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| author | Thomas Gleixner <tglx@linutronix.de> | 2024-07-31 12:23:51 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2024-08-19 05:41:18 +0200 |
| commit | 668c6c4a7e9e9f081c06b70f30104fb7013437ed (patch) | |
| tree | fde3fc562a97d278841929e5422c7acc212209f1 | |
| parent | 005c318981bc84bbc79621550d3c0e4de92fa2fe (diff) | |
| download | linux-668c6c4a7e9e9f081c06b70f30104fb7013437ed.tar.gz linux-668c6c4a7e9e9f081c06b70f30104fb7013437ed.tar.bz2 linux-668c6c4a7e9e9f081c06b70f30104fb7013437ed.zip | |
tick/broadcast: Move per CPU pointer access into the atomic section
commit 6881e75237a84093d0986f56223db3724619f26e upstream.
The recent fix for making the take over of the broadcast timer more
reliable retrieves a per CPU pointer in preemptible context.
This went unnoticed as compilers hoist the access into the non-preemptible
region where the pointer is actually used. But of course it's valid that
the compiler keeps it at the place where the code puts it which rightfully
triggers:
BUG: using smp_processor_id() in preemptible [00000000] code:
caller is hotplug_cpu__broadcast_tick_pull+0x1c/0xc0
Move it to the actual usage site which is in a non-preemptible region.
Fixes: f7d43dd206e7 ("tick/broadcast: Make takeover of broadcast hrtimer reliable")
Reported-by: David Wang <00107082@163.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Yu Liao <liaoyu15@huawei.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/all/87ttg56ers.ffs@tglx
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | kernel/time/tick-broadcast.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/kernel/time/tick-broadcast.c b/kernel/time/tick-broadcast.c index 792ef33ba487..dc3838c00d6c 100644 --- a/kernel/time/tick-broadcast.c +++ b/kernel/time/tick-broadcast.c @@ -944,7 +944,6 @@ void tick_broadcast_switch_to_oneshot(void) #ifdef CONFIG_HOTPLUG_CPU void hotplug_cpu__broadcast_tick_pull(int deadcpu) { - struct tick_device *td = this_cpu_ptr(&tick_cpu_device); struct clock_event_device *bc; unsigned long flags; @@ -970,6 +969,8 @@ void hotplug_cpu__broadcast_tick_pull(int deadcpu) * device to avoid the starvation. */ if (tick_check_broadcast_expired()) { + struct tick_device *td = this_cpu_ptr(&tick_cpu_device); + cpumask_clear_cpu(smp_processor_id(), tick_broadcast_force_mask); tick_program_event(td->evtdev->next_event, 1); } |