kernel/linux.git/drivers/tty, branch linux-4.13.y

serial: 8250_fintek: Fix finding base_port with activated SuperIO

2017-11-24T07:35:58+00:00

commit fd97e66c5529046e989a0879c3bb58fddb592c71 upstream. The SuperIO will be configured at boot time by BIOS, but some BIOS will not deactivate the SuperIO when the end of configuration. It'll lead to mismatch for pdata->base_port in probe_setup_port(). So we'll deactivate all SuperIO before activate special base_port in fintek_8250_enter_key(). Tested on iBASE MI802. Tested-by: Ji-Ze Hong (Peter Hong) Signed-off-by: Ji-Ze Hong (Peter Hong) Reviewd-by: Alan Cox Signed-off-by: Greg Kroah-Hartman

serial: omap: Fix EFR write on RTS deassertion

2017-11-24T07:35:58+00:00

commit 2a71de2f7366fb1aec632116d0549ec56d6a3940 upstream. Commit 348f9bb31c56 ("serial: omap: Fix RTS handling") sought to enable auto RTS upon manual RTS assertion and disable it on deassertion. However it seems the latter was done incorrectly, it clears all bits in the Extended Features Register *except* auto RTS. Fixes: 348f9bb31c56 ("serial: omap: Fix RTS handling") Cc: Peter Hurley Signed-off-by: Lukas Wunner Signed-off-by: Greg Kroah-Hartman

tty: fix __tty_insert_flip_char regression

2017-09-27T12:43:12+00:00

commit 8a5a90a2a477b86a3dc2eaa5a706db9bfdd647ca upstream. Sergey noticed a small but fatal mistake in __tty_insert_flip_char, leading to an oops in an interrupt handler when using any serial port. The problem is that I accidentally took the tty_buffer pointer before calling __tty_buffer_request_room(), which replaces the buffer. This moves the pointer lookup to the right place after allocating the new buffer space. Fixes: 979990c62848 ("tty: improve tty_insert_flip_char() fast path") Reported-by: Sergey Senozhatsky Tested-by: Sergey Senozhatsky Signed-off-by: Arnd Bergmann Signed-off-by: Greg Kroah-Hartman

tty: improve tty_insert_flip_char() slow path

2017-09-27T12:43:12+00:00

commit 065ea0a7afd64d6cf3464bdd1d8cd227527e2045 upstream. While working on improving the fast path of tty_insert_flip_char(), I noticed that by calling tty_buffer_request_room(), we needlessly move to the separate flag buffer mode for the tty, even when all characters use TTY_NORMAL as the flag. This changes the code to call __tty_buffer_request_room() with the correct flag, which will then allocate a regular buffer when it rounds out of space but no special flags have been used. I'm guessing that this is the behavior that Peter Hurley intended when he introduced the compacted flip buffers. Fixes: acc0f67f307f ("tty: Halve flip buffer GFP_ATOMIC memory consumption") Cc: Peter Hurley Signed-off-by: Arnd Bergmann Signed-off-by: Greg Kroah-Hartman

tty: improve tty_insert_flip_char() fast path

2017-09-27T12:43:12+00:00

commit 979990c6284814617d8f2179d197f72ff62b5d85 upstream. kernelci.org reports a crazy stack usage for the VT code when CONFIG_KASAN is enabled: drivers/tty/vt/keyboard.c: In function 'kbd_keycode': drivers/tty/vt/keyboard.c:1452:1: error: the frame size of 2240 bytes is larger than 2048 bytes [-Werror=frame-larger-than=] The problem is that tty_insert_flip_char() gets inlined many times into kbd_keycode(), and also into other functions, and each copy requires 128 bytes for stack redzone to check for a possible out-of-bounds access on the 'ch' and 'flags' arguments that are passed into tty_insert_flip_string_flags as a variable-length string. This introduces a new __tty_insert_flip_char() function for the slow path, which receives the two arguments by value. This completely avoids the problem and the stack usage goes back down to around 100 bytes. Without KASAN, this is also slightly better, as we don't have to spill the arguments to the stack but can simply pass 'ch' and 'flag' in registers, saving a few bytes in .text for each call site. This should be backported to linux-4.0 or later, which first introduced the stack sanitizer in the kernel. Fixes: c420f167db8c ("kasan: enable stack instrumentation") Signed-off-by: Arnd Bergmann Signed-off-by: Greg Kroah-Hartman

pty: Repair TIOCGPTPEER

2017-08-24T20:23:03+00:00

The implementation of TIOCGPTPEER has two issues. When /dev/ptmx (as opposed to /dev/pts/ptmx) is opened the wrong vfsmount is passed to dentry_open. Which results in the kernel displaying the wrong pathname for the peer. The second is simply by caching the vfsmount and dentry of the peer it leaves them open, in a way they were not previously Which because of the inreased reference counts can cause unnecessary behaviour differences resulting in regressions. To fix these move the ioctl into tty_io.c at a generic level allowing the ioctl to have access to the struct file on which the ioctl is being called. This allows the path of the slave to be derived when opening the slave through TIOCGPTPEER instead of requiring the path to the slave be cached. Thus removing the need for caching the path. A new function devpts_ptmx_path is factored out of devpts_acquire and used to implement a function devpts_mntget. The new function devpts_mntget takes a filp to perform the lookup on and fsi so that it can confirm that the superblock that is found by devpts_ptmx_path is the proper superblock. v2: Lots of fixes to make the code actually work v3: Suggestions by Linus - Removed the unnecessary initialization of filp in ptm_open_peer - Simplified devpts_ptmx_path as gotos are no longer required [ This is the fix for the issue that was reverted in commit 143c97cc6529, but this time without breaking 'pbuilder' due to increased reference counts - Linus ] Fixes: 54ebbfb16034 ("tty: add TIOCGPTPEER ioctl") Reported-by: Christian Brauner Reported-and-tested-by: Stefan Lippers-Hollmann Signed-off-by: "Eric W. Biederman" Signed-off-by: Linus Torvalds

