kernel/linux.git/drivers/comedi, branch v7.0.12

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

2026-06-09T10:32:41+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()

2026-06-09T10:32:41+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: dt2815: add hardware detection to prevent crash

2026-04-02T12:40:27+00:00

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

comedi: runflags cannot determine whether to reclaim chanlist

2026-04-02T12:39:58+00:00

syzbot reported a memory leak [1], because commit 4e1da516debb ("comedi: Add reference counting for Comedi command handling") did not consider the exceptional exit case in do_cmd_ioctl() where runflags is not set. This caused chanlist not to be properly freed by do_become_nonbusy(), as it only frees chanlist when runflags is correctly set. Added a check in do_become_nonbusy() for the case where runflags is not set, to properly free the chanlist memory. [1] BUG: memory leak backtrace (crc 844a0efa): __comedi_get_user_chanlist drivers/comedi/comedi_fops.c:1815 [inline] do_cmd_ioctl.part.0+0x112/0x350 drivers/comedi/comedi_fops.c:1890 do_cmd_ioctl drivers/comedi/comedi_fops.c:1858 [inline] Fixes: 4e1da516debb ("comedi: Add reference counting for Comedi command handling") Reported-by: syzbot+f238baf6ded841b5a82e@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=f238baf6ded841b5a82e Signed-off-by: Edward Adam Davis Reviewed-by: Ian Abbott Cc: stable # 6.19 Signed-off-by: Ian Abbott Link: https://patch.msgid.link/20260310111104.70959-1-abbotti@mev.co.uk Signed-off-by: Greg Kroah-Hartman

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

2026-04-02T12:39:39+00:00

`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: me_daq: Fix potential overrun of firmware buffer

2026-04-02T12:39:29+00:00

`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: me4000: Fix potential overrun of firmware buffer

2026-04-02T12:39:21+00:00

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

2026-04-02T12:38:28+00:00

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

Convert remaining multi-line kmalloc_obj/flex GFP_KERNEL uses

2026-02-22T16:26:33+00:00

Conversion performed via this Coccinelle script: // SPDX-License-Identifier: GPL-2.0-only // Options: --include-headers-for-types --all-includes --include-headers --keep-comments virtual patch @gfp depends on patch && !(file in "tools") && !(file in "samples")@ identifier ALLOC = {kmalloc_obj,kmalloc_objs,kmalloc_flex, kzalloc_obj,kzalloc_objs,kzalloc_flex, kvmalloc_obj,kvmalloc_objs,kvmalloc_flex, kvzalloc_obj,kvzalloc_objs,kvzalloc_flex}; @@ ALLOC(... - , GFP_KERNEL ) $ make coccicheck MODE=patch COCCI=gfp.cocci Build and boot tested x86_64 with Fedora 42's GCC and Clang: Linux version 6.19.0+ (user@host) (gcc (GCC) 15.2.1 20260123 (Red Hat 15.2.1-7), GNU ld version 2.44-12.fc42) #1 SMP PREEMPT_DYNAMIC 1970-01-01 Linux version 6.19.0+ (user@host) (clang version 20.1.8 (Fedora 20.1.8-4.fc42), LLD 20.1.8) #1 SMP PREEMPT_DYNAMIC 1970-01-01 Signed-off-by: Kees Cook Signed-off-by: Linus Torvalds

Convert more 'alloc_obj' cases to default GFP_KERNEL arguments

2026-02-22T04:03:00+00:00

This converts some of the visually simpler cases that have been split over multiple lines. I only did the ones that are easy to verify the resulting diff by having just that final GFP_KERNEL argument on the next line. Somebody should probably do a proper coccinelle script for this, but for me the trivial script actually resulted in an assertion failure in the middle of the script. I probably had made it a bit _too_ trivial. So after fighting that far a while I decided to just do some of the syntactically simpler cases with variations of the previous 'sed' scripts. The more syntactically complex multi-line cases would mostly really want whitespace cleanup anyway. Signed-off-by: Linus Torvalds