First, I'm not sure whether my discovery is correct.
Suppose such follow scene: We call sleep() at kernel/virtio_disk.c:285, and then the spinlock disk.vdisk_lock will be released at kernel/proc.c:548 but without modifying the state of p->chan and p->state correctly; Unfortunately another hart has received virto_disk's interrupt request and executes to kernel/virtio_disk.c:321 at the same time, then this interrupt processing couldn't find a process that meet the conditions if(p->state == SLEEPING && p->chan == chan) { at kernel/proc.c:574. The wakeup() function does nothing! And the worse is, when line 551 and 552 in kernel/proc.c done after wakeup()'s traversal, the state of own process who invoked virto_disk_rw() will be SLEEPING forever!
First, I'm not sure whether my discovery is correct. Suppose such follow scene: We call
sleep()atkernel/virtio_disk.c:285, and then the spinlockdisk.vdisk_lockwill be released atkernel/proc.c:548but without modifying the state ofp->chanandp->statecorrectly; Unfortunately another hart has received virto_disk's interrupt request and executes tokernel/virtio_disk.c:321at the same time, then this interrupt processing couldn't find a process that meet the conditionsif(p->state == SLEEPING && p->chan == chan) {atkernel/proc.c:574. Thewakeup()function does nothing! And the worse is, when line 551 and 552 inkernel/proc.cdone afterwakeup()'s traversal, the state of own process who invokedvirto_disk_rw()will be SLEEPING forever!