On Thu, Aug 21, 2025 at 01:12:28PM +0000, Jinjie Ruan wrote:
From: Thomas Gleixner tglx@linutronix.de
Hogan reported a vector setup race, which overwrites the interrupt descriptor in the per CPU vector array resulting in a disfunctional device.
CPU0 CPU1 interrupt is raised in APIC IRR but not handled free_irq() per_cpu(vector_irq, CPU1)[vector] = VECTOR_SHUTDOWN;
request_irq() common_interrupt() d = this_cpu_read(vector_irq[vector]);
per_cpu(vector_irq, CPU1)[vector] = desc; if (d == VECTOR_SHUTDOWN) this_cpu_write(vector_irq[vector], VECTOR_UNUSED);free_irq() cannot observe the pending vector in the CPU1 APIC as there is no way to query the remote CPUs APIC IRR.
This requires that request_irq() uses the same vector/CPU as the one which was freed, but this also can be triggered by a spurious interrupt.
Interestingly enough this problem managed to be hidden for more than a decade.
Prevent this by reevaluating vector_irq under the vector lock, which is held by the interrupt activation code when vector_irq is updated.
To avoid ifdeffery or IS_ENABLED() nonsense, move the [un]lock_vector_lock() declarations out under the CONFIG_IRQ_DOMAIN_HIERARCHY guard as it's only provided when CONFIG_X86_LOCAL_APIC=y.
The current CONFIG_IRQ_DOMAIN_HIERARCHY guard is selected by CONFIG_X86_LOCAL_APIC, but can also be selected by other parts of the Kconfig system, which makes 32-bit UP builds with CONFIG_X86_LOCAL_APIC=n fail.
Can we just get rid of this !APIC nonsense once and forever?
Fixes: 9345005f4eed ("x86/irq: Fix do_IRQ() interrupt warning for cpu hotplug retriggered irqs") Cc: stable@vger.kernel.org#6.6.x Cc: gregkh@linuxfoundation.org Reported-by: Hogan Wang hogan.wang@huawei.com Signed-off-by: Thomas Gleixner tglx@linutronix.de Tested-by: Hogan Wang hogan.wang@huawei.com Link: https://lore.kernel.org/all/draft-87ikjhrhhh.ffs@tglx [ Conflicts in arch/x86/kernel/irq.c because call_irq_handler() has been refactored to do apic_eoi() according to the return value. Conflincts in arch/x86/include/asm/hw_irq.h because (un)lock_vector_lock() are already controlled by CONFIG_X86_LOCAL_APIC. ] Signed-off-by: Jinjie Ruan ruanjinjie@huawei.com
arch/x86/kernel/irq.c | 65 +++++++++++++++++++++++++++++++++---------- 1 file changed, 51 insertions(+), 14 deletions(-)
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This is not the correct way to submit patches for inclusion in the stable kernel tree. Please read: https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html for how to do this properly.
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