` kbuild test robot
  1 sibling, 1 reply; 5+ messages in thread
From: kbuild test robot @ 2019-05-18 20:48 UTC (permalink / raw)
  To: Marco Elver
  Cc: kbuild-all, aryabinin, dvyukov, glider, andreyknvl, akpm,
	linux-kernel, linux-mm, kasan-dev, Marco Elver

[-- Attachment #1: Type: text/plain, Size: 8371 bytes --]

Hi Marco,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on linus/master]
[also build test WARNING on v5.1 next-20190517]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Marco-Elver/mm-kasan-Print-frame-description-for-stack-bugs/20190519-040214
config: xtensa-allyesconfig (attached as .config)
compiler: xtensa-linux-gcc (GCC) 8.1.0
reproduce:
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # save the attached .config to linux build tree
        GCC_VERSION=8.1.0 make.cross ARCH=xtensa 

If you fix the issue, kindly add following tag
Reported-by: kbuild test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

   In file included from include/linux/printk.h:7,
                    from include/linux/kernel.h:15,
                    from include/linux/kallsyms.h:10,
                    from include/linux/ftrace.h:11,
                    from mm/kasan/report.c:18:
   mm/kasan/report.c: In function 'print_decoded_frame_descr':
>> include/linux/kern_levels.h:5:18: warning: format '%zu' expects argument of type 'size_t', but argument 2 has type 'long unsigned int' [-Wformat=]
    #define KERN_SOH "\001"  /* ASCII Start Of Header */
                     ^~~~~~
   include/linux/kern_levels.h:11:18: note: in expansion of macro 'KERN_SOH'
    #define KERN_ERR KERN_SOH "3" /* error conditions */
                     ^~~~~~~~
   include/linux/printk.h:304:9: note: in expansion of macro 'KERN_ERR'
     printk(KERN_ERR pr_fmt(fmt), ##__VA_ARGS__)
            ^~~~~~~~
   mm/kasan/report.c:233:2: note: in expansion of macro 'pr_err'
     pr_err("this frame has %zu %s:\n", num_objects,
     ^~~~~~
   mm/kasan/report.c:233:27: note: format string is defined here
     pr_err("this frame has %zu %s:\n", num_objects,
                            ~~^
                            %lu
   In file included from include/linux/printk.h:7,
                    from include/linux/kernel.h:15,
                    from include/linux/kallsyms.h:10,
                    from include/linux/ftrace.h:11,
                    from mm/kasan/report.c:18:
>> include/linux/kern_levels.h:5:18: warning: format '%zu' expects argument of type 'size_t', but argument 2 has type 'long unsigned int' [-Wformat=]
    #define KERN_SOH "\001"  /* ASCII Start Of Header */
                     ^~~~~~
   include/linux/kern_levels.h:11:18: note: in expansion of macro 'KERN_SOH'
    #define KERN_ERR KERN_SOH "3" /* error conditions */
                     ^~~~~~~~
   include/linux/printk.h:304:9: note: in expansion of macro 'KERN_ERR'
     printk(KERN_ERR pr_fmt(fmt), ##__VA_ARGS__)
            ^~~~~~~~
   mm/kasan/report.c:260:3: note: in expansion of macro 'pr_err'
      pr_err(" [%zu, %zu) '%s'", offset, offset + size, token);
      ^~~~~~
   mm/kasan/report.c:260:15: note: format string is defined here
      pr_err(" [%zu, %zu) '%s'", offset, offset + size, token);
                ~~^
                %lu
   In file included from include/linux/printk.h:7,
                    from include/linux/kernel.h:15,
                    from include/linux/kallsyms.h:10,
                    from include/linux/ftrace.h:11,
                    from mm/kasan/report.c:18:
   include/linux/kern_levels.h:5:18: warning: format '%zu' expects argument of type 'size_t', but argument 3 has type 'long unsigned int' [-Wformat=]
    #define KERN_SOH "\001"  /* ASCII Start Of Header */
                     ^~~~~~
   include/linux/kern_levels.h:11:18: note: in expansion of macro 'KERN_SOH'
    #define KERN_ERR KERN_SOH "3" /* error conditions */
                     ^~~~~~~~
   include/linux/printk.h:304:9: note: in expansion of macro 'KERN_ERR'
     printk(KERN_ERR pr_fmt(fmt), ##__VA_ARGS__)
