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path: root/drivers/tty/tty_io.c
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2022-03-22memcg: enable accounting for tty-related objectsVasily Averin
At each login the user forces the kernel to create a new terminal and allocate up to ~1Kb memory for the tty-related structures. By default it's allowed to create up to 4096 ptys with 1024 reserve for initial mount namespace only and the settings are controlled by host admin. Though this default is not enough for hosters with thousands of containers per node. Host admin can be forced to increase it up to NR_UNIX98_PTY_MAX = 1<<20. By default container is restricted by pty mount_opt.max = 1024, but admin inside container can change it via remount. As a result, one container can consume almost all allowed ptys and allocate up to 1Gb of unaccounted memory. It is not enough per-se to trigger OOM on host, however anyway, it allows to significantly exceed the assigned memcg limit and leads to troubles on the over-committed node. It makes sense to account for them to restrict the host's memory consumption from inside the memcg-limited container. Link: https://lkml.kernel.org/r/5d4bca06-7d4f-a905-e518-12981ebca1b3@virtuozzo.com Signed-off-by: Vasily Averin <vvs@virtuozzo.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Shakeel Butt <shakeelb@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Jiri Slaby <jirislaby@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-12-21tty: tty_io: Switch to vmalloc() fallback in case of TTY_NO_WRITE_SPLITAndy Shevchenko
When TTY_NO_WRITE_SPLIT is set and 64 KiB chunks are used, allow vmalloc() fallback. Supply __GFP_RETRY_MAYFAIL to make kmalloc() preferable over vmalloc() since we may want a better performance. Note, both current users copy data to another buffer anyway, so the type of our allocation doesn't affect their expectations. Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Link: https://lore.kernel.org/r/20211220133250.3070-1-andriy.shevchenko@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-11-26tty: add kernel-doc for tty_standard_installJiri Slaby
It is the only missing exported function which is not documented. Fix it. Signed-off-by: Jiri Slaby <jslaby@suse.cz> Link: https://lore.kernel.org/r/20211126081611.11001-23-jslaby@suse.cz Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-11-26tty: add kernel-doc for more tty_driver functionsJiri Slaby
The only documented function for tty_driver structure allocation/registration was __tty_alloc_driver(). Fix highlighting in that comment. And add kernel-doc headers to all tty_driver_kref_put(), tty_register_driver(), and tty_unregister_driver() -- i.e. the main ones. More to follow later. Signed-off-by: Jiri Slaby <jslaby@suse.cz> Link: https://lore.kernel.org/r/20211126081611.11001-18-jslaby@suse.cz Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-11-26tty: reformat kernel-doc in tty_io.cJiri Slaby
Kernel-doc is a bit strict about some formatting. So fix these: 1) When there is a tab in comments, it thinks the line is a continuation one. So the description of the functions end up as descriptions of the last parameter described. Remove the tabs. 2) Remove newlines before parameters description and after the comments. This was not wrong per se, only inconsistent with the rest of the file. 3) Add periods to the end of sentences where appropriate. 4) Add "()" to function names and "%" to constants, so that they are properly highlighted. By the above, this patch also unifies these docs with the other kernel-doc's in this file. Signed-off-by: Jiri Slaby <jslaby@suse.cz> Link: https://lore.kernel.org/r/20211126081611.11001-13-jslaby@suse.cz Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-11-25tty: remove file from tty_ldisc_ops::ioctl and compat_ioctlJiri Slaby
After the previous patches, noone needs 'file' parameter in neither ioctl hook from tty_ldisc_ops. So remove 'file' from both of them. Cc: Marcel Holtmann <marcel@holtmann.org> Cc: Johan Hedberg <johan.hedberg@gmail.com> Cc: Luiz Augusto von Dentz <luiz.dentz@gmail.com> Cc: Wolfgang Grandegger <wg@grandegger.com> Cc: Marc Kleine-Budde <mkl@pengutronix.de> Cc: "David S. Miller" <davem@davemloft.net> Cc: Jakub Kicinski <kuba@kernel.org> Cc: Andreas Koensgen <ajk@comnets.uni-bremen.de> Cc: Paul Mackerras <paulus@samba.org> Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com> [NFC] Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com> Acked-by: Marc Kleine-Budde <mkl@pengutronix.de> Signed-off-by: Jiri Slaby <jslaby@suse.cz> Link: https://lore.kernel.org/r/20211122094529.24171-1-jslaby@suse.cz Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-11-25tty: clean up whitespace in __do_SAK()Jiri Slaby
