[PATCH 02/11] signal/sh: Ensure si_signo is initialized in do_divide_error

[PATCH 02/11] signal/sh: Ensure si_signo is initialized in do_divide_error

[Eric W. Biederman]

Set si_signo.

Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Rich Felker <dalias@libc.org>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: linux-sh@vger.kernel.org
Cc: stable@vger.kernel.org
Fixes: 0983b31849bb ("sh: Wire up division and address error exceptions on SH-2A.")
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
---
 arch/sh/kernel/traps_32.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/sh/kernel/traps_32.c b/arch/sh/kernel/traps_32.c
index 57cff00cad17..b3770bb26211 100644
--- a/arch/sh/kernel/traps_32.c
+++ b/arch/sh/kernel/traps_32.c
@@ -609,7 +609,8 @@ asmlinkage void do_divide_error(unsigned long r4)
 		break;
 	}
 
-	force_sig_info(SIGFPE, &info, current);
+	info.si_signo = SIGFPE;
+	force_sig_info(info.si_signo, &info, current);
 }
 #endif
 
-- 
2.14.1

[PATCH 03/11] signal/openrisc: Fix do_unaligned_access to send the proper signal

[Eric W. Biederman]

While reviewing the signal sending on openrisc the do_unaligned_access
function stood out because it is obviously wrong.  A comment about an
si_code set above when actually si_code is never set.  Leading to a
random si_code being sent to userspace in the event of an unaligned
access.

Looking further SIGBUS BUS_ADRALN is the proper pair of signal and
si_code to send for an unaligned access. That is what other
architectures do and what is required by posix.

Given that do_unaligned_access is broken in a way that no one can be
relying on it on openrisc fix the code to just do the right thing.

Cc: stable@vger.kernel.org
Fixes: 769a8a96229e ("OpenRISC: Traps")
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: openrisc@lists.librecores.org
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
---
 arch/openrisc/kernel/traps.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/arch/openrisc/kernel/traps.c b/arch/openrisc/kernel/traps.c
index 4085d72fa5ae..9e38dc66c9e4 100644
--- a/arch/openrisc/kernel/traps.c
+++ b/arch/openrisc/kernel/traps.c
@@ -266,12 +266,12 @@ asmlinkage void do_unaligned_access(struct pt_regs *regs, unsigned long address)
 	siginfo_t info;
 
 	if (user_mode(regs)) {
-		/* Send a SIGSEGV */
-		info.si_signo = SIGSEGV;
+		/* Send a SIGBUS */
+		info.si_signo = SIGBUS;
 		info.si_errno = 0;
-		/* info.si_code has been set above */
-		info.si_addr = (void *)address;
-		force_sig_info(SIGSEGV, &info, current);
+		info.si_code = BUS_ADRALN;
+		info.si_addr = (void __user *)address;
+		force_sig_info(SIGBUS, &info, current);
 	} else {
 		printk("KERNEL: Unaligned Access 0x%.8lx\n", address);
 		show_registers(regs);
-- 
2.14.1

Re: [PATCH 03/11] signal/openrisc: Fix do_unaligned_access to send the proper signal

[Stafford Horne]

On Thu, Jan 11, 2018 at 06:59:32PM -0600, Eric W. Biederman wrote:
> While reviewing the signal sending on openrisc the do_unaligned_access
> function stood out because it is obviously wrong.  A comment about an
> si_code set above when actually si_code is never set.  Leading to a
> random si_code being sent to userspace in the event of an unaligned
> access.
> 
> Looking further SIGBUS BUS_ADRALN is the proper pair of signal and
> si_code to send for an unaligned access. That is what other
> architectures do and what is required by posix.
> 
> Given that do_unaligned_access is broken in a way that no one can be
> relying on it on openrisc fix the code to just do the right thing.

Thanks, this looks good to me.

Acked-by: Stafford Horne <shorne@gmail.com>

I see you have a series of related issues, so I guess you want to get them
merged together.  Let me know if I should put this patch onto my queue
seperately.

Trivia: this looks to have been copied from the mm page fault handling code,
hence the strange comment.

