kernel/linux.git/drivers/comedi, branch v6.12.93

comedi: comedi_test: Fix limiting of convert_arg in waveform_ai_cmdtest()

2026-06-09T10:25:56+00:00

commit 8a3bee801d420be8a7a0bae4a26547b353b8fe22 upstream. The function checks and possibly modifies the description of an asynchronous command to be run on the analog input subdevice of a comedi device attached to the "comedi_test" driver, returning 0 if no modifications were required, or a positive value that indicates which step of the checking process it failed on. Step 4 fixes up various argument values for various trigger sources. There are two bugs in the fixing up of the `convert_arg` value to keep the `scan_begin_arg` value within the range of `unsigned int` when `scan_begin_src` and `convert_src` both have the value `TRIG_TIMER`, which indicates that the corresponding `_arg` values hold a time period in nanoseconds. The code also uses `scan_end_arg` which hold the number of "conversions" within each "scan". The goal is to end up with the scan period being less than or equal to the convert period multiplied by the number of conversions per scan. It intends to do that by clamping the `convert_arg` value to a maximum value of `UINT_MAX / scan_end_arg` rounded down to a multiple of 1000 (`NSEC_PER_USEC`). (The rounding from nanoseconds to microseconds is because the driver is modelling a device that uses a 1 MHz clock for timing. This is partly because that is a more typical timing base for real hardware devices driven by comedi, and partly because the driver used to use `struct timeval` internally.) The first bug is that the code checks if `scan_begin_arg == TRIG_TIMER` when it should be checking if `scan_begin_src == TRIG_TIMER`. The bugged check will always fail because if `scan_begin_src == TRIG_TIMER`, then `scan_begin_arg` will be at least 1000 (`NSEC_PER_USEC`), otherwise `scan_begin_src == TRIG_FOLLOW` and `scan_begin_arg` will be 0. (N.B `TRIG_TIMER` is defined as `0x10`.) The second bug is that is rounding the maximum value down to a multiple of 1000000000 (`NSEC_PER_SEC`) instead of 1000 (`NSEC_PER_USEC`), however this bug is not reached due to the first bug. This patch fixes both bugs. Fixes: 783ddaebd397 ("staging: comedi: comedi_test: support scan_begin_src == TRIG_FOLLOW") Fixes: 5afdcad2f818 ("staging: comedi: comedi_test: limit maximum convert_arg") Cc: stable Signed-off-by: Ian Abbott Link: https://patch.msgid.link/20260422144637.27692-1-abbotti@mev.co.uk Signed-off-by: Greg Kroah-Hartman Signed-off-by: Greg Kroah-Hartman

comedi: comedi_test: fix check for valid scan_begin_src in waveform_ai_cmdtest()

2026-06-09T10:25:56+00:00

commit 542f5248cb481073203e0dadab5bcbd28aeae308 upstream. Commit 783ddaebd397 ("staging: comedi: comedi_test: support scan_begin_src == TRIG_FOLLOW") neglected to add a test that `scan_begin_src` has only one bit set. The allowed values are `TRIG_FOLLOW` and `TRIG_TIMER`, but the code incorrectly also allows `TRIG_FOLLOW | TRIG_TIMER`. Add a call to `comedi_check_trigger_is_unique()` to check that only one trigger source bit is set. Fixes: 783ddaebd397 ("staging: comedi: comedi_test: support scan_begin_src == TRIG_FOLLOW") Cc: stable Signed-off-by: Ian Abbott Link: https://patch.msgid.link/20260422162138.36003-1-abbotti@mev.co.uk Signed-off-by: Greg Kroah-Hartman Signed-off-by: Greg Kroah-Hartman

comedi: me4000: Fix potential overrun of firmware buffer

2026-04-11T12:24:47+00:00

commit 3fb43a7a5b44713f892c58ead2e5f3a1bc9f4ee7 upstream. `me4000_xilinx_download()` loads the firmware that was requested by `request_firmware()`. It is possible for it to overrun the source buffer because it blindly trusts the file format. It reads a data stream length from the first 4 bytes into variable `file_length` and reads the data stream contents of length `file_length` from offset 16 onwards. Add a test to ensure that the supplied firmware is long enough to contain the header and the data stream. On failure, log an error and return `-EINVAL`. Note: The firmware loading was totally broken before commit ac584af59945 ("staging: comedi: me4000: fix firmware downloading"), but that is the most sensible target for this fix. Fixes: ac584af59945 ("staging: comedi: me4000: fix firmware downloading") Cc: stable Signed-off-by: Ian Abbott Link: https://patch.msgid.link/20260205133949.71722-1-abbotti@mev.co.uk Signed-off-by: Greg Kroah-Hartman