Remove spaces before the 'i' variable declaration and wrap parameters of group_send_sig_info(). Signed-off-by: Jiri Slaby <jslaby@suse.cz> Link: https://lore.kernel.org/r/20211118071911.12059-4-jslaby@suse.cz Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-11-25tty: remove tty NULL check from __do_SAK()Jiri Slaby
Both do_SAK_work() and vc_SAK() provide a valid tty to __do_SAK(), so remove the check. Signed-off-by: Jiri Slaby <jslaby@suse.cz> Link: https://lore.kernel.org/r/20211118071911.12059-3-jslaby@suse.cz Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-11-25tty: remove TTY_SOFT_SAK part from __do_SAK()Jiri Slaby
Remove the TTY_SOFT_SAK part. It is never defined, so this is only confusing. It was actually never defined since its introduction in 0.99.14g. Signed-off-by: Jiri Slaby <jslaby@suse.cz> Link: https://lore.kernel.org/r/20211118071911.12059-2-jslaby@suse.cz Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-08-26tty: Fix data race between tiocsti() and flush_to_ldisc()Nguyen Dinh Phi
The ops->receive_buf() may be accessed concurrently from these two functions. If the driver flushes data to the line discipline receive_buf() method while tiocsti() is waiting for the ops->receive_buf() to finish its work, the data race will happen. For example: tty_ioctl |tty_ldisc_receive_buf ->tioctsi | ->tty_port_default_receive_buf | ->tty_ldisc_receive_buf ->hci_uart_tty_receive | ->hci_uart_tty_receive ->h4_recv | ->h4_recv In this case, the h4 receive buffer will be overwritten by the latecomer, and we will lost the data. Hence, change tioctsi() function to use the exclusive lock interface from tty_buffer to avoid the data race. Reported-by: syzbot+97388eb9d31b997fe1d0@syzkaller.appspotmail.com Reviewed-by: Jiri Slaby <jirislaby@kernel.org> Signed-off-by: Nguyen Dinh Phi <phind.uet@gmail.com> Link: https://lore.kernel.org/r/20210823000641.2082292-1-phind.uet@gmail.com Cc: stable <stable@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-07-27tty: drop put_tty_driverJiri Slaby
put_tty_driver() is an alias for tty_driver_kref_put(). There is no need for two exported identical functions, therefore switch all users of old put_tty_driver() to new tty_driver_kref_put() and remove the former for good. Cc: Richard Henderson <rth@twiddle.net> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: Matt Turner <mattst88@gmail.com> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Jeff Dike <jdike@addtoit.com> Cc: Richard Weinberger <richard@nod.at> Cc: Anton Ivanov <anton.ivanov@cambridgegreys.com> Cc: Chris Zankel <chris@zankel.net> Cc: Max Filippov <jcmvbkbc@gmail.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Samuel Iglesias Gonsalvez <siglesias@igalia.com> Cc: Jens Taprogge <jens.taprogge@taprogge.org> Cc: Karsten Keil <isdn@linux-pingi.de> Cc: Scott Branden <scott.branden@broadcom.com> Cc: Ulf Hansson <ulf.hansson@linaro.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Jakub Kicinski <kuba@kernel.org> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: David Lin <dtwlin@gmail.com> Cc: Johan Hovold <johan@kernel.org> Cc: Alex Elder <elder@kernel.org> Cc: Jiri Slaby <jirislaby@kernel.org> Cc: Laurentiu Tudor <laurentiu.tudor@nxp.com> Cc: Jiri Kosina <jikos@kernel.org> Cc: David Sterba <dsterba@suse.com> Cc: Shawn Guo <shawnguo@kernel.org> Cc: Sascha Hauer <s.hauer@pengutronix.de> Cc: Pengutronix Kernel Team <kernel@pengutronix.de> Cc: Fabio Estevam <festevam@gmail.com> Cc: NXP Linux Team <linux-imx@nxp.com> Cc: Oliver Neukum <oneukum@suse.com> Cc: Felipe Balbi <balbi@kernel.org> Cc: Mathias Nyman <mathias.nyman@intel.com> Cc: Marcel Holtmann <marcel@holtmann.org> Cc: Johan Hedberg <johan.hedberg@gmail.com> Cc: Luiz Augusto von Dentz <luiz.dentz@gmail.com> Acked-by: Alex Elder <elder@linaro.org> Acked-by: Christian Borntraeger <borntraeger@de.ibm.com> Acked-by: Max Filippov <jcmvbkbc@gmail.com> Acked-by: David Sterba <dsterba@suse.com> Acked-by: Samuel Iglesias Gonsálvez <siglesias@igalia.com> Signed-off-by: Jiri Slaby <jslaby@suse.cz> Link: https://lore.kernel.org/r/20210723074317.32690-8-jslaby@suse.cz Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-07-27tty: make tty_set_operations an inlineJiri Slaby
