From 66c53aaa9c82766d4e9253748c6988441d8c2dc1 Mon Sep 17 00:00:00 2001 From: Peter Hurley Date: Thu, 7 May 2015 14:19:21 -0400 Subject: earlycon: Revert log warnings Log warnings meant to help diagnose problems setting up earlycon are reporting false positives for 'console='. Revert to the previous behavior which reported nothing. Cc: Maciej W. Rozycki Cc: Robert Schwebel Signed-off-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/earlycon.c | 9 ++------- 1 file changed, 2 insertions(+), 7 deletions(-) diff --git a/drivers/tty/serial/earlycon.c b/drivers/tty/serial/earlycon.c index 5fdc9f3ecd64..6dc471e30e79 100644 --- a/drivers/tty/serial/earlycon.c +++ b/drivers/tty/serial/earlycon.c @@ -187,13 +187,8 @@ static int __init param_setup_earlycon(char *buf) return 0; err = setup_earlycon(buf); - if (err == -ENOENT) { - pr_warn("no match for %s\n", buf); - err = 0; - } else if (err == -EALREADY) { - pr_warn("already registered\n"); - err = 0; - } + if (err == -ENOENT || err == -EALREADY) + return 0; return err; } early_param("earlycon", param_setup_earlycon); -- cgit v1.2.3 From 66cf1d8473780fcb1a90e86fd19ba276520deb14 Mon Sep 17 00:00:00 2001 From: Semen Protsenko Date: Thu, 30 Apr 2015 18:35:27 +0300 Subject: serial: omap: Fix error handling in probe There is pm_qos_add_request() being executed on serial_omap_probe(), which stores "&up->pm_qos_request" from omap-serial driver to "pm_qos_array[PM_QOS_CPU_DMA_LATENCY]->constraints". If serial_omap_probe() fails after pm_qos_add_request() (e.g. on uart_add_one_port() call), pm_qos_array still keeping pm_qos_request struct from omap-serial driver, which is not valid anymore (since driver failed). This leads further to kernel crash on pm_qos_update_target(), executing from some completely different driver. We were observing this while trying to run audio playback while having one of omap-serial driver instances failed on uart_add_one_port() call: Unable to handle kernel paging request at virtual address fffffffc Backtrace: (plist_add) from (pm_qos_update_target) (pm_qos_update_target) from (pm_qos_add_request) (pm_qos_add_request) from (snd_pcm_hw_params) (snd_pcm_hw_params) from (snd_pcm_common_ioctl1) (snd_pcm_common_ioctl1) from (snd_pcm_playback_ioctl1) (snd_pcm_playback_ioctl1) from (snd_pcm_playback_ioctl) (snd_pcm_playback_ioctl) from (do_vfs_ioctl) (do_vfs_ioctl) from (SyS_ioctl) (SyS_ioctl) from (ret_fast_syscall) This patch adds pm_qos_remove_request() on fail path in serial_omap_probe() in order to fix this issue. While at it, free the wakeup settings on fail path as well, just like it's done in serial_omap_remove(). Signed-off-by: Semen Protsenko Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/omap-serial.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/tty/serial/omap-serial.c b/drivers/tty/serial/omap-serial.c index 211479aa34bb..7f49172ccd86 100644 --- a/drivers/tty/serial/omap-serial.c +++ b/drivers/tty/serial/omap-serial.c @@ -1735,6 +1735,8 @@ static int serial_omap_probe(struct platform_device *pdev) err_add_port: pm_runtime_put(&pdev->dev); pm_runtime_disable(&pdev->dev); + pm_qos_remove_request(&up->pm_qos_request); + device_init_wakeup(up->dev, false); err_rs485: err_port_line: return ret; -- cgit v1.2.3 From ec61847855094d6f6144340b26f14203f25dd4e9 Mon Sep 17 00:00:00 2001 