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