comedi: me_daq: Fix potential overrun of firmware buffer

2026-04-11T12:24:47+00:00

commit cc797d4821c754c701d9714b58bea947e31dbbe0 upstream. `me2600_xilinx_download()` loads the firmware that was requested by `request_firmware()`. It is possible for it to overrun the source buffer because it blindly trusts the file format. It reads a data stream length from the first 4 bytes into variable `file_length` and reads the data stream contents of length `file_length` from offset 16 onwards. Although it checks that the supplied firmware is at least 16 bytes long, it does not check that it is long enough to contain the data stream. Add a test to ensure that the supplied firmware is long enough to contain the header and the data stream. On failure, log an error and return `-EINVAL`. Fixes: 85acac61096f9 ("Staging: comedi: add me_daq driver") Cc: stable Signed-off-by: Ian Abbott Link: https://patch.msgid.link/20260205140130.76697-1-abbotti@mev.co.uk Signed-off-by: Greg Kroah-Hartman

comedi: ni_atmio16d: Fix invalid clean-up after failed attach

2026-04-11T12:24:47+00:00

commit 101ab946b79ad83b36d5cfd47de587492a80acf0 upstream. If the driver's COMEDI "attach" handler function (`atmio16d_attach()`) returns an error, the COMEDI core will call the driver's "detach" handler function (`atmio16d_detach()`) to clean up. This calls `reset_atmio16d()` unconditionally, but depending on where the error occurred in the attach handler, the device may not have been sufficiently initialized to call `reset_atmio16d()`. It uses `dev->iobase` as the I/O port base address and `dev->private` as the pointer to the COMEDI device's private data structure. `dev->iobase` may still be set to its initial value of 0, which would result in undesired writes to low I/O port addresses. `dev->private` may still be `NULL`, which would result in null pointer dereferences. Fix `atmio16d_detach()` by checking that `dev->private` is valid (non-null) before calling `reset_atmio16d()`. This implies that `dev->iobase` was set correctly since that is set up before `dev->private`. Fixes: 2323b276308a ("Staging: comedi: add ni_at_atmio16d driver") Cc: stable Signed-off-by: Ian Abbott Link: https://patch.msgid.link/20260128150011.5006-1-abbotti@mev.co.uk Signed-off-by: Greg Kroah-Hartman

comedi: Reinit dev->spinlock between attachments to low-level drivers

2026-04-11T12:24:47+00:00

commit 4b9a9a6d71e3e252032f959fb3895a33acb5865c upstream. `struct comedi_device` is the main controlling structure for a COMEDI device created by the COMEDI subsystem. It contains a member `spinlock` containing a spin-lock that is initialized by the COMEDI subsystem, but is reserved for use by a low-level driver attached to the COMEDI device (at least since commit 25436dc9d84f ("Staging: comedi: remove RT code")). Some COMEDI devices (those created on initialization of the COMEDI subsystem when the "comedi.comedi_num_legacy_minors" parameter is non-zero) can be attached to different low-level drivers over their lifetime using the `COMEDI_DEVCONFIG` ioctl command. This can result in inconsistent lock states being reported when there is a mismatch in the spin-lock locking levels used by each low-level driver to which the COMEDI device has been attached. Fix it by reinitializing `dev->spinlock` before calling the low-level driver's `attach` function pointer if `CONFIG_LOCKDEP` is enabled. Reported-by: syzbot+cc9f7f4a7df09f53c4a4@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=cc9f7f4a7df09f53c4a4 Fixes: ed9eccbe8970 ("Staging: add comedi core") Cc: stable Signed-off-by: Ian Abbott Link: https://patch.msgid.link/20260225132427.86578-1-abbotti@mev.co.uk Signed-off-by: Greg Kroah-Hartman

