On 08/19/2013 10:44 AM, Viresh Kumar wrote:
Many serial driver triggers a lockdep warning for if tty_flip_buffer_push() is
called with uart_port->lock locked. This never shows up on UP kernels and comes
up only on SMP kernels.
Crash looks like this (produced with samsung.c driver):
Please review commit 677fe555cbfb188af58cce105f4dae9505e58c31
'serial: imx: Fix recursive locking bug' to see if that is actually the problem
you're having with the samsung serial driver.
-----
[<c0014d58>] (unwind_backtrace+0x0/0xf8) from [<c0011908>] (show_stack+0x10/0x14)
[<c0011908>] (show_stack+0x10/0x14) from [<c035da34>] (dump_stack+0x6c/0xac)
[<c035da34>] (dump_stack+0x6c/0xac) from [<c01b59ac>] (do_raw_spin_unlock+0xc4/0xd8)
[<c01b59ac>] (do_raw_spin_unlock+0xc4/0xd8) from [<c03627e4>] (_raw_spin_unlock_irqrestore+0xc/0)
[<c03627e4>] (_raw_spin_unlock_irqrestore+0xc/0x38) from [<c020a1a8>] (s3c24xx_serial_rx_chars+0)
[<c020a1a8>] (s3c24xx_serial_rx_chars+0x12c/0x260) from [<c020aae8>] (s3c64xx_serial_handle_irq+)
[<c020aae8>] (s3c64xx_serial_handle_irq+0x48/0x60) from [<c006aaa0>] (handle_irq_event_percpu+0x)
[<c006aaa0>] (handle_irq_event_percpu+0x50/0x194) from [<c006ac20>] (handle_irq_event+0x3c/0x5c)
[<c006ac20>] (handle_irq_event+0x3c/0x5c) from [<c006d864>] (handle_fasteoi_irq+0x80/0x13c)
[<c006d864>] (handle_fasteoi_irq+0x80/0x13c) from [<c006a4a4>] (generic_handle_irq+0x20/0x30)
[<c006a4a4>] (generic_handle_irq+0x20/0x30) from [<c000f454>] (handle_IRQ+0x38/0x94)
[<c000f454>] (handle_IRQ+0x38/0x94) from [<c0008538>] (gic_handle_irq+0x34/0x68)
[<c0008538>] (gic_handle_irq+0x34/0x68) from [<c00123c0>] (__irq_svc+0x40/0x70)
Exception stack(0xc04cdf70 to 0xc04cdfb8)
df60: 00000000 00000000 0000166e 00000000
df80: c04cc000 c050278f c050278f 00000001 c04d444c 410fc0f4 c03649b0 00000000
dfa0: 00000001 c04cdfb8 c000f758 c000f75c 60070013 ffffffff
[<c00123c0>] (__irq_svc+0x40/0x70) from [<c000f75c>] (arch_cpu_idle+0x28/0x30)
[<c000f75c>] (arch_cpu_idle+0x28/0x30) from [<c0054888>] (cpu_startup_entry+0x5c/0x148)
[<c0054888>] (cpu_startup_entry+0x5c/0x148) from [<c0497aa4>] (start_kernel+0x334/0x38c)
BUG: spinlock lockup suspected on CPU#0, kworker/0:1/360
lock: s3c24xx_serial_ports+0x1d8/0x370, .magic: dead4ead, .owner: <none>/-1, .owner_cpu: -1
CPU: 0 PID: 360 Comm: kworker/0:1 Not tainted 3.11.0-rc6-next-20130819-00003-g75485f1 #2
Workqueue: events flush_to_ldisc
[<c0014d58>] (unwind_backtrace+0x0/0xf8) from [<c0011908>] (show_stack+0x10/0x14)
[<c0011908>] (show_stack+0x10/0x14) from [<c035da34>] (dump_stack+0x6c/0xac)
[<c035da34>] (dump_stack+0x6c/0xac) from [<c01b581c>] (do_raw_spin_lock+0x100/0x17c)
[<c01b581c>] (do_raw_spin_lock+0x100/0x17c) from [<c03628a0>] (_raw_spin_lock_irqsave+0x20/0x28)
[<c03628a0>] (_raw_spin_lock_irqsave+0x20/0x28) from [<c0203224>] (uart_start+0x18/0x34)
[<c0203224>] (uart_start+0x18/0x34) from [<c01ef890>] (__receive_buf+0x4b4/0x738)
[<c01ef890>] (__receive_buf+0x4b4/0x738) from [<c01efb44>] (n_tty_receive_buf2+0x30/0x98)
[<c01efb44>] (n_tty_receive_buf2+0x30/0x98) from [<c01f2ba8>] (flush_to_ldisc+0xec/0x138)
[<c01f2ba8>] (flush_to_ldisc+0xec/0x138) from [<c0031af0>] (process_one_work+0xfc/0x348)
[<c0031af0>] (process_one_work+0xfc/0x348) from [<c0032138>] (worker_thread+0x138/0x37c)
[<c0032138>] (worker_thread+0x138/0x37c) from [<c0037a7c>] (kthread+0xa4/0xb0)
[<c0037a7c>] (kthread+0xa4/0xb0) from [<c000e5f8>] (ret_from_fork+0x14/0x3c)
-----
This patchset modifies these drivers to release the port lock before calling
tty_flip_buffer_push() and reacquire it after the call.
