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Subject[RFC][PATCHv2 0/4] less deadlock prone serial consoles
Date
	Hello,


RFC


The patch set reduces the number of ways serial consoles
can deadlock the system, including the recently reported deadlock
in panic().

The test scenario I ran on my x86_64 box:
- panic() the system while one of the CPUs holds 8250's
uart_port->lock.

Test results:

base | patched
-----------------------------------------
deadlock | flush logbuf
| reboot the system

To keep the cover letter short, please find full description in
commit messages.

P.S. since this is RFC I modify only 8250 serial driver.

Sergey Senozhatsky (4):
panic: avoid deadlocks in re-entrant console drivers
printk: move printk_safe macros to printk header
seial: introduce uart_port locking helpers
tty: 8250: switch to uart_port locking helpers

drivers/tty/serial/8250/8250_core.c | 8 +--
drivers/tty/serial/8250/8250_dma.c | 4 +-
drivers/tty/serial/8250/8250_port.c | 81 +++++++++++++----------------
include/linux/printk.h | 40 ++++++++++++++
include/linux/serial_core.h | 48 +++++++++++++++++
kernel/panic.c | 6 +++
kernel/printk/internal.h | 37 -------------
kernel/printk/printk_safe.c | 6 ++-
8 files changed, 141 insertions(+), 89 deletions(-)

--
2.19.1

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