[PATCH -tip 1/2] x86/alternatives: Fix build warning

[PATCH -tip 1/2] x86/alternatives: Fix build warning

[Masami Hiramatsu]

Fixes below warnings.

====
FYI, there's this new build warning on x86 defconfig:

arch/x86/kernel/alternative.c: In function 'alternatives_text_reserved':
arch/x86/kernel/alternative.c:402: warning: comparison of distinct pointer types lacks a cast
arch/x86/kernel/alternative.c:402: warning: comparison of distinct pointer types lacks a cast
arch/x86/kernel/alternative.c:405: warning: comparison of distinct pointer types lacks a cast
arch/x86/kernel/alternative.c:405: warning: comparison of distinct pointer types lacks a cast

Caused by:

2cfa197: ftrace/alternatives: Introducing *_text_reserved functions
====

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Reported-by: Ingo Molnar <mingo@elte.hu>
---

 arch/x86/kernel/alternative.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
index 3832fdc..99d9920 100644
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -399,10 +399,10 @@ int alternatives_text_reserved(void *start, void *end)
 	u8 **ptr;
 
 	list_for_each_entry(mod, &smp_alt_modules, next) {
-		if (mod->text > end || mod->text_end < start)
+		if (mod->text > (u8 *)end || mod->text_end < (u8 *)start)
 			continue;
 		for (ptr = mod->locks; ptr < mod->locks_end; ptr++)
-			if (start <= *ptr && end >= *ptr)
+			if ((u8 *)start <= *ptr && (u8 *)end >= *ptr)
 				return 1;
 	}
 


-- 
Masami Hiramatsu

Software Engineer
Hitachi Computer Products (America), Inc.
Software Solutions Division

e-mail: mhiramat@redhat.com

[PATCH -tip 2/2] kprobes: Add mcount in kprobes blacklist

[Masami Hiramatsu]

Since mcount function can be called from everywhere,
it should be blacklisted. Moreover, the "mcount" symbol
is a special symbol name. So, it is better to put it in
the generic blacklist.

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
---

 kernel/kprobes.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index c3340e8..ccec774 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -94,6 +94,7 @@ static struct kprobe_blackpoint kprobe_blacklist[] = {
 	{"native_get_debugreg",},
 	{"irq_entries_start",},
 	{"common_interrupt",},
+	{"mcount",},	/* mcount can be called from everywhere */
 	{NULL}    /* Terminator */
 };
 


-- 
Masami Hiramatsu

Software Engineer
Hitachi Computer Products (America), Inc.
Software Solutions Division

e-mail: mhiramat@redhat.com

Re: [PATCH -tip 1/2] x86/alternatives: Fix build warning

[Ingo Molnar]

* Masami Hiramatsu <mhiramat@redhat.com> wrote:

> Fixes below warnings.
> 
> ====
> FYI, there's this new build warning on x86 defconfig:
> 
> arch/x86/kernel/alternative.c: In function 'alternatives_text_reserved':
> arch/x86/kernel/alternative.c:402: warning: comparison of distinct pointer types lacks a cast
> arch/x86/kernel/alternative.c:402: warning: comparison of distinct pointer types lacks a cast
> arch/x86/kernel/alternative.c:405: warning: comparison of distinct pointer types lacks a cast
> arch/x86/kernel/alternative.c:405: warning: comparison of distinct pointer types lacks a cast
> 
> Caused by:
> 
> 2cfa197: ftrace/alternatives: Introducing *_text_reserved functions
> ====
> 
> Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
> Reported-by: Ingo Molnar <mingo@elte.hu>
> ---
> 
>  arch/x86/kernel/alternative.c |    4 ++--
>  1 files changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
> index 3832fdc..99d9920 100644
> --- a/arch/x86/kernel/alternative.c
> +++ b/arch/x86/kernel/alternative.c
> @@ -399,10 +399,10 @@ int alternatives_text_reserved(void *start, void *end)
>  	u8 **ptr;
>  
>  	list_for_each_entry(mod, &smp_alt_modules, next) {
> -		if (mod->text > end || mod->text_end < start)
> +		if (mod->text > (u8 *)end || mod->text_end < (u8 *)start)
>  			continue;
>  		for (ptr = mod->locks; ptr < mod->locks_end; ptr++)
> -			if (start <= *ptr && end >= *ptr)
> +			if ((u8 *)start <= *ptr && (u8 *)end >= *ptr)
>  				return 1;
>  	}

Such casts are a bit ugly and in general type casts are somewhat dangerous.

One possible solution would be to add intermediary local variables 
(text_start/text_end) with u8 * type and assign start/end to them - which can 
be done without a cast.

