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charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 14. 10. 26, 8:49, sashiko-bot@kernel.org wrote: > Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider: > - [High] tty: serial: 8250_hp300: NULL pointer dereference on hpdca device removal > -- > > commit f913317bfee3afed5e144530ca60f25858464754 > Author: Jiri Slaby (SUSE) > Date: Tue Oct 13 06:48:51 2026 +0000 > > serial: 8250: make port operations work on struct uart_8250_port > > This commit switches the interface of port operations to use > struct uart_8250_port instead of the line number, returning the registered > port or an ERR_PTR() on failure. It updates all drivers to store the port > pointer instead of the line number. > >> diff --git a/drivers/tty/serial/8250/8250_hp300.c b/drivers/tty/serial/8250/8250_hp300.c >> index 59ec0c7377a1c..e9599c5c2fead 100644 >> --- a/drivers/tty/serial/8250/8250_hp300.c >> +++ b/drivers/tty/serial/8250/8250_hp300.c > [ ... ] >> @@ -177,9 +177,8 @@ static int hpdca_init_one(struct dio_dev *d, >> uart.port.membase = (char *)(uart.port.mapbase + DIO_VIRADDRBASE); >> uart.port.regshift = 1; >> uart.port.dev = &d->dev; >> - line = serial8250_register_8250_port(&uart); >> - >> - if (line < 0) { >> + uport = serial8250_register_8250_port(&uart); >> + if (IS_ERR(uport)) { >> dev_notice(&d->dev, >> "8250_hp300: register_serial() DCA scode %d irq %d failed\n", >> d->scode, uart.port.irq); >> return 0; Am I hallucinating or you do? I have: return -ENOMEM; on that line. >> } >> >> /* Enable board-interrupts */ >> out_8(d->resource.start + DIO_VIRADDRBASE + DCA_IC, DCA_IC_IE); >> - dio_set_drvdata(d, (void *)line); >> + dio_set_drvdata(d, uport); >> >> /* Reset the DCA */ >> out_8(d->resource.start + DIO_VIRADDRBASE + DCA_ID, 0xff); > > [Severity: High] > If serial8250_register_8250_port() fails here and returns an ERR_PTR, this > function logs a warning and returns 0 (success). In this failure path, > dio_set_drvdata() is skipped, leaving the device's driver data as NULL. > > Because the driver returns 0, the device is considered successfully bound. > When the device is later removed, hpdca_remove_one() is called: > >> @@ -287,14 +283,13 @@ static int __init hp300_8250_init(void) >> #ifdef CONFIG_HPDCA >> static void hpdca_remove_one(struct dio_dev *d) >> { >> - int line; >> + struct uart_8250_port *uport = dio_get_drvdata(d); >> >> - line = (int) dio_get_drvdata(d); >> if (d->resource.start) { >> /* Disable board-interrupts */ >> out_8(d->resource.start + DIO_VIRADDRBASE + DCA_IC, 0); >> } >> - serial8250_unregister_port(line); >> + serial8250_unregister_port(uport); >> } >> #endif > > Will this lead to a NULL pointer dereference? > > If the registration failed during probe, uport will be NULL here. Since > serial8250_unregister_port() unconditionally dereferences the pointer (e.g., > checking uart->em485), passing NULL will cause a kernel panic. > > Should the failure path in hpdca_init_one() return an error code instead of > 0, or should hpdca_remove_one() check for a valid uport before > unregistering? > > Note: This replaces a prior bug where passing an uninitialized 0 line number > caused the driver to erroneously unregister ttyS0 instead of crashing. > -- js suse labs