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authorQipan Li <Qipan.Li@csr.com>2014-05-26 19:02:07 +0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-05-28 12:22:43 -0700
commit07d410e06463f3c1c106e2bb2a7ff23eff1e71c9 (patch)
treeb8b6092ae11b4856fac7720215be563ee089598c /drivers/tty/serial/sirfsoc_uart.h
parent205c384f73e56d6b7d309b883a2064cd07ab5427 (diff)
serial: sirf: fix spinlock deadlock issue
commit fb78b811422cd2d8c8605949cc4cc13618347ad5 provide a workaround for kernel panic, but bring potential deadlock risk. that is in sirfsoc_rx_tmo_process_tl while enter into sirfsoc_uart_pio_rx_chars cpu hold uart_port->lock, if uart interrupt comes cpu enter into sirfsoc_uart_isr and deadlock occurs in getting uart_port->lock. the patch replace spin_lock version to spin_lock_irq* version to avoid spinlock dead lock issue. let function tty_flip_buffer_push in tasklet outof spin_lock_irq* protect area to avoid add the pair of spin_lock and spin_unlock for tty_flip_buffer_push. BTW drop self defined unused spinlock protect of tx_lock/rx_lock. 56274.220464] BUG: spinlock lockup suspected on CPU#0, swapper/0/0 [56274.223648] lock: 0xc05d9db0, .magic: dead4ead, .owner: swapper/0/0, .owner_cpu: 0 [56274.231278] CPU: 0 PID: 0 Comm: swapper/0 Tainted: G O 3.10.35 #1 [56274.238241] [<c0015530>] (unwind_backtrace+0x0/0xf4) from [<c00120d8>] (show_stack+0x10/0x14) [56274.246742] [<c00120d8>] (show_stack+0x10/0x14) from [<c01b11b0>] (do_raw_spin_lock+0x110/0x184) [56274.255501] [<c01b11b0>] (do_raw_spin_lock+0x110/0x184) from [<c02124c8>] (sirfsoc_uart_isr+0x20/0x42c) [56274.264874] [<c02124c8>] (sirfsoc_uart_isr+0x20/0x42c) from [<c0075790>] (handle_irq_event_percpu+0x54/0x17c) [56274.274758] [<c0075790>] (handle_irq_event_percpu+0x54/0x17c) from [<c00758f4>] (handle_irq_event+0x3c/0x5c) [56274.284561] [<c00758f4>] (handle_irq_event+0x3c/0x5c) from [<c0077fa0>] (handle_level_irq+0x98/0xfc) [56274.293670] [<c0077fa0>] (handle_level_irq+0x98/0xfc) from [<c0074f44>] (generic_handle_irq+0x2c/0x3c) [56274.302952] [<c0074f44>] (generic_handle_irq+0x2c/0x3c) from [<c000ef80>] (handle_IRQ+0x40/0x90) [56274.311706] [<c000ef80>] (handle_IRQ+0x40/0x90) from [<c000dc80>] (__irq_svc+0x40/0x70) [56274.319697] [<c000dc80>] (__irq_svc+0x40/0x70) from [<c038113c>] (_raw_spin_unlock_irqrestore+0x10/0x48) [56274.329158] [<c038113c>] (_raw_spin_unlock_irqrestore+0x10/0x48) from [<c0200034>] (tty_port_tty_get+0x58/0x90) [56274.339213] [<c0200034>] (tty_port_tty_get+0x58/0x90) from [<c0212008>] (sirfsoc_uart_pio_rx_chars+0x1c/0xc8) [56274.349097] [<c0212008>] (sirfsoc_uart_pio_rx_chars+0x1c/0xc8) from [<c0212ef8>] (sirfsoc_rx_tmo_process_tl+0xe4/0x1fc) [56274.359853] [<c0212ef8>] (sirfsoc_rx_tmo_process_tl+0xe4/0x1fc) from [<c0027c04>] (tasklet_action+0x84/0x114) [56274.369739] [<c0027c04>] (tasklet_action+0x84/0x114) from [<c0027db4>] (__do_softirq+0x120/0x200) [56274.378585] [<c0027db4>] (__do_softirq+0x120/0x200) from [<c0027f44>] (do_softirq+0x54/0x5c) [56274.386998] [<c0027f44>] (do_softirq+0x54/0x5c) from [<c00281ec>] (irq_exit+0x9c/0xd0) [56274.394899] [<c00281ec>] (irq_exit+0x9c/0xd0) from [<c000ef84>] (handle_IRQ+0x44/0x90) [56274.402790] [<c000ef84>] (handle_IRQ+0x44/0x90) from [<c000dc80>] (__irq_svc+0x40/0x70) [56274.410774] [<c000dc80>] (__irq_svc+0x40/0x70) from [<c0288af4>] (cpuidle_enter_state+0x50/0xe0) [56274.419532] [<c0288af4>] (cpuidle_enter_state+0x50/0xe0) from [<c0288c34>] (cpuidle_idle_call+0xb0/0x148) [56274.429080] [<c0288c34>] (cpuidle_idle_call+0xb0/0x148) from [<c000f3ac>] (arch_cpu_idle+0x8/0x38) [56274.438016] [<c000f3ac>] (arch_cpu_idle+0x8/0x38) from [<c0059344>] (cpu_startup_entry+0xfc/0x140) [56274.446956] [<c0059344>] (cpu_startup_entry+0xfc/0x140) from [<c04a3a54>] (start_kernel+0x2d8/0x2e4) Signed-off-by: Qipan Li <Qipan.Li@csr.com> Signed-off-by: Barry Song <Baohua.Song@csr.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty/serial/sirfsoc_uart.h')
-rw-r--r--drivers/tty/serial/sirfsoc_uart.h2
1 files changed, 0 insertions, 2 deletions
diff --git a/drivers/tty/serial/sirfsoc_uart.h b/drivers/tty/serial/sirfsoc_uart.h
index 4280819e1888..69a62ebd3afc 100644
--- a/drivers/tty/serial/sirfsoc_uart.h
+++ b/drivers/tty/serial/sirfsoc_uart.h
@@ -424,8 +424,6 @@ struct sirfsoc_uart_port {
struct dma_chan *tx_dma_chan;
dma_addr_t tx_dma_addr;
struct dma_async_tx_descriptor *tx_dma_desc;
- spinlock_t rx_lock;
- spinlock_t tx_lock;
struct tasklet_struct rx_dma_complete_tasklet;
struct tasklet_struct rx_tmo_process_tasklet;
unsigned int rx_io_count;