Similar stuff was already done for few other drivers in the past, like:
commit 2389b272168ceec056ca1d8a870a97fa9c26e11a
Author: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Date: Tue May 29 21:53:50 2007 +0100
[ARM] 4417/1: Serial: Fix AMBA drivers locking
This is build tested for all drivers and tested on Samsung's Arndale board for
samsung.c driver. Rebased over linux-next (Problem was reproduced on this
branch):
commit 1e712b0818569846d6b926ecb6bf32b3dea73609
Author: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx>
Date: Fri Aug 16 17:06:26 2013 +1000
Add linux-next specific files for 20130816
Signed-off-by: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx>
Cc: Bryan Huntsman <bryanh@xxxxxxxxxxxxxx>
Cc: Daniel Walker <dwalker@xxxxxxxxxx>
Cc: David Brown <davidb@xxxxxxxxxxxxxx>
Cc: Stephen Warren <swarren@xxxxxxxxxxxxx>
Cc: Tobias Klauser <tklauser@xxxxxxxxxx>
Cc: Tony Prisk <linux@xxxxxxxxxxxxxxx>
Viresh Kumar (25):
tty: serial: altera_jtag: drop uart_port->lock before calling
tty_flip_buffer_push()
tty: serial: altera: drop uart_port->lock before calling
tty_flip_buffer_push()
tty: serial: apbuart: drop uart_port->lock before calling
tty_flip_buffer_push()
tty: serial: ar933x: drop uart_port->lock before calling
tty_flip_buffer_push()
tty: serial: arc: drop uart_port->lock before calling
tty_flip_buffer_push()
tty: serial: bcm63xx: drop uart_port->lock before calling
tty_flip_buffer_push()
tty: serial: bfin_sport: drop uart_port->lock before calling
tty_flip_buffer_push()
tty: serial: efm32: drop uart_port->lock before calling
tty_flip_buffer_push()
tty: serial: icom: drop uart_port->lock before calling
tty_flip_buffer_push()
tty: serial: lpc32xx_hs: don't call tty_flip_buffer_push() twice
tty: serial: lpc32xx_hs: drop uart_port->lock before calling
tty_flip_buffer_push()
tty: serial: m32r_sio: drop uart_port->lock before calling
tty_flip_buffer_push()
tty: serial: mcf: drop uart_port->lock before calling
tty_flip_buffer_push()
tty: serial: mfd: drop uart_port->lock before calling
tty_flip_buffer_push()
tty: serial: mpsc: drop uart_port->lock before calling
tty_flip_buffer_push()
tty: serial: msm: drop uart_port->lock before calling
tty_flip_buffer_push()
tty: serial: netx: drop uart_port->lock before calling
tty_flip_buffer_push()
tty: serial: nwpserial: drop uart_port->lock before calling
tty_flip_buffer_push()
tty: serial: pnx8xxx: drop uart_port->lock before calling
tty_flip_buffer_push()
tty: serial: rp2: drop uart_port->lock before calling
tty_flip_buffer_push()
tty: serial: sa1100: drop uart_port->lock before calling
tty_flip_buffer_push()
tty: serial: samsung: drop uart_port->lock before calling
tty_flip_buffer_push()
tty: serial: tegra: drop uart_port->lock before calling
tty_flip_buffer_push()
tty: serial: sirfsoc: drop uart_port->lock before calling
tty_flip_buffer_push()
tty: serial: vt8500: drop uart_port->lock before calling
tty_flip_buffer_push()
drivers/tty/serial/altera_jtaguart.c | 2 ++
drivers/tty/serial/altera_uart.c | 2 ++
drivers/tty/serial/apbuart.c | 2 ++
drivers/tty/serial/ar933x_uart.c | 2 ++
drivers/tty/serial/arc_uart.c | 2 ++
drivers/tty/serial/bcm63xx_uart.c | 2 ++
drivers/tty/serial/bfin_sport_uart.c | 5 +++--
drivers/tty/serial/efm32-uart.c | 4 ++--
drivers/tty/serial/icom.c | 3 +++
drivers/tty/serial/lpc32xx_hs.c | 7 ++++---
drivers/tty/serial/m32r_sio.c | 3 +++
drivers/tty/serial/mcf.c | 2 ++
drivers/tty/serial/mfd.c | 14 ++++++++++----
drivers/tty/serial/mpsc.c | 11 ++++++++---
drivers/tty/serial/msm_serial.c | 5 +++++
drivers/tty/serial/netx-serial.c | 6 ++++--
drivers/tty/serial/nwpserial.c | 3 +++
drivers/tty/serial/pnx8xxx_uart.c | 3 +++
drivers/tty/serial/rp2.c | 2 ++
drivers/tty/serial/sa1100.c | 3 +++
drivers/tty/serial/samsung.c | 5 ++++-
drivers/tty/serial/serial-tegra.c | 10 ++++++++--
drivers/tty/serial/sirfsoc_uart.c | 3 +++
drivers/tty/serial/vt8500_serial.c | 2 ++
24 files changed, 84 insertions(+), 19 deletions(-)
--
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