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2021-04-15tty: clean include/linux/tty.h upGreg Kroah-Hartman1-34/+0
There are a lot of tty-core-only functions that are listed in include/linux/tty.h. Move them to drivers/tty/tty.h so that no one else can accidentally call them or think that they are public functions. Cc: Jiri Slaby <jirislaby@kernel.org> Link: https://lore.kernel.org/r/20210408125134.3016837-14-gregkh@linuxfoundation.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-04-15tty: move some tty-only functions to drivers/tty/tty.hGreg Kroah-Hartman1-16/+0
The flow change and restricted_tty_write() logic is internal to the tty core only, so move it out of the include/linux/tty.h file. Cc: Jiri Slaby <jirislaby@kernel.org> Link: https://lore.kernel.org/r/20210408125134.3016837-12-gregkh@linuxfoundation.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-04-15tty: make tty_release_redirect() staticGreg Kroah-Hartman1-1/+0
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: move some internal tty lock enums and functions out of tty.hGreg Kroah-Hartman1-26/+0
Move the TTY_LOCK_* enums and tty_ldisc lock functions out of the global tty.h into the local header file to clean things up. Cc: Jiri Slaby <jirislaby@kernel.org> Link: https://lore.kernel.org/r/20210408125134.3016837-10-gregkh@linuxfoundation.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-04-15tty: audit: move some local functions out of tty.hGreg Kroah-Hartman1-10/+0
The functions tty_audit_add_data() and tty_audit_tiocsti() are local to the tty core code, and do not need to be in a "kernel-wide" header file so move them to drivers/tty/tty.h Cc: Jiri Slaby <jirislaby@kernel.org> Link: https://lore.kernel.org/r/20210408125134.3016837-9-gregkh@linuxfoundation.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-04-15tty: create internal tty.h fileGreg Kroah-Hartman1-12/+0
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: clarify that not all ttys have a class deviceJohan Hovold1-1/+1
Commit 30004ac9c090 ("tty: add tty_struct->dev pointer to corresponding device instance") added a struct device pointer field to struct tty_struct which was populated with the corresponding tty class device during initialisation. Unfortunately, not all ttys have a class device (e.g. pseudoterminals and serdev) in which case the device pointer will be set to NULL, something which have bit driver authors over the years. In retrospect perhaps this field should never have been added, but let's at least document the current behaviour. Signed-off-by: Johan Hovold <johan@kernel.org> Link: https://lore.kernel.org/r/20210409073512.6876-1-johan@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-03-10tty: let tty_unregister_driver return voidJiri Slaby1-1/+1
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>
2021-02-21Merge tag 'tty-5.12-rc1' of ↵Linus Torvalds1-4/+7
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 ...
2021-01-25Commit 9bb48c82aced ("tty: implement write_iter") converted the ttySami Tolvanen1-0/+1
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>
2021-01-07tty: Export redirect releaseCorey Minyard1-0/+1
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>
2021-01-07tty_port: drop last traces of low_latencyJiri Slaby1-2/+1
The main purpose of tty_port::low_latency was removed in commit a9c3f68f3cd8 (tty: Fix low_latency BUG) back in 2014. It was left in place for drivers as an optional tune knob. But only one driver has been using it until the previous commit. So remove this misconcept completely, given there are no users. Signed-off-by: Jiri Slaby <jslaby@suse.cz> Link: https://lore.kernel.org/r/20210105120239.28031-11-jslaby@suse.cz Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-12-28tty: new helper function tty_get_icount()Uwe Kleine-König1-0/+2
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>
2020-12-28tty: rename tty_kopen() and add new function tty_kopen_shared()Uwe Kleine-König1-2/+3
Introduce a new function tty_kopen_shared() that yields a struct tty_struct. The semantic difference to tty_kopen() is that the tty is expected to be used already. So rename tty_kopen() to tty_kopen_exclusive() for clearness, adapt the single user and put the common code in a new static helper function. tty_kopen_shared is to be used to implement an LED trigger for tty devices in one of the next patches. Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Link: https://lore.kernel.org/r/20201218104246.591315-2-u.kleine-koenig@pengutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-12-09tty: use const parameters in port-flag accessorsJohan Hovold1-6/+6
