diff mbox

arm: kgdb: fix NUMREGBYTES so that gdb_regs[] is the correct size

Message ID 20180405200916.27964-1-drivshin@awxrd.com (mailing list archive)
State New, archived
Headers show

Commit Message

David Rivshin April 5, 2018, 8:09 p.m. UTC
From: David Rivshin <DRivshin@allworx.com>

NUMREGBYTES (which is used as the size for gdb_regs[]) is incorrectly based
on DBG_MAX_REG_NUM instead of GDB_MAX_REGS. DBG_MAX_REG_NUM is the number
of total registers, while GDB_MAX_REGS is the number of 'unsigned longs'
it takes to serialize those registers. Since FP registers require 3
'unsigned longs' each, DBG_MAX_REG_NUM is smaller than GDB_MAX_REGS.

This causes GDB 8.0 give the following error on connect:
"Truncated register 19 in remote 'g' packet"

This also causes the register serialization/deserialization logic to
overflow gdb_regs[], overwriting whatever follows.

Fixes: 834b2964b7ab ("kgdb,arm: fix register dump")
Cc: <stable@vger.kernel.org> # 2.6.37+
Signed-off-by: David Rivshin <drivshin@allworx.com>
---
 arch/arm/include/asm/kgdb.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)


base-commit: 0adb32858b0bddf4ada5f364a84ed60b196dbcda

Comments

Rabin Vincent April 5, 2018, 8:48 p.m. UTC | #1
On Thu, Apr 05, 2018 at 04:09:16PM -0400, David Rivshin wrote:
> From: David Rivshin <DRivshin@allworx.com>
> 
> NUMREGBYTES (which is used as the size for gdb_regs[]) is incorrectly based
> on DBG_MAX_REG_NUM instead of GDB_MAX_REGS. DBG_MAX_REG_NUM is the number
> of total registers, while GDB_MAX_REGS is the number of 'unsigned longs'
> it takes to serialize those registers. Since FP registers require 3
> 'unsigned longs' each, DBG_MAX_REG_NUM is smaller than GDB_MAX_REGS.
> 
> This causes GDB 8.0 give the following error on connect:
> "Truncated register 19 in remote 'g' packet"
> 
> This also causes the register serialization/deserialization logic to
> overflow gdb_regs[], overwriting whatever follows.
> 
> Fixes: 834b2964b7ab ("kgdb,arm: fix register dump")
> Cc: <stable@vger.kernel.org> # 2.6.37+
> Signed-off-by: David Rivshin <drivshin@allworx.com>

Acked-by: Rabin Vincent <rabin@rab.in>
Daniel Thompson April 6, 2018, 1:25 p.m. UTC | #2
On Thu, Apr 05, 2018 at 04:09:16PM -0400, David Rivshin wrote:
> From: David Rivshin <DRivshin@allworx.com>
> 
> NUMREGBYTES (which is used as the size for gdb_regs[]) is incorrectly based
> on DBG_MAX_REG_NUM instead of GDB_MAX_REGS. DBG_MAX_REG_NUM is the number
> of total registers, while GDB_MAX_REGS is the number of 'unsigned longs'
> it takes to serialize those registers. Since FP registers require 3
> 'unsigned longs' each, DBG_MAX_REG_NUM is smaller than GDB_MAX_REGS.
> 
> This causes GDB 8.0 give the following error on connect:
> "Truncated register 19 in remote 'g' packet"
> 
> This also causes the register serialization/deserialization logic to
> overflow gdb_regs[], overwriting whatever follows.
> 
> Fixes: 834b2964b7ab ("kgdb,arm: fix register dump")
> Cc: <stable@vger.kernel.org> # 2.6.37+
> Signed-off-by: David Rivshin <drivshin@allworx.com>

I pointed some trivial autotests at both gdb-7.12 and gdb-8.0. Results
look good to me!

