kernel/linux.git/drivers/i2c, branch v7.1-rc6

i2c: virtio: mark device ready before registering the adapter

2026-05-30T13:56:07+00:00

virtio_i2c_probe() synchronously probes child i2c drivers on the bus, but peripherals may use the bus at probe for tasks like reading a chip id. The vhost-user-i2c backend stalls at such probes unless DRIVER_OK is already set before the virtqueue is first kicked. Set DRIVER_OK explicitly before i2c_add_adapter(), as done for the same reason in commit f5866db64f34 ("virtio_console: enable VQs early") and commit 71e4b8bf0482 ("virtio_rpmsg: set DRIVER_OK before using device"). Signed-off-by: Alexis Bouzigues Signed-off-by: Wolfram Sang

i2c: davinci: fix division by zero on missing clock-frequency

2026-05-26T23:07:05+00:00

When the 'clock-frequency' property is missing from the device tree, the driver falls back to DAVINCI_I2C_DEFAULT_BUS_FREQ. However, this macro was defined in kHz (100), whereas the device tree property is expected in Hz. The probe function divided the fallback value by 1000, causing integer truncation that resulted in dev->bus_freq = 0. This triggered a deterministic division-by-zero kernel panic when calculating clock dividers later in the probe sequence. Fix this by redefining DAVINCI_I2C_DEFAULT_BUS_FREQ in Hz (100000) to match the expected device tree property unit, allowing the existing division logic to work correctly for both cases. Fixes: b04ce6385979 ("i2c: davinci: kill platform data") Reported-by: Sashiko Closes: https://lore.kernel.org/all/20260514044726.57297C2BCB7@smtp.kernel.org/ Signed-off-by: Chaitanya Sabnis Cc: # v6.14+ Reviewed-by: Bartosz Golaszewski Signed-off-by: Andi Shyti Link: https://lore.kernel.org/r/20260526102240.4949-1-chaitanya.msabnis@gmail.com

i2c: smbus: fix a potential uninitialization bug

2026-05-19T10:43:08+00:00

In i2c_smbus_xfer_emulated(), there are two buffers: msgbuf0 and msgbuf1, which are used to save a series of messages, as mentioned in the comment. According to the value of the variable 'size', msgbuf0 is initialized to various values. In contrast, msgbuf1 is left uninitialized until the function i2c_transfer() is invoked. However, msgbuf1 is not always initialized on all possible execution paths (implementation) of i2c_transfer(). Thus, it is possible that msgbuf1 may still be uninitialized even after the invocation of the function i2c_transfer(), especially when the return value of i2c_transfer() is not checked properly. In the following execution, the uninitialized msgbuf1 will be used, such as for security checks. Since uninitialized values can be random and arbitrary, this will cause undefined behaviors or even check bypass. For example, it is expected that if the value of 'size' is I2C_SMBUS_BLOCK_PROC_CALL, the value of data->block[0] should not be larger than I2C_SMBUS_BLOCK_MAX. This patch initializes the first byte of msgbuf1 with 0 to avoid such undefined behaviors or security issues. Signed-off-by: Wenwen Wang [wsa: reworded commit message a little] Signed-off-by: Wolfram Sang

i2c: tegra: make tegra_i2c_mutex_unlock() return void

2026-05-13T22:14:20+00:00

tegra_i2c_mutex_unlock() returning an error that overwrites the transfer result causes silent loss of I2C transfer errors. If the transfer failed but the unlock succeeded, the error was lost and the function incorrectly reported success. Rather than propagating the unlock error (which is not actionable by the caller - the I2C message may have been sent regardless), convert the function to return void and WARN on the unexpected condition. If the unlock fails, subsequent lock attempts will fail anyway, making the error visible on the next transfer. Fixes: 6077cfd716fb ("i2c: tegra: Add support for SW mutex register") Signed-off-by: Saurav Sachidanand Cc: # v7.0+ Reviewed-by: Jon Hunter Acked-by: Thierry Reding Signed-off-by: Andi Shyti Link: https://lore.kernel.org/r/20260507221145.62183-3-sauravsc@amazon.com