            ^~~~~~~~
   mm/kasan/report.c:260:3: note: in expansion of macro 'pr_err'
      pr_err(" [%zu, %zu) '%s'", offset, offset + size, token);
      ^~~~~~
   mm/kasan/report.c:260:20: note: format string is defined here
      pr_err(" [%zu, %zu) '%s'", offset, offset + size, token);
                     ~~^
                     %lu
--
   In file included from include/linux/printk.h:7,
                    from include/linux/kernel.h:15,
                    from include/linux/kallsyms.h:10,
                    from include/linux/ftrace.h:11,
                    from mm//kasan/report.c:18:
   mm//kasan/report.c: In function 'print_decoded_frame_descr':
>> include/linux/kern_levels.h:5:18: warning: format '%zu' expects argument of type 'size_t', but argument 2 has type 'long unsigned int' [-Wformat=]
    #define KERN_SOH "\001"  /* ASCII Start Of Header */
                     ^~~~~~
   include/linux/kern_levels.h:11:18: note: in expansion of macro 'KERN_SOH'
    #define KERN_ERR KERN_SOH "3" /* error conditions */
                     ^~~~~~~~
   include/linux/printk.h:304:9: note: in expansion of macro 'KERN_ERR'
     printk(KERN_ERR pr_fmt(fmt), ##__VA_ARGS__)
            ^~~~~~~~
   mm//kasan/report.c:233:2: note: in expansion of macro 'pr_err'
     pr_err("this frame has %zu %s:\n", num_objects,
     ^~~~~~
   mm//kasan/report.c:233:27: note: format string is defined here
     pr_err("this frame has %zu %s:\n", num_objects,
                            ~~^
                            %lu
   In file included from include/linux/printk.h:7,
                    from include/linux/kernel.h:15,
                    from include/linux/kallsyms.h:10,
                    from include/linux/ftrace.h:11,
                    from mm//kasan/report.c:18:
>> include/linux/kern_levels.h:5:18: warning: format '%zu' expects argument of type 'size_t', but argument 2 has type 'long unsigned int' [-Wformat=]
    #define KERN_SOH "\001"  /* ASCII Start Of Header */
                     ^~~~~~
   include/linux/kern_levels.h:11:18: note: in expansion of macro 'KERN_SOH'
    #define KERN_ERR KERN_SOH "3" /* error conditions */
                     ^~~~~~~~
   include/linux/printk.h:304:9: note: in expansion of macro 'KERN_ERR'
     printk(KERN_ERR pr_fmt(fmt), ##__VA_ARGS__)
            ^~~~~~~~
   mm//kasan/report.c:260:3: note: in expansion of macro 'pr_err'
      pr_err(" [%zu, %zu) '%s'", offset, offset + size, token);
      ^~~~~~
   mm//kasan/report.c:260:15: note: format string is defined here
      pr_err(" [%zu, %zu) '%s'", offset, offset + size, token);
                ~~^
                %lu
   In file included from include/linux/printk.h:7,
                    from include/linux/kernel.h:15,
                    from include/linux/kallsyms.h:10,
                    from include/linux/ftrace.h:11,
                    from mm//kasan/report.c:18:
   include/linux/kern_levels.h:5:18: warning: format '%zu' expects argument of type 'size_t', but argument 3 has type 'long unsigned int' [-Wformat=]
    #define KERN_SOH "\001"  /* ASCII Start Of Header */
                     ^~~~~~
   include/linux/kern_levels.h:11:18: note: in expansion of macro 'KERN_SOH'
    #define KERN_ERR KERN_SOH "3" /* error conditions */
                     ^~~~~~~~
   include/linux/printk.h:304:9: note: in expansion of macro 'KERN_ERR'
     printk(KERN_ERR pr_fmt(fmt), ##__VA_ARGS__)
            ^~~~~~~~
   mm//kasan/report.c:260:3: note: in expansion of macro 'pr_err'
      pr_err(" [%zu, %zu) '%s'", offset, offset + size, token);
      ^~~~~~
   mm//kasan/report.c:260:20: note: format string is defined here
      pr_err(" [%zu, %zu) '%s'", offset, offset + size, token);
                     ~~^
                     %lu

vim +5 include/linux/kern_levels.h

314ba352 Joe Perches 2012-07-30  4  
04d2c8c8 Joe Perches 2012-07-30 @5  #define KERN_SOH	"\001"		/* ASCII Start Of Header */
04d2c8c8 Joe Perches 2012-07-30  6  #define KERN_SOH_ASCII	'\001'
04d2c8c8 Joe Perches 2012-07-30  7  

