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McKenney wrote: > This commit adds a new rcutorture.n_up_down kernel boot parameter > that specifies the number of outstanding SRCU up/down readers, which > begin in kthread context and end in an hrtimer handler. There is a new > kthread ("rcu_torture_updown") that scans an per-reader array looking > for elements whose readers have ended. This kthread sleeps between one > and two milliseconds between consecutive scans. > > [ paulmck: Apply kernel test robot feedback. ] > [ paulmck: Apply Z qiang feedback. ] > > Signed-off-by: Paul E. McKenney For completeness, posting our discussion for the archives, an issue exists in this patch causing the following errors on an ARM64 machine with 288 CPUs: When running SRCU-P test, we intermittently see: [ 9500.806108] ??? Writer stall state RTWS_SYNC(21) g18446744073709551218 f0x0 ->state 0x2 cpu 4 [ 9515.833356] ??? Writer stall state RTWS_SYNC(21) g18446744073709551218 f0x0 ->state 0x2 cpu 4 It bisected to just this patch. thanks, - Joel