From: Saubhik Mukherjee <firstname.lastname@example.org> To: email@example.com, firstname.lastname@example.org Cc: email@example.com, 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 port->dev. 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 ` Greg KH 2021-06-14 9:57 ` Saubhik Mukherjee 2021-06-14 10:01 ` Greg KH
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