Declare the port parameter to the flag-test accessors as const. This is currently mostly cosmetic as the accessors are already inlined. Suggested-by: Jiri Slaby <jirislaby@kernel.org> Signed-off-by: Johan Hovold <johan@kernel.org> Link: https://lore.kernel.org/r/20201202113942.27024-3-johan@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-12-09tty: use assign_bit() in port-flag accessorsJohan Hovold1-24/+6
Use the new assign_bit() wrapper in the port-flag accessors instead of open coding. Suggested-by: Jiri Slaby <jirislaby@kernel.org> Signed-off-by: Johan Hovold <johan@kernel.org> Link: https://lore.kernel.org/r/20201202113942.27024-2-johan@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-12-07Merge 5.10-rc7 into tty-nextGreg Kroah-Hartman1-0/+4
We want the tty fixes in here as well. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-12-04tty: Fix ->session lockingJann Horn1-0/+4
Currently, locking of ->session is very inconsistent; most places protect it using the legacy tty mutex, but disassociate_ctty(), __do_SAK(), tiocspgrp() and tiocgsid() don't. Two of the writers hold the ctrl_lock (because they already need it for ->pgrp), but __proc_set_tty() doesn't do that yet. On a PREEMPT=y system, an unprivileged user can theoretically abuse this broken locking to read 4 bytes of freed memory via TIOCGSID if tiocgsid() is preempted long enough at the right point. (Other things might also go wrong, especially if root-only ioctls are involved; I'm not sure about that.) Change the locking on ->session such that: - tty_lock() is held by all writers: By making disassociate_ctty() hold it. This should be fine because the same lock can already be taken through the call to tty_vhangup_session(). The tricky part is that we need to shorten the area covered by siglock to be able to take tty_lock() without ugly retry logic; as far as I can tell, this should be fine, since nothing in the signal_struct is touched in the `if (tty)` branch. - ctrl_lock is held by all writers: By changing __proc_set_tty() to hold the lock a little longer. - All readers that aren't holding tty_lock() hold ctrl_lock: By adding locking to tiocgsid() and __do_SAK(), and expanding the area covered by ctrl_lock in tiocspgrp(). Cc: stable@kernel.org Signed-off-by: Jann Horn <jannh@google.com> Reviewed-by: Jiri Slaby <jirislaby@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-12-04tty: Remove dead termiox codeJann Horn1-1/+0
set_termiox() and the TCGETX handler bail out with -EINVAL immediately if ->termiox is NULL, but there are no code paths that can set ->termiox to a non-NULL pointer; and no such code paths seem to have existed since the termiox mechanism was introduced back in commit 1d65b4a088de ("tty: Add termiox") in v2.6.28. Similarly, no driver actually implements .set_termiox; and it looks like no driver ever has. Delete this dead code; but leave the definition of struct termiox in the UAPI headers intact. Signed-off-by: Jann Horn <jannh@google.com> Link: https://lore.kernel.org/r/20201203020331.2394754-1-jannh@google.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-11-06tty: tty_io: Move 'tty_sysctl_init's prototype to shared spaceLee Jones1-0/+1
Fixes the following W=1 kernel build warning(s): drivers/tty/tty_ldisc.c:883:6: warning: no previous prototype for ‘tty_sysctl_init’ [-Wmissing-prototypes] 883 | void tty_sysctl_init(void) | ^~~~~~~~~~~~~~~ Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Jiri Slaby <jirislaby@kernel.org> Cc: Nick Holloway <alfie@dcs.warwick.ac.uk> Cc: -- <julian@uhunix.uhcc.hawaii.edu> Cc: Marko Kohtala <Marko.Kohtala@hut.fi> Cc: Bill Hawes <whawes@star.net> Cc: "C. Scott Ananian" <cananian@alumni.princeton.edu> Cc: Russell King <rmk@arm.linux.org.uk> Cc: Andrew Morton <andrewm@uow.edu.eu> Signed-off-by: Lee Jones <lee.jones@linaro.org> Link: https://lore.kernel.org/r/20201104193549.4026187-5-lee.jones@linaro.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-05-04gcc-10 warnings: fix low-hanging fruitLinus Torvalds1-1/+1