i2c: tegra: fix pm_runtime leak on mutex_lock failure

2026-05-13T22:14:06+00:00

If tegra_i2c_mutex_lock() fails, the function returns without calling pm_runtime_put(), leaking the runtime PM reference acquired by the preceding pm_runtime_get_sync(). This prevents the device from ever entering runtime suspend. Add the missing pm_runtime_put() before returning on lock failure. Fixes: 6077cfd716fb ("i2c: tegra: Add support for SW mutex register") Signed-off-by: Saurav Sachidanand Cc: # v7.0+ Reviewed-by: Jon Hunter Acked-by: Thierry Reding Signed-off-by: Andi Shyti Link: https://lore.kernel.org/r/20260507221145.62183-2-sauravsc@amazon.com

i2c: smbus: reject oversized block transfers in the common path

2026-05-07T08:59:07+00:00

The SMBus block transfer length data->block[0] is validated in i2c_smbus_xfer_emulated() but that check runs too late for tracepoints and is skipped entirely when the adapter provides a native smbus_xfer implementation. This allows user-controlled oversized block lengths to reach tracepoint memcpy calls and driver callbacks unchecked. Add an early validation in __i2c_smbus_xfer() that rejects block transfers whose caller-supplied length is zero or exceeds I2C_SMBUS_BLOCK_MAX before any tracepoint fires or driver callback runs. data->block[0] is filled in by the device on SMBus block reads, so the check is scoped to operations where the length is actually supplied by the caller. This is consistent with the existing -EINVAL convention in the emulated path and protects all downstream consumers at once: the smbus_write tracepoint, all native smbus_xfer driver implementations, and the emulated path. Two distinct bugs are fixed by this change: Bug 1: smbus_write tracepoint OOB (include/trace/events/smbus.h) trace_smbus_write() fires before any validation and copies data->block[0]+1 bytes into a 34-byte event buffer. With block[0]=0xfe the tracepoint copies 255 bytes, overflowing by 221. BUG: KASAN: stack-out-of-bounds in trace_event_raw_event_smbus_write+0x27c/0x530 Read of size 255 at addr ffff88800d98fcf8 by task poc_smbus/91 Call Trace: __asan_memcpy+0x23/0x80 trace_event_raw_event_smbus_write+0x27c/0x530 __i2c_smbus_xfer+0x43a/0xa40 i2c_smbus_xfer+0x19e/0x340 i2cdev_ioctl_smbus+0x38f/0x7f0 i2cdev_ioctl+0x35e/0x680 __x64_sys_ioctl+0x147/0x1e0 do_syscall_64+0xcf/0x15a0 entry_SYSCALL_64_after_hwframe+0x76/0x7e Bug 2: i2c-stub I2C_SMBUS_I2C_BLOCK_DATA OOB (drivers/i2c/i2c-stub.c) stub_xfer() implements .smbus_xfer directly and only clamps block[0] against 256-command, not I2C_SMBUS_BLOCK_MAX. With block[0]=0xff and command=0 the loop accesses block[1+i] for i up to 254, far past the 34-byte union. UBSAN: array-index-out-of-bounds in drivers/i2c/i2c-stub.c:223:44 index 34 is out of range for type '__u8 [34]' Call Trace: __ubsan_handle_out_of_bounds+0xd7/0x120 stub_xfer+0x1971/0x198f [i2c_stub] __i2c_smbus_xfer+0x306/0xa40 i2c_smbus_xfer+0x19e/0x340 i2cdev_ioctl_smbus+0x38f/0x7f0 i2cdev_ioctl+0x35e/0x680 __x64_sys_ioctl+0x147/0x1e0 do_syscall_64+0xcf/0x15a0 entry_SYSCALL_64_after_hwframe+0x76/0x7e Both traces reproduced on v7.0-rc6+i2c/for-current with KASAN+UBSAN. Fixes: 8a325997d95d ("i2c: Add message transfer tracepoints for SMBUS [ver #2]") Fixes: 4710317891e4 ("i2c-stub: Implement I2C block support") Reported-by: Xiang Mei Signed-off-by: Weiming Shi Signed-off-by: Wolfram Sang

