Hello,
My static analysis tool reports several possible ABBA deadlock in the
rdmavt driver in Linux 5.18:
rvt_ruc_loopback()
spin_lock_irqsave(&sqp->s_lock, flags); --> Line 3190 (Lock A)
spin_lock(&sqp->r_lock); --> Line 3195 (Lock B)
rvt_qp_mr_clean()
spin_lock_irq(&qp->r_lock); --> Line 698 (Lock B)
spin_lock(&qp->s_lock); --> Line 700 (Lock A)
rvt_rc_timeout()
spin_lock_irqsave(&qp->r_lock, flags); --> Line 2595 (Lock B)
spin_lock(&qp->s_lock); --> Line 2596 (Lock A)
rvt_modify_qp()
spin_lock_irq(&qp->r_lock); --> Line 1419 (Lock B)
spin_lock(&qp->s_lock); --> Line 1421(Lock A)
_rvt_reset_qp()
spin_lock_irq(&qp->r_lock); --> Line 907 (Lock B)
spin_lock(&qp->s_lock); --> Line 909 (Lock A)
rvt_reset_qp()
spin_lock_irq(&qp->r_lock); --> Line 936 (Lock B)
spin_lock(&qp->s_lock); --> Line 938 (Lock A)
When rvt_ruc_loopback() is concurrently executed with rvt_qp_mr_clean(),
rvt_rc_timeout(), rvt_modify_qp(), _rvt_reset_qp() or rvt_reset_qp(),
the deadlocks can occur.
I am not quite sure whether these possible deadlocks are real and how to
fix them if real.
Any feedback would be appreciated, thanks :)
Reported-by: TOTE Robot <oslab@xxxxxxxxxxxxxxx>
Best wishes,
Jia-Ju Bai