Revert "pty: fix the cached path of the pty slave file descriptor in the master"

2017-08-24T01:16:11+00:00

This reverts commit c8c03f1858331e85d397bacccd34ef409aae993c. It turns out that while fixing the ptmx file descriptor to have the correct 'struct path' to the associated slave pty is a really good thing, it breaks some user space tools for a very annoying reason. The problem is that /dev/ptmx and its associated slave pty (/dev/pts/X) are on different mounts. That was what caused us to have the wrong path in the first place (we would mix up the vfsmount of the 'ptmx' node, with the dentry of the pty slave node), but it also means that now while we use the right vfsmount, having the pty master open also keeps the pts mount busy. And it turn sout that that makes 'pbuilder' very unhappy, as noted by Stefan Lippers-Hollmann: "This patch introduces a regression for me when using pbuilder 0.228.7[2] (a helper to build Debian packages in a chroot and to create and update its chroots) when trying to umount /dev/ptmx (inside the chroot) on Debian/ unstable (full log and pbuilder configuration file[3] attached). [...] Setting up build-essential (12.3) ... Processing triggers for libc-bin (2.24-15) ... I: unmounting dev/ptmx filesystem W: Could not unmount dev/ptmx: umount: /var/cache/pbuilder/build/1340/dev/ptmx: target is busy (In some cases useful info about processes that use the device is found by lsof(8) or fuser(1).)" apparently pbuilder tries to unmount the /dev/pts filesystem while still holding at least one master node open, which is arguably not very nice, but we don't break user space even when fixing other bugs. So this commit has to be reverted. I'll try to figure out a way to avoid caching the path to the slave pty in the master pty. The only thing that actually wants that slave pty path is the "TIOCGPTPEER" ioctl, and I think we could just recreate the path at that time. Reported-by: Stefan Lippers-Hollmann Cc: Eric W Biederman Cc: Christian Brauner Cc: Al Viro Signed-off-by: Linus Torvalds

pty: fix the cached path of the pty slave file descriptor in the master

2017-08-17T16:10:48+00:00

Christian Brauner reported that if you use the TIOCGPTPEER ioctl() to get a slave pty file descriptor, the resulting file descriptor doesn't look right in /proc//fd/. In particular, he wanted to use readlink() on /proc/self/fd/ to get the pathname of the slave pty (basically implementing "ptsname{_r}()"). The reason for that was that we had generated the wrong 'struct path' when we create the pty in ptmx_open(). In particular, the dentry was correct, but the vfsmount pointed to the mount of the ptmx node. That _can_ be correct - in case you use "/dev/pts/ptmx" to open the master - but usually is not. The normal case is to use /dev/ptmx, which then looks up the pts/ directory, and then the vfsmount of the ptmx node is obviously the /dev directory, not the /dev/pts/ directory. We actually did have the right vfsmount available, but in the wrong place (it gets looked up in 'devpts_acquire()' when we get a reference to the pts filesystem), and so ptmx_open() used the wrong mnt pointer. The end result of this confusion was that the pty worked fine, but when if you did TIOCGPTPEER to get the slave side of the pty, end end result would also work, but have that dodgy 'struct path'. And then when doing "d_path()" on to get the pathname, the vfsmount would not match the root of the pts directory, and d_path() would return an empty pathname thinking that the entry had escaped a bind mount into another mount. This fixes the problem by making devpts_acquire() return the vfsmount for the pts filesystem, allowing ptmx_open() to trivially just use the right mount for the pts dentry, and create the proper 'struct path'. Reported-by: Christian Brauner Cc: Al Viro Acked-by: Eric Biederman Signed-off-by: Linus Torvalds

Merge tag 'tty-4.13-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty

2017-08-13T19:33:35+00:00

Pull tty/serial fixes from Greg KH: "Here are two tty serial driver fixes for 4.13-rc5. One is a revert of a -rc1 patch that turned out to not be a good idea, and the other is a fix for the pl011 serial driver. Both have been in linux-next with no reported issues" * tag 'tty-4.13-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: Revert "serial: Delete dead code for CIR serial ports" tty: pl011: fix initialization order of QDF2400 E44

Revert "serial: Delete dead code for CIR serial ports"

2017-08-01T16:50:18+00:00

This reverts commit 1104321a7b3bb670dc614ffa7958c553e7b3b836. The code is not dead at all and breaks winbond-cir. Serial: 8250/16550 driver, 32 ports, IRQ sharing enabled 00:02: ttyS0 at I/O 0x3f8 (irq = 4, base_baud = 115200) is a 16550A 00:03: ttyS1 at I/O 0x2f8 (irq = 3, base_baud = 115200) is a CIR port lirc lirc0: lirc_dev: driver ir-lirc-codec (winbond-cir) registered at minor = 0 winbond-cir 00:03: Region 0x2f8-0x2ff already in use! winbond-cir: probe of 00:03 failed with error -16 Signed-off-by: Sean Young Reviewed-by: Matthias Brugger Signed-off-by: Greg Kroah-Hartman