From: Saubhik Mukherjee <email@example.com>
To: firstname.lastname@example.org, email@example.com
Cc: firstname.lastname@example.org, email@example.com,
Subject: [question] Is it possible to remove an active port (without shutdown)?
Date: Fri, 11 Jun 2021 15:03:42 +0530 [thread overview]
Message-ID: <firstname.lastname@example.org> (raw)
Consider the following events involving drivers/tty/serial/owl-uart.c:
Suppose the driver is registered, and the owl_uart_probe() was called.
Then uart_startup() can be called in serial core. This calls
owl_uart_startup() which registers the interrupt handler owl_uart_irq.
Now suppose uart_remove_one_port() in serial core is called. This
detaches port from the core. This calls owl_uart_release_port(port).
This writes NULL to port->membase after iounmap of port->membase from
During this point, an interrupt is triggered and the interrupt callback
owl_uart_irq() is called (parallel with uart_remove_one_port()). This
tries to read port->membase to send or receive chars (with spinlock on
port->lock). This introduces a race condition on port->membase.
QUESTION: Is it possible to remove an active port (without shutdown)?
next reply other threads:[~2021-06-11 9:35 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-11 9:33 Saubhik Mukherjee [this message]
2021-06-11 9:47 ` [question] Is it possible to remove an active port (without shutdown)? Greg KH
2021-06-14 9:57 ` Saubhik Mukherjee
2021-06-14 10:01 ` Greg KH
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