Since commit f34d7a5b7010 (tty: The big operations rework) in 2008, tty_set_operations() is a simple one-line assignment. There is no reason for this to be an exported function, hence move it to a header and make an inline from that. Signed-off-by: Jiri Slaby <jslaby@suse.cz> Link: https://lore.kernel.org/r/20210723074317.32690-7-jslaby@suse.cz Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-05-20tty: fix kernel-doc for {start,stop}_ttyJiri Slaby
Commit f9e053dcfc02 (tty: Serialize tty flow control changes with flow_lock) renamed start_tty to __start_tty and stop_tty to __stop_tty and introduced new start_tty and stop_tty. But it left kernel-doc comments on the old locations: tty_io.c:785: warning: expecting prototype for stop_tty(). Prototype was for __stop_tty() instead tty_io.c:816: warning: expecting prototype for start_tty(). Prototype was for __start_tty() instead Fix that by moving the comments to appropriate locations. Signed-off-by: Jiri Slaby <jslaby@suse.cz> Link: https://lore.kernel.org/r/20210519072153.3859-4-jslaby@suse.cz Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-05-20tty: fix kernel-doc for tty_{read,write}Jiri Slaby
After commits a9cbbb80e3e7 (tty: avoid using vfs_iocb_iter_write() for redirected console writes) and dd78b0c483e3 (tty: implement read_iter), the tty_read and tty_write kernel-doc comments don't match the code: tty_io.c:931: warning: Function parameter or member 'iocb' not described in 'tty_read' tty_io.c:931: warning: Function parameter or member 'to' not described in 'tty_read' tty_io.c:931: warning: Excess function parameter 'file' description in 'tty_read' tty_io.c:931: warning: Excess function parameter 'buf' description in 'tty_read' tty_io.c:931: warning: Excess function parameter 'count' description in 'tty_read' tty_io.c:931: warning: Excess function parameter 'ppos' description in 'tty_read' tty_io.c:1115: warning: Function parameter or member 'iocb' not described in 'file_tty_write' tty_io.c:1115: warning: Function parameter or member 'from' not described in 'file_tty_write' tty_io.c:1115: warning: expecting prototype for tty_write(). Prototype was for file_tty_write() instead Fix them to correspond the reality, i.e. the switch from read/write to read_iter/write_iter. Cc: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Jiri Slaby <jslaby@suse.cz> Link: https://lore.kernel.org/r/20210519072153.3859-3-jslaby@suse.cz Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-05-13tty: tty_io: Remove return in void functionXiaofei Tan
Remove return in void function, reported by checkpatch.pl. Signed-off-by: Xiaofei Tan <tanxiaofei@huawei.com> Link: https://lore.kernel.org/r/1620811585-18582-15-git-send-email-tanxiaofei@huawei.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-05-13tty: tty_io: Delete a blank line before EXPORT_SYMBOL(foo)Xiaofei Tan
Delete a blank line before EXPORT_SYMBOL(foo) so that EXPORT_SYMBOL(foo) immediately follow its function/variable, reported by checkpatch.pl. Signed-off-by: Xiaofei Tan <tanxiaofei@huawei.com> Link: https://lore.kernel.org/r/1620811585-18582-14-git-send-email-tanxiaofei@huawei.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-05-13tty: tty_io: Fix an issue of code indent for conditional statementsXiaofei Tan
Fix an issue of code indent for conditional statements,reported by checkpatch.pl. Signed-off-by: Xiaofei Tan <tanxiaofei@huawei.com> Link: https://lore.kernel.org/r/1620811585-18582-13-git-send-email-tanxiaofei@huawei.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-05-13tty: tty_io: Remove the repeated word 'can'Xiaofei Tan
Remove the repeated word 'can' following advice of checkpatch.pl Signed-off-by: Xiaofei Tan <tanxiaofei@huawei.com> Link: https://lore.kernel.org/r/1620811585-18582-12-git-send-email-tanxiaofei@huawei.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-05-13tty: tty_io: Fix coding style issues of block commentsXiaofei Tan
Fix coding style issues of block comments, reported by checkpatch.pl. Besides, add a period at the end of the sentenses. Signed-off-by: Xiaofei Tan <tanxiaofei@huawei.com> Link: https://lore.kernel.org/r/1620811585-18582-11-git-send-email-tanxiaofei@huawei.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-05-13tty: tty_io: Fix trailing whitespace issuesXiaofei Tan