Thanks,

	Ingo

[tip:perf/core] kprobes: Add mcount to the kprobes blacklist

[tip-bot for Masami Hiramatsu]

Commit-ID:  5ecaafdbf44b1ba400b746c60c401d54c7ee0863
Gitweb:     http://git.kernel.org/tip/5ecaafdbf44b1ba400b746c60c401d54c7ee0863
Author:     Masami Hiramatsu <mhiramat@redhat.com>
AuthorDate: Fri, 5 Feb 2010 01:24:34 -0500
Committer:  Ingo Molnar <mingo@elte.hu>
CommitDate: Fri, 5 Feb 2010 08:13:57 +0100

kprobes: Add mcount to the kprobes blacklist

Since mcount function can be called from everywhere,
it should be blacklisted. Moreover, the "mcount" symbol
is a special symbol name. So, it is better to put it in
the generic blacklist.

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: systemtap <systemtap@sources.redhat.com>
Cc: DLE <dle-develop@lists.sourceforge.net>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <20100205062433.3745.36726.stgit@dhcp-100-2-132.bos.redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
 kernel/kprobes.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index c3340e8..ccec774 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -94,6 +94,7 @@ static struct kprobe_blackpoint kprobe_blacklist[] = {
 	{"native_get_debugreg",},
 	{"irq_entries_start",},
 	{"common_interrupt",},
+	{"mcount",},	/* mcount can be called from everywhere */
 	{NULL}    /* Terminator */
 };
 

Re: [PATCH -tip 1/2] x86/alternatives: Fix build warning

[Masami Hiramatsu]

Ingo Molnar wrote:
> 
> * Masami Hiramatsu <mhiramat@redhat.com> wrote:
> 
>> Fixes below warnings.
>>
>> ====
>> FYI, there's this new build warning on x86 defconfig:
>>
>> arch/x86/kernel/alternative.c: In function 'alternatives_text_reserved':
>> arch/x86/kernel/alternative.c:402: warning: comparison of distinct pointer types lacks a cast
>> arch/x86/kernel/alternative.c:402: warning: comparison of distinct pointer types lacks a cast
>> arch/x86/kernel/alternative.c:405: warning: comparison of distinct pointer types lacks a cast
>> arch/x86/kernel/alternative.c:405: warning: comparison of distinct pointer types lacks a cast
>>
>> Caused by:
>>
>> 2cfa197: ftrace/alternatives: Introducing *_text_reserved functions
>> ====
>>
>> Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
>> Reported-by: Ingo Molnar <mingo@elte.hu>
>> ---
>>
>>  arch/x86/kernel/alternative.c |    4 ++--
>>  1 files changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
>> index 3832fdc..99d9920 100644
>> --- a/arch/x86/kernel/alternative.c
>> +++ b/arch/x86/kernel/alternative.c
>> @@ -399,10 +399,10 @@ int alternatives_text_reserved(void *start, void *end)
>>  	u8 **ptr;
>>  
>>  	list_for_each_entry(mod, &smp_alt_modules, next) {
>> -		if (mod->text > end || mod->text_end < start)
>> +		if (mod->text > (u8 *)end || mod->text_end < (u8 *)start)
>>  			continue;
>>  		for (ptr = mod->locks; ptr < mod->locks_end; ptr++)
>> -			if (start <= *ptr && end >= *ptr)
>> +			if ((u8 *)start <= *ptr && (u8 *)end >= *ptr)
>>  				return 1;
>>  	}
> 
> Such casts are a bit ugly and in general type casts are somewhat dangerous.

I doubt this type casting is dangerous..., but yeah, it's ugly :-)

> One possible solution would be to add intermediary local variables 
> (text_start/text_end) with u8 * type and assign start/end to them - which can 
> be done without a cast.

Sure, I'll update it.

Thank you,


-- 
Masami Hiramatsu

Software Engineer
Hitachi Computer Products (America), Inc.
Software Solutions Division

e-mail: mhiramat@redhat.com

[PATCH -tip v2] x86/alternatives: Fix build warning

[Masami Hiramatsu]

Fixes below warnings.

====
FYI, there's this new build warning on x86 defconfig:

arch/x86/kernel/alternative.c: In function 'alternatives_text_reserved':
arch/x86/kernel/alternative.c:402: warning: comparison of distinct pointer types lacks a cast
arch/x86/kernel/alternative.c:402: warning: comparison of distinct pointer types lacks a cast
arch/x86/kernel/alternative.c:405: warning: comparison of distinct pointer types lacks a cast
arch/x86/kernel/alternative.c:405: warning: comparison of distinct pointer types lacks a cast

Caused by:

2cfa197: ftrace/alternatives: Introducing *_text_reserved functions
====

Changes in v2:
 - Use local variables to compare, instead of type casts.