:::::: The code at line 5 was first introduced by commit
:::::: 04d2c8c83d0e3ac5f78aeede51babb3236200112 printk: convert the format for KERN_<LEVEL> to a 2 byte pattern

:::::: TO: Joe Perches <joe@perches.com>
:::::: CC: Linus Torvalds <torvalds@linux-foundation.org>

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

[-- Attachment #2: .config.gz --]
[-- Type: application/gzip, Size: 57531 bytes --]

^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: [PATCH] mm/kasan: Print frame description for stack bugs
  2019-05-18 20:48 ` kbuild test robot
@ 2019-05-22  2:10   ` Andrew Morton
  2019-05-22 10:02     ` Marco Elver
  0 siblings, 1 reply; 5+ messages in thread
From: Andrew Morton @ 2019-05-22  2:10 UTC (permalink / raw)
  To: kbuild test robot
  Cc: Marco Elver, kbuild-all, aryabinin, dvyukov, glider, andreyknvl,
	linux-kernel, linux-mm, kasan-dev

On Sun, 19 May 2019 04:48:21 +0800 kbuild test robot <lkp@intel.com> wrote:

> Hi Marco,
> 
> Thank you for the patch! Perhaps something to improve:
> 
> [auto build test WARNING on linus/master]
> [also build test WARNING on v5.1 next-20190517]
> [if your patch is applied to the wrong git tree, please drop us a note to help improve the system]
> 
> url:    https://github.com/0day-ci/linux/commits/Marco-Elver/mm-kasan-Print-frame-description-for-stack-bugs/20190519-040214
> config: xtensa-allyesconfig (attached as .config)
> compiler: xtensa-linux-gcc (GCC) 8.1.0
> reproduce:
>         wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
>         chmod +x ~/bin/make.cross
>         # save the attached .config to linux build tree
>         GCC_VERSION=8.1.0 make.cross ARCH=xtensa 
> 
> If you fix the issue, kindly add following tag
> Reported-by: kbuild test robot <lkp@intel.com>
> 

This, I assume?

--- a/mm/kasan/report.c~mm-kasan-print-frame-description-for-stack-bugs-fix
+++ a/mm/kasan/report.c
@@ -230,7 +230,7 @@ static void print_decoded_frame_descr(co
 		return;
 
 	pr_err("\n");
-	pr_err("this frame has %zu %s:\n", num_objects,
+	pr_err("this frame has %lu %s:\n", num_objects,
 	       num_objects == 1 ? "object" : "objects");
 
 	while (num_objects--) {
@@ -257,7 +257,7 @@ static void print_decoded_frame_descr(co
 		strreplace(token, ':', '\0');
 
 		/* Finally, print object information. */
-		pr_err(" [%zu, %zu) '%s'", offset, offset + size, token);
+		pr_err(" [%lu, %lu) '%s'", offset, offset + size, token);
 	}
 }
 
_


^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: [PATCH] mm/kasan: Print frame description for stack bugs
  2019-05-22  2:10   ` Andrew Morton
@ 2019-05-22 10:02     ` Marco Elver
  0 siblings, 0 replies; 5+ messages in thread
From: Marco Elver @ 2019-05-22 10:02 UTC (permalink / raw)
  To: Andrew Morton
  Cc: kbuild test robot, kbuild-all, Andrey Ryabinin, Dmitry Vyukov,
	Alexander Potapenko, Andrey Konovalov, LKML,
	Linux Memory Management List, kasan-dev

I've sent v3. If possible, please replace current version with v3,
which also includes the fix.

