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| author | Arnd Bergmann <arnd@arndb.de> | 2024-02-16 17:31:44 +0100 |
|---|---|---|
| committer | Hans Verkuil <hverkuil-cisco@xs4all.nl> | 2024-02-28 16:00:33 +0100 |
| commit | 7a4cf27d1f0538f779bf31b8c99eda394e277119 (patch) | |
| tree | 981502d78820dd81b26439ec28977fd5a1f18289 /drivers/media | |
| parent | 0a0b79ea55de8514e1750884e5fec77f9fdd01ee (diff) | |
| download | lwn-7a4cf27d1f0538f779bf31b8c99eda394e277119.tar.gz lwn-7a4cf27d1f0538f779bf31b8c99eda394e277119.zip | |
media: dvb-frontends: avoid stack overflow warnings with clang
A previous patch worked around a KASAN issue in stv0367, now a similar
problem showed up with clang:
drivers/media/dvb-frontends/stv0367.c:1222:12: error: stack frame size (3624) exceeds limit (2048) in 'stv0367ter_set_frontend' [-Werror,-Wframe-larger-than]
1214 | static int stv0367ter_set_frontend(struct dvb_frontend *fe)
Rework the stv0367_writereg() function to be simpler and mark both
register access functions as noinline_for_stack so the temporary
i2c_msg structures do not get duplicated on the stack when KASAN_STACK
is enabled.
Fixes: 3cd890dbe2a4 ("media: dvb-frontends: fix i2c access helpers for KASAN")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Justin Stitt <justinstitt@google.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Diffstat (limited to 'drivers/media')
| -rw-r--r-- | drivers/media/dvb-frontends/stv0367.c | 34 |
1 files changed, 8 insertions, 26 deletions
diff --git a/drivers/media/dvb-frontends/stv0367.c b/drivers/media/dvb-frontends/stv0367.c index 48326434488c..72540ef4e5f8 100644 --- a/drivers/media/dvb-frontends/stv0367.c +++ b/drivers/media/dvb-frontends/stv0367.c @@ -118,50 +118,32 @@ static const s32 stv0367cab_RF_LookUp2[RF_LOOKUP_TABLE2_SIZE][RF_LOOKUP_TABLE2_S } }; -static -int stv0367_writeregs(struct stv0367_state *state, u16 reg, u8 *data, int len) +static noinline_for_stack +int stv0367_writereg(struct stv0367_state *state, u16 reg, u8 data) { - u8 buf[MAX_XFER_SIZE]; + u8 buf[3] = { MSB(reg), LSB(reg), data }; struct i2c_msg msg = { .addr = state->config->demod_address, .flags = 0, .buf = buf, - .len = len + 2 + .len = 3, }; int ret; - if (2 + len > sizeof(buf)) { - printk(KERN_WARNING - "%s: i2c wr reg=%04x: len=%d is too big!\n", - KBUILD_MODNAME, reg, len); - return -EINVAL; - } - - - buf[0] = MSB(reg); - buf[1] = LSB(reg); - memcpy(buf + 2, data, len); - if (i2cdebug) printk(KERN_DEBUG "%s: [%02x] %02x: %02x\n", __func__, - state->config->demod_address, reg, buf[2]); + state->config->demod_address, reg, data); ret = i2c_transfer(state->i2c, &msg, 1); if (ret != 1) printk(KERN_ERR "%s: i2c write error! ([%02x] %02x: %02x)\n", - __func__, state->config->demod_address, reg, buf[2]); + __func__, state->config->demod_address, reg, data); return (ret != 1) ? -EREMOTEIO : 0; } -static int stv0367_writereg(struct stv0367_state *state, u16 reg, u8 data) -{ - u8 tmp = data; /* see gcc.gnu.org/bugzilla/show_bug.cgi?id=81715 */ - - return stv0367_writeregs(state, reg, &tmp, 1); -} - -static u8 stv0367_readreg(struct stv0367_state *state, u16 reg) +static noinline_for_stack +u8 stv0367_readreg(struct stv0367_state *state, u16 reg) { u8 b0[] = { 0, 0 }; u8 b1[] = { 0 }; |