[ Upstream commit ab705c8c35e18652abc6239c07cf3441f03e2cda ]
Correct some left shifts of the signed integer constant 1 by some unsigned number less than 32. Change the constant to 1U to avoid shifting a 1 into the sign bit.
The corrected functions are comedi_dio_insn_config(), comedi_dio_update_state(), and __comedi_device_postconfig().
Fixes: e523c6c86232 ("staging: comedi: drivers: introduce comedi_dio_insn_config()") Fixes: 05e60b13a36b ("staging: comedi: drivers: introduce comedi_dio_update_state()") Fixes: 09567cb4373e ("staging: comedi: initialize subdevice s->io_bits in postconfig") Cc: stable@vger.kernel.org # 5.13+ Signed-off-by: Ian Abbott abbotti@mev.co.uk Link: https://lore.kernel.org/r/20250707121555.65424-1-abbotti@mev.co.uk Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/staging/comedi/drivers.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-)
diff --git a/drivers/staging/comedi/drivers.c b/drivers/staging/comedi/drivers.c index 750a6ff3c03c..6bb7b8a1e75d 100644 --- a/drivers/staging/comedi/drivers.c +++ b/drivers/staging/comedi/drivers.c @@ -339,10 +339,10 @@ int comedi_dio_insn_config(struct comedi_device *dev, unsigned int *data, unsigned int mask) { - unsigned int chan_mask = 1 << CR_CHAN(insn->chanspec); + unsigned int chan = CR_CHAN(insn->chanspec);
- if (!mask) - mask = chan_mask; + if (!mask && chan < 32) + mask = 1U << chan;
switch (data[0]) { case INSN_CONFIG_DIO_INPUT: @@ -382,7 +382,7 @@ EXPORT_SYMBOL_GPL(comedi_dio_insn_config); unsigned int comedi_dio_update_state(struct comedi_subdevice *s, unsigned int *data) { - unsigned int chanmask = (s->n_chan < 32) ? ((1 << s->n_chan) - 1) + unsigned int chanmask = (s->n_chan < 32) ? ((1U << s->n_chan) - 1) : 0xffffffff; unsigned int mask = data[0] & chanmask; unsigned int bits = data[1]; @@ -625,8 +625,8 @@ static int insn_rw_emulate_bits(struct comedi_device *dev, if (insn->insn == INSN_WRITE) { if (!(s->subdev_flags & SDF_WRITABLE)) return -EINVAL; - _data[0] = 1 << (chan - base_chan); /* mask */ - _data[1] = data[0] ? (1 << (chan - base_chan)) : 0; /* bits */ + _data[0] = 1U << (chan - base_chan); /* mask */ + _data[1] = data[0] ? (1U << (chan - base_chan)) : 0; /* bits */ }
ret = s->insn_bits(dev, s, &_insn, _data); @@ -709,7 +709,7 @@ static int __comedi_device_postconfig(struct comedi_device *dev)
if (s->type == COMEDI_SUBD_DO) { if (s->n_chan < 32) - s->io_bits = (1 << s->n_chan) - 1; + s->io_bits = (1U << s->n_chan) - 1; else s->io_bits = 0xffffffff; }
[ Sasha's backport helper bot ]
Hi,
✅ All tests passed successfully. No issues detected. No action required from the submitter.
The upstream commit SHA1 provided is correct: ab705c8c35e18652abc6239c07cf3441f03e2cda
Status in newer kernel trees: 6.15.y | Not found 6.12.y | Not found 6.6.y | Not found 6.1.y | Not found 5.15.y | Not found
Note: The patch differs from the upstream commit: --- 1: ab705c8c35e1 ! 1: 0d19deff7ec8 comedi: Fix some signed shift left operations @@ Metadata ## Commit message ## comedi: Fix some signed shift left operations
+ [ Upstream commit ab705c8c35e18652abc6239c07cf3441f03e2cda ] + Correct some left shifts of the signed integer constant 1 by some unsigned number less than 32. Change the constant to 1U to avoid shifting a 1 into the sign bit. @@ Commit message Link: https://lore.kernel.org/r/20250707121555.65424-1-abbotti@mev.co.uk Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
- ## drivers/comedi/drivers.c ## -@@ drivers/comedi/drivers.c: int comedi_dio_insn_config(struct comedi_device *dev, + ## drivers/staging/comedi/drivers.c ## +@@ drivers/staging/comedi/drivers.c: int comedi_dio_insn_config(struct comedi_device *dev, unsigned int *data, unsigned int mask) { @@ drivers/comedi/drivers.c: int comedi_dio_insn_config(struct comedi_device *dev,
switch (data[0]) { case INSN_CONFIG_DIO_INPUT: -@@ drivers/comedi/drivers.c: EXPORT_SYMBOL_GPL(comedi_dio_insn_config); +@@ drivers/staging/comedi/drivers.c: EXPORT_SYMBOL_GPL(comedi_dio_insn_config); unsigned int comedi_dio_update_state(struct comedi_subdevice *s, unsigned int *data) { @@ drivers/comedi/drivers.c: EXPORT_SYMBOL_GPL(comedi_dio_insn_config); : 0xffffffff; unsigned int mask = data[0] & chanmask; unsigned int bits = data[1]; -@@ drivers/comedi/drivers.c: static int insn_rw_emulate_bits(struct comedi_device *dev, +@@ drivers/staging/comedi/drivers.c: static int insn_rw_emulate_bits(struct comedi_device *dev, if (insn->insn == INSN_WRITE) { if (!(s->subdev_flags & SDF_WRITABLE)) return -EINVAL; @@ drivers/comedi/drivers.c: static int insn_rw_emulate_bits(struct comedi_device * }
ret = s->insn_bits(dev, s, &_insn, _data); -@@ drivers/comedi/drivers.c: static int __comedi_device_postconfig(struct comedi_device *dev) +@@ drivers/staging/comedi/drivers.c: static int __comedi_device_postconfig(struct comedi_device *dev)
if (s->type == COMEDI_SUBD_DO) { if (s->n_chan < 32)
---
Results of testing on various branches:
| Branch | Patch Apply | Build Test | |---------------------------|-------------|------------| | origin/linux-5.10.y | Success | Success |
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Ian Abbott -
Sasha Levin