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

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