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Reported-by: Ingo Molnar <mingo@elte.hu>
---

 arch/x86/kernel/alternative.c |    6 ++++--
 1 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
index 3832fdc..e6ea034 100644
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -397,12 +397,14 @@ int alternatives_text_reserved(void *start, void *end)
 {
 	struct smp_alt_module *mod;
 	u8 **ptr;
+	u8 *text_start = start;
+	u8 *text_end = end;
 
 	list_for_each_entry(mod, &smp_alt_modules, next) {
-		if (mod->text > end || mod->text_end < start)
+		if (mod->text > text_end || mod->text_end < text_start)
 			continue;
 		for (ptr = mod->locks; ptr < mod->locks_end; ptr++)
-			if (start <= *ptr && end >= *ptr)
+			if (text_start <= *ptr && text_end >= *ptr)
 				return 1;
 	}
 


-- 
Masami Hiramatsu

Software Engineer
Hitachi Computer Products (America), Inc.
Software Solutions Division

e-mail: mhiramat@redhat.com

[tip:perf/core] x86/alternatives: Fix build warning

[tip-bot for Masami Hiramatsu]

Commit-ID:  076dc4a65a6d99a16979e2c7917e669fb8c91ee5
Gitweb:     http://git.kernel.org/tip/076dc4a65a6d99a16979e2c7917e669fb8c91ee5
Author:     Masami Hiramatsu <mhiramat@redhat.com>
AuthorDate: Fri, 5 Feb 2010 12:16:47 -0500
Committer:  Ingo Molnar <mingo@elte.hu>
CommitDate: Sun, 7 Feb 2010 18:08:24 +0100

x86/alternatives: Fix build warning

Fixes these warnings:

 arch/x86/kernel/alternative.c: In function 'alternatives_text_reserved':
 arch/x86/kernel/alternative.c:402: warning: comparison of distinct pointer types lacks a cast
 arch/x86/kernel/alternative.c:402: warning: comparison of distinct pointer types lacks a cast
 arch/x86/kernel/alternative.c:405: warning: comparison of distinct pointer types lacks a cast
 arch/x86/kernel/alternative.c:405: warning: comparison of distinct pointer types lacks a cast

Caused by:

  2cfa197: ftrace/alternatives: Introducing *_text_reserved functions

Changes in v2:
  - Use local variables to compare, instead of type casts.

Reported-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: systemtap <systemtap@sources.redhat.com>
Cc: DLE <dle-develop@lists.sourceforge.net>
LKML-Reference: <20100205171647.15750.37221.stgit@dhcp-100-2-132.bos.redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
 arch/x86/kernel/alternative.c |    6 ++++--
 1 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
index 3c13284..e63b80e 100644
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -395,12 +395,14 @@ int alternatives_text_reserved(void *start, void *end)
 {
 	struct smp_alt_module *mod;
 	u8 **ptr;
+	u8 *text_start = start;
+	u8 *text_end = end;
 
 	list_for_each_entry(mod, &smp_alt_modules, next) {
-		if (mod->text > end || mod->text_end < start)
+		if (mod->text > text_end || mod->text_end < text_start)
 			continue;
 		for (ptr = mod->locks; ptr < mod->locks_end; ptr++)
-			if (start <= *ptr && end >= *ptr)
+			if (text_start <= *ptr && text_end >= *ptr)
 				return 1;
 	}
 

[tip:tracing/urgent] kprobes: Add mcount to the kprobes blacklist

[tip-bot for Masami Hiramatsu]

Commit-ID:  8b833c506c05c498d4215e2c260be44225daf6de
Gitweb:     http://git.kernel.org/tip/8b833c506c05c498d4215e2c260be44225daf6de
Author:     Masami Hiramatsu <mhiramat@redhat.com>
AuthorDate: Fri, 5 Feb 2010 01:24:34 -0500
Committer:  Ingo Molnar <mingo@elte.hu>
CommitDate: Mon, 15 Feb 2010 05:45:49 +0100

kprobes: Add mcount to the kprobes blacklist

Since mcount function can be called from everywhere,
it should be blacklisted. Moreover, the "mcount" symbol
is a special symbol name. So, it is better to put it in
the generic blacklist.

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: systemtap <systemtap@sources.redhat.com>
Cc: DLE <dle-develop@lists.sourceforge.net>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <20100205062433.3745.36726.stgit@dhcp-100-2-132.bos.redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
 kernel/kprobes.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index b7df302..c4b4343 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -93,6 +93,7 @@ static struct kprobe_blackpoint kprobe_blacklist[] = {
 	{"native_get_debugreg",},
 	{"irq_entries_start",},
 	{"common_interrupt",},
+	{"mcount",},	/* mcount can be called from everywhere */
 	{NULL}    /* Terminator */
 };