diff options
| author | Qipan Li <Qipan.Li@csr.com> | 2014-01-27 10:23:39 +0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-02-13 22:02:19 +0400 |
| commit | fb78b811422cd2d8c8605949cc4cc13618347ad5 (patch) | |
| tree | 426d743f1abac0cf8d43d19f1b97a2f9d5acff9f /drivers/tty/serial/sirfsoc_uart.c | |
| parent | 333c085e4b0cd9df04b087d29f87969a4e26dfa9 (diff) | |
| download | linux-fb78b811422cd2d8c8605949cc4cc13618347ad5.tar.xz | |
serial: sirf: fix kernel panic caused by unpaired spinlock
commit 8b9ade9f74f8a279 coming from Viresh Kumar "tty: serial: sirfsoc: drop
uart_port->lock before calling tty_flip_buffer_push()" broke sirfsoc uart
driver by knic:
[ 5.129122] BUG: spinlock already unlocked on CPU#0, ip6tables/1331
[ 5.132554] lock: sirfsoc_uart_ports+0x4/0x8a0, .magic: dead4ead,
.owner: <none>/-1, .owner_cpu: -1
[ 5.141651] CPU: 0 PID: 1331 Comm: ip6tables Tainted: G
W O 3.10.16 #3
[ 5.148866] [<c0013528>] (unwind_backtrace+0x0/0xe0) from
[<c0010e70>] (show_stack+0x10/0x14)
[ 5.157362] [<c0010e70>] (show_stack+0x10/0x14) from
[<c01a5e68>] (do_raw_spin_unlock+0x40/0xc8)
[ 5.166125] [<c01a5e68>] (do_raw_spin_unlock+0x40/0xc8) from
[<c03ff8b4>] (_raw_spin_unlock+0x8/0x40)
[ 5.175322] [<c03ff8b4>] (_raw_spin_unlock+0x8/0x40) from
[<c0203fcc>] (sirfsoc_uart_pio_rx_chars+0xa4/0xc0)
[ 5.185120] [<c0203fcc>]
(sirfsoc_uart_pio_rx_chars+0xa4/0xc0) from [<c0204fb8>]
(sirfsoc_rx_tmo_process_tl+0xdc/0x1e0)
[ 5.195875] [<c0204fb8>]
(sirfsoc_rx_tmo_process_tl+0xdc/0x1e0) from [<c0024b50>]
(tasklet_action+0x8c/0xec)
[ 5.205673] [<c0024b50>] (tasklet_action+0x8c/0xec) from
[<c00242a8>] (__do_softirq+0xec/0x1d4)
[ 5.214347] [<c00242a8>] (__do_softirq+0xec/0x1d4) from
[<c0024428>] (do_softirq+0x48/0x54)
[ 5.222674] [<c0024428>] (do_softirq+0x48/0x54) from
[<c0024690>] (irq_exit+0x74/0xc0)
[ 5.230573] [<c0024690>] (irq_exit+0x74/0xc0) from
[<c000e1e8>] (handle_IRQ+0x6c/0x90)
[ 5.238465] [<c000e1e8>] (handle_IRQ+0x6c/0x90) from
[<c000d500>] (__irq_svc+0x40/0x70)
[ 5.246446] [<c000d500>] (__irq_svc+0x40/0x70) from
[<c0092e7c>] (mark_page_accessed+0xc/0x68)
[ 5.255034] [<c0092e7c>] (mark_page_accessed+0xc/0x68) from
[<c00a2a4c>] (unmap_single_vma+0x3bc/0x550)
[ 5.264402] [<c00a2a4c>] (unmap_single_vma+0x3bc/0x550) from
[<c00a3b4c>] (unmap_vmas+0x44/0x54)
[ 5.273164] [<c00a3b4c>] (unmap_vmas+0x44/0x54) from
[<c00a81a8>] (exit_mmap+0xc4/0x1e0)
[ 5.281233] [<c00a81a8>] (exit_mmap+0xc4/0x1e0) from
[<c001bb78>] (mmput+0x3c/0xdc)
[ 5.288868] [<c001bb78>] (mmput+0x3c/0xdc) from [<c0021b0c>]
(do_exit+0x30c/0x828)
[ 5.296413] [<c0021b0c>] (do_exit+0x30c/0x828) from
[<c0022dac>] (do_group_exit+0x4c/0xb0)
[ 5.304653] [<c0022dac>] (do_group_exit+0x4c/0xb0) from
[<c0022e20>] (__wake_up_parent+0x0/0x18)
Root cause:
the commit dropped uart_port->lock before calling tty_flip_buffer_push(), but in sirfsoc-uart,
sirfsoc_uart_pio_rx_chars() can be called by sirfsoc_rx_tmo_process_tl(). here uart_port->lock
has not been taken yet. so that caused unpaired lock/unlock.
Solution:
This patch is doing a quick fix for that, it adds spin_lock/unlock(&port->lock) protect to
sirfsoc_uart_pio_rx_chars() in sirfsoc_rx_tmo_process_tl() to keep spin_lock/unlock in pair.
Signed-off-by: Qipan Li <Qipan.Li@csr.com>
Signed-off-by: Barry Song <Baohua.Song@csr.com>
Cc: stable <stable@vger.kernel.org> # 3.12
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty/serial/sirfsoc_uart.c')
| -rw-r--r-- | drivers/tty/serial/sirfsoc_uart.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/drivers/tty/serial/sirfsoc_uart.c b/drivers/tty/serial/sirfsoc_uart.c index 49a2ffd101a7..b7bfe24d4ebc 100644 --- a/drivers/tty/serial/sirfsoc_uart.c +++ b/drivers/tty/serial/sirfsoc_uart.c @@ -542,8 +542,10 @@ static void sirfsoc_rx_tmo_process_tl(unsigned long param) wr_regl(port, ureg->sirfsoc_rx_dma_io_ctrl, rd_regl(port, ureg->sirfsoc_rx_dma_io_ctrl) | SIRFUART_IO_MODE); - sirfsoc_uart_pio_rx_chars(port, 4 - sirfport->rx_io_count); spin_unlock_irqrestore(&sirfport->rx_lock, flags); + spin_lock(&port->lock); + sirfsoc_uart_pio_rx_chars(port, 4 - sirfport->rx_io_count); + spin_unlock(&port->lock); if (sirfport->rx_io_count == 4) { spin_lock_irqsave(&sirfport->rx_lock, flags); sirfport->rx_io_count = 0; |