comedi: dt2815: add hardware detection to prevent crash

2026-04-11T12:24:47+00:00

commit 93853512f565e625df2397f0d8050d6aafd7c3ad upstream. The dt2815 driver crashes when attached to I/O ports without actual hardware present. This occurs because syzkaller or users can attach the driver to arbitrary I/O addresses via COMEDI_DEVCONFIG ioctl. When no hardware exists at the specified port, inb() operations return 0xff (floating bus), but outb() operations can trigger page faults due to undefined behavior, especially under race conditions: BUG: unable to handle page fault for address: 000000007fffff90 #PF: supervisor write access in kernel mode #PF: error_code(0x0002) - not-present page RIP: 0010:dt2815_attach+0x6e0/0x1110 Add hardware detection by reading the status register before attempting any write operations. If the read returns 0xff, assume no hardware is present and fail the attach with -ENODEV. This prevents crashes from outb() operations on non-existent hardware. Reported-by: syzbot+72f94b474d6e50b71ffc@syzkaller.appspotmail.com Cc: stable Closes: https://syzkaller.appspot.com/bug?extid=72f94b474d6e50b71ffc Tested-by: syzbot+72f94b474d6e50b71ffc@syzkaller.appspotmail.com Reviewed-by: Ian Abbott Signed-off-by: Deepanshu Kartikey Link: [https://lore.kernel.org/all/20260126070458.10974-1-kartikey406@gmail.com/T/] Link: [https://lore.kernel.org/all/20260126070458.10974-1-kartikey406@gmail.com/T/ Link: https://patch.msgid.link/20260309104859.503529-1-kartikey406@gmail.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Greg Kroah-Hartman

comedi: Fix getting range information for subdevices 16 to 255

2026-01-30T09:28:40+00:00

commit 10d28cffb3f6ec7ad67f0a4cd32c2afa92909452 upstream. The `COMEDI_RANGEINFO` ioctl does not work properly for subdevice indices above 15. Currently, the only in-tree COMEDI drivers that support more than 16 subdevices are the "8255" driver and the "comedi_bond" driver. Making the ioctl work for subdevice indices up to 255 is achievable. It needs minor changes to the handling of the `COMEDI_RANGEINFO` and `COMEDI_CHANINFO` ioctls that should be mostly harmless to user-space, apart from making them less broken. Details follow... The `COMEDI_RANGEINFO` ioctl command gets the list of supported ranges (usually with units of volts or milliamps) for a COMEDI subdevice or channel. (Only some subdevices have per-channel range tables, indicated by the `SDF_RANGETYPE` flag in the subdevice information.) It uses a `range_type` value and a user-space pointer, both supplied by user-space, but the `range_type` value should match what was obtained using the `COMEDI_CHANINFO` ioctl (if the subdevice has per-channel range tables) or `COMEDI_SUBDINFO` ioctl (if the subdevice uses a single range table for all channels). Bits 15 to 0 of the `range_type` value contain the length of the range table, which is the only part that user-space should care about (so it can use a suitably sized buffer to fetch the range table). Bits 23 to 16 store the channel index, which is assumed to be no more than 255 if the subdevice has per-channel range tables, and is set to 0 if the subdevice has a single range table. For `range_type` values produced by the `COMEDI_SUBDINFO` ioctl, bits 31 to 24 contain the subdevice index, which is assumed to be no more than 255. But for `range_type` values produced by the `COMEDI_CHANINFO` ioctl, bits 27 to 24 contain the subdevice index, which is assumed to be no more than 15, and bits 31 to 28 contain the COMEDI device's minor device number for some unknown reason lost in the mists of time. The `COMEDI_RANGEINFO` ioctl extract the length from bits 15 to 0 of the user-supplied `range_type` value, extracts the channel index from bits 23 to 16 (only used if the subdevice has per-channel range tables), extracts the subdevice index from bits 27 to 24, and ignores bits 31 to 28. So for subdevice indices 16 to 255, the `COMEDI_SUBDINFO` or `COMEDI_CHANINFO` ioctl will report a `range_type` value that doesn't work with the `COMEDI_RANGEINFO` ioctl. It will either get the range table for the subdevice index modulo 16, or will fail with `-EINVAL`. To fix this, always use bits 31 to 24 of the `range_type` value to hold the subdevice index (assumed to be no more than 255). This affects the `COMEDI_CHANINFO` and `COMEDI_RANGEINFO` ioctls. There should not be anything in user-space that depends on the old, broken usage, although it may now see different values in bits 31 to 28 of the `range_type` values reported by the `COMEDI_CHANINFO` ioctl for subdevices that have per-channel subdevices. User-space should not be trying to decode bits 31 to 16 of the `range_type` values anyway. Fixes: ed9eccbe8970 ("Staging: add comedi core") Cc: stable@vger.kernel.org #5.17+ Signed-off-by: Ian Abbott Link: https://patch.msgid.link/20251203162438.176841-1-abbotti@mev.co.uk Signed-off-by: Greg Kroah-Hartman Signed-off-by: Greg Kroah-Hartman

