BMC/Intel-BMC/linux.git/drivers/tty, branch dev-4.3

Merge tag 'v4.3.6' into dev-4.3

2016-02-22T05:13:27+00:00

This is the 4.3.6 stable release Signed-off-by: Joel Stanley

tty: Fix unsafe ldisc reference via ioctl(TIOCGETD)

2016-02-19T22:28:34+00:00

commit 5c17c861a357e9458001f021a7afa7aab9937439 upstream. ioctl(TIOCGETD) retrieves the line discipline id directly from the ldisc because the line discipline id (c_line) in termios is untrustworthy; userspace may have set termios via ioctl(TCSETS*) without actually changing the line discipline via ioctl(TIOCSETD). However, directly accessing the current ldisc via tty->ldisc is unsafe; the ldisc ptr dereferenced may be stale if the line discipline is changing via ioctl(TIOCSETD) or hangup. Wait for the line discipline reference (just like read() or write()) to retrieve the "current" line discipline id. Signed-off-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman

tty: Retry failed reopen if tty teardown in-progress

2016-02-19T22:28:34+00:00

commit 7f22f6c935cda600660e623a411fe380015d28d9 upstream. A small window exists where a tty reopen will observe the tty just prior to imminent teardown (tty->count == 0); in this case, open() returns EIO to userspace. Instead, retry the open after checking for signals and yielding; this interruptible retry loop allows teardown to commence and initialize a new tty on retry. Never retry the BSD master pty reopen; there is no guarantee the pty pair teardown is imminent since the slave file descriptors may remain open indefinitely. Signed-off-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman

tty: Fix GPF in flush_to_ldisc()

2016-02-19T22:28:34+00:00

commit 9ce119f318ba1a07c29149301f1544b6c4bea52a upstream. A line discipline which does not define a receive_buf() method can can cause a GPF if data is ever received [1]. Oddly, this was known to the author of n_tracesink in 2011, but never fixed. [1] GPF report BUG: unable to handle kernel NULL pointer dereference at (null) IP: [< (null)>] (null) PGD 3752d067 PUD 37a7b067 PMD 0 Oops: 0010 [#1] SMP KASAN Modules linked in: CPU: 2 PID: 148 Comm: kworker/u10:2 Not tainted 4.4.0-rc2+ #51 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 Workqueue: events_unbound flush_to_ldisc task: ffff88006da94440 ti: ffff88006db60000 task.ti: ffff88006db60000 RIP: 0010:[<0000000000000000>] [< (null)>] (null) RSP: 0018:ffff88006db67b50 EFLAGS: 00010246 RAX: 0000000000000102 RBX: ffff88003ab32f88 RCX: 0000000000000102 RDX: 0000000000000000 RSI: ffff88003ab330a6 RDI: ffff88003aabd388 RBP: ffff88006db67c48 R08: ffff88003ab32f9c R09: ffff88003ab31fb0 R10: ffff88003ab32fa8 R11: 0000000000000000 R12: dffffc0000000000 R13: ffff88006db67c20 R14: ffffffff863df820 R15: ffff88003ab31fb8 FS: 0000000000000000(0000) GS:ffff88006dc00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b CR2: 0000000000000000 CR3: 0000000037938000 CR4: 00000000000006e0 Stack: ffffffff829f46f1 ffff88006da94bf8 ffff88006da94bf8 0000000000000000 ffff88003ab31fb0 ffff88003aabd438 ffff88003ab31ff8 ffff88006430fd90 ffff88003ab32f9c ffffed0007557a87 1ffff1000db6cf78 ffff88003ab32078 Call Trace: [] process_one_work+0x8f1/0x17a0 kernel/workqueue.c:2030 [] worker_thread+0xd4/0x1180 kernel/workqueue.c:2162 [] kthread+0x1cf/0x270 drivers/block/aoe/aoecmd.c:1302 [] ret_from_fork+0x3f/0x70 arch/x86/entry/entry_64.S:468 Code: Bad RIP value. RIP [< (null)>] (null) RSP CR2: 0000000000000000 ---[ end trace a587f8947e54d6ea ]--- Reported-by: Dmitry Vyukov Signed-off-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman

n_tty: Fix unsafe reference to "other" ldisc

2016-02-19T22:28:34+00:00

commit 6d27a63caad3f13e96cf065d2d96828c2006be6b upstream. Although n_tty_check_unthrottle() has a valid ldisc reference (since the tty core gets the ldisc ref in tty_read() before calling the line discipline read() method), it does not have a valid ldisc reference to the "other" pty of a pty pair. Since getting an ldisc reference for tty->link essentially open-codes tty_wakeup(), just replace with the equivalent tty_wakeup(). Signed-off-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman

n_tty: Fix poll() after buffer-limited eof push read

2016-02-19T22:28:34+00:00

commit ac8f3bf8832a405cc6e4dccb1d26d5cb2994d234 upstream. commit 40d5e0905a03 ("n_tty: Fix EOF push handling") fixed EOF push for reads. However, that approach still allows a condition mismatch between poll() and read(), where poll() returns POLLIN but read() blocks. This state can happen when a previous read() returned because the user buffer was full and the next character was an EOF not at the beginning of the line. While the next read() will properly identify the condition and advance the read buffer tail without improperly indicating an EOF file condition (ie., read() will not mistakenly return 0), poll() will mistakenly indicate POLLIN. Although a possible solution would be to peek at the input buffer in n_tty_poll(), the better solution in this patch is to eat the EOF during the previous read() (ie., fix the problem by eliminating the condition). The current canon line buffer copy limits the scan for next end-of-line to the smaller of either, a. the remaining user buffer size b. completed lines in the input buffer When the remaining user buffer size is exactly one less than the end-of-line marked by EOF push, the EOF is not scanned nor skipped but left for subsequent reads. In the example below, the scan index 'eol' has stopped at the EOF because it is past the scan limit of 5 (not because it has found the next set bit in read_flags) user buffer [*nr = 5] _ _ _ _ _ read_flags 0 0 0 0 0 1 input buffer h e l l o [EOF] ^ ^ / / tail eol result: found = 0, tail += 5, *nr += 5 Instead, allow the scan to peek ahead 1 byte (while still limiting the scan to completed lines in the input buffer). For the example above, result: found = 1, tail += 6, *nr += 5 Because the scan limit is now bumped +1 byte, when the scan is completed, the tail advance and the user buffer copy limit is re-clamped to *nr when EOF is _not_ found. Fixes: 40d5e0905a03 ("n_tty: Fix EOF push handling") Signed-off-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman

serial/aspeed-vuart: Perform enable/disable on driver bind/unbind

2016-02-12T04:38:57+00:00

Rather than exposing an enable sysfs attribute, we can just set the VUART enabled bit when we bind to the device, and clear it on unbind. We don't want to do this on open/release, as the host may be using this bit to configure serial output modes, which is independent of whether the devices has been opened by BMC userspace. Signed-off-by: Jeremy Kerr Signed-off-by: Joel Stanley

serial/aspeed-vuart: Only disable host tx discard when serial port is in use

2016-02-12T04:15:21+00:00

OpenPOWER firmware doesn't like it when the host-side of the VUART's FIFO is not drained. This change only disables host TX discard mode when the port has been opened. Signed-off-by: Jeremy Kerr Tested-by: Norman James Signed-off-by: Joel Stanley

serial/aspeed-vuart: Fix typo

2016-02-10T06:22:03+00:00

Signed-off-by: Joel Stanley

serial/aspeed-vuart: Disable host TX discard mode during init

2016-02-10T06:20:56+00:00

If host TX discard mode is enabled, we don't see the LSR[RBR} bit getting set on new characters written on the host side. This makes the VUART a little useless. This change set this bit during VUART initialisation, to disable host TX discard. Signed-off-by: Jeremy Kerr Signed-off-by: Joel Stanley