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syzbot reported "sleeping function called from invalid context" in vhost_net_busy_poll(). Commit0308813724("vhost_net: basic polling support") introduced a busy-poll loop and preempt_{disable,enable}() around it, where each iteration calls a sleepable function inside the loop. The purpose of disabling preemption was to keep local_clock()-based timeout accounting on a single CPU, rather than as a requirement of busy-poll itself: https://lore.kernel.org/1448435489-5949-4-git-send-email-jasowang@redhat.com From this perspective, migrate_disable() is sufficient here, so replace preempt_disable() with migrate_disable(), avoiding sleepable accesses from a preempt-disabled context. Fixes:0308813724("vhost_net: basic polling support") Tested-by: syzbot+6985cb8e543ea90ba8ee@syzkaller.appspotmail.com Reported-by: syzbot+6985cb8e543ea90ba8ee@syzkaller.appspotmail.com Closes: https://lore.kernel.org/all/69e6a414.050a0220.24bfd3.002d.GAE@google.com/T/ Signed-off-by: Kohei Enju <kohei@enjuk.jp> Acked-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org>