comedi: dmm32at: serialize use of paged registers

2026-01-30T09:28:40+00:00

commit e03b29b55f2b7c345a919a6ee36633b06bf3fb56 upstream. Some of the hardware registers of the DMM-32-AT board are multiplexed, using the least significant two bits of the Miscellaneous Control register to select the function of registers at offsets 12 to 15: 00 => 8254 timer/counter registers are accessible 01 => 8255 digital I/O registers are accessible 10 => Reserved 11 => Calibration registers are accessible The interrupt service routine (`dmm32at_isr()`) clobbers the bottom two bits of the register with value 00, which would interfere with access to the 8255 registers by the `dm32at_8255_io()` function (used for Comedi instruction handling on the digital I/O subdevice). Make use of the generic Comedi device spin-lock `dev->spinlock` (which is otherwise unused by this driver) to serialize access to the miscellaneous control register and paged registers. Fixes: 3c501880ac44 ("Staging: comedi: add dmm32at driver") Cc: stable@vger.kernel.org Signed-off-by: Ian Abbott Link: https://patch.msgid.link/20260112162835.91688-1-abbotti@mev.co.uk Signed-off-by: Greg Kroah-Hartman

comedi: check device's attached status in compat ioctls

2025-12-12T17:37:21+00:00

commit 0de7d9cd07a2671fa6089173bccc0b2afe6b93ee upstream. Syzbot identified an issue [1] that crashes kernel, seemingly due to unexistent callback dev->get_valid_routes(). By all means, this should not occur as said callback must always be set to get_zero_valid_routes() in __comedi_device_postconfig(). As the crash seems to appear exclusively in i386 kernels, at least, judging from [1] reports, the blame lies with compat versions of standard IOCTL handlers. Several of them are modified and do not use comedi_unlocked_ioctl(). While functionality of these ioctls essentially copy their original versions, they do not have required sanity check for device's attached status. This, in turn, leads to a possibility of calling select IOCTLs on a device that has not been properly setup, even via COMEDI_DEVCONFIG. Doing so on unconfigured devices means that several crucial steps are missed, for instance, specifying dev->get_valid_routes() callback. Fix this somewhat crudely by ensuring device's attached status before performing any ioctls, improving logic consistency between modern and compat functions. [1] Syzbot report: BUG: kernel NULL pointer dereference, address: 0000000000000000 ... CR2: ffffffffffffffd6 CR3: 000000006c717000 CR4: 0000000000352ef0 Call Trace: get_valid_routes drivers/comedi/comedi_fops.c:1322 [inline] parse_insn+0x78c/0x1970 drivers/comedi/comedi_fops.c:1401 do_insnlist_ioctl+0x272/0x700 drivers/comedi/comedi_fops.c:1594 compat_insnlist drivers/comedi/comedi_fops.c:3208 [inline] comedi_compat_ioctl+0x810/0x990 drivers/comedi/comedi_fops.c:3273 __do_compat_sys_ioctl fs/ioctl.c:695 [inline] __se_compat_sys_ioctl fs/ioctl.c:638 [inline] __ia32_compat_sys_ioctl+0x242/0x370 fs/ioctl.c:638 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline] ... Reported-by: syzbot+ab8008c24e84adee93ff@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=ab8008c24e84adee93ff Fixes: 3fbfd2223a27 ("comedi: get rid of compat_alloc_user_space() mess in COMEDI_CHANINFO compat") Cc: stable Reviewed-by: Ian Abbott Signed-off-by: Nikita Zhandarovich Link: https://patch.msgid.link/20251023132234.395794-1-n.zhandarovich@fintech.ru Signed-off-by: Greg Kroah-Hartman