Fix trailing whitespace issues, reported by checkpatch.pl. Signed-off-by: Xiaofei Tan <tanxiaofei@huawei.com> Link: https://lore.kernel.org/r/1620811585-18582-10-git-send-email-tanxiaofei@huawei.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-05-13tty: tty_io: Fix spaces required around that ':'Xiaofei Tan
Fix spaces required around that ':', reported by checkpatch.pl. Signed-off-by: Xiaofei Tan <tanxiaofei@huawei.com> Link: https://lore.kernel.org/r/1620811585-18582-9-git-send-email-tanxiaofei@huawei.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-05-13tty: tty_io: Add a blank line after declarationsXiaofei Tan
Add a blank line after declarations, reported by checkpatch.pl. Signed-off-by: Xiaofei Tan <tanxiaofei@huawei.com> Link: https://lore.kernel.org/r/1620811585-18582-8-git-send-email-tanxiaofei@huawei.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-05-13tty: tty_io: Remove spaces before tabsXiaofei Tan
Remove spaces before tabs following the advice of checkpatch.pl. Signed-off-by: Xiaofei Tan <tanxiaofei@huawei.com> Link: https://lore.kernel.org/r/1620811585-18582-7-git-send-email-tanxiaofei@huawei.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-05-13tty: cumulate and document tty_struct::ctrl* membersJiri Slaby
Group the ctrl members under a single struct called ctrl. The new struct contains 'pgrp', 'session', 'pktstatus', and 'packet'. 'pktstatus' and 'packet' used to be bits in a bitfield. The struct also contains the lock protecting them to share the same cache line. Note that commit c545b66c6922b (tty: Serialize tcflow() with other tty flow control changes) added a padding to the original bitfield. It was for the bitfield to occupy a whole 64b word to avoid interferring stores on Alpha (cannot we evaporate this arch with weird implications to C code yet?). But it doesn't work as expected as the padding (tty_struct::ctrl_unused) is aligned to a 8B boundary too and occupies some bytes from the next word. So make it reliable by: 1) setting __aligned of the struct -- that aligns the start, and 2) making 'unsigned long unused[0]' as the last member of the struct -- pads the end. Add a kerneldoc comment for this grouped members. Signed-off-by: Jiri Slaby <jslaby@suse.cz> Cc: "David S. Miller" <davem@davemloft.net> Cc: Jakub Kicinski <kuba@kernel.org> Cc: netdev@vger.kernel.org Link: https://lore.kernel.org/r/20210505091928.22010-14-jslaby@suse.cz Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-05-13tty: cumulate and document tty_struct::flow* membersJiri Slaby
Group the flow flags under a single struct called flow. The new struct contains 'stopped' and 'tco_stopped' bools which used to be bits in a bitfield. The struct also contains the lock protecting them to potentially share the same cache line. Note that commit c545b66c6922b (tty: Serialize tcflow() with other tty flow control changes) added a padding to the original bitfield. It was for the bitfield to occupy a whole 64b word to avoid interferring stores on Alpha (cannot we evaporate this arch with weird implications to C code yet?). But it doesn't work as expected as the padding (tty_struct::unused) is aligned to a 8B boundary too and occupies some bytes from the next word. So make it reliable by: 1) setting __aligned of the struct -- that aligns the start, and 2) making 'unsigned long unused[0]' as the last member of the struct -- pads the end. This is also the perfect time to start the documentation of tty_struct where all this lives. So we start by documenting what these bools actually serve for. And why we do all the alignment dances. Only the few up-to-date information from the Theodore's comment made it into this new Kerneldoc comment. Signed-off-by: Jiri Slaby <jslaby@suse.cz> Cc: "David S. Miller" <davem@davemloft.net> Cc: Jakub Kicinski <kuba@kernel.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Ulf Hansson <ulf.hansson@linaro.org> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Shawn Guo <shawnguo@kernel.org> Cc: Sascha Hauer <s.hauer@pengutronix.de> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: "Maciej W. Rozycki" <macro@orcam.me.uk> Link: https://lore.kernel.org/r/20210505091928.22010-13-jslaby@suse.cz Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-04-15tty: make tty_release_redirect() staticGreg Kroah-Hartman
No one calls this outside of the tty_io.c file, so mark this static and do not export the symbol anymore. Cc: Jiri Slaby <jirislaby@kernel.org> Link: https://lore.kernel.org/r/20210408125134.3016837-11-gregkh@linuxfoundation.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-04-15tty: create internal tty.h fileGreg Kroah-Hartman
