Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
HID: i2c-hid: remove I2C_HID_READ_PENDING flag to prevent lock-up
commit 9c0f59e upstream. The flag I2C_HID_READ_PENDING is used to serialize I2C operations. However, this is not necessary, because I2C core already has its own locking for that. More importantly, this flag can cause a lock-up: if the flag is set in i2c_hid_xfer() and an interrupt happens, the interrupt handler (i2c_hid_irq) will check this flag and return immediately without doing anything, then the interrupt handler will be invoked again in an infinite loop. Since interrupt handler is an RT task, it takes over the CPU and the flag-clearing task never gets scheduled, thus we have a lock-up. Delete this unnecessary flag. Reported-and-tested-by: Eva Kurchatova <[email protected]> Closes: https://lore.kernel.org/r/CA+eeCSPUDpUg76ZO8dszSbAGn+UHjcyv8F1J-CUPVARAzEtW9w@mail.gmail.com Fixes: 4a200c3 ("HID: i2c-hid: introduce HID over i2c specification implementation") Cc: <[email protected]> Signed-off-by: Nam Cao <[email protected]> Signed-off-by: Jiri Kosina <[email protected]> [apply to v4.19 -> v5.15] Signed-off-by: Nam Cao <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>
- Loading branch information