[PATCH] perf tools: Fix arm64 build error with gcc-11

Subsystems: performance events subsystem, the rest

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5 messages, 3 authors, 2021-02-10 · open the first message on its own page

[PATCH] perf tools: Fix arm64 build error with gcc-11

From: Jianlin Lv <hidden>
Date: 2021-02-09 11:42:42 

gcc version: 11.0.0 20210208 (experimental) (GCC)

Following build error on arm64:

.......
In function ‘printf’,
    inlined from ‘regs_dump__printf’ at util/session.c:1141:3,
    inlined from ‘regs__printf’ at util/session.c:1169:2:
/usr/include/aarch64-linux-gnu/bits/stdio2.h:107:10: \
  error: ‘%-5s’ directive argument is null [-Werror=format-overflow=]

107 |   return __printf_chk (__USE_FORTIFY_LEVEL - 1, __fmt, \
                __va_arg_pack ());

......
In function ‘fprintf’,
  inlined from ‘perf_sample__fprintf_regs.isra’ at \
    builtin-script.c:622:14:
/usr/include/aarch64-linux-gnu/bits/stdio2.h:100:10: \
	error: ‘%5s’ directive argument is null [-Werror=format-overflow=]
  100 |   return __fprintf_chk (__stream, __USE_FORTIFY_LEVEL - 1, __fmt,
  101 |                         __va_arg_pack ());

cc1: all warnings being treated as errors
.......

This patch fixes Wformat-overflow warnings by replacing the return
value NULL of perf_reg_name with "unknown".

Signed-off-by: Jianlin Lv <redacted>
---
 tools/perf/arch/arm64/include/perf_regs.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/perf/arch/arm64/include/perf_regs.h b/tools/perf/arch/arm64/include/perf_regs.h
index baaa5e64a3fb..901419f907c0 100644
--- a/tools/perf/arch/arm64/include/perf_regs.h
+++ b/tools/perf/arch/arm64/include/perf_regs.h
@@ -85,10 +85,10 @@ static inline const char *perf_reg_name(int id)
 	case PERF_REG_ARM64_PC:
 		return "pc";
 	default:
-		return NULL;
+		return "unknown";
 	}
 
-	return NULL;
+	return "unknown";
 }
 
 #endif /* ARCH_PERF_REGS_H */
-- 
2.25.1


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Re: [PATCH] perf tools: Fix arm64 build error with gcc-11

From: Leo Yan <hidden>
Date: 2021-02-09 12:18:35 

Hi Jianlin,

On Tue, Feb 09, 2021 at 07:33:57PM +0800, Jianlin Lv wrote:
quoted hunk
gcc version: 11.0.0 20210208 (experimental) (GCC)

Following build error on arm64:

.......
In function ‘printf’,
    inlined from ‘regs_dump__printf’ at util/session.c:1141:3,
    inlined from ‘regs__printf’ at util/session.c:1169:2:
/usr/include/aarch64-linux-gnu/bits/stdio2.h:107:10: \
  error: ‘%-5s’ directive argument is null [-Werror=format-overflow=]

107 |   return __printf_chk (__USE_FORTIFY_LEVEL - 1, __fmt, \
                __va_arg_pack ());

......
In function ‘fprintf’,
  inlined from ‘perf_sample__fprintf_regs.isra’ at \
    builtin-script.c:622:14:
/usr/include/aarch64-linux-gnu/bits/stdio2.h:100:10: \
	error: ‘%5s’ directive argument is null [-Werror=format-overflow=]
  100 |   return __fprintf_chk (__stream, __USE_FORTIFY_LEVEL - 1, __fmt,
  101 |                         __va_arg_pack ());

cc1: all warnings being treated as errors
.......

This patch fixes Wformat-overflow warnings by replacing the return
value NULL of perf_reg_name with "unknown".

