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    hwtracing: hisi_ptt: Fix potential sleep in atomic context · 5a848148
    Yicong Yang 提交于
    driver inclusion
    category: bugfix
    bugzilla: https://gitee.com/openeuler/kernel/issues/I7BZYX
    CVE: NA
    
    Reference: NA
    
    --------------------------------------------------------------------------
    
    From: Yicong Yang <yangyicong@hisilicon.com>
    
    We're using pci_irq_vector() to obtain the interrupt number and then
    bind it to the CPU start perf under the protection of spinlock in
    pmu::start(). pci_irq_vector() might sleep since [1] because it will
    call msi_domain_get_virq() to get the MSI interrupt number and it
    needs to acquire dev->msi.data->mutex. Getting a mutex will sleep on
    contention. So use pci_irq_vector() in an atomic context is problematic.
    
    This patch cached the interrupt number in the probe() and uses the
    cached data instead to avoid potential sleep.
    
    [1] commit 82ff8e6b ("PCI/MSI: Use msi_get_virq() in pci_get_vector()")
    Fixes: ff0de066 ("hwtracing: hisi_ptt: Add trace function support for HiSilicon PCIe Tune and Trace device")
    Reviewed-by: NJonathan Cameron <Jonathan.Cameron@huawei.com>
    Signed-off-by: NYicong Yang <yangyicong@hisilicon.com>
    5a848148
hisi_ptt.c 38.3 KB