There are a number of functions and #defines in include/linux/tty.h that do not belong there as they are private to the tty core code. Create an initial drivers/tty/tty.h file and copy the odd "tty logging" macros into it to seed the file with some initial things that we know nothing outside of the tty core should be calling. Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp> Cc: Jiri Slaby <jirislaby@kernel.org> Link: https://lore.kernel.org/r/20210408125134.3016837-2-gregkh@linuxfoundation.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-04-10tty: refactor TIOCSSERIAL handlingJohan Hovold
Factor out the deprecated serial flags handling and tty-operation check shared with the compat TIOCSSERIAL handler. Signed-off-by: Johan Hovold <johan@kernel.org> Link: https://lore.kernel.org/r/20210407095208.31838-6-johan@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-04-10tty: use pr_warn_ratelimited() for deprecated serial flagsJohan Hovold
Use pr_warn_ratelimited() when warning about deprecated serial flags instead of open coding. Signed-off-by: Johan Hovold <johan@kernel.org> Link: https://lore.kernel.org/r/20210407095208.31838-5-johan@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-04-10tty: fix return value for unsupported ioctlsJohan Hovold
Drivers should return -ENOTTY ("Inappropriate I/O control operation") when an ioctl isn't supported, while -EINVAL is used for invalid arguments. Fix up the TIOCMGET, TIOCMSET and TIOCGICOUNT helpers which returned -EINVAL when a tty driver did not implement the corresponding operations. Note that the TIOCMGET and TIOCMSET helpers predate git and do not get a corresponding Fixes tag below. Fixes: d281da7ff6f7 ("tty: Make tiocgicount a handler") Signed-off-by: Johan Hovold <johan@kernel.org> Link: https://lore.kernel.org/r/20210407095208.31838-3-johan@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-03-15Merge 5.12-rc3 into tty-nextGreg Kroah-Hartman
Resolves a merge issue with: drivers/tty/hvc/hvcs.c and we want the tty/serial fixes from 5.12-rc3 in here as well. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-03-10tty: localise ptychar and make it constJiri Slaby
ptychar was not const, so mark it as such. And move this variable to the only place where it's used. Signed-off-by: Jiri Slaby <jslaby@suse.cz> Link: https://lore.kernel.org/r/20210302062214.29627-36-jslaby@suse.cz Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-03-10tty: let tty_unregister_driver return voidJiri Slaby
Now that noone checks the return value, switch the return type of tty_unregister_driver to void. We can do that as we always return zero. Generally, drivers are not allowed to call tty_unregister_driver while there are open devices. Signed-off-by: Jiri Slaby <jslaby@suse.cz> Link: https://lore.kernel.org/r/20210302062214.29627-35-jslaby@suse.cz Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-03-10Revert "drivers:tty:pty: Fix a race causing data loss on close"Greg Kroah-Hartman
This reverts commit 33d4ae98859873ddd49e22e4ca724387548b3d89. Pierre-Louis writes: Our SOF/audio CI shows an across-the-board regression when we try v5.12-rc1, specifically on pause/resume tests with an interactive terminal running 'aplay -i' commands managed by expect to simulate the user pressing the space bar to pause/unpause. It turns out the processes are not longer killed and the audio devices remain busy (see publicly available test results listed below). git bisect points to commit 33d4ae9885987 ("drivers:tty:pty: Fix a race causing data loss on close"). Reverting the patch fixes the issue on all test devices. Further analysis with Corey Minyard points to a problem where a slave tty will not get a SIGHUP when the master is closed. So revert this for now: Reported-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com> Link: https://lore.kernel.org/r/00154592-c5ee-aaba-956e-b265473b53bc@linux.intel.com Cc: Corey Minyard <cminyard@mvista.com> Cc: Jiri Slaby <jirislaby@kernel.org> Cc: Mark Brown <broonie@kernel.org>, Fixes: 33d4ae988598 ("drivers:tty:pty: Fix a race causing data loss on close") Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-02-20Merge tag 'tty-5.12-rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty Pull tty/serial driver updates from Greg KH: "Here is the big set of tty/serial driver changes for 5.12-rc1. Nothing huge, just lots of good cleanups and additions: - n_tty line discipline cleanups - vt core cleanups and reworks to make the code more "modern" - stm32 driver additions - tty led support added to the tty core and led layer - minor serial driver fixups and additions All of these have been in linux-next for a while with no reported issues" * tag 'tty-5.