Signed-off-by: Jianlin Lv <redacted>
---
 tools/perf/arch/arm64/include/perf_regs.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/perf/arch/arm64/include/perf_regs.h b/tools/perf/arch/arm64/include/perf_regs.h
index baaa5e64a3fb..901419f907c0 100644
--- a/tools/perf/arch/arm64/include/perf_regs.h
+++ b/tools/perf/arch/arm64/include/perf_regs.h
@@ -85,10 +85,10 @@ static inline const char *perf_reg_name(int id)
 	case PERF_REG_ARM64_PC:
 		return "pc";
 	default:
-		return NULL;
+		return "unknown";
 	}
 
-	return NULL;
+	return "unknown";
This issue is a common issue crossing all archs.  So it's better to
change the code in the places where calls perf_reg_name(), e.g. in
util/session.c:

--- a/tools/perf/util/session.c
+++ b/tools/perf/util/session.c
@@ -1135,12 +1135,14 @@ static void branch_stack__printf(struct perf_sample *sample, bool callstack)
 static void regs_dump__printf(u64 mask, u64 *regs)
 {
        unsigned rid, i = 0;
+       char *reg_name;
 
        for_each_set_bit(rid, (unsigned long *) &mask, sizeof(mask) * 8) {
                u64 val = regs[i++];
 
+               reg_name = perf_reg_name(rid);
                printf(".... %-5s 0x%016" PRIx64 "\n",
-                      perf_reg_name(rid), val);
+                      reg_name ?: "Unknown", val);
        }
 }

And another potential issue is the format specifier "%-5s", it prints
out maximum to 5 chars, but actually string "Unknown" has 7 chars.
Actually the format specifier breaks other archs register names, e.g.
[1][2], seems to me, it's better to change as "%-8s", you might need
to use a dedicated patch for format specifier changes.

Thanks,
Leo


[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/tools/perf/arch/powerpc/include/perf_regs.h#n57
[2] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/tools/perf/arch/csky/include/perf_regs.h#n83

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Re: [PATCH] perf tools: Fix arm64 build error with gcc-11

From: John Garry <hidden>
Date: 2021-02-09 14:20:57 

On 09/02/2021 12:17, Leo Yan wrote:
quoted hunk
Hi Jianlin,

On Tue, Feb 09, 2021 at 07:33:57PM +0800, Jianlin Lv wrote:
quoted
gcc version: 11.0.0 20210208 (experimental) (GCC)

Following build error on arm64:

.......
In function ‘printf’,
     inlined from ‘regs_dump__printf’ at util/session.c:1141:3,
     inlined from ‘regs__printf’ at util/session.c:1169:2:
/usr/include/aarch64-linux-gnu/bits/stdio2.h:107:10: \
   error: ‘%-5s’ directive argument is null [-Werror=format-overflow=]

107 |   return __printf_chk (__USE_FORTIFY_LEVEL - 1, __fmt, \
                 __va_arg_pack ());

......
In function ‘fprintf’,
   inlined from ‘perf_sample__fprintf_regs.isra’ at \
     builtin-script.c:622:14:
/usr/include/aarch64-linux-gnu/bits/stdio2.h:100:10: \
	error: ‘%5s’ directive argument is null [-Werror=format-overflow=]
   100 |   return __fprintf_chk (__stream, __USE_FORTIFY_LEVEL - 1, __fmt,
   101 |                         __va_arg_pack ());

cc1: all warnings being treated as errors
.......

This patch fixes Wformat-overflow warnings by replacing the return
value NULL of perf_reg_name with "unknown".

Signed-off-by: Jianlin Lv <redacted>
---
  tools/perf/arch/arm64/include/perf_regs.h | 4 ++--
  1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/perf/arch/arm64/include/perf_regs.h b/tools/perf/arch/arm64/include/perf_regs.h
index baaa5e64a3fb..901419f907c0 100644
--- a/tools/perf/arch/arm64/include/perf_regs.h
+++ b/tools/perf/arch/arm64/include/perf_regs.h
@@ -85,10 +85,10 @@ static inline const char *perf_reg_name(int id)
  	case PERF_REG_ARM64_PC:
  		return "pc";
  	default:
-		return NULL;
+		return "unknown";
  	}
  
-	return NULL;
+	return "unknown";
This issue is a common issue crossing all archs.  So it's better to
change the code in the places where calls perf_reg_name(), e.g. in
util/session.c:

--- a/tools/perf/util/session.c
+++ b/tools/perf/util/session.c
@@ -1135,12 +1135,14 @@ static void branch_stack__printf(struct perf_sample *sample, bool callstack)
  static void regs_dump__printf(u64 mask, u64 *regs)
  {
         unsigned rid, i = 0;
+       char *reg_name;
  
         for_each_set_bit(rid, (unsigned long *) &mask, sizeof(mask) * 8) {
                 u64 val = regs[i++];
  
+               reg_name = perf_reg_name(rid);
                 printf(".... %-5s 0x%016" PRIx64 "\n",
-                      perf_reg_name(rid), val);
+                      reg_name ?: "Unknown", val);
         }
  }

And another potential issue is the format specifier "%-5s", it prints
out maximum to 5 chars, 
Doesn't the width field specify the min, not max, number of characters?