Due to a bug-report that was compiler-dependent, I updated one of my machines to gcc-10. That shows a lot of new warnings. Happily they seem to be mostly the valid kind, but it's going to cause a round of churn for getting rid of them.. This is the really low-hanging fruit of removing a couple of zero-sized arrays in some core code. We have had a round of these patches before, and we'll have many more coming, and there is nothing special about these except that they were particularly trivial, and triggered more warnings than most. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-02-10serdev: ttyport: restore client ops on deregistrationJohan Hovold1-0/+2
The serdev tty-port controller driver should reset the tty-port client operations also on deregistration to avoid a NULL-pointer dereference in case the port is later re-registered as a normal tty device. Note that this can only happen with tty drivers such as 8250 which have statically allocated port structures that can end up being reused and where a later registration would not register a serdev controller (e.g. due to registration errors or if the devicetree has been changed in between). Specifically, this can be an issue for any statically defined ports that would be registered by 8250 core when an 8250 driver is being unbound. Fixes: bed35c6dfa6a ("serdev: add a tty port controller driver") Cc: stable <stable@vger.kernel.org> # 4.11 Reported-by: Loic Poulain <loic.poulain@linaro.org> Signed-off-by: Johan Hovold <johan@kernel.org> Link: https://lore.kernel.org/r/20200210145730.22762-1-johan@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-12-10Merge 4.20-rc6 into tty-nextGreg Kroah-Hartman1-0/+1
We want the TTY changes in here as well. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-12-05tty: Don't block on IO when ldisc change is pendingDmitry Safonov1-0/+7
There might be situations where tty_ldisc_lock() has blocked, but there is already IO on tty and it prevents line discipline changes. It might theoretically turn into dead-lock. Basically, provide more priority to pending tty_ldisc_lock() than to servicing reads/writes over tty. User-visible issue was reported by Mikulas where on pa-risc with Debian 5 reboot took either 80 seconds, 3 minutes or 3:25 after proper locking in tty_reopen(). Cc: Jiri Slaby <jslaby@suse.com> Reported-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Dmitry Safonov <dima@arista.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-12-05USB: serial: console: fix reported terminal settingsJohan Hovold1-0/+1
The USB-serial console implementation has never reported the actual terminal settings used. Despite storing the corresponding cflags in its struct console, these were never honoured on later tty open() where the tty termios would be left initialised to the driver defaults. Unlike the serial console implementation, the USB-serial code calls subdriver open() already at console setup. While calling set_termios() and write() before open() looks like it could work for some USB-serial drivers, others definitely do not expect this, so modelling this after serial core is going to be intrusive, if at all possible. Instead, use a (renamed) tty helper to save the termios data used at console setup so that the tty termios reflects the actual terminal settings after a subsequent tty open(). Note that the calls to tty_init_termios() (tty_driver_install()) and tty_save_termios() are serialised using the disconnect mutex. This specifically fixes a regression that was triggered by a recent change adding software flow control to the pl2303 driver: a getty trying to disable flow control while leaving the baud rate unchanged would now also set the baud rate to the driver default (prior to the flow-control change this had been a noop). Fixes: 7041d9c3f01b ("USB: serial: pl2303: add support for tx xon/xoff flow control") Cc: stable <stable@vger.kernel.org> # 4.18 Cc: Florian Zumbiehl <florz@florz.de> Reported-by: Jarkko Nikula <jarkko.nikula@linux.intel.com> Tested-by: Jarkko Nikula <jarkko.nikula@linux.intel.com> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Johan Hovold <johan@kernel.org>
2018-09-14move compat handling of tty ioctls to tty_compat_ioctl()Al Viro1-2/+0
ioctls that are * callable only via tty_ioctl() * not driver-specific * not demand data structure conversions * either always need passing arg as is or always demand compat_ptr() get intercepted in tty_compat_ioctl() from the very beginning and redirecter to tty_ioctl(). As the result, their entries in fs/compat_ioctl.c (some of those had been missing, BTW) got removed, as well as n_tty_compat_ioctl_helper() (now it's never called with any cmd it would accept). Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2018-06-06Merge tag 'usb-4.18-rc1' of ↵Linus Torvalds1-1/+1