Tested-by: Daniel Thompson <daniel.thompson@linaro.org>

> ---
>  arch/arm/include/asm/kgdb.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/arm/include/asm/kgdb.h b/arch/arm/include/asm/kgdb.h
> index 3b73fdcf3627a..8de1100d10674 100644
> --- a/arch/arm/include/asm/kgdb.h
> +++ b/arch/arm/include/asm/kgdb.h
> @@ -77,7 +77,7 @@ extern int kgdb_fault_expected;
>  
>  #define KGDB_MAX_NO_CPUS	1
>  #define BUFMAX			400
> -#define NUMREGBYTES		(DBG_MAX_REG_NUM << 2)
> +#define NUMREGBYTES		(GDB_MAX_REGS << 2)
>  #define NUMCRITREGBYTES		(32 << 2)
>  
>  #define _R0			0
> 
> base-commit: 0adb32858b0bddf4ada5f364a84ed60b196dbcda
> -- 
> 2.14.3
>
Daniel Thompson April 6, 2018, 1:49 p.m. UTC | #3
On 06/04/18 14:25, Daniel Thompson wrote:
> On Thu, Apr 05, 2018 at 04:09:16PM -0400, David Rivshin wrote:
>> From: David Rivshin <DRivshin@allworx.com>
>>
>> NUMREGBYTES (which is used as the size for gdb_regs[]) is incorrectly based
>> on DBG_MAX_REG_NUM instead of GDB_MAX_REGS. DBG_MAX_REG_NUM is the number
>> of total registers, while GDB_MAX_REGS is the number of 'unsigned longs'
>> it takes to serialize those registers. Since FP registers require 3
>> 'unsigned longs' each, DBG_MAX_REG_NUM is smaller than GDB_MAX_REGS.
>>
>> This causes GDB 8.0 give the following error on connect:
>> "Truncated register 19 in remote 'g' packet"
>>
>> This also causes the register serialization/deserialization logic to
>> overflow gdb_regs[], overwriting whatever follows.
>>
>> Fixes: 834b2964b7ab ("kgdb,arm: fix register dump")
>> Cc: <stable@vger.kernel.org> # 2.6.37+
>> Signed-off-by: David Rivshin <drivshin@allworx.com>
> 
> I pointed some trivial autotests at both gdb-7.12 and gdb-8.0. Results
> look good to me!
> 
> Tested-by: Daniel Thompson <daniel.thompson@linaro.org>

BTW I noticed that myself and Jason in the only "real people" in
To: . Most arch specific patches end up making their way upstream via 
the arch maintainer rather than via the kgdb tree so personally I would 
choose to the arch maintainers in the To: field as well.

I certainly think you will have to follow up via Russell King's patch 
tracker once you think its had enough time on the ML for review.


Daniel.


> 
>> ---
>>   arch/arm/include/asm/kgdb.h | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/arch/arm/include/asm/kgdb.h b/arch/arm/include/asm/kgdb.h
>> index 3b73fdcf3627a..8de1100d10674 100644
>> --- a/arch/arm/include/asm/kgdb.h
>> +++ b/arch/arm/include/asm/kgdb.h
>> @@ -77,7 +77,7 @@ extern int kgdb_fault_expected;
>>   
>>   #define KGDB_MAX_NO_CPUS	1
>>   #define BUFMAX			400
>> -#define NUMREGBYTES		(DBG_MAX_REG_NUM << 2)
>> +#define NUMREGBYTES		(GDB_MAX_REGS << 2)
>>   #define NUMCRITREGBYTES		(32 << 2)
>>   
>>   #define _R0			0
>>
>> base-commit: 0adb32858b0bddf4ada5f364a84ed60b196dbcda
>> -- 
>> 2.14.3
>>
David Rivshin April 6, 2018, 4:36 p.m. UTC | #4
On Fri, 6 Apr 2018 14:49:22 +0100
Daniel Thompson <daniel.thompson@linaro.org> wrote:

