| Message ID | 20240315154150.28391-1-emil.kronborg@protonmail.com |
|---|---|
| State | Superseded |
| Headers | show |
| Series | serial: mxs-auart: add spinlock around changing cts state | expand |
On Fri, Mar 15, 2024 at 03:42:29PM +0000, Emil Kronborg wrote: > The uart_handle_cts_change() function in serial_core expects the caller > to hold uport->lock. For example, I have seen the below kernel splat, > when the Bluetooth driver is loaded on an i.MX28 board. > > [ 85.119255] ------------[ cut here ]------------ > [ 85.124413] WARNING: CPU: 0 PID: 27 at /drivers/tty/serial/serial_core.c:3453 uart_handle_cts_change+0xb4/0xec Add: mxs_auart_modem_status() mxs_auart_irq_handle() May help understand why need add lock in mxs_auart_irq_handle(). > [ 85.134694] Modules linked in: hci_uart bluetooth ecdh_generic ecc wlcore_sdio configfs > [ 85.143314] CPU: 0 PID: 27 Comm: kworker/u3:0 Not tainted 6.6.3-00021-gd62a2f068f92 #1 > [ 85.151396] Hardware name: Freescale MXS (Device Tree) > [ 85.156679] Workqueue: hci0 hci_power_on [bluetooth] > [ 85.164243] unwind_backtrace from show_stack+0x10/0x14 > (...) > > Signed-off-by: Emil Kronborg <emil.kronborg@protonmail.com> Cc stable and add fix tag Frank > --- > drivers/tty/serial/mxs-auart.c | 8 ++++++-- > 1 file changed, 6 insertions(+), 2 deletions(-) > > diff --git a/drivers/tty/serial/mxs-auart.c b/drivers/tty/serial/mxs-auart.c > index 4749331fe618..1e8853eae504 100644 > --- a/drivers/tty/serial/mxs-auart.c > +++ b/drivers/tty/serial/mxs-auart.c > @@ -1086,11 +1086,13 @@ static void mxs_auart_set_ldisc(struct uart_port *port, > > static irqreturn_t mxs_auart_irq_handle(int irq, void *context) > { > - u32 istat; > + u32 istat, stat; > struct mxs_auart_port *s = context; > u32 mctrl_temp = s->mctrl_prev; > - u32 stat = mxs_read(s, REG_STAT); > > + uart_port_lock(&s->port); > + > + stat = mxs_read(s, REG_STAT); > istat = mxs_read(s, REG_INTR); > > /* ack irq */ > @@ -1126,6 +1128,8 @@ static irqreturn_t mxs_auart_irq_handle(int irq, void *context) > istat &= ~AUART_INTR_TXIS; > } > > + uart_port_unlock(&s->port); > + > return IRQ_HANDLED; > } > > -- > 2.44.0 > >
diff --git a/drivers/tty/serial/mxs-auart.c b/drivers/tty/serial/mxs-auart.c index 4749331fe618..1e8853eae504 100644 --- a/drivers/tty/serial/mxs-auart.c +++ b/drivers/tty/serial/mxs-auart.c @@ -1086,11 +1086,13 @@ static void mxs_auart_set_ldisc(struct uart_port *port, static irqreturn_t mxs_auart_irq_handle(int irq, void *context) { - u32 istat; + u32 istat, stat; struct mxs_auart_port *s = context; u32 mctrl_temp = s->mctrl_prev; - u32 stat = mxs_read(s, REG_STAT); + uart_port_lock(&s->port); + + stat = mxs_read(s, REG_STAT); istat = mxs_read(s, REG_INTR); /* ack irq */ @@ -1126,6 +1128,8 @@ static irqreturn_t mxs_auart_irq_handle(int irq, void *context) istat &= ~AUART_INTR_TXIS; } + uart_port_unlock(&s->port); + return IRQ_HANDLED; }
The uart_handle_cts_change() function in serial_core expects the caller to hold uport->lock. For example, I have seen the below kernel splat, when the Bluetooth driver is loaded on an i.MX28 board. [ 85.119255] ------------[ cut here ]------------ [ 85.124413] WARNING: CPU: 0 PID: 27 at /drivers/tty/serial/serial_core.c:3453 uart_handle_cts_change+0xb4/0xec [ 85.134694] Modules linked in: hci_uart bluetooth ecdh_generic ecc wlcore_sdio configfs [ 85.143314] CPU: 0 PID: 27 Comm: kworker/u3:0 Not tainted 6.6.3-00021-gd62a2f068f92 #1 [ 85.151396] Hardware name: Freescale MXS (Device Tree) [ 85.156679] Workqueue: hci0 hci_power_on [bluetooth] [ 85.164243] unwind_backtrace from show_stack+0x10/0x14 (...) Signed-off-by: Emil Kronborg <emil.kronborg@protonmail.com> --- drivers/tty/serial/mxs-auart.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)