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb Pull USB and PHY updates from Greg KH: "Here is the big USB pull request for 4.18-rc1. Lots of stuff here, the highlights are: - phy driver updates and new additions - usual set of xhci driver updates - normal set of musb updates - gadget driver updates and new controllers - typec work, it's getting closer to getting fully out of the staging portion of the tree. - lots of minor cleanups and bugfixes. All of these have been in linux-next for a while with no reported issues" * tag 'usb-4.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb: (263 commits) Revert "xhci: Reset Renesas uPD72020x USB controller for 32-bit DMA issue" xhci: Add quirk to zero 64bit registers on Renesas PCIe controllers xhci: Allow more than 32 quirks usb: xhci: force all memory allocations to node selftests: add test for USB over IP driver USB: typec: fsusb302: no need to check return value of debugfs_create_dir() USB: gadget: udc: s3c2410_udc: no need to check return value of debugfs_create functions USB: gadget: udc: renesas_usb3: no need to check return value of debugfs_create functions USB: gadget: udc: pxa27x_udc: no need to check return value of debugfs_create functions USB: gadget: udc: gr_udc: no need to check return value of debugfs_create functions USB: gadget: udc: bcm63xx_udc: no need to check return value of debugfs_create functions USB: udc: atmel_usba_udc: no need to check return value of debugfs_create functions USB: dwc3: no need to check return value of debugfs_create functions USB: dwc2: no need to check return value of debugfs_create functions USB: core: no need to check return value of debugfs_create functions USB: chipidea: no need to check return value of debugfs_create functions USB: ehci-hcd: no need to check return value of debugfs_create functions USB: fhci-hcd: no need to check return value of debugfs_create functions USB: fotg210-hcd: no need to check return value of debugfs_create functions USB: imx21-hcd: no need to check return value of debugfs_create functions ...
2018-05-22tty: add missing const to termios hw-change helperJohan Hovold1-1/+1
Add missing const qualifiers to the parameters of the termios hw-change helper, which is used by a few USB serial drivers. This specifically allows the pl2303 driver to use const arguments in one of its helper as well. Cc: Jiri Slaby <jslaby@suse.com> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Johan Hovold <johan@kernel.org>
2018-05-16proc: introduce proc_create_seq{,_data}Christoph Hellwig1-1/+2
Variants of proc_create{,_data} that directly take a struct seq_operations argument and drastically reduces the boilerplate code in the callers. All trivial callers converted over. Signed-off-by: Christoph Hellwig <hch@lst.de>
2018-04-23tty: Don't call panic() at tty_ldisc_init()Tetsuo Handa1-1/+1
syzbot is reporting kernel panic [1] triggered by memory allocation failure at tty_ldisc_get() from tty_ldisc_init(). But since both tty_ldisc_get() and caller of tty_ldisc_init() can cleanly handle errors, tty_ldisc_init() does not need to call panic() when tty_ldisc_get() failed. [1] https://syzkaller.appspot.com/bug?id=883431818e036ae6a9981156a64b821110f39187 Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Reported-by: syzbot <syzkaller@googlegroups.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Jiri Slaby <jslaby@suse.com> Cc: stable <stable@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-02-28tty: make n_tty_read() always abort if hangup is in progressTejun Heo1-0/+1
A tty is hung up by __tty_hangup() setting file->f_op to hung_up_tty_fops, which is skipped on ttys whose write operation isn't tty_write(). This means that, for example, /dev/console whose write op is redirected_tty_write() is never actually marked hung up. Because n_tty_read() uses the hung up status to decide whether to abort the waiting readers, the lack of hung-up marking can lead to the following scenario. 1. A session contains two processes. The leader and its child. The child ignores SIGHUP. 2. The leader exits and starts disassociating from the controlling terminal (/dev/console). 3. __tty_hangup() skips setting f_op to hung_up_tty_fops. 4. SIGHUP is delivered and ignored. 