> On 06/04/18 14:25, Daniel Thompson wrote:
> > On Thu, Apr 05, 2018 at 04:09:16PM -0400, David Rivshin wrote:  
> >> From: David Rivshin <DRivshin@allworx.com>
> >>
> >> NUMREGBYTES (which is used as the size for gdb_regs[]) is incorrectly based
> >> on DBG_MAX_REG_NUM instead of GDB_MAX_REGS. DBG_MAX_REG_NUM is the number
> >> of total registers, while GDB_MAX_REGS is the number of 'unsigned longs'
> >> it takes to serialize those registers. Since FP registers require 3
> >> 'unsigned longs' each, DBG_MAX_REG_NUM is smaller than GDB_MAX_REGS.
> >>
> >> This causes GDB 8.0 give the following error on connect:
> >> "Truncated register 19 in remote 'g' packet"
> >>
> >> This also causes the register serialization/deserialization logic to
> >> overflow gdb_regs[], overwriting whatever follows.
> >>
> >> Fixes: 834b2964b7ab ("kgdb,arm: fix register dump")
> >> Cc: <stable@vger.kernel.org> # 2.6.37+
> >> Signed-off-by: David Rivshin <drivshin@allworx.com>  
> > 
> > I pointed some trivial autotests at both gdb-7.12 and gdb-8.0. Results
> > look good to me!
> > 
> > Tested-by: Daniel Thompson <daniel.thompson@linaro.org>  
> 
> BTW I noticed that myself and Jason in the only "real people" in
> To: . Most arch specific patches end up making their way upstream via 
> the arch maintainer rather than via the kgdb tree so personally I would 
> choose to the arch maintainers in the To: field as well.
> 
> I certainly think you will have to follow up via Russell King's patch 
> tracker once you think its had enough time on the ML for review.

Thanks for testing and the pointer, I wasn't sure what tree this would 
go through.

Russell, if you have no objections I'll let this soak on the ML for a 
bit longer, and then submit it to your patch tracker with collected tags.


> 
> 
> Daniel.
> 
> 
> >   
> >> ---
> >>   arch/arm/include/asm/kgdb.h | 2 +-
> >>   1 file changed, 1 insertion(+), 1 deletion(-)
> >>
> >> diff --git a/arch/arm/include/asm/kgdb.h b/arch/arm/include/asm/kgdb.h
> >> index 3b73fdcf3627a..8de1100d10674 100644
> >> --- a/arch/arm/include/asm/kgdb.h
> >> +++ b/arch/arm/include/asm/kgdb.h
> >> @@ -77,7 +77,7 @@ extern int kgdb_fault_expected;
> >>   
> >>   #define KGDB_MAX_NO_CPUS	1
> >>   #define BUFMAX			400
> >> -#define NUMREGBYTES		(DBG_MAX_REG_NUM << 2)
> >> +#define NUMREGBYTES		(GDB_MAX_REGS << 2)
> >>   #define NUMCRITREGBYTES		(32 << 2)
> >>   
> >>   #define _R0			0
> >>
> >> base-commit: 0adb32858b0bddf4ada5f364a84ed60b196dbcda
> >> -- 
> >> 2.14.3
> >>  
>
Sasha Levin April 10, 2018, 1:51 p.m. UTC | #5
Hi,

[This is an automated email]

This commit has been processed because it contains a "Fixes:" tag,
fixing commit: 834b2964b7ab kgdb,arm: fix register dump.

The bot has also determined it's probably a bug fixing patch. (score: 97.9682)

The bot has tested the following trees: v4.16.1, v4.15.16, v4.14.33, v4.9.93, v4.4.127.

v4.16.1: Build OK!
v4.15.16: Build OK!
v4.14.33: Build OK!
v4.9.93: Build OK!
v4.4.127: Build OK!

--
Thanks,
Sasha
diff mbox

Patch

diff --git a/arch/arm/include/asm/kgdb.h b/arch/arm/include/asm/kgdb.h
index 3b73fdcf3627a..8de1100d10674 100644
--- a/arch/arm/include/asm/kgdb.h
+++ b/arch/arm/include/asm/kgdb.h
@@ -77,7 +77,7 @@  extern int kgdb_fault_expected;
 
 #define KGDB_MAX_NO_CPUS	1
 #define BUFMAX			400
-#define NUMREGBYTES		(DBG_MAX_REG_NUM << 2)
+#define NUMREGBYTES		(GDB_MAX_REGS << 2)
 #define NUMCRITREGBYTES		(32 << 2)
 
 #define _R0			0