| Message ID | 1416993716-21005-1-git-send-email-dbaryshkov@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Dmitry Eremin-Solenikov <dbaryshkov@gmail.com> writes: > Both uart_handle_dcd_change() and uart_handle_cts_change() require a > port lock to be held and will emit a warning when lockdep is enabled. > Held corresponding lock. > > This fixes the following warnings: > > ------------[ cut here ]------------ > WARNING: CPU: 0 PID: 0 at drivers/tty/serial/serial_core.c:2760 uart_handle_dcd_change+0xc8/0xf8() > Modules linked in: > CPU: 0 PID: 0 Comm: swapper Not tainted 3.18.0-rc5+ #26 > [<c000dff8>] (unwind_backtrace) from [<c000bc70>] (show_stack+0x10/0x14) > [<c000bc70>] (show_stack) from [<c00192ac>] (warn_slowpath_common+0x6c/0x8c) > [<c00192ac>] (warn_slowpath_common) from [<c00192e8>] (warn_slowpath_null+0x1c/0x24) > [<c00192e8>] (warn_slowpath_null) from [<c0182984>] (uart_handle_dcd_change+0xc8/0xf8) > [<c0182984>] (uart_handle_dcd_change) from [<c018625c>] (serial_pxa_irq+0x268/0x3b0) > [<c018625c>] (serial_pxa_irq) from [<c004d0d4>] (handle_irq_event_percpu+0x50/0x16c) > [<c004d0d4>] (handle_irq_event_percpu) from [<c004d22c>] (handle_irq_event+0x3c/0x5c) > [<c004d22c>] (handle_irq_event) from [<c004f7d0>] (handle_level_irq+0x94/0x118) > [<c004f7d0>] (handle_level_irq) from [<c004ca0c>] (generic_handle_irq+0x20/0x30) > [<c004ca0c>] (generic_handle_irq) from [<c004cbe0>] (__handle_domain_irq+0x38/0x70) > [<c004cbe0>] (__handle_domain_irq) from [<c00085c4>] (ichp_handle_irq+0x24/0x34) > [<c00085c4>] (ichp_handle_irq) from [<c000c7e4>] (__irq_svc+0x44/0x54) > Exception stack(0xc07c7f58 to 0xc07c7fa0) > 7f40: 00000001 00000001 > 7f60: 00000000 20000013 c07c6000 00000000 00000000 c07ce0a4 c07d7798 00000000 > 7f80: c07e8fb8 0000004c 00000000 c07c7fa0 c0044798 c0009f20 20000013 ffffffff > [<c000c7e4>] (__irq_svc) from [<c0009f20>] (arch_cpu_idle+0x28/0x38) > [<c0009f20>] (arch_cpu_idle) from [<c003c974>] (cpu_startup_entry+0x1b8/0x220) > [<c003c974>] (cpu_startup_entry) from [<c0338c54>] (start_kernel+0x39c/0x40c) > ---[ end trace 4c1b7ae03f6d9d30 ]--- > ------------[ cut here ]------------ > WARNING: CPU: 0 PID: 0 at drivers/tty/serial/serial_core.c:2791 uart_handle_cts_change+0xa0/0xdc() > Modules linked in: > CPU: 0 PID: 0 Comm: swapper Tainted: G W 3.18.0-rc5+ #26 > [<c000dff8>] (unwind_backtrace) from [<c000bc70>] (show_stack+0x10/0x14) > [<c000bc70>] (show_stack) from [<c00192ac>] (warn_slowpath_common+0x6c/0x8c) > [<c00192ac>] (warn_slowpath_common) from [<c00192e8>] (warn_slowpath_null+0x1c/0x24) > [<c00192e8>] (warn_slowpath_null) from [<c018528c>] (uart_handle_cts_change+0xa0/0xdc) > [<c018528c>] (uart_handle_cts_change) from [<c018624c>] (serial_pxa_irq+0x258/0x3b0) > [<c018624c>] (serial_pxa_irq) from [<c004d0d4>] (handle_irq_event_percpu+0x50/0x16c) > [<c004d0d4>] (handle_irq_event_percpu) from [<c004d22c>] (handle_irq_event+0x3c/0x5c) > [<c004d22c>] (handle_irq_event) from [<c004f7d0>] (handle_level_irq+0x94/0x118) > [<c004f7d0>] (handle_level_irq) from [<c004ca0c>] (generic_handle_irq+0x20/0x30) > [<c004ca0c>] (generic_handle_irq) from [<c004cbe0>] (__handle_domain_irq+0x38/0x70) > [<c004cbe0>] (__handle_domain_irq) from [<c00085c4>] (ichp_handle_irq+0x24/0x34) > [<c00085c4>] (ichp_handle_irq) from [<c000c7e4>] (__irq_svc+0x44/0x54) > Exception stack(0xc07c7f58 to 0xc07c7fa0) > 7f40: 00000001 00000001 > 7f60: 00000000 20000013 c07c6000 00000000 00000000 c07ce0a4 c07d7798 00000000 > 7f80: c07e8fb8 0000004c 00000000 c07c7fa0 c0044798 c0009f20 20000013 ffffffff > [<c000c7e4>] (__irq_svc) from [<c0009f20>] (arch_cpu_idle+0x28/0x38) > [<c0009f20>] (arch_cpu_idle) from [<c003c974>] (cpu_startup_entry+0x1b8/0x220) > [<c003c974>] (cpu_startup_entry) from [<c0338c54>] (start_kernel+0x39c/0x40c) > ---[ end trace 4c1b7ae03f6d9d31 ]--- > > Signed-off-by: Dmitry Eremin-Solenikov <dbaryshkov@gmail.com> > --- > [Changes since v1 - lock whole function, not just check_modem_status().] Acked-by: Robert Jarzmik <robert.jarzmik@free.fr>
diff --git a/drivers/tty/serial/pxa.c b/drivers/tty/serial/pxa.c index 21b7d8b8..7788d53 100644 --- a/drivers/tty/serial/pxa.c +++ b/drivers/tty/serial/pxa.c @@ -223,6 +223,7 @@ static void serial_pxa_start_tx(struct uart_port *port) } } +/* should hold up->port.lock */ static inline void check_modem_status(struct uart_pxa_port *up) { int status; @@ -255,12 +256,14 @@ static inline irqreturn_t serial_pxa_irq(int irq, void *dev_id) iir = serial_in(up, UART_IIR); if (iir & UART_IIR_NO_INT) return IRQ_NONE; + spin_lock(&up->port.lock); lsr = serial_in(up, UART_LSR); if (lsr & UART_LSR_DR) receive_chars(up, &lsr); check_modem_status(up); if (lsr & UART_LSR_THRE) transmit_chars(up); + spin_unlock(&up->port.lock); return IRQ_HANDLED; }
Both uart_handle_dcd_change() and uart_handle_cts_change() require a port lock to be held and will emit a warning when lockdep is enabled. Held corresponding lock. This fixes the following warnings: ------------[ cut here ]------------ WARNING: CPU: 0 PID: 0 at drivers/tty/serial/serial_core.c:2760 uart_handle_dcd_change+0xc8/0xf8() Modules linked in: CPU: 0 PID: 0 Comm: swapper Not tainted 3.18.0-rc5+ #26 [<c000dff8>] (unwind_backtrace) from [<c000bc70>] (show_stack+0x10/0x14) [<c000bc70>] (show_stack) from [<c00192ac>] (warn_slowpath_common+0x6c/0x8c) [<c00192ac>] (warn_slowpath_common) from [<c00192e8>] (warn_slowpath_null+0x1c/0x24) [<c00192e8>] (warn_slowpath_null) from [<c0182984>] (uart_handle_dcd_change+0xc8/0xf8) [<c0182984>] (uart_handle_dcd_change) from [<c018625c>] (serial_pxa_irq+0x268/0x3b0) [<c018625c>] (serial_pxa_irq) from [<c004d0d4>] (handle_irq_event_percpu+0x50/0x16c) [<c004d0d4>] (handle_irq_event_percpu) from [<c004d22c>] (handle_irq_event+0x3c/0x5c) [<c004d22c>] (handle_irq_event) from [<c004f7d0>] (handle_level_irq+0x94/0x118) [<c004f7d0>] (handle_level_irq) from [<c004ca0c>] (generic_handle_irq+0x20/0x30) [<c004ca0c>] (generic_handle_irq) from [<c004cbe0>] (__handle_domain_irq+0x38/0x70) [<c004cbe0>] (__handle_domain_irq) from [<c00085c4>] (ichp_handle_irq+0x24/0x34) [<c00085c4>] (ichp_handle_irq) from [<c000c7e4>] (__irq_svc+0x44/0x54) Exception stack(0xc07c7f58 to 0xc07c7fa0) 7f40: 00000001 00000001 7f60: 00000000 20000013 c07c6000 00000000 00000000 c07ce0a4 c07d7798 00000000 7f80: c07e8fb8 0000004c 00000000 c07c7fa0 c0044798 c0009f20 20000013 ffffffff [<c000c7e4>] (__irq_svc) from [<c0009f20>] (arch_cpu_idle+0x28/0x38) [<c0009f20>] (arch_cpu_idle) from [<c003c974>] (cpu_startup_entry+0x1b8/0x220) [<c003c974>] (cpu_startup_entry) from [<c0338c54>] (start_kernel+0x39c/0x40c) ---[ end trace 4c1b7ae03f6d9d30 ]--- ------------[ cut here ]------------ WARNING: CPU: 0 PID: 0 at drivers/tty/serial/serial_core.c:2791 uart_handle_cts_change+0xa0/0xdc() Modules linked in: CPU: 0 PID: 0 Comm: swapper Tainted: G W 3.18.0-rc5+ #26 [<c000dff8>] (unwind_backtrace) from [<c000bc70>] (show_stack+0x10/0x14) [<c000bc70>] (show_stack) from [<c00192ac>] (warn_slowpath_common+0x6c/0x8c) [<c00192ac>] (warn_slowpath_common) from [<c00192e8>] (warn_slowpath_null+0x1c/0x24) [<c00192e8>] (warn_slowpath_null) from [<c018528c>] (uart_handle_cts_change+0xa0/0xdc) [<c018528c>] (uart_handle_cts_change) from [<c018624c>] (serial_pxa_irq+0x258/0x3b0) [<c018624c>] (serial_pxa_irq) from [<c004d0d4>] (handle_irq_event_percpu+0x50/0x16c) [<c004d0d4>] (handle_irq_event_percpu) from [<c004d22c>] (handle_irq_event+0x3c/0x5c) [<c004d22c>] (handle_irq_event) from [<c004f7d0>] (handle_level_irq+0x94/0x118) [<c004f7d0>] (handle_level_irq) from [<c004ca0c>] (generic_handle_irq+0x20/0x30) [<c004ca0c>] (generic_handle_irq) from [<c004cbe0>] (__handle_domain_irq+0x38/0x70) [<c004cbe0>] (__handle_domain_irq) from [<c00085c4>] (ichp_handle_irq+0x24/0x34) [<c00085c4>] (ichp_handle_irq) from [<c000c7e4>] (__irq_svc+0x44/0x54) Exception stack(0xc07c7f58 to 0xc07c7fa0) 7f40: 00000001 00000001 7f60: 00000000 20000013 c07c6000 00000000 00000000 c07ce0a4 c07d7798 00000000 7f80: c07e8fb8 0000004c 00000000 c07c7fa0 c0044798 c0009f20 20000013 ffffffff [<c000c7e4>] (__irq_svc) from [<c0009f20>] (arch_cpu_idle+0x28/0x38) [<c0009f20>] (arch_cpu_idle) from [<c003c974>] (cpu_startup_entry+0x1b8/0x220) [<c003c974>] (cpu_startup_entry) from [<c0338c54>] (start_kernel+0x39c/0x40c) ---[ end trace 4c1b7ae03f6d9d31 ]--- Signed-off-by: Dmitry Eremin-Solenikov <dbaryshkov@gmail.com> --- [Changes since v1 - lock whole function, not just check_modem_status().] drivers/tty/serial/pxa.c | 3 +++ 1 file changed, 3 insertions(+)