linux/drivers/tty
Douglas Anderson 81eaadcae8 kgdboc: disable the console lock when in kgdb
After commit ddde3c18b7 ("vt: More locking checks") kdb / kgdb has
become useless because my console is filled with spews of:

WARNING: CPU: 0 PID: 0 at .../drivers/tty/vt/vt.c:3846 con_is_visible+0x50/0x74
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.3.0-rc1+ #48
Hardware name: Rockchip (Device Tree)
Backtrace:
[<c020ce9c>] (dump_backtrace) from [<c020d188>] (show_stack+0x20/0x24)
[<c020d168>] (show_stack) from [<c0a8fc14>] (dump_stack+0xb0/0xd0)
[<c0a8fb64>] (dump_stack) from [<c0232c58>] (__warn+0xec/0x11c)
[<c0232b6c>] (__warn) from [<c0232dc4>] (warn_slowpath_null+0x4c/0x58)
[<c0232d78>] (warn_slowpath_null) from [<c06338a0>] (con_is_visible+0x50/0x74)
[<c0633850>] (con_is_visible) from [<c0634078>] (con_scroll+0x108/0x1ac)
[<c0633f70>] (con_scroll) from [<c0634160>] (lf+0x44/0x88)
[<c063411c>] (lf) from [<c06363ec>] (vt_console_print+0x1a4/0x2bc)
[<c0636248>] (vt_console_print) from [<c02f628c>] (vkdb_printf+0x420/0x8a4)
[<c02f5e6c>] (vkdb_printf) from [<c02f6754>] (kdb_printf+0x44/0x60)
[<c02f6714>] (kdb_printf) from [<c02fa6f4>] (kdb_main_loop+0xf4/0x6e0)
[<c02fa600>] (kdb_main_loop) from [<c02fd5f0>] (kdb_stub+0x268/0x398)
[<c02fd388>] (kdb_stub) from [<c02f3ba0>] (kgdb_cpu_enter+0x1f8/0x674)
[<c02f39a8>] (kgdb_cpu_enter) from [<c02f4330>] (kgdb_handle_exception+0x1c4/0x1fc)
[<c02f416c>] (kgdb_handle_exception) from [<c0210fe0>] (kgdb_compiled_brk_fn+0x30/0x3c)
[<c0210fb0>] (kgdb_compiled_brk_fn) from [<c020d7ac>] (do_undefinstr+0x180/0x1a0)
[<c020d62c>] (do_undefinstr) from [<c0201b44>] (__und_svc_finish+0x0/0x3c)
...
[<c02f3224>] (kgdb_breakpoint) from [<c02f3310>] (sysrq_handle_dbg+0x58/0x6c)
[<c02f32b8>] (sysrq_handle_dbg) from [<c062abf0>] (__handle_sysrq+0xac/0x154)

Let's disable this warning when we're in kgdb to avoid the spew.  The
whole system is stopped when we're in kgdb so we can't exactly wait
for someone else to drop the lock.  Presumably the best we can do is
to disable the warning and hope for the best.