5. tty_ldisc_hangup() is invoked. It wakes up the waits which should clear the read lockers of tty->ldisc_sem. 6. The reader wakes up but because tty_hung_up_p() is false, it doesn't abort and goes back to sleep while read-holding tty->ldisc_sem. 7. The leader progresses to tty_ldisc_lock() in tty_ldisc_hangup() and is now stuck in D sleep indefinitely waiting for tty->ldisc_sem. The following is Alan's explanation on why some ttys aren't hung up. http://lkml.kernel.org/r/20171101170908.6ad08580@alans-desktop 1. It broke the serial consoles because they would hang up and close down the hardware. With tty_port that *should* be fixable properly for any cases remaining. 2. The console layer was (and still is) completely broken and doens't refcount properly. So if you turn on console hangups it breaks (as indeed does freeing consoles and half a dozen other things). As neither can be fixed quickly, this patch works around the problem by introducing a new flag, TTY_HUPPING, which is used solely to tell n_tty_read() that hang-up is in progress for the console and the readers should be aborted regardless of the hung-up status of the device. The following is a sample hung task warning caused by this issue. INFO: task agetty:2662 blocked for more than 120 seconds. Not tainted 4.11.3-dbg-tty-lockup-02478-gfd6c7ee-dirty #28 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. 0 2662 1 0x00000086 Call Trace: __schedule+0x267/0x890 schedule+0x36/0x80 schedule_timeout+0x23c/0x2e0 ldsem_down_write+0xce/0x1f6 tty_ldisc_lock+0x16/0x30 tty_ldisc_hangup+0xb3/0x1b0 __tty_hangup+0x300/0x410 disassociate_ctty+0x6c/0x290 do_exit+0x7ef/0xb00 do_group_exit+0x3f/0xa0 get_signal+0x1b3/0x5d0 do_signal+0x28/0x660 exit_to_usermode_loop+0x46/0x86 do_syscall_64+0x9c/0xb0 entry_SYSCALL64_slow_path+0x25/0x25 The following is the repro. Run "$PROG /dev/console". The parent process hangs in D state. #include <sys/types.h> #include <sys/stat.h> #include <sys/wait.h> #include <sys/ioctl.h> #include <fcntl.h> #include <unistd.h> #include <stdio.h> #include <stdlib.h> #include <errno.h> #include <signal.h> #include <time.h> #include <termios.h> int main(int argc, char **argv) { struct sigaction sact = { .sa_handler = SIG_IGN }; struct timespec ts1s = { .tv_sec = 1 }; pid_t pid; int fd; if (argc < 2) { fprintf(stderr, "test-hung-tty /dev/$TTY\n"); return 1; } /* fork a child to ensure that it isn't already the session leader */ pid = fork(); if (pid < 0) { perror("fork"); return 1; } if (pid > 0) { /* top parent, wait for everyone */ while (waitpid(-1, NULL, 0) >= 0) ; if (errno != ECHILD) perror("waitpid"); return 0; } /* new session, start a new session and set the controlling tty */ if (setsid() < 0) { perror("setsid"); return 1; } fd = open(argv[1], O_RDWR); if (fd < 0) { perror("open"); return 1; } if (ioctl(fd, TIOCSCTTY, 1) < 0) { perror("ioctl"); return 1; } /* fork a child, sleep a bit and exit */ pid = fork(); if (pid < 0) { perror("fork"); return 1; } if (pid > 0) { nanosleep(&ts1s, NULL); printf("Session leader exiting\n"); exit(0); } /* * The child ignores SIGHUP and keeps reading from the controlling * tty. Because SIGHUP is ignored, the child doesn't get killed on * parent exit and the bug in n_tty makes the read(2) block the * parent's control terminal hangup attempt. The parent ends up in * D sleep until the child is explicitly killed. */ sigaction(SIGHUP, &sact, NULL); printf("Child reading tty\n"); while (1) { char buf[1024]; if (read(fd, buf, sizeof(buf)) < 0) { perror("read"); return 1; } } return 0; } Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Alan Cox <alan@llwyncelyn.cymru> Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-01-23tty: fix data race between tty_init_dev and flush of bufGaurav Kohli1-0/+2
There can be a race, if receive_buf call comes before tty initialization completes in n_tty_open and tty->disc_data may be NULL. CPU0 CPU1 ---- ---- 000|n_tty_receive_buf_common() n_tty_open() -001|n_tty_receive_buf2() tty_ldisc_open.isra.3() -002|tty_ldisc_receive_buf(inline) tty_ldisc_setup() Using ldisc semaphore lock in tty_init_dev till disc_data initializes completely. Signed-off-by: Gaurav Kohli <gkohli@codeaurora.org> Reviewed-by: Alan Cox <alan@linux.intel.com> Cc: stable <stable@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-11-02License cleanup: add SPDX GPL-2.0 license identifier to files with no licenseGreg Kroah-Hartman1-0/+1
Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-08-28tty: undo export of tty_open_by_driverOkash Khawaja1-5/+0
Since we have tty_kopen, we no longer need to export tty_open_by_driver. This patch makes this function static. Signed-off-by: Okash Khawaja <okash.khawaja@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-08-28tty: resolve tty contention between kernel and user spaceOkash Khawaja1-0/+21
The commit 12e84c71b7d4 ("tty: export tty_open_by_driver") exports tty_open_by_device to allow tty to be opened from inside kernel which works fine except that it doesn't handle contention with user space or another kernel-space open of the same tty. For example, opening a tty from user space while it is kernel opened results in failure and a kernel log message about mismatch between tty->count and tty's file open count. This patch makes kernel access to tty exclusive, so that if a user process or kernel opens a kernel opened tty, it gets -EBUSY. It does this by adding TTY_KOPENED flag to tty->flags. When this flag is set, tty_open_by_driver returns -EBUSY. Instead of overloading tty_open_by_driver for both kernel and user space, this patch creates a separate function tty_kopen which closely follows tty_open_by_driver. tty_kclose closes the tty opened by tty_kopen. To address the mismatch between tty->count and #fd's, this patch adds #kopen's to the count before comparing it with tty->count. That way check_tty_count reflects correct usage count. Returning -EBUSY on tty open is a change in the interface. I have tested this with minicom, picocom and commands like "echo foo > /dev/ttyS0". They all correctly report "Device or resource busy" when the tty is already kernel opened. Signed-off-by: Okash Khawaja <okash.khawaja@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-07-19Merge tag 'gcc-plugins-v4.13-rc2' of ↵Linus Torvalds1-1/+1
git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux Pull structure randomization updates from Kees Cook: "Now that IPC and other changes have landed, enable manual markings for randstruct plugin, including the task_struct. This is the rest of what was staged in -next for the gcc-plugins, and comes in three patches, largest first: - mark "easy" structs with __randomize_layout - mark task_struct with an optional anonymous struct to isolate the __randomize_layout section - mark structs to opt _out_ of automated marking (which will come later) And, FWIW, this continues to pass allmodconfig (normal and patched to enable gcc-plugins) builds of x86_64, i386, arm64, arm, powerpc, and s390 for me" * tag 'gcc-plugins-v4.13-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: randstruct: opt-out externally exposed function pointer structs task_struct: Allow randomized layout randstruct: Mark various structs for randomization
2017-07-04Merge tag 'tty-4.13-rc1' of ↵Linus Torvalds1-1/+0
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty Pull tty/serial updates from Greg KH: "Here is the large tty/serial patchset for 4.13-rc1. A lot of tty and serial driver updates are in here, along with some fixups for some __get/put_user usages that were reported. Nothing huge, just lots of development by a number of different developers, full details in the shortlog. All of these have been in linux-next for a while" * tag 'tty-4.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (71 commits) tty: serial: lpuart: add a more accurate baud rate calculation method tty: serial: lpuart: add earlycon support for imx7ulp tty: serial: lpuart: add imx7ulp support dt-bindings: serial: fsl-lpuart: add i.MX7ULP support tty: serial: lpuart: add little endian 32 bit register support tty: serial: lpuart: refactor lpuart32_{read|write} prototype tty: serial: lpuart: introduce lpuart_soc_data to represent SoC property serial: imx-serial - move DMA buffer configuration to DT serial: imx: Enable RTSD only when needed serial: imx: Remove unused members from imx_port struct serial: 8250: 8250_omap: Fix race b/w dma completion and RX timeout serial: 8250: Fix THRE flag usage for CAP_MINI tty/serial: meson_uart: update to stable bindings dt-bindings: serial: Add bindings for the Amlogic Meson UARTs serial: Delete dead code for CIR serial ports serial: sirf: make of_device_ids const serial/mpsc: switch to dma_alloc_attrs tty: serial: Add Actions Semi Owl UART earlycon dt-bindings: serial: Document Actions Semi Owl UARTs tty/serial: atmel: make the driver DT only ...