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (54 commits) serial: core: Remove BUG_ON(in_interrupt()) check vt_ioctl: Remove in_interrupt() check dt-bindings: serial: imx: Switch to my personal address vt: keyboard, use new API for keyboard_tasklet serial: stm32: improve platform_get_irq condition handling in init_port serial: ifx6x60: Remove driver for deprecated platform tty: fix up iterate_tty_read() EOVERFLOW handling tty: fix up hung_up_tty_read() conversion tty: fix up hung_up_tty_write() conversion tty: teach the n_tty ICANON case about the new "cookie continuations" too tty: teach n_tty line discipline about the new "cookie continuations" tty: clean up legacy leftovers from n_tty line discipline tty: implement read_iter tty: convert tty_ldisc_ops 'read()' function to take a kernel pointer serial: remove sirf prima/atlas driver serial: mxs-auart: Remove <asm/cacheflush.h> serial: mxs-auart: Remove serial_mxs_probe_dt() serial: fsl_lpuart: Use of_device_get_match_data() dt-bindings: serial: renesas,hscif: Add r8a779a0 support tty: serial: Drop unused efm32 serial driver ...
2021-02-20tty: protect tty_write from odd low-level tty disciplinesLinus Torvalds
Al root-caused a new warning from syzbot to the ttyprintk tty driver returning a write count larger than the data the tty layer actually gave it. Which confused the tty write code mightily, and with the new iov_iter based code, caused a WARNING in iov_iter_revert(). syzbot correctly bisected the source of the new warning to commit 9bb48c82aced ("tty: implement write_iter"), but the oddity goes back much further, it just didn't get caught by anything before. Reported-by: syzbot+3d2c27c2b7dc2a94814d@syzkaller.appspotmail.com Fixes: 9bb48c82aced ("tty: implement write_iter") Debugged-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-01-29tty: avoid using vfs_iocb_iter_write() for redirected console writesLinus Torvalds
It turns out that the vfs_iocb_iter_{read,write}() functions are entirely broken, and don't actually use the passed-in file pointer for IO - only for the preparatory work (permission checking and for the write_iter function lookup). That worked fine for overlayfs, which always builds the new iocb with the same file pointer that it passes in, but in the general case it ends up doing nonsensical things (and could cause an iterator call that doesn't even match the passed-in file pointer). This subtly broke the tty conversion to write_iter in commit 9bb48c82aced ("tty: implement write_iter"), because the console redirection didn't actually end up redirecting anything, since the passed-in file pointer was basically ignored, and the actual write was done with the original non-redirected console tty after all. The main visible effect of this is that the console messages were no longer logged to /var/log/boot.log during graphical boot. Fix the issue by simply not using the vfs write "helper" function at all, and just redirecting the write entirely internally to the tty layer. Do the target writability permission checks when actually registering the target tty with TIOCCONS instead of at write time. Fixes: 9bb48c82aced ("tty: implement write_iter") Reported-and-tested-by: Hans de Goede <hdegoede@redhat.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: stable@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-01-25Commit 9bb48c82aced ("tty: implement write_iter") converted the ttySami Tolvanen
layer to use write_iter. Fix the redirected_tty_write declaration also in n_tty and change the comparisons to use write_iter instead of write. [ Also moved the declaration of redirected_tty_write() to the proper location in a header file. The reason for the bug was the bogus extern declaration in n_tty.c silently not matching the changed definition in tty_io.c, and because it wasn't in a shared header file, there was no cross-checking of the declaration. Sami noticed because Clang's Control Flow Integrity checking ended up incidentally noticing the inconsistent declaration. - Linus ] Fixes: 9bb48c82aced ("tty: implement write_iter") Signed-off-by: Sami Tolvanen <samitolvanen@google.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-01-22tty: fix up hung_up_tty_write() conversionLinus Torvalds