Fixes: ddde3c18b7 ("vt: More locking checks")
Cc: Daniel Vetter <daniel.vetter@intel.com>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://lore.kernel.org/r/20190725183551.169208-1-dianders@chromium.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-07-30 17:39:39 +02:00
..
hvc docs: powerpc: convert docs to ReST and rename to *.rst 2019-07-17 06:57:51 -03:00
ipwireless tty: add SPDX identifiers to Kconfig and Makefiles 2019-04-04 18:48:43 +02:00
serdev tty: add SPDX identifiers to Kconfig and Makefiles 2019-04-04 18:48:43 +02:00
serial kgdboc: disable the console lock when in kgdb 2019-07-30 17:39:39 +02:00
vt vt: Grab console_lock around con_is_bound in show_bind 2019-07-25 13:47:35 +02:00
amiserial.c kill TIOCSERGSTRUCT 2018-10-13 00:50:53 -04:00
cyclades.c cyclades: switch to ->[sg]et_serial() 2018-10-13 00:50:30 -04:00
ehv_bytechan.c tty: Convert to using %pOFn instead of device_node.name 2018-09-18 16:07:25 +02:00
goldfish.c headers: separate linux/mod_devicetable.h from linux/platform_device.h 2018-07-07 17:52:26 +02:00
isicom.c isicom: switch to ->[sg]et_serial() 2018-10-13 00:50:31 -04:00
Kconfig docs: serial: move it to the driver-api 2019-07-15 11:03:03 -03:00
Makefile tty: Add NULL TTY driver 2019-04-16 15:21:34 +02:00
mips_ejtag_fdc.c
moxa.c moxa: switch to ->[sg]et_serial() 2018-10-13 00:50:32 -04:00
moxa.h tty: moxa: Add support for CMSPAR 2017-11-28 15:32:33 +01:00
mxser.c mxser: switch to ->[sg]et_serial() 2018-10-13 00:50:32 -04:00
mxser.h
n_gsm.c tty: n_gsm: Mark expected switch fall-throughs 2019-02-26 12:30:44 +01:00
n_hdlc.c tty/n_hdlc: mark expected switch fall-through 2019-02-14 10:49:19 +01:00
n_null.c
n_r3964.c tty: Don't block on IO when ldisc change is pending 2018-12-05 12:16:33 +01:00
n_tracerouter.c
n_tracesink.c
n_tracesink.h
n_tty.c n_tty: check for negative and zero space return from tty_write_room 2019-04-16 15:21:33 +02:00
nozomi.c tty/nozomi: use pci_iomap instead of ioremap_nocache 2019-02-12 10:26:45 +01:00
pty.c Revert "tty: pty: Fix race condition between release_one_tty and pty_write" 2019-03-29 15:47:40 +01:00
rocket_int.h
rocket.c TTY/Serial patches for 5.2-rc1 2019-05-08 10:07:28 -07:00
rocket.h tty: rocket: Remove RCPK_GET_STRUCT ioctl 2019-04-25 11:58:56 +02:00
synclink_gt.c synclink_gt(): fix compat_ioctl() 2018-10-13 00:50:52 -04:00
synclink.c tty/synclink: remove ISA support 2019-02-12 08:51:33 +01:00
synclinkmp.c synclink: reduce pointless checks in ->ioctl() 2018-10-13 00:50:43 -04:00
sysrq.c panic: avoid the extra noise dmesg 2019-05-14 19:52:51 -07:00
tty_audit.c audit: join tty records to their syscall 2019-02-07 21:33:54 -05:00
tty_baudrate.c termios, tty/tty_baudrate.c: fix buffer overrun 2018-11-08 03:36:45 -08:00
tty_buffer.c tty: increase the default flip buffer limit to 2*640K 2019-01-30 12:03:58 +01:00
tty_io.c tty: tty_io: fix driver refcount imbalance on error path 2019-05-24 10:09:12 +02:00
tty_ioctl.c move compat handling of tty ioctls to tty_compat_ioctl() 2018-09-14 11:12:17 -04:00
tty_jobctrl.c tty: fix read of tty->pgrp outside of ctrl_lock 2019-03-28 01:28:23 +09:00
tty_ldisc.c proc/sysctl: add shared variables for range check 2019-07-18 17:08:07 -07:00
tty_ldsem.c tty/ldsem, locking/rwsem: Add missing ACQUIRE to read_failed sleep loop 2019-07-25 15:39:24 +02:00
tty_mutex.c
tty_port.c Revert "tty: fix NULL pointer issue when tty_port ops is not set" 2019-04-16 15:21:34 +02:00
ttynull.c tty: Add NULL TTY driver 2019-04-16 15:21:34 +02:00
vcc.c tty: fix up a few remaining files without SPDX identifiers 2019-04-04 18:48:43 +02:00