i2c: stub: Reject I2C block transfers with invalid length

2026-05-04T11:23:53+00:00

The I2C_SMBUS_I2C_BLOCK_DATA case in stub_xfer() uses data->block[0] as the transfer length. The existing check only clamps it to avoid overrunning the chip->words[256] register array, but does not validate it against I2C_SMBUS_BLOCK_MAX (32), which is the limit of the union i2c_smbus_data.block buffer (34 bytes total). The driver is a development/test tool (CONFIG_I2C_STUB=m, not built by default) that must be loaded with a chip_addr= parameter. A local user with access to /dev/i2c-* can issue an I2C_SMBUS ioctl with I2C_SMBUS_I2C_BLOCK_DATA and data->block[0] > 32, causing stub_xfer() to read or write past the end of the union i2c_smbus_data.block buffer: BUG: KASAN: stack-out-of-bounds in stub_xfer (drivers/i2c/i2c-stub.c:223) Read of size 1 at addr ffff88800abcfd92 by task exploit/81 Call Trace: stub_xfer (drivers/i2c/i2c-stub.c:223) __i2c_smbus_xfer (drivers/i2c/i2c-core-smbus.c:593) i2c_smbus_xfer (drivers/i2c/i2c-core-smbus.c:536) i2cdev_ioctl_smbus (drivers/i2c/i2c-dev.c:391) i2cdev_ioctl (drivers/i2c/i2c-dev.c:478) __x64_sys_ioctl (fs/ioctl.c:583) do_syscall_64 (arch/x86/entry/syscall_64.c:94) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130) The bug exists because i2c-stub implements .smbus_xfer directly, bypassing the I2C_SMBUS_BLOCK_MAX validation in i2c_smbus_xfer_emulated(). The I2C_SMBUS_BLOCK_DATA case in the same function correctly validates against I2C_SMBUS_BLOCK_MAX, but the I2C_SMBUS_I2C_BLOCK_DATA case does not. Fix by rejecting transfers with data->block[0] == 0 or data->block[0] > I2C_SMBUS_BLOCK_MAX with -EINVAL, consistent with both the I2C_SMBUS_BLOCK_DATA case in the same function and the I2C_SMBUS_I2C_BLOCK_DATA validation in i2c_smbus_xfer_emulated(). Fixes: 4710317891e4 ("i2c-stub: Implement I2C block support") Reported-by: Xiang Mei Signed-off-by: Weiming Shi Reviewed-by: Jean Delvare Signed-off-by: Wolfram Sang

i2c: Compare the return value of gpiod_get_direction against GPIO_LINE_DIRECTION_OUT

2026-05-04T10:19:25+00:00

The GPIO_LINE_DIRECTION_* definitions have just recently been exposed to gpio consumers.h by breaking them out in a separate defs.h file. Use this to validate the gpio direction instead of the hard-coded literal. Signed-off-by: Nikola Z. Ivanov Signed-off-by: Wolfram Sang

i2c: dev: prevent integer overflow in I2C_TIMEOUT ioctl

2026-05-04T09:31:35+00:00

While fuzzing with Syzkaller, a persistent `schedule_timeout: wrong timeout value` warning was observed, accompanied by SMBus controller state machine corruption. The I2C_TIMEOUT ioctl accepts a user-provided timeout in multiples of 10 ms. The user argument is checked against INT_MAX, but it is subsequently multiplied by 10 before being passed to msecs_to_jiffies(). A malicious user can pass a large value (e.g., 429496729) that passes the `arg > INT_MAX` check but overflows when multiplied by 10. This results in a truncated 32-bit unsigned value that bypasses the internal `(int)m < 0` check in `msecs_to_jiffies()`. The truncated value is then assigned to `client->adapter->timeout` (a signed 32-bit int), which is reinterpreted as a negative number. When passed to wait_for_completion_timeout(), this negative value undergoes sign extension to a 64-bit unsigned long, triggering the `schedule_timeout` warning and causing premature returns. This leaves the SMBus state machine in an unrecoverable state, constituting a local Denial of Service (DoS). Fix this by bounding the user argument to `INT_MAX / 10`. Signed-off-by: Mingyu Wang <25181214217@stu.xidian.edu.cn> [wsa: move the comment as well] Signed-off-by: Wolfram Sang

i2c: acpi: Add ELAN0678 to i2c_acpi_force_100khz_device_ids

2026-05-04T09:17:46+00:00

The ELAN0678 touchpad (04F3:3195) found in the Lenovo ThinkPad X13 exhibits excessive smoothing when the I2C bus runs at 400KHz, making the touchpad feel sluggish when plugged into AC power. This is the same issue previously fixed for ELAN06FA. The device's ACPI table (Lenovo TP-R22) specifies 0x00061A80 (400KHz) for the I2cSerialBusV2 descriptor. Forcing the bus to 100KHz eliminates the sluggish behavior. Signed-off-by: Niels Franke Acked-by: Mika Westerberg [wsa: kept the sorting] Signed-off-by: Wolfram Sang