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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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a2b7861bb3
Currently, in PREEMPT_COUNT=n kernel, kvm_async_pf_task_wait() could call schedule() to reschedule in some cases. This could result in accidentally ending the current RCU read-side critical section early, causing random memory corruption in the guest, or otherwise preempting the currently running task inside between preempt_disable and preempt_enable. The difficulty to handle this well is because we don't know whether an async PF delivered in a preemptible section or RCU read-side critical section for PREEMPT_COUNT=n, since preempt_disable()/enable() and rcu_read_lock/unlock() are both no-ops in that case. To cure this, we treat any async PF interrupting a kernel context as one that cannot be preempted, preventing kvm_async_pf_task_wait() from choosing the schedule() path in that case. To do so, a second parameter for kvm_async_pf_task_wait() is introduced, so that we know whether it's called from a context interrupting the kernel, and the parameter is set properly in all the callsites. Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Wanpeng Li <wanpeng.li@hotmail.com> Cc: stable@vger.kernel.org Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Radim Krčmář <rkrcmar@redhat.com> |
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.. | ||
cpuid.c | ||
cpuid.h | ||
debugfs.c | ||
emulate.c | ||
hyperv.c | ||
hyperv.h | ||
i8254.c | ||
i8254.h | ||
i8259.c | ||
ioapic.c | ||
ioapic.h | ||
irq_comm.c | ||
irq.c | ||
irq.h | ||
Kconfig | ||
kvm_cache_regs.h | ||
lapic.c | ||
lapic.h | ||
Makefile | ||
mmu_audit.c | ||
mmu.c | ||
mmu.h | ||
mmutrace.h | ||
mtrr.c | ||
page_track.c | ||
paging_tmpl.h | ||
pmu_amd.c | ||
pmu_intel.c | ||
pmu.c | ||
pmu.h | ||
svm.c | ||
trace.h | ||
tss.h | ||
vmx.c | ||
x86.c | ||
x86.h |