A typical code fragment was copied across many dvb-frontend drivers and
causes large stack frames when built with with CONFIG_KASAN on gcc-5/6/7:
drivers/media/dvb-frontends/cxd2841er.c:3225:1: error: the frame size of 3992 bytes is larger than 3072 bytes [-Werror=frame-larger-than=]
drivers/media/dvb-frontends/cxd2841er.c:3404:1: error: the frame size of 3136 bytes is larger than 3072 bytes [-Werror=frame-larger-than=]
drivers/media/dvb-frontends/stv0367.c:3143:1: error: the frame size of 4016 bytes is larger than 3072 bytes [-Werror=frame-larger-than=]
drivers/media/dvb-frontends/stv090x.c:3430:1: error: the frame size of 5312 bytes is larger than 3072 bytes [-Werror=frame-larger-than=]
drivers/media/dvb-frontends/stv090x.c:4248:1: error: the frame size of 4872 bytes is larger than 3072 bytes [-Werror=frame-larger-than=]
gcc-8 now solves this by consolidating the stack slots for the argument
variables, but on older compilers we can get the same behavior by taking
the pointer of a local variable rather than the inline function argument.
Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81715
Cc: stable@vger.kernel.org
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
It is not clear what this return value means. All implemenations
return 0, and the one caller ignores the value. Let's remove this
useless return value completely.
Signed-off-by: Max Kellermann <max.kellermann@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
These structures are only used to copy into other structures, so declare
them as const.
The semantic patch that makes this change is as follows:
(http://coccinelle.lip6.fr/)
// <smpl>
@r disable optional_qualifier@
identifier i;
position p;
@@
static struct dvb_tuner_ops i@p = { ... };
@ok1@
identifier r.i;
expression e;
position p;
@@
e = i@p
@ok2@
identifier r.i;
expression e1, e2;
position p;
@@
memcpy(e1, &i@p, e2)
@bad@
position p != {r.p,ok1.p,ok2.p};
identifier r.i;
struct dvb_tuner_ops e;
@@
e@i@p
@depends on !bad disable optional_qualifier@
identifier r.i;
@@
static
+const
struct dvb_tuner_ops i = { ... };
// </smpl>
Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Tuning a card with Sony ASCOT2E produces the following error:
kernel: i2c i2c-9: wr reg=0006: len=11 is too big!
MAX_WRITE_REGSIZE is defined as 10, buf[MAX_WRITE_REGSIZE + 1] buffer is
used in ascot2e_write_regs().
The problem is that exactly 10 bytes are written in ascot2e_set_params():
/* Set BW_OFFSET (0x0F) value from parameter table */
data[9] = ascot2e_sett[tv_system].bw_offset;
ascot2e_write_regs(priv, 0x06, data, 10);
The test in write_regs is as follows:
if (len + 1 >= sizeof(buf))
10 + 1 = 11 and that would be exactly the size of buf. Since 10 bytes +
buf[0] = reg would seem to fit into buf[], this shouldn't be an error.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
The Linux stack is short; we need to be able to count the number
of bytes used at stack on each function. So, we don't like to
use variable-length arrays, as complained by smatch:
drivers/media/dvb-frontends/horus3a.c:57:19: warning: Variable length array is used.
The max usecase of the driver seems to be 10 bytes + 1 for the
register.
So, let's be safe and allocate 11 bytes for the write buffer.
This should be enough to cover all cases. If not, let's print
an error message.
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
