2018-04-05 20:30:49

by David Rivshin

[permalink] [raw]
Subject: [PATCH] arm: kgdb: fix NUMREGBYTES so that gdb_regs[] is the correct size

From: David Rivshin <[email protected]>

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: <[email protected]> # 2.6.37+
Signed-off-by: David Rivshin <[email protected]>
---
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



2018-04-05 20:50:09

by Rabin Vincent

[permalink] [raw]
Subject: Re: [PATCH] arm: kgdb: fix NUMREGBYTES so that gdb_regs[] is the correct size

On Thu, Apr 05, 2018 at 04:09:16PM -0400, David Rivshin wrote:
> From: David Rivshin <[email protected]>
>
> 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: <[email protected]> # 2.6.37+
> Signed-off-by: David Rivshin <[email protected]>

Acked-by: Rabin Vincent <[email protected]>

2018-04-06 13:51:33

by Daniel Thompson

[permalink] [raw]
Subject: Re: [PATCH] arm: kgdb: fix NUMREGBYTES so that gdb_regs[] is the correct size

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 <[email protected]>
>>
>> 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: <[email protected]> # 2.6.37+
>> Signed-off-by: David Rivshin <[email protected]>
>
> I pointed some trivial autotests at both gdb-7.12 and gdb-8.0. Results
> look good to me!
>
> Tested-by: Daniel Thompson <[email protected]>

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
>>


2018-04-06 15:36:24

by Daniel Thompson

[permalink] [raw]
Subject: Re: [PATCH] arm: kgdb: fix NUMREGBYTES so that gdb_regs[] is the correct size

On Thu, Apr 05, 2018 at 04:09:16PM -0400, David Rivshin wrote:
> From: David Rivshin <[email protected]>
>
> 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: <[email protected]> # 2.6.37+
> Signed-off-by: David Rivshin <[email protected]>

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

Tested-by: Daniel Thompson <[email protected]>

> ---
> 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
>

2018-04-06 16:38:58

by David Rivshin

[permalink] [raw]
Subject: Re: [PATCH] arm: kgdb: fix NUMREGBYTES so that gdb_regs[] is the correct size

On Fri, 6 Apr 2018 14:49:22 +0100
Daniel Thompson <[email protected]> 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 <[email protected]>
> >>
> >> 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: <[email protected]> # 2.6.37+
> >> Signed-off-by: David Rivshin <[email protected]>
> >
> > I pointed some trivial autotests at both gdb-7.12 and gdb-8.0. Results
> > look good to me!
> >
> > Tested-by: Daniel Thompson <[email protected]>
>
> 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
> >>
>


2018-04-10 13:55:46

by Sasha Levin

[permalink] [raw]
Subject: Re: [PATCH] arm: kgdb: fix NUMREGBYTES so that gdb_regs[] is the correct size

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