In commit "tty: implement write_iter", I left the write_iter conversion of the hung up tty case alone, because I incorrectly thought it didn't matter. Jiri showed me the errors of my ways, and pointed out the problems with that incomplete conversion. Fix it all up. Reported-by: Jiri Slaby <jirislaby@kernel.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Reviewed-by: Jiri Slaby <jirislaby@kernel.org> Link: https://lore.kernel.org/r/CAHk-=wh+-rGsa=xruEWdg_fJViFG8rN9bpLrfLz=_yBYh2tBhA@mail.gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-01-22tty: fix up iterate_tty_read() EOVERFLOW handlingLinus Torvalds
When I converted the tty_ldisc_ops 'read()' function to take a kernel pointer, I was a bit too aggressive about the ldisc returning EOVERFLOW. Yes, we want to have EOVERFLOW override any partially read data (because the whole point is that the buffer was too small for the whole packet, and we don't want to see partial packets), but it shouldn't override a previous EFAULT. And in fact, it really is just EOVERFLOW that is special and should throw away any partially read data, not "any error". Admittedly EOVERFLOW is currently the only one that can happen for a continuation read - and if the first read iteration returns an error we won't have this issue. So this is more of a technicality, but let's just make the intent very explicit, and re-organize the error handling a bit so that this is all clearer. Reported-by: Jiri Slaby <jirislaby@kernel.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Reviewed-by: Jiri Slaby <jirislaby@kernel.org> Link: https://lore.kernel.org/r/CAHk-=wh+-rGsa=xruEWdg_fJViFG8rN9bpLrfLz=_yBYh2tBhA@mail.gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-01-22tty: fix up hung_up_tty_read() conversionLinus Torvalds
In commit "tty: implement read_iter", I left the read_iter conversion of the hung up tty case alone, because I incorrectly thought it didn't matter. Jiri showed me the errors of my ways, and pointed out the problems with that incomplete conversion. Fix it all up. Reported-by: Jiri Slaby <jirislaby@kernel.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Reviewed-by: Jiri Slaby <jirislaby@kernel.org> Link: https://lore.kernel.org/r/CAHk-=wh+-rGsa=xruEWdg_fJViFG8rN9bpLrfLz=_yBYh2tBhA@mail.gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-01-22tty: fix up hung_up_tty_write() conversionLinus Torvalds
In commit "tty: implement write_iter", I left the write_iter conversion of the hung up tty case alone, because I incorrectly thought it didn't matter. Jiri showed me the errors of my ways, and pointed out the problems with that incomplete conversion. Fix it all up. Reported-by: Jiri Slaby <jirislaby@kernel.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Reviewed-by: Jiri Slaby <jirislaby@kernel.org> Link: https://lore.kernel.org/r/CAHk-=wh+-rGsa=xruEWdg_fJViFG8rN9bpLrfLz=_yBYh2tBhA@mail.gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-01-21Merge branch 'tty-splice' of ↵Greg Kroah-Hartman
git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux into tty-next Fixes both the "splice/sendfile to a tty" and "splice/sendfile from a tty" regression from 5.10. * 'tty-splice' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux: tty: teach the n_tty ICANON case about the new "cookie continuations" too tty: teach n_tty line discipline about the new "cookie continuations" tty: clean up legacy leftovers from n_tty line discipline tty: implement read_iter tty: convert tty_ldisc_ops 'read()' function to take a kernel pointer tty: implement write_iter
2021-01-21Merge 9bb48c82aced ("tty: implement write_iter") into tty-linusGreg Kroah-Hartman
We want the single "splice/sendfile to a tty" regression fix into tty-linus so it can get into 5.11-final, while the larger patch series fixing "splice/sendfile from a tty" should wait for 5.12-rc1 so that we get more testing. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-01-20tty: implement write_iterLinus Torvalds
This makes the tty layer use the .write_iter() function instead of the traditional .write() functionality. That allows writev(), but more importantly also makes it possible to enable .splice_write() for ttys, reinstating the "splice to tty" functionality that was lost in commit 36e2c7421f02 ("fs: don't allow splice read/write without explicit ops"). Fixes: 36e2c7421f02 ("fs: don't allow splice read/write without explicit ops") Reported-by: Oliver Giles <ohw.giles@gmail.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-01-20tty: implement read_iterLinus Torvalds