From: Dave Martin Date: Fri, 8 May 2015 14:07:50 +0100 Subject: Revert "serial/amba-pl011: Leave the TX IRQ alone when the UART is not open" MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit This reverts commit f2ee6dfa0e8597eea8b98d240b0033994e20d215. Jakub Kiciński observed that this patch can cause the pl011 driver to hang if if the only process with a pl011 port open is killed by a signal, pl011_shutdown() can get called with an arbitrary amount of data still in the FIFO. Calling _shutdown() with the TX FIFO non-empty is questionable behaviour and my itself be a bug. Since the affected patch was speculative anyway, and brings limited benefit, the simplest course is to remove the assumption that TXIS will always be left asserted after the port is shut down. Signed-off-by: Dave Martin Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/amba-pl011.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c index 5a4e9d579585..6f5a0720a8c8 100644 --- a/drivers/tty/serial/amba-pl011.c +++ b/drivers/tty/serial/amba-pl011.c @@ -1639,6 +1639,9 @@ static int pl011_startup(struct uart_port *port) writew(uap->vendor->ifls, uap->port.membase + UART011_IFLS); + /* Assume that TX IRQ doesn't work until we see one: */ + uap->tx_irq_seen = 0; + spin_lock_irq(&uap->port.lock); /* restore RTS and DTR */ @@ -1702,7 +1705,7 @@ static void pl011_shutdown(struct uart_port *port) spin_lock_irq(&uap->port.lock); uap->im = 0; writew(uap->im, uap->port.membase + UART011_IMSC); - writew(0xffff & ~UART011_TXIS, uap->port.membase + UART011_ICR); + writew(0xffff, uap->port.membase + UART011_ICR); spin_unlock_irq(&uap->port.lock); pl011_dma_shutdown(uap); -- cgit v1.2.3 From 8f9cfeed3eae86c70d3b04445a6f2036b27b6304 Mon Sep 17 00:00:00 2001 From: Pan Xinhui Date: Sat, 28 Mar 2015 10:42:56 +0800 Subject: tty/n_gsm.c: fix a memory leak when gsmtty is removed when gsmtty_remove put dlci, it will cause memory leak if dlci->port's refcount is zero. So we do the cleanup work in .cleanup callback instead. dlci will be last put in two call chains. 1) gsmld_close -> gsm_cleanup_mux -> gsm_dlci_release -> dlci_put 2) gsmld_remove -> dlci_put so there is a race. the memory leak depends on the race. In call chain 2. we hit the memory leak. below comment tells. release_tty -> tty_driver_remove_tty -> gsmtty_remove -> dlci_put -> tty_port_destructor (WARN_ON(port->itty) and return directly) | tty->port->itty = NULL; | tty_kref_put ---> release_one_tty -> gsmtty_cleanup (added by our patch) So our patch fix the memory leak by doing the cleanup work after tty core did. Signed-off-by: Pan Xinhui Fixes: dfabf7ffa30585 Cc: stable # 3.14+ Acked-by: Jiri Slaby Signed-off-by: Greg Kroah-Hartman --- drivers/tty/n_gsm.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c index 91abc00aa833..2c34c3249972 100644 --- a/drivers/tty/n_gsm.c +++ b/drivers/tty/n_gsm.c @@ -3170,7 +3170,7 @@ static int gsmtty_break_ctl(struct tty_struct *tty, int state) return gsmtty_modem_update(dlci, encode); } -static void gsmtty_remove(struct tty_driver *driver, struct tty_struct *tty) +static void gsmtty_cleanup(struct tty_struct *tty) { struct gsm_dlci *dlci = tty->driver_data; struct gsm_mux *gsm = dlci->gsm; @@ -3178,7 +3178,6 @@ static void gsmtty_remove(struct tty_driver *driver, struct tty_struct *tty) dlci_put(dlci); dlci_put(gsm->dlci[0]); mux_put(gsm); - driver->ttys[tty->index] = NULL; } /* Virtual ttys for the demux */ @@ -3199,7 +3198,7 @@ static const struct tty_operations gsmtty_ops = { .tiocmget = gsmtty_tiocmget, .tiocmset = gsmtty_tiocmset, .break_ctl = gsmtty_break_ctl, - .remove = gsmtty_remove, + .cleanup = gsmtty_cleanup, }; -- cgit v1.2.3 From 1a48632ffed61352a7810ce089dc5a8bcd505a60 Mon Sep 17 00:00:00 2001 From: Peter Hurley Date: Mon, 13 Apr 2015 13:24:34 -0400 Subject: pty: Fix input race when closing A read() from a pty master may mistakenly indicate EOF (errno == -EIO) after the pty slave has closed, even though input data remains to be read. For example, pty slave | input worker | pty master | | | | n_tty_read() pty_write() | | input avail? no add data | | sleep schedule worker --->| | . |---> flush_to_ldisc() | . pty_close() | fill read buffer | . wait for worker | wakeup reader --->| . | read buffer full? |---> input avail ? yes |<--- yes - exit worker | copy 4096 bytes to user TTY_OTHER_CLOSED <---| |<--- kick worker | | **** New read() before worker starts **** | | n_tty_read() | | input avail? no | | TTY_OTHER_CLOSED? yes | | return -EIO Several conditions are required to trigger this race: 1. the ldisc read buffer must become full so the input worker exits 2. the read() count parameter must be >= 4096 so the ldisc read buffer is empty 3. the subsequent read() occurs before the kicked worker has processed more input However, the underlying cause of the race is that data is pipelined, while tty state is not; ie., data already written by the pty slave end is not yet visible to the pty master end, but state changes by the pty slave end are visible to the pty master end immediately. Pipeline the TTY_OTHER_CLOSED state through input worker to the reader. 1. Introduce TTY_OTHER_DONE which is set by the input worker when TTY_OTHER_CLOSED is set and either the input buffers are flushed or input processing has completed. Readers/polls are woken when TTY_OTHER_DONE is set. 2. Reader/poll checks TTY_OTHER_DONE instead of TTY_OTHER_CLOSED. 3. A new input worker is started from pty_close() after setting TTY_OTHER_CLOSED, which ensures the TTY_OTHER_DONE state will be set if the last input worker is already finished (or just about to exit). Remove tty_flush_to_ldisc(); no in-tree callers. Fixes: 52bce7f8d4fc ("pty, n_tty: Simplify input processing on final close") Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=96311 BugLink: http://bugs.launchpad.net/bugs/1429756 Cc: # 3.19+ Reported-by: Andy Whitcroft Reported-by: H.J. Lu Signed-off-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman --- Documentation/serial/tty.txt | 3 +++ drivers/tty/n_hdlc.c | 4 ++-- drivers/tty/n_tty.c | 22 ++++++++++++++++++---- drivers/tty/pty.c | 5 +++-- drivers/tty/tty_buffer.c | 41 +++++++++++++++++++++++++++-------------- include/linux/tty.h | 2 +- 6 files changed, 54 insertions(+), 23 deletions(-) diff --git a/Documentation/serial/tty.txt b/Documentation/serial/tty.txt index 1e52d67d0abf..dbe6623fed1c 100644 --- a/Documentation/serial/tty.txt +++ b/Documentation/serial/tty.txt @@ -198,6 +198,9 @@ TTY_IO_ERROR If set, causes all subsequent userspace read/write TTY_OTHER_CLOSED Device is a pty and the other side has closed. +TTY_OTHER_DONE Device is a pty and the