2017-06-30randstruct: Mark various structs for randomizationKees Cook1-1/+1
This marks many critical kernel structures for randomization. These are structures that have been targeted in the past in security exploits, or contain functions pointers, pointers to function pointer tables, lists, workqueues, ref-counters, credentials, permissions, or are otherwise sensitive. This initial list was extracted from Brad Spengler/PaX Team's code in the last public patch of grsecurity/PaX based on my understanding of the code. Changes or omissions from the original code are mine and don't reflect the original grsecurity/PaX code. Left out of this list is task_struct, which requires special handling and will be covered in a subsequent patch. Signed-off-by: Kees Cook <keescook@chromium.org>
2017-06-27tty: add function to convert device name to numberOkash Khawaja1-0/+3
The function converts strings like ttyS0 and ttyUSB0 to dev_t like (4, 64) and (188, 0). It does this by scanning tty_drivers list for corresponding device name and index. If the driver is not registered, this function returns -ENODEV. It also acquires tty_mutex. Signed-off-by: Okash Khawaja <okash.khawaja@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-06-25tty: define tty_open_by_driver when CONFIG_TTY is not definedOkash Khawaja1-0/+3
This patch adds definition of tty_open_by_driver when CONFIG_TTY is not defined. This was supposed to have been included in commit 12e84c71b7d4ee38d51377fd494ac748ee4e6912 ("tty: export tty_open_by_driver"). The patch follows convention for other such functions and returns NULL. Signed-off-by: Okash Khawaja <okash.khawaja@gmail.com> Reviewed-by: Samuel Thibault <samuel.thibault@ens-lyon.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-06-13tty: drop unused alt_speed from tty_structJohan Hovold1-1/+0
Drop the now unused alt_speed field from struct tty_struct. Setting an alt_speed using the ASYNC_SPD flags has been deprecated since v2.1.69, and has been broken for all tty drivers but serial-core since v3.10 and commit 6865ff222cca ("TTY: do not warn about setting speed via SPD_*") without anyone noticing. Note that serial-core still supports changing speed using TIOCSSERIAL and SPD flags (including "alt-speeds"), but also warns about it being deprecated since pre-git. Signed-off-by: Johan Hovold <johan@kernel.org> Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> Reviewed-by: Alan Cox <alan@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-06-12Merge 4.12-rc5 into staging-nextGreg Kroah-Hartman1-0/+9
We want the IIO fixes and other staging driver fixes in here as well. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-05-18tty/serdev: add serdev registration interfaceJohan Hovold1-0/+9
Add a new interface for registering a serdev controller and clients, and a helper function to deregister serdev devices (or a tty device) that were previously registered using the new interface. Once every driver currently using the tty_port_register_device() helpers have been vetted and converted to use the new serdev registration interface (at least for deregistration), we can move serdev registration to the current helpers and get rid of the serdev-specific functions. Reviewed-by: Rob Herring <robh@kernel.org> Signed-off-by: Johan Hovold <johan@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-05-16tty: export tty_open_by_driverOkash Khawaja1-0/+2
This exports tty_open_by_driver so that it can be called from other places inside the kernel. The checks for null file pointer are based on Alan Cox's patch here: http://www.mail-archive.com/linux-kernel@vger.kernel.org/msg1215095.html. Description below is quoted from it: "[RFC] tty_port: allow a port to be opened with a tty that has no file handle Let us create tty objects entirely in kernel space. Untested proposal to show why all the ideas around rewriting half the uart stack are not needed. With this a kernel created non file backed tty object could be used to handle data, and set terminal modes. Not all ldiscs can cope with this as N_TTY in particular has to work back to the fs/tty layer. The tty_port code is however otherwise clean of file handles as far as I can tell as is the low level tty port write path used by the ldisc, the configuration low level interfaces and most of the ldiscs. Currently you don't have any exposure to see tty hangups because those are built around the file layer. However a) it's a fixed port so you probably don't care about that b) if you do we can add a callback and c) you almost certainly don't want the userspace tear down/rebuild behaviour