linux-brain/include
Frederic Weisbecker 337bba09d8 rcu/nocb: Perform deferred wake up before last idle's need_resched() check
commit 43789ef3f7d61aa7bed0cb2764e588fc990c30ef upstream.

Entering RCU idle mode may cause a deferred wake up of an RCU NOCB_GP
kthread (rcuog) to be serviced.

Usually a local wake up happening while running the idle task is handled
in one of the need_resched() checks carefully placed within the idle
loop that can break to the scheduler.

Unfortunately the call to rcu_idle_enter() is already beyond the last
generic need_resched() check and we may halt the CPU with a resched
request unhandled, leaving the task hanging.

Fix this with splitting the rcuog wakeup handling from rcu_idle_enter()
and place it before the last generic need_resched() check in the idle
loop. It is then assumed that no call to call_rcu() will be performed
after that in the idle loop until the CPU is put in low power mode.

Fixes: 96d3fd0d31 (rcu: Break call_rcu() deadlock involving scheduler and perf)
Reported-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20210131230548.32970-3-frederic@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-03-04 10:26:47 +01:00
..
acpi ACPICA: Fix exception code class checks 2021-03-04 10:26:14 +01:00
asm-generic vmlinux.lds.h: add DWARF v5 sections 2021-03-04 10:26:09 +01:00
clocksource
crypto crypto: algif_aead - Only wake up when ctx->more is zero 2020-08-21 13:05:30 +02:00
drm iommu/vt-d: Move intel_iommu_gfx_mapped to Intel IOMMU header 2020-11-24 13:29:17 +01:00
dt-bindings clk: imx8mn: Fix incorrect clock defines 2020-03-18 07:17:55 +01:00
keys KEYS: Don't write out to userspace while holding key semaphore 2020-04-23 10:36:45 +02:00
kvm
linux rcu/nocb: Perform deferred wake up before last idle's need_resched() check 2021-03-04 10:26:47 +01:00
math-emu
media media: v4l2-fwnode: Return -EINVAL for invalid bus-type 2020-12-30 11:51:08 +01:00
misc
net tcp: fix SO_RCVLOWAT related hangs under mem pressure 2021-03-04 10:26:17 +01:00
pcmcia
ras
rdma RDMA/umem: Fix signature of stub ib_umem_find_best_pgsz() 2020-10-29 09:57:47 +01:00
scsi scsi: libiscsi: Fix NOP race condition 2020-12-02 08:49:49 +01:00
soc irqchip/eznps: Fix build error for !ARC700 builds 2020-09-17 13:47:47 +02:00
sound ALSA: hda: fix jack detection with Realtek codecs when in D3 2020-10-29 09:57:25 +01:00
target scsi: target: fix hang when multiple threads try to destroy the same iscsi session 2020-04-21 09:05:04 +02:00
trace writeback: Drop I_DIRTY_TIME_EXPIRE 2021-01-30 13:54:11 +01:00
uapi ICMPv6: Add ICMPv6 Parameter Problem, code 3 definition 2021-02-03 23:25:55 +01:00
vdso
video
xen Xen/gntdev: correct error checking in gntdev_map_grant_pages() 2021-02-23 15:02:26 +01:00