Many thanks,
-- Marco


On Wed, 22 May 2019 at 04:10, Andrew Morton <akpm@linux-foundation.org> wrote:
>
> On Sun, 19 May 2019 04:48:21 +0800 kbuild test robot <lkp@intel.com> wrote:
>
> > Hi Marco,
> >
> > Thank you for the patch! Perhaps something to improve:
> >
> > [auto build test WARNING on linus/master]
> > [also build test WARNING on v5.1 next-20190517]
> > [if your patch is applied to the wrong git tree, please drop us a note to help improve the system]
> >
> > url:    https://github.com/0day-ci/linux/commits/Marco-Elver/mm-kasan-Print-frame-description-for-stack-bugs/20190519-040214
> > config: xtensa-allyesconfig (attached as .config)
> > compiler: xtensa-linux-gcc (GCC) 8.1.0
> > reproduce:
> >         wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
> >         chmod +x ~/bin/make.cross
> >         # save the attached .config to linux build tree
> >         GCC_VERSION=8.1.0 make.cross ARCH=xtensa
> >
> > If you fix the issue, kindly add following tag
> > Reported-by: kbuild test robot <lkp@intel.com>
> >
>
> This, I assume?
>
> --- a/mm/kasan/report.c~mm-kasan-print-frame-description-for-stack-bugs-fix
> +++ a/mm/kasan/report.c
> @@ -230,7 +230,7 @@ static void print_decoded_frame_descr(co
>                 return;
>
>         pr_err("\n");
> -       pr_err("this frame has %zu %s:\n", num_objects,
> +       pr_err("this frame has %lu %s:\n", num_objects,
>                num_objects == 1 ? "object" : "objects");
>
>         while (num_objects--) {
> @@ -257,7 +257,7 @@ static void print_decoded_frame_descr(co
>                 strreplace(token, ':', '\0');
>
>                 /* Finally, print object information. */
> -               pr_err(" [%zu, %zu) '%s'", offset, offset + size, token);
> +               pr_err(" [%lu, %lu) '%s'", offset, offset + size, token);
>         }
>  }
>
> _
>
> --
> You received this message because you are subscribed to the Google Groups "kasan-dev" group.
> To unsubscribe from this group and stop receiving emails from it, send an email to kasan-dev+unsubscribe@googlegroups.com.
> To post to this group, send email to kasan-dev@googlegroups.com.
> To view this discussion on the web visit https://groups.google.com/d/msgid/kasan-dev/20190521191050.b8ddb9bb660d13330896529e%40linux-foundation.org.
> For more options, visit https://groups.google.com/d/optout.

^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: [PATCH] mm/kasan: Print frame description for stack bugs
  2019-05-17 13:10 [PATCH] mm/kasan: Print frame description for stack bugs Marco Elver
  2019-05-18 20:48 ` kbuild test robot
@ 2019-05-23  9:50 ` kbuild test robot
  1 sibling, 0 replies; 5+ messages in thread
From: kbuild test robot @ 2019-05-23  9:50 UTC (permalink / raw)
  To: Marco Elver
  Cc: kbuild-all, aryabinin, dvyukov, glider, andreyknvl, akpm,
	linux-kernel, linux-mm, kasan-dev, Marco Elver

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Hi Marco,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on linus/master]
[also build test WARNING on v5.2-rc1 next-20190522]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Marco-Elver/mm-kasan-Print-frame-description-for-stack-bugs/20190519-040214
config: xtensa-allmodconfig (attached as .config)
compiler: xtensa-linux-gcc (GCC) 7.4.0
reproduce:
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # save the attached .config to linux build tree
        GCC_VERSION=7.4.0 make.cross ARCH=xtensa 

If you fix the issue, kindly add following tag
Reported-by: kbuild test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