anyway. This should however be sufficient if we wanted for example to enumerate all the bluetooth bound fixed ports via ACPI and make them directly available. It doesn't deal with the case of a user opening a port that's also kernel opened and that would need some locking out (so it returned EBUSY if bound to a kernel device of some kind). That needs resolving along with how you "up" or "down" your new bluetooth device, or enumerate it while providing the existing tty API to avoid regressions (and to debug)." The exported funtion is used later in this patch set to gain access to tty_struct. [changed export symbol level - gkh] Signed-off-by: Okash Khawaja <okash.khawaja@gmail.com> Reviewed-by: Samuel Thibault <samuel.thibault@ens-lyon.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-04-18tty: split job control support into a file of its ownNicolas Pitre1-0/+6
This makes it easier for job control to become optional and/or usable independently from tty_io.c, as well as providing a nice purpose separation. No logical changes from this patch. Signed-off-by: Nicolas Pitre <nico@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-04-18console: move console_init() out of tty_io.cNicolas Pitre1-3/+4
All the console driver handling code lives in printk.c. Move console_init() there as well so console support can still be used when the TTY code is configured out. No logical changes from this patch. Signed-off-by: Nicolas Pitre <nico@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-02-03tty_port: Add port client functionsRob Herring1-1/+8
Introduce a client (upward direction) operations struct for tty_port clients. Initially supported operations are for receiving data and write wake-up. This will allow for having clients other than an ldisc. Convert the calls to the ldisc to use the client ops as the default operations. Signed-off-by: Rob Herring <robh@kernel.org> Reviewed-By: Sebastian Reichel <sre@kernel.org> Tested-By: Sebastian Reichel <sre@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-01-19tty: constify tty_ldisc_receive_buf buffer pointerRob Herring1-1/+1
This is needed to work with the client operations which uses const ptrs. Really, the flags pointer could be const, too, but this would be a tree wide fix. Signed-off-by: Rob Herring <robh@kernel.org> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Reviewed-By: Sebastian Reichel <sre@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-01-19tty: move the non-file related parts of tty_release to new tty_release_structRob Herring1-0/+1
For in-kernel tty users, we need to be able to create and destroy 'struct tty' that are not associated with a file. The creation side is fine, but tty_release() needs to be split into the file handle portion and the struct tty portion. Introduce a new function, tty_release_struct, to handle just the destroying of a struct tty. Signed-off-by: Rob Herring <robh@kernel.org> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Reviewed-By: Sebastian Reichel <sre@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-05-21Merge tag 'tty-4.7-rc1' of ↵Linus Torvalds1-3/+86
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty Pull tty and serial driver updates from Greg KH: "Here's the large TTY and Serial driver update for 4.7-rc1. A few new serial drivers are added here, and Peter has fixed a bunch of long-standing bugs in the tty layer and serial drivers as normal. Full details in the shortlog. All of these have been in linux-next for a while with no reported issues" * tag 'tty-4.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (88 commits) MAINTAINERS: 8250: remove website reference serial: core: Fix port mutex assert if lockdep disabled serial: 8250_dw: fix wrong logic in dw8250_check_lcr() tty: vt, finish looping on duplicate tty: vt, return error when con_startup fails QE-UART: add "fsl,t1040-ucc-uart" to of_device_id serial: mctrl_gpio: Drop support for out1-gpios and out2-gpios serial: 8250dw: Add device HID for future AMD UART controller Fix OpenSSH pty regression on close serial: mctrl_gpio: add IRQ locking serial: 8250: Integrate Fintek into 8250_base serial: mps2-uart: add support for early console serial: mps2-uart: add MPS2 UART driver dt-bindings: document the MPS2 UART bindings serial: sirf: Use generic uart-has-rtscts DT property serial: sirf: Introduce helper variable struct device_node *np serial: mxs-auart: Use generic uart-has-rtscts DT property serial: imx: Use generic uart-has-rtscts DT property doc: DT: Add Generic Serial Device Tree Bindings serial: 8250: of: Make tegra_serial_handle_break() static ...