  $ grep -r "info.si_code has been set above" arch/
  arch/cris/mm/fault.c:           /* info.si_code has been set above */
  arch/m32r/mm/fault.c:           /* info.si_code has been set above */
  arch/mn10300/mm/fault.c:                /* info.si_code has been set above */
  arch/openrisc/mm/fault.c:               /* info.si_code has been set above */
  arch/openrisc/kernel/traps.c:           /* info.si_code has been set above */
  arch/arc/mm/fault.c:            /* info.si_code has been set above */
  arch/xtensa/mm/fault.c:         /* info.si_code has been set above */
  arch/mips/mm/fault.c:           /* info.si_code has been set above */
  arch/score/mm/fault.c:          /* info.si_code has been set above */
  arch/frv/mm/fault.c:            /* info.si_code has been set above */

-Stafford

> Cc: stable@vger.kernel.org
> Fixes: 769a8a96229e ("OpenRISC: Traps")
> Cc: Jonas Bonn <jonas@southpole.se>
> Cc: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
> Cc: Stafford Horne <shorne@gmail.com>
> Cc: Arnd Bergmann <arnd@arndb.de>
> Cc: openrisc@lists.librecores.org
> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
> ---
>  arch/openrisc/kernel/traps.c | 10 +++++-----
>  1 file changed, 5 insertions(+), 5 deletions(-)
> 
> diff --git a/arch/openrisc/kernel/traps.c b/arch/openrisc/kernel/traps.c
> index 4085d72fa5ae..9e38dc66c9e4 100644
> --- a/arch/openrisc/kernel/traps.c
> +++ b/arch/openrisc/kernel/traps.c
> @@ -266,12 +266,12 @@ asmlinkage void do_unaligned_access(struct pt_regs *regs, unsigned long address)
>  	siginfo_t info;
>  
>  	if (user_mode(regs)) {
> -		/* Send a SIGSEGV */
> -		info.si_signo = SIGSEGV;
> +		/* Send a SIGBUS */
> +		info.si_signo = SIGBUS;
>  		info.si_errno = 0;
> -		/* info.si_code has been set above */
> -		info.si_addr = (void *)address;
> -		force_sig_info(SIGSEGV, &info, current);
> +		info.si_code = BUS_ADRALN;
> +		info.si_addr = (void __user *)address;
> +		force_sig_info(SIGBUS, &info, current);
>  	} else {
>  		printk("KERNEL: Unaligned Access 0x%.8lx\n", address);
>  		show_registers(regs);
> -- 
> 2.14.1
> 

Re: [PATCH 03/11] signal/openrisc: Fix do_unaligned_access to send the proper signal

[Eric W. Biederman]

Stafford Horne <shorne@gmail.com> writes:

> On Thu, Jan 11, 2018 at 06:59:32PM -0600, Eric W. Biederman wrote:
>> While reviewing the signal sending on openrisc the do_unaligned_access
>> function stood out because it is obviously wrong.  A comment about an
>> si_code set above when actually si_code is never set.  Leading to a
>> random si_code being sent to userspace in the event of an unaligned
>> access.
>> 
>> Looking further SIGBUS BUS_ADRALN is the proper pair of signal and
>> si_code to send for an unaligned access. That is what other
>> architectures do and what is required by posix.
>> 
>> Given that do_unaligned_access is broken in a way that no one can be
>> relying on it on openrisc fix the code to just do the right thing.
>
> Thanks, this looks good to me.
>
> Acked-by: Stafford Horne <shorne@gmail.com>
>
> I see you have a series of related issues, so I guess you want to get them
> merged together.  Let me know if I should put this patch onto my queue
> seperately.

Yes,  I have a follow on patch that restructures the code that fills out
siginfo, and makes the it a little less error prone.  I am hoping to
merge all of it in the next merge window.  *Fingers crossed*

And having it all in one tree will facilitate that.

> Trivia: this looks to have been copied from the mm page fault handling code,
> hence the strange comment.
>
>   $ grep -r "info.si_code has been set above" arch/
>   arch/cris/mm/fault.c:           /* info.si_code has been set above */
>   arch/m32r/mm/fault.c:           /* info.si_code has been set above */
>   arch/mn10300/mm/fault.c:                /* info.si_code has been set above */
>   arch/openrisc/mm/fault.c:               /* info.si_code has been set above */
>   arch/openrisc/kernel/traps.c:           /* info.si_code has been set above */
>   arch/arc/mm/fault.c:            /* info.si_code has been set above */
>   arch/xtensa/mm/fault.c:         /* info.si_code has been set above */
>   arch/mips/mm/fault.c:           /* info.si_code has been set above */
>   arch/score/mm/fault.c:          /* info.si_code has been set above */
>   arch/frv/mm/fault.c:            /* info.si_code has been set above */
>

It looks like it.    When I look at those I can actually find the
si_code being set higher up in the code.  It looks like the si_code
value was missed when this work was done.

Eric