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coresight: trbe: Fix TRBE potential sleep in atomic context
authorJunhao He <hejunhao3@huawei.com>
Fri, 18 Aug 2023 08:40:52 +0000 (16:40 +0800)
committerSuzuki K Poulose <suzuki.poulose@arm.com>
Fri, 18 Aug 2023 15:42:26 +0000 (16:42 +0100)
commitc0a232f1e19e378c5c4e5973a996392942c80090
tree541a744fa0bff98e426dcaebfbd7ba20fc4e057a
parent1a9e02673e2550f5612099e64e8761f0c8fc0f50
coresight: trbe: Fix TRBE potential sleep in atomic context

smp_call_function_single() will allocate an IPI interrupt vector to
the target processor and send a function call request to the interrupt
vector. After the target processor receives the IPI interrupt, it will
execute arm_trbe_remove_coresight_cpu() call request in the interrupt
handler.

According to the device_unregister() stack information, if other process
is useing the device, the down_write() may sleep, and trigger deadlocks
or unexpected errors.

  arm_trbe_remove_coresight_cpu
    coresight_unregister
      device_unregister
        device_del
          kobject_del
            __kobject_del
              sysfs_remove_dir
                kernfs_remove
                  down_write ---------> it may sleep

Add a helper arm_trbe_disable_cpu() to disable TRBE precpu irq and reset
per TRBE.
Simply call arm_trbe_remove_coresight_cpu() directly without useing the
smp_call_function_single(), which is the same as registering the TRBE
coresight device.

Fixes: 3fbf7f011f24 ("coresight: sink: Add TRBE driver")
Signed-off-by: Junhao He <hejunhao3@huawei.com>
Link: https://lore.kernel.org/r/20230814093813.19152-2-hejunhao3@huawei.com
[ Remove duplicate cpumask checks during removal ]
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
[ v3 - Remove the operation of assigning NULL to cpudata->drvdata ]
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20230818084052.10116-1-hejunhao3@huawei.com
drivers/hwtracing/coresight/coresight-trbe.c