Cheers,
John

but actually string "Unknown" has 7 chars.
Actually the format specifier breaks other archs register names, e.g.
[1][2], seems to me, it's better to change as "%-8s", you might need
to use a dedicated patch for format specifier changes.

Thanks,
Leo


[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/tools/perf/arch/powerpc/include/perf_regs.h#n57
[2] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/tools/perf/arch/csky/include/perf_regs.h#n83
.

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Re: [PATCH] perf tools: Fix arm64 build error with gcc-11

From: Leo Yan <hidden>
Date: 2021-02-09 14:45:32 

On Tue, Feb 09, 2021 at 02:18:26PM +0000, John Garry wrote:
On 09/02/2021 12:17, Leo Yan wrote:
quoted
Hi Jianlin,

On Tue, Feb 09, 2021 at 07:33:57PM +0800, Jianlin Lv wrote:
quoted
gcc version: 11.0.0 20210208 (experimental) (GCC)

Following build error on arm64:

.......
In function ‘printf’,
     inlined from ‘regs_dump__printf’ at util/session.c:1141:3,
     inlined from ‘regs__printf’ at util/session.c:1169:2:
/usr/include/aarch64-linux-gnu/bits/stdio2.h:107:10: \
   error: ‘%-5s’ directive argument is null [-Werror=format-overflow=]

107 |   return __printf_chk (__USE_FORTIFY_LEVEL - 1, __fmt, \
                 __va_arg_pack ());

......
In function ‘fprintf’,
   inlined from ‘perf_sample__fprintf_regs.isra’ at \
     builtin-script.c:622:14:
/usr/include/aarch64-linux-gnu/bits/stdio2.h:100:10: \
	error: ‘%5s’ directive argument is null [-Werror=format-overflow=]
   100 |   return __fprintf_chk (__stream, __USE_FORTIFY_LEVEL - 1, __fmt,
   101 |                         __va_arg_pack ());

cc1: all warnings being treated as errors
.......

This patch fixes Wformat-overflow warnings by replacing the return
value NULL of perf_reg_name with "unknown".

Signed-off-by: Jianlin Lv <redacted>
---
  tools/perf/arch/arm64/include/perf_regs.h | 4 ++--
  1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/perf/arch/arm64/include/perf_regs.h b/tools/perf/arch/arm64/include/perf_regs.h
index baaa5e64a3fb..901419f907c0 100644
--- a/tools/perf/arch/arm64/include/perf_regs.h
+++ b/tools/perf/arch/arm64/include/perf_regs.h
@@ -85,10 +85,10 @@ static inline const char *perf_reg_name(int id)
  	case PERF_REG_ARM64_PC:
  		return "pc";
  	default:
-		return NULL;
+		return "unknown";
  	}
-	return NULL;
+	return "unknown";
This issue is a common issue crossing all archs.  So it's better to
change the code in the places where calls perf_reg_name(), e.g. in
util/session.c:

--- a/tools/perf/util/session.c
+++ b/tools/perf/util/session.c
@@ -1135,12 +1135,14 @@ static void branch_stack__printf(struct perf_sample *sample, bool callstack)
  static void regs_dump__printf(u64 mask, u64 *regs)
  {
         unsigned rid, i = 0;
+       char *reg_name;
         for_each_set_bit(rid, (unsigned long *) &mask, sizeof(mask) * 8) {
                 u64 val = regs[i++];
+               reg_name = perf_reg_name(rid);
                 printf(".... %-5s 0x%016" PRIx64 "\n",
-                      perf_reg_name(rid), val);
+                      reg_name ?: "Unknown", val);
         }
  }

And another potential issue is the format specifier "%-5s", it prints
out maximum to 5 chars,
Doesn't the width field specify the min, not max, number of characters?
Thanks for correction, John.

I wrongly understood it and sorry for confusion.  Wiki says [1]:

"The Width field specifies a minimum number of characters to output,
and is typically used to pad fixed-width fields in tabulated output,
where the fields would otherwise be smaller, although it does not
cause truncation of oversized fields."

