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| author | Nicholas Piggin <npiggin@gmail.com> | 2022-01-24 15:39:28 +0100 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2022-01-25 06:50:10 +0100 |
| commit | 8defc2a5dd8f4c0cb19ecbaca8d3e89ab98524da (patch) | |
| tree | 78608ba49ddba38f09811bf36ebdd12534df8520 /arch/powerpc | |
| parent | KVM: PPC: Book3S HV Nested: Fix nested HFSCR being clobbered with multiple vCPUs (diff) | |
| download | linux-8defc2a5dd8f4c0cb19ecbaca8d3e89ab98524da.tar.xz linux-8defc2a5dd8f4c0cb19ecbaca8d3e89ab98524da.zip | |
powerpc/64s/interrupt: Fix decrementer storm
The decrementer exception can fail to be cleared when the interrupt
returns in the case where the decrementer wraps with the next timer
still beyond decrementer_max. This results in a decrementer interrupt
storm. This is triggerable with small decrementer system with hard
and soft watchdogs disabled.
Fix this by always programming the decrementer if there was no timer.
Fixes: 0faf20a1ad16 ("powerpc/64s/interrupt: Don't enable MSR[EE] in irq handlers unless perf is in use")
Reported-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220124143930.3923442-1-npiggin@gmail.com
Diffstat (limited to 'arch/powerpc')
| -rw-r--r-- | arch/powerpc/kernel/time.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c index 62361cc7281c..cd0b8b71ecdd 100644 --- a/arch/powerpc/kernel/time.c +++ b/arch/powerpc/kernel/time.c @@ -649,8 +649,9 @@ DEFINE_INTERRUPT_HANDLER_ASYNC(timer_interrupt) __this_cpu_inc(irq_stat.timer_irqs_event); } else { now = *next_tb - now; - if (now <= decrementer_max) - set_dec_or_work(now); + if (now > decrementer_max) + now = decrementer_max; + set_dec_or_work(now); __this_cpu_inc(irq_stat.timer_irqs_others); } |