   In file included from include/linux/printk.h:7:0,
                    from include/linux/kernel.h:15,
                    from include/linux/kallsyms.h:10,
                    from include/linux/ftrace.h:11,
                    from mm/kasan/report.c:18:
   mm/kasan/report.c: In function 'print_decoded_frame_descr':
   include/linux/kern_levels.h:5:18: warning: format '%zu' expects argument of type 'size_t', but argument 2 has type 'long unsigned int' [-Wformat=]
    #define KERN_SOH "\001"  /* ASCII Start Of Header */
                     ^
   include/linux/kern_levels.h:11:18: note: in expansion of macro 'KERN_SOH'
    #define KERN_ERR KERN_SOH "3" /* error conditions */
                     ^~~~~~~~
   include/linux/printk.h:304:9: note: in expansion of macro 'KERN_ERR'
     printk(KERN_ERR pr_fmt(fmt), ##__VA_ARGS__)
            ^~~~~~~~
>> mm/kasan/report.c:233:2: note: in expansion of macro 'pr_err'
     pr_err("this frame has %zu %s:\n", num_objects,
     ^~~~~~
   mm/kasan/report.c:233:27: note: format string is defined here
     pr_err("this frame has %zu %s:\n", num_objects,
                            ~~^
                            %lu
   In file included from include/linux/printk.h:7:0,
                    from include/linux/kernel.h:15,
                    from include/linux/kallsyms.h:10,
                    from include/linux/ftrace.h:11,
                    from mm/kasan/report.c:18:
   include/linux/kern_levels.h:5:18: warning: format '%zu' expects argument of type 'size_t', but argument 2 has type 'long unsigned int' [-Wformat=]
    #define KERN_SOH "\001"  /* ASCII Start Of Header */
                     ^
   include/linux/kern_levels.h:11:18: note: in expansion of macro 'KERN_SOH'
    #define KERN_ERR KERN_SOH "3" /* error conditions */
                     ^~~~~~~~
   include/linux/printk.h:304:9: note: in expansion of macro 'KERN_ERR'
     printk(KERN_ERR pr_fmt(fmt), ##__VA_ARGS__)
            ^~~~~~~~
   mm/kasan/report.c:260:3: note: in expansion of macro 'pr_err'
      pr_err(" [%zu, %zu) '%s'", offset, offset + size, token);
      ^~~~~~
   mm/kasan/report.c:260:15: note: format string is defined here
      pr_err(" [%zu, %zu) '%s'", offset, offset + size, token);
                ~~^
                %lu
   In file included from include/linux/printk.h:7:0,
                    from include/linux/kernel.h:15,
                    from include/linux/kallsyms.h:10,
                    from include/linux/ftrace.h:11,
                    from mm/kasan/report.c:18:
   include/linux/kern_levels.h:5:18: warning: format '%zu' expects argument of type 'size_t', but argument 3 has type 'long unsigned int' [-Wformat=]
    #define KERN_SOH "\001"  /* ASCII Start Of Header */
                     ^
   include/linux/kern_levels.h:11:18: note: in expansion of macro 'KERN_SOH'
    #define KERN_ERR KERN_SOH "3" /* error conditions */
                     ^~~~~~~~
   include/linux/printk.h:304:9: note: in expansion of macro 'KERN_ERR'
     printk(KERN_ERR pr_fmt(fmt), ##__VA_ARGS__)
            ^~~~~~~~
   mm/kasan/report.c:260:3: note: in expansion of macro 'pr_err'
      pr_err(" [%zu, %zu) '%s'", offset, offset + size, token);
      ^~~~~~
   mm/kasan/report.c:260:20: note: format string is defined here
      pr_err(" [%zu, %zu) '%s'", offset, offset + size, token);
                     ~~^
                     %lu

vim +/pr_err +233 mm/kasan/report.c

   214	
   215	static void print_decoded_frame_descr(const char *frame_descr)
   216	{
   217		/*
   218		 * We need to parse the following string:
   219		 *    "n alloc_1 alloc_2 ... alloc_n"
   220		 * where alloc_i looks like
   221		 *    "offset size len name"
   222		 * or "offset size len name:line".
   223		 */
   224	
   225		char token[64];
   226		unsigned long num_objects;
   227	
   228		if (!tokenize_frame_descr(&frame_descr, token, sizeof(token),
   229					  &num_objects))
   230			return;
   231	
   232		pr_err("\n");
 > 233		pr_err("this frame has %zu %s:\n", num_objects,
   234		       num_objects == 1 ? "object" : "objects");
   235	
   236		while (num_objects--) {
   237			unsigned long offset;
   238			unsigned long size;
   239	
   240			/* access offset */
   241			if (!tokenize_frame_descr(&frame_descr, token, sizeof(token),
   242						  &offset))
   243				return;
   244			/* access size */
   245			if (!tokenize_frame_descr(&frame_descr, token, sizeof(token),
   246						  &size))
   247				return;
   248			/* name length (unused) */
   249			if (!tokenize_frame_descr(&frame_descr, NULL, 0, NULL))
   250				return;
   251			/* object name */
   252			if (!tokenize_frame_descr(&frame_descr, token, sizeof(token),
   253						  NULL))
   254				return;
   255	
   256			/* Strip line number, if it exists. */
   257			strreplace(token, ':', '\0');
   258	
   259			/* Finally, print object information. */
   260			pr_err(" [%zu, %zu) '%s'", offset, offset + size, token);
   261		}
   262	}
   263	

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

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^ permalink raw reply	[flat|nested] 5+ messages in thread

end of thread, other threads:[~2019-05-23  9:51 UTC | newest]

Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-05-17 13:10 [PATCH] mm/kasan: Print frame description for stack bugs Marco Elver
2019-05-18 20:48 ` kbuild test robot
2019-05-22  2:10   ` Andrew Morton
2019-05-22 10:02     ` Marco Elver
2019-05-23  9:50 ` kbuild test robot

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