Thanks,
Leo

[1] https://en.wikipedia.org/wiki/Printf_format_string#Width_field

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RE: [PATCH] perf tools: Fix arm64 build error with gcc-11

From: Jianlin Lv <hidden>
Date: 2021-02-10 02:37:03 

quoted hunk
-----Original Message-----
From: Leo Yan <redacted>
Sent: Tuesday, February 9, 2021 8:17 PM
To: Jianlin Lv <redacted>
Cc: john.garry@huawei.com; will@kernel.org; mathieu.poirier@linaro.org;
peterz@infradead.org; mingo@redhat.com; acme@kernel.org; Mark Rutland
[off-list ref]; alexander.shishkin@linux.intel.com;
jolsa@redhat.com; namhyung@kernel.org; linux-arm-
kernel@lists.infradead.org; linux-kernel@vger.kernel.org
Subject: Re: [PATCH] perf tools: Fix arm64 build error with gcc-11

Hi Jianlin,

On Tue, Feb 09, 2021 at 07:33:57PM +0800, Jianlin Lv wrote:
quoted
gcc version: 11.0.0 20210208 (experimental) (GCC)

Following build error on arm64:

.......
In function ‘printf’,
    inlined from ‘regs_dump__printf’ at util/session.c:1141:3,
    inlined from ‘regs__printf’ at util/session.c:1169:2:
/usr/include/aarch64-linux-gnu/bits/stdio2.h:107:10: \
  error: ‘%-5s’ directive argument is null [-Werror=format-overflow=]

107 |   return __printf_chk (__USE_FORTIFY_LEVEL - 1, __fmt, \
                __va_arg_pack ());

......
In function ‘fprintf’,
  inlined from ‘perf_sample__fprintf_regs.isra’ at \
    builtin-script.c:622:14:
/usr/include/aarch64-linux-gnu/bits/stdio2.h:100:10: \
	error: ‘%5s’ directive argument is null [-Werror=format-overflow=]
  100 |   return __fprintf_chk (__stream, __USE_FORTIFY_LEVEL - 1, __fmt,
  101 |                         __va_arg_pack ());

cc1: all warnings being treated as errors .......

This patch fixes Wformat-overflow warnings by replacing the return
value NULL of perf_reg_name with "unknown".

Signed-off-by: Jianlin Lv <redacted>
---
 tools/perf/arch/arm64/include/perf_regs.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/perf/arch/arm64/include/perf_regs.h
b/tools/perf/arch/arm64/include/perf_regs.h
index baaa5e64a3fb..901419f907c0 100644
--- a/tools/perf/arch/arm64/include/perf_regs.h
+++ b/tools/perf/arch/arm64/include/perf_regs.h
@@ -85,10 +85,10 @@ static inline const char *perf_reg_name(int id)
 	case PERF_REG_ARM64_PC:
 		return "pc";
 	default:
-		return NULL;
+		return "unknown";
 	}

-	return NULL;
+	return "unknown";
This issue is a common issue crossing all archs.  So it's better to change the
code in the places where calls perf_reg_name(), e.g. in
util/session.c:

--- a/tools/perf/util/session.c
+++ b/tools/perf/util/session.c
@@ -1135,12 +1135,14 @@ static void branch_stack__printf(struct
perf_sample *sample, bool callstack)  static void regs_dump__printf(u64
mask, u64 *regs)  {
        unsigned rid, i = 0;
+       char *reg_name;

        for_each_set_bit(rid, (unsigned long *) &mask, sizeof(mask) * 8) {
                u64 val = regs[i++];

+               reg_name = perf_reg_name(rid);
                printf(".... %-5s 0x%016" PRIx64 "\n",
-                      perf_reg_name(rid), val);
+                      reg_name ?: "Unknown", val);
        }
 }
Thanks for your comments, I will send a v2 of the patch today.

Jianlin


And another potential issue is the format specifier "%-5s", it prints out
maximum to 5 chars, but actually string "Unknown" has 7 chars.
Actually the format specifier breaks other archs register names, e.g.
[1][2], seems to me, it's better to change as "%-8s", you might need to use a
dedicated patch for format specifier changes.

Thanks,
Leo


[1]
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/tools/
perf/arch/powerpc/include/perf_regs.h#n57
[2]
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/tools/
perf/arch/csky/include/perf_regs.h#n83
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