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author | Thomas Gleixner <tglx@linutronix.de> | 2023-06-15 11:18:30 +0200 |
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committer | Thomas Gleixner <tglx@linutronix.de> | 2023-06-16 20:45:28 +0200 |
commit | 13bb06f8dd42071cb9a49f6e21099eea05d4b856 (patch) | |
tree | 0601f36ced15ca75bd8d0199f964974991ab1c9d /drivers/gpu/host1x/job.c | |
parent | 858fd168a95c5b9669aac8db6c14a9aeab446375 (diff) | |
download | linux-stable-13bb06f8dd42071cb9a49f6e21099eea05d4b856.tar.gz linux-stable-13bb06f8dd42071cb9a49f6e21099eea05d4b856.tar.bz2 linux-stable-13bb06f8dd42071cb9a49f6e21099eea05d4b856.zip |
tick/common: Align tick period during sched_timer setup
The tick period is aligned very early while the first clock_event_device is
registered. At that point the system runs in periodic mode and switches
later to one-shot mode if possible.
The next wake-up event is programmed based on the aligned value
(tick_next_period) but the delta value, that is used to program the
clock_event_device, is computed based on ktime_get().
With the subtracted offset, the device fires earlier than the exact time
frame. With a large enough offset the system programs the timer for the
next wake-up and the remaining time left is too small to make any boot
progress. The system hangs.
Move the alignment later to the setup of tick_sched timer. At this point
the system switches to oneshot mode and a high resolution clocksource is
available. At this point it is safe to align tick_next_period because
ktime_get() will now return accurate (not jiffies based) time.
[bigeasy: Patch description + testing].
Fixes: e9523a0d81899 ("tick/common: Align tick period with the HZ tick.")
Reported-by: Mathias Krause <minipli@grsecurity.net>
Reported-by: "Bhatnagar, Rishabh" <risbhat@amazon.com>
Suggested-by: Mathias Krause <minipli@grsecurity.net>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Richard W.M. Jones <rjones@redhat.com>
Tested-by: Mathias Krause <minipli@grsecurity.net>
Acked-by: SeongJae Park <sj@kernel.org>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/5a56290d-806e-b9a5-f37c-f21958b5a8c0@grsecurity.net
Link: https://lore.kernel.org/12c6f9a3-d087-b824-0d05-0d18c9bc1bf3@amazon.com
Link: https://lore.kernel.org/r/20230615091830.RxMV2xf_@linutronix.de
Diffstat (limited to 'drivers/gpu/host1x/job.c')
0 files changed, 0 insertions, 0 deletions