P.S. Just to clarify, On 8/16/25 10:29 AM, Yunseong Kim wrote: > While testing a PREEMPT_RT enabled kernel (based on v6.17.0-rc1), > I encountered a "BUG: sleeping function called from invalid context" > error originating from the USB/IP VHCI driver. > > On PREEMPT_RT configurations, standard spin_lock() calls are replaced by > rt_spin_lock(). Since rt_spin_lock() may sleep when contended, it must not > be called from an atomic context (e.g., with interrupts disabled). > > The issue occurs within the vhci_urb_enqueue function This function > explicitly disables local interrupts using local_irq_disable() immediately > before calling usb_hcd_giveback_urb(), adhering to HCD requirements. > > This error reported after this work: > Link: https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git/commit/?h=usb-linus&id=9528d32873b38281ae105f2f5799e79ae9d086c2 To be clear and avoid any misunderstanding, reporting was done after this work "kcov, usb: Don't disable interrupts in kcov_remote_start_usb_softirq()" because the fuzzing could proceed smoothly on PREEMPT_RT following this work, which allowed the issue to be discovered. It does not mean that this step introduced the error at all.
