[patch v2] x86_64, traps: always true condition

[patch v2] x86_64, traps: always true condition

[Dan Carpenter]

We should be checking IS_ERR() here.  PTR_ERR() is always true.

Fixes: fe3d197f8431 ('x86, mpx: On-demand kernel allocation of bounds tables')
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
---
v2: Use correct fixes tag.

diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index 67d817e..f176d96 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -331,7 +331,7 @@ dotraplinkage void do_bounds(struct pt_regs *regs, long error_code)
 		break; /* Success, it was handled */
 	case 1: /* Bound violation. */
 		info = mpx_generate_siginfo(regs, xsave_buf);
-		if (PTR_ERR(info)) {
+		if (IS_ERR(info)) {
 			/*
 			 * We failed to decode the MPX instruction.  Act as if
 			 * the exception was not caused by MPX.

Re: [patch v2] x86_64, traps: always true condition

[Dave Hansen]

On 11/25/2014 09:21 AM, Dan Carpenter wrote:
> We should be checking IS_ERR() here.  PTR_ERR() is always true.
> 
> Fixes: fe3d197f8431 ('x86, mpx: On-demand kernel allocation of bounds tables')
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> ---
> v2: Use correct fixes tag.
> 
> diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
> index 67d817e..f176d96 100644
> --- a/arch/x86/kernel/traps.c
> +++ b/arch/x86/kernel/traps.c
> @@ -331,7 +331,7 @@ dotraplinkage void do_bounds(struct pt_regs *regs, long error_code)
>  		break; /* Success, it was handled */
>  	case 1: /* Bound violation. */
>  		info = mpx_generate_siginfo(regs, xsave_buf);
> -		if (PTR_ERR(info)) {
> +		if (IS_ERR(info)) {
>  			/*
>  			 * We failed to decode the MPX instruction.  Act as if
>  			 * the exception was not caused by MPX.

I checked that this works on real hardware.  The si_addr field in the
generated siginfo was empty without this patch applied.  With this
patch, it has good (looking at least) contents.

Thanks for catching this!

Tested-by: Dave Hansen <dave.hansen@intel.com>

Re: [patch v2] x86_64, traps: always true condition

[Dave Hansen]

On 11/25/2014 09:21 AM, Dan Carpenter wrote:
> We should be checking IS_ERR() here.  PTR_ERR() is always true.
>
> Fixes: fe3d197f8431 ('x86, mpx: On-demand kernel allocation of bounds
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> ---
> v2: Use correct fixes tag.
>
> diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
> index 67d817e..f176d96 100644
> --- a/arch/x86/kernel/traps.c
> +++ b/arch/x86/kernel/traps.c
> @@ -331,7 +331,7 @@ dotraplinkage void do_bounds(struct pt_regs >  	
break; /* Success, it was handled */
>  	case 1: /* Bound violation. */
>  		info = mpx_generate_siginfo(regs, xsave_buf);
> -		if (PTR_ERR(info)) {
> +		if (IS_ERR(info)) {
>  			/*
>  			 * We failed to decode the MPX instruction.
>  			 * the exception was not caused by MPX.

I checked that this works on real hardware.  The si_addr field in the
generated siginfo was empty without this patch applied.  With this
patch, it has good (looking at least) contents.

Thanks for catching this!

Tested-by: Dave Hansen <dave.hansen@intel.com>

[tip:x86/mpx] x86_64/traps: Fix always true condition

[tip-bot for Dan Carpenter]

Commit-ID:  e10abb2f770eeb673d23c19980216b0fb62b4f50
Gitweb:     http://git.kernel.org/tip/e10abb2f770eeb673d23c19980216b0fb62b4f50
Author:     Dan Carpenter <dan.carpenter@oracle.com>
AuthorDate: Tue, 25 Nov 2014 20:21:14 +0300
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Mon, 8 Dec 2014 12:06:59 +0100

x86_64/traps: Fix always true condition

We should be checking IS_ERR() here.  PTR_ERR() is always true.

Fixes: fe3d197f8431 ('x86, mpx: On-demand kernel allocation of
bounds tables')
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Link: http://lkml.kernel.org/r/20141125172114.GA24535@mwanda
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 arch/x86/kernel/traps.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index 651d5d4..f73fc4a 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -323,7 +323,7 @@ dotraplinkage void do_bounds(struct pt_regs *regs, long error_code)
 		break; /* Success, it was handled */
 	case 1: /* Bound violation. */
 		info = mpx_generate_siginfo(regs, xsave_buf);
-		if (PTR_ERR(info)) {
+		if (IS_ERR(info)) {
 			/*
 			 * We failed to decode the MPX instruction.  Act as if
 			 * the exception was not caused by MPX.