Sumit Garg 5946d1f5b3 kdb: Switch to use safer dbg_io_ops over console APIs ... In kgdb context, calling console handlers aren't safe due to locks used in those handlers which could in turn lead to a deadlock. Although, using oops_in_progress increases the chance to bypass locks in most console handlers but it might not be sufficient enough in case a console uses more locks (VT/TTY is good example). Currently when a driver provides both polling I/O and a console then kdb will output using the console. We can increase robustness by using the currently active polling I/O driver (which should be lockless) instead of the corresponding console. For several common cases (e.g. an embedded system with a single serial port that is used both for console output and debugger I/O) this will result in no console handler being used. In order to achieve this we need to reverse the order of preference to use dbg_io_ops (uses polling I/O mode) over console APIs. So we just store "struct console" that represents debugger I/O in dbg_io_ops and while emitting kdb messages, skip console that matches dbg_io_ops console in order to avoid duplicate messages. After this change, "is_console" param becomes redundant and hence removed. Suggested-by: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Sumit Garg <sumit.garg@linaro.org> Link: https://lore.kernel.org/r/1591264879-25920-5-git-send-email-sumit.garg@linaro.org Reviewed-by: Douglas Anderson <dianders@chromium.org> Reviewed-by: Petr Mladek <pmladek@suse.com> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>		2020-06-26 15:40:16 +01:00
..
hvc	tty: hvc_console, fix crashes on parallel open/close	2020-05-27 10:55:36 +02:00
ipwireless
serdev
serial	kdb: Switch to use safer dbg_io_ops over console APIs	2020-06-26 15:40:16 +01:00
vt	mmap locking API: convert mmap_sem comments	2020-06-09 09:39:14 -07:00
amiserial.c
cyclades.c
ehv_bytechan.c
goldfish.c
isicom.c
Kconfig	treewide: replace '---help---' in Kconfig files with 'help'	2020-06-14 01:57:21 +09:00
Makefile
mips_ejtag_fdc.c
moxa.c
moxa.h
mxser.c	tty: mxser: make mxser_change_speed() return void	2020-05-15 14:47:05 +02:00
mxser.h
n_gsm.c	tty: n_gsm: Fix bogus i++ in gsm_data_kick	2020-05-19 16:19:54 +02:00
n_hdlc.c	n_hdlc_tty_read(): remove pointless access_ok()	2020-05-29 11:03:03 -04:00
n_null.c
n_r3964.c
n_tracerouter.c
n_tracesink.c
n_tracesink.h
n_tty.c
nozomi.c
pty.c
rocket_int.h
rocket.c
rocket.h
synclink_gt.c
synclink.c
synclinkmp.c
sysrq.c	kernel: rename show_stack_loglvl() => show_stack()	2020-06-09 09:39:13 -07:00
tty_audit.c
tty_baudrate.c
tty_buffer.c
tty_io.c
tty_ioctl.c
tty_jobctrl.c
tty_ldisc.c
tty_ldsem.c
tty_mutex.c
tty_port.c
ttynull.c
vcc.c