[PATCH] m68k: fix sigreturn decoding

[Andreas Schwab]

"Dmitry V. Levin" <ldv-u2l5PoMzF/Vg9hUCZPvPmw at public.gmane.org> writes:

> On Wed, Mar 11, 2015 at 03:10:34PM +0100, Andreas Schwab wrote:
>> * sigreturn.c (sys_sigreturn) [M68K]: Fetch the words of the
>> signal mask from the proper place.
>> ---
>>  sigreturn.c | 14 +++++++++++++-
>>  1 file changed, 13 insertions(+), 1 deletion(-)
>> 
>> diff --git a/sigreturn.c b/sigreturn.c
>> index 648bd0a..a96257f 100644
>> --- a/sigreturn.c
>> +++ b/sigreturn.c
>> @@ -128,8 +128,20 @@ sys_sigreturn(struct tcb *tcp)
>>  		long addr;
>>  		if (upeek(tcp->pid, 4*PT_USP, &addr) < 0)
>>  			return 0;
>> +		/* Fetch pointer to struct sigcontext.  */
>> +		if (umove(tcp, addr + 2 * sizeof(int), &addr) < 0)
>> +			return 0;
>> +		unsigned long mask[NSIG / 8 / sizeof(long)];
>> +		/* Fetch first word of signal mask.  */
>> +		if (umove(tcp, addr, &mask[0]) < 0)
>> +			return 0;
>> +		/* Fetch remaining words of signal mask, located
>> +		   immediately before.  */
>> +		addr -= sizeof (mask) - sizeof(long);
>> +		if (umoven(tcp, addr, sizeof (mask) - sizeof(long), (char *) &mask[1]) < 0)
>> +			return 0;
>
> You might want to save a syscall here by fetching the whole sizeof(mask)
> in a single umoven call.

They are not consecutive.

Andreas.

-- 
Andreas Schwab, SUSE Labs, schwab at suse.de
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