kernel/linux
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ synced 2026-10-20 19:23:40 +00:00
Code Issues Releases Packages Activity
linux/drivers/tty/hvc
History
Roger Pau Monne 7a83bb6d56 hvc/xen: prevent concurrent accesses to the shared ring 
[ Upstream commit 6214894f49 ]

The hvc machinery registers both a console and a tty device based on
the hv ops provided by the specific implementation.  Those two
interfaces however have different locks, and there's no single locks
that's shared between the tty and the console implementations, hence
the driver needs to protect itself against concurrent accesses.
Otherwise concurrent calls using the split interfaces are likely to
corrupt the ring indexes, leaving the console unusable.

Introduce a lock to xencons_info to serialize accesses to the shared
ring.  This is only required when using the shared memory console,
concurrent accesses to the hypercall based console implementation are
not an issue.

Note the conditional logic in domU_read_console() is slightly modified
so the notify_daemon() call can be done outside of the locked region:
it's an hypercall and there's no need for it to be done with the lock
held.

Fixes: b536b4b962 ('xen: use the hvc console infrastructure for Xen console')
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/20221130150919.13935-1-roger.pau@citrix.com
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
History 2023-03-30 12:47:48 +02:00
..
hvc_console.c tty: drop put_tty_driver 2021-07-27 12:17:21 +02:00
hvc_console.h tty: hvc: Use the correct style for SPDX License Identifier 2020-03-18 13:01:05 +01:00
hvc_dcc.c hvc: dcc: Add earlycon support 2019-10-11 08:38:07 +02:00
hvc_irq.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
hvc_iucv.c tty: hvc: fix return value of __setup handler 2022-04-08 14:23:50 +02:00
hvc_opal.c tty: hvc: hvc_opal: Staticify function invoked by reference 2020-11-06 10:54:05 +01:00
hvc_riscv_sbi.c tty: Don't force RISCV SBI console as preferred console 2019-05-16 20:42:11 -07:00
hvc_rtas.c tty: hvc: Remove redundant license text 2017-11-08 13:08:12 +01:00
hvc_udbg.c tty: hvc: make symbol 'hvc_udbg_dev' static 2021-04-10 10:41:40 +02:00
hvc_vio.c tty: hvc: udbg_hvc: retry putc on -EAGAIN 2021-05-23 20:51:36 +10:00
hvc_xen.c hvc/xen: prevent concurrent accesses to the shared ring 2023-03-30 12:47:48 +02:00
hvcs.c tty: drop put_tty_driver 2021-07-27 12:17:21 +02:00
hvsi.c tty: stop using alloc_tty_driver 2021-07-27 12:17:20 +02:00
hvsi_lib.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
Kconfig tty: hvc: fix link error with CONFIG_SERIAL_CORE_CONSOLE=n 2020-09-27 14:17:43 +02:00
Makefile TTY/Serial driver patches for 4.17-rc1 2018-04-04 18:43:49 -07:00