other side has closed and + all pending input processing has been completed. + TTY_NO_WRITE_SPLIT Prevent driver from splitting up writes into smaller chunks. diff --git a/drivers/tty/n_hdlc.c b/drivers/tty/n_hdlc.c index 644ddb841d9f..bbc4ce66c2c1 100644 --- a/drivers/tty/n_hdlc.c +++ b/drivers/tty/n_hdlc.c @@ -600,7 +600,7 @@ static ssize_t n_hdlc_tty_read(struct tty_struct *tty, struct file *file, add_wait_queue(&tty->read_wait, &wait); for (;;) { - if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) { + if (test_bit(TTY_OTHER_DONE, &tty->flags)) { ret = -EIO; break; } @@ -828,7 +828,7 @@ static unsigned int n_hdlc_tty_poll(struct tty_struct *tty, struct file *filp, /* set bits for operations that won't block */ if (n_hdlc->rx_buf_list.head) mask |= POLLIN | POLLRDNORM; /* readable */ - if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) + if (test_bit(TTY_OTHER_DONE, &tty->flags)) mask |= POLLHUP; if (tty_hung_up_p(filp)) mask |= POLLHUP; diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c index cf6e0f2e1331..cc57a3a6b02b 100644 --- a/drivers/tty/n_tty.c +++ b/drivers/tty/n_tty.c @@ -1949,6 +1949,18 @@ static inline int input_available_p(struct tty_struct *tty, int poll) return ldata->commit_head - ldata->read_tail >= amt; } +static inline int check_other_done(struct tty_struct *tty) +{ + int done = test_bit(TTY_OTHER_DONE, &tty->flags); + if (done) { + /* paired with cmpxchg() in check_other_closed(); ensures + * read buffer head index is not stale + */ + smp_mb__after_atomic(); + } + return done; +} + /** * copy_from_read_buf - copy read data directly * @tty: terminal device @@ -2167,7 +2179,7 @@ static ssize_t n_tty_read(struct tty_struct *tty, struct file *file, struct n_tty_data *ldata = tty->disc_data; unsigned char __user *b = buf; DEFINE_WAIT_FUNC(wait, woken_wake_function); - int c; + int c, done; int minimum, time; ssize_t retval = 0; long timeout; @@ -2235,8 +2247,10 @@ static ssize_t n_tty_read(struct tty_struct *tty, struct file *file, ((minimum - (b - buf)) >= 1)) ldata->minimum_to_wake = (minimum - (b - buf)); + done = check_other_done(tty); + if (!input_available_p(tty, 0)) { - if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) { + if (done) { retval = -EIO; break; } @@ -2443,12 +2457,12 @@ static unsigned int n_tty_poll(struct tty_struct *tty, struct file *file, poll_wait(file, &tty->read_wait, wait); poll_wait(file, &tty->write_wait, wait); + if (check_other_done(tty)) + mask |= POLLHUP; if (input_available_p(tty, 1)) mask |= POLLIN | POLLRDNORM; if (tty->packet && tty->link->ctrl_status) mask |= POLLPRI | POLLIN | POLLRDNORM; - if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) - mask |= POLLHUP; if (tty_hung_up_p(file)) mask |= POLLHUP; if (!(mask & (POLLHUP | POLLIN | POLLRDNORM))) { diff --git a/drivers/tty/pty.c b/drivers/tty/pty.c index e72ee629cead..4d5e8409769c 100644 --- a/drivers/tty/pty.c +++ b/drivers/tty/pty.c @@ -53,9 +53,8 @@ static void pty_close(struct tty_struct *tty, struct file *filp) /* Review - krefs on tty_link ?? */ if (!tty->link) return; - tty_flush_to_ldisc(tty->link); set_bit(TTY_OTHER_CLOSED, &tty->link->flags); - wake_up_interruptible(&tty->link->read_wait); + tty_flip_buffer_push(tty->link->port); wake_up_interruptible(&tty->link->write_wait); if (tty->driver->subtype == PTY_TYPE_MASTER) { set_bit(TTY_OTHER_CLOSED, &tty->flags); @@ -243,7 +242,9 @@ static int pty_open(struct tty_struct *tty, struct file *filp) goto out; clear_bit(TTY_IO_ERROR, &tty->flags); + /* TTY_OTHER_CLOSED must be cleared before TTY_OTHER_DONE */ clear_bit(TTY_OTHER_CLOSED, &tty->link->flags); + clear_bit(TTY_OTHER_DONE, &tty->link->flags); set_bit(TTY_THROTTLED, &tty->flags); return 0; diff --git a/drivers/tty/tty_buffer.c b/drivers/tty/tty_buffer.c index 75661641f5fe..2f78b77f0f81 100644 --- a/drivers/tty/tty_buffer.c +++ b/drivers/tty/tty_buffer.c @@ -37,6 +37,28 @@ #define TTY_BUFFER_PAGE (((PAGE_SIZE - sizeof(struct tty_buffer)) / 2) & ~0xFF) +/* + * If all tty flip buffers have been processed by flush_to_ldisc() or + * dropped by tty_buffer_flush(), check if the linked pty has been closed. + * If so, wake the reader/poll to process + */ +static inline void check_other_closed(struct tty_struct *tty) +{ + unsigned long flags, old; + + /* transition from TTY_OTHER_CLOSED => TTY_OTHER_DONE must be atomic */ + for (flags = ACCESS_ONCE(tty->flags); + test_bit(TTY_OTHER_CLOSED, &flags); + ) { + old = flags; + __set_bit(TTY_OTHER_DONE, &flags); + flags = cmpxchg(&tty->flags, old, flags); + if (old == flags) { + wake_up_interruptible(&tty->read_wait); + break; + } + } +} /** * tty_buffer_lock_exclusive - gain exclusive access to buffer @@ -229,6 +251,8 @@ void tty_buffer_flush(struct tty_struct *tty, struct tty_ldisc *ld) if (ld && ld->ops->flush_buffer) ld->ops->flush_buffer(tty); + check_other_closed(tty); + atomic_dec(&buf->priority); mutex_unlock(&buf->lock); } @@ -471,8 +495,10 @@ static void flush_to_ldisc(struct work_struct *work) smp_rmb(); count = head->commit - head->read; if (!count) { - if (next == NULL) + if (next == NULL) { + check_other_closed(tty); break; + } buf->head = next; tty_buffer_free(port, head); continue; @@ -488,19 +514,6 @@ static void flush_to_ldisc(struct work_struct *work) tty_ldisc_deref(disc); } -/** - * tty_flush_to_ldisc - * @tty: tty to push - * - * Push the terminal flip buffers to the line discipline. - * - * Must not be called from IRQ context. - */ -void tty_flush_to_ldisc(struct tty_struct *tty) -{ - flush_work(&tty->port->buf.work); -} - /** * tty_flip_buffer_push - terminal * @port: tty port to push diff --git a/include/linux/tty.h b/include/linux/tty.h index fe5623c9af71..d76631f615c2 100644 --- a/include/linux/tty.h +++ b/include/linux/tty.h @@ -339,6 +339,7 @@ struct tty_file_private { #define TTY_EXCLUSIVE 3 /* Exclusive open mode */ #define TTY_DEBUG 4 /* Debugging */ #define TTY_DO_WRITE_WAKEUP 5 /* Call write_wakeup after queuing new */ +#define TTY_OTHER_DONE 6 /* Closed pty has completed input processing */ #define TTY_LDISC_OPEN 11 /* Line discipline is open */ #define TTY_PTY_LOCK 16 /* pty private */ #define TTY_NO_WRITE_SPLIT 17 /* Preserve write boundaries to driver */ @@ -462,7 +463,6 @@ extern int tty_hung_up_p(struct file *filp); extern void do_SAK(struct tty_struct *tty); extern void __do_SAK(struct tty_struct *tty); extern void no_tty(void); -extern void tty_flush_to_ldisc(struct tty_struct *tty); extern void tty_buffer_free_all(struct tty_port *port); extern void tty_buffer_flush(struct tty_struct *tty, struct tty_ldisc *ld); extern void tty_buffer_init(struct tty_port *port); -- cgit v1.2.3