Now that the ldisc read() function takes kernel pointers, it's fairly straightforward to make the tty file operations use .read_iter() instead of .read(). That automatically gives us vread() and friends, and also makes it possible to do .splice_read() on ttys again. Fixes: 36e2c7421f02 ("fs: don't allow splice read/write without explicit ops") Reported-by: Oliver Giles <ohw.giles@gmail.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-01-20tty: convert tty_ldisc_ops 'read()' function to take a kernel pointerLinus Torvalds
The tty line discipline .read() function was passed the final user pointer destination as an argument, which doesn't match the 'write()' function, and makes it very inconvenient to do a splice method for ttys. This is a conversion to use a kernel buffer instead. NOTE! It does this by passing the tty line discipline ->read() function an additional "cookie" to fill in, and an offset into the cookie data. The line discipline can fill in the cookie data with its own private information, and then the reader will repeat the read until either the cookie is cleared or it runs out of data. The only real user of this is N_HDLC, which can use this to handle big packets, even if the kernel buffer is smaller than the whole packet. Cc: Christoph Hellwig <hch@lst.de> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-01-07drivers:tty:pty: Fix a race causing data loss on closeCorey Minyard
Remove the tty_vhangup() from the pty code and just release the redirect. The tty_vhangup() results in data loss and data out of order issues. If you write to a pty master an immediately close the pty master, the receiver might get a chunk of data dropped, but then receive some later data. That's obviously something rather unexpected for a user. It certainly confused my test program. It turns out that tty_vhangup() on the slave pty gets called from pty_close(), and that causes the data on the slave side to be flushed, but due to races more data can be copied into the slave side's buffer after that. Consider the following sequence: thread1 thread2 thread3 ------- ------- ------- | |-write data into buffer, | | n_tty buffer is filled | | along with other buffers | |-pty_close(master) | |--tty_vhangup(slave) | |---tty_ldisc_hangup() | |----n_tty_flush_buffer() | |-----reset_buffer_flags() |-n_tty_read() | |--up_read(&tty->termios_rwsem); | |------down_read(&tty->termios_rwsem) | |------clear n_tty buffer contents | |------up_read(&tty->termios_rwsem) |--tty_buffer_flush_work() | |--schedules work calling | | flush_to_ldisc() | | |-flush_to_ldisc() | |--receive_buf() | |---tty_port_default_receive_buf() | |----tty_ldisc_receive_buf() | |-----n_tty_receive_buf2() | |------n_tty_receive_buf_common() | |-------down_read(&tty->termios_rwsem) | |-------__receive_buf() | | copies data into n_tty buffer | |-------up_read(&tty->termios_rwsem) |--down_read(&tty->termios_rwsem) |--copy buffer data to user >From this sequence, you can see that thread2 writes to the buffer then only clears the part of the buffer in n_tty. The n_tty receive buffer code then copies more data into the n_tty buffer. But part of the vhangup, releasing the redirect, is still required to avoid issues with consoles running on pty slaves. So do that. As far as I can tell, that is all that should be required. Signed-off-by: Corey Minyard <cminyard@mvista.com> Link: https://lore.kernel.org/r/20201124004902.1398477-3-minyard@acm.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-01-07tty: Export redirect releaseCorey Minyard
This will be required by the pty code when it removes tty_vhangup() on master close. Signed-off-by: Corey Minyard <cminyard@mvista.com> Link: https://lore.kernel.org/r/20201124004902.1398477-2-minyard@acm.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-12-28tty: new helper function tty_get_icount()Uwe Kleine-König
For a given struct tty_struct this yields the corresponding statistics about sent and received characters (and some more) which is needed to implement an LED trigger for tty devices. The new function is then used to simplify tty_tiocgicount(). Reviewed-by: Pavel Machek <pavel@ucw.cz> Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Link: https://lore.kernel.org/r/20201218104246.591315-3-u.kleine-koenig@pengutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>