- 18 Mar, 2013 40 commits
-
-
Peter Hurley authored
Signed-off-by:
Peter Hurley <peter@hurleysoftware.com> Signed-off-by:
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-
Peter Hurley authored
Now that tty_ldisc_assign() is a one-line file-scoped function, remove it and perform the simple assignment at its call sites. Signed-off-by:
-
Peter Hurley authored
Merge get_ldisc() into its only call site. Note how, after merging, the unsafe acquire of an ldisc reference is obvious. CPU 0 in tty_ldisc_try() | CPU 1 in tty_ldisc_halt() | test_bit(TTY_LDISC, &tty_flags) | if (true) | clear_bit(TTY_LDISC, &tty_flags) tty->ldisc != 0? | atomic_read(&tty->ldisc->users) if (true) | ret_val == 1? atomic_inc(&tty->ldisc->users) | if (false) | wait | <goes on assuming safe ldisc use> | <doesn't wait - proceeds w/ close> | The spin lock in tty_ldisc_try() does nothing wrt synchronizing the ldisc halt since it's not acquired as part of halting. Signed-off-by: -
Peter Hurley authored
tty_ldisc_ref()/tty_ldisc_unref() have usage semantics equivalent to down_read_trylock()/up_read(). Only callers of tty_ldisc_put() are performing the additional operations necessary for proper ldisc teardown, and then only after ensuring no outstanding 'read lock' remains. Thus, tty_ldisc_unref() should never be the last reference; WARN if it is. Conversely, tty_ldisc_put() should never be destructing if the use count != 1. Signed-off-by:
-
Peter Hurley authored
test_bit() is already atomic; drop mutex lock/unlock. Signed-off-by:
-
Peter Hurley authored
Expected typical debug log: [ 582.721965] tty_open: opening pts3... [ 582.721970] tty_open: opening pts3... [ 582.721977] tty_release: pts3 (tty count=3)... [ 582.721980] tty_release: ptm3 (tty count=1)... [ 582.722015] pts3 vhangup... [ 582.722020] tty_ldisc_hangup: pts3: closing ldisc: ffff88007a920540 [ 582.724128] tty_release: pts3 (tty count=2)... [ 582.724217] tty_ldisc_hangup: pts3: re-opened ldisc: ffff88007a920580 [ 582.724221] tty_release: ptm3: final close [ 582.724234] tty_ldisc_release: ptm3: closing ldisc: ffff88007a920a80 [ 582.724238] tty_ldisc_release: ptm3: ldisc closed [ 582.724241] tty_release: ptm3: freeing structure... [ 582.724741] tty_open: opening pts3... Signed-off-by:
-
Peter Hurley authored
Expected typical log output: [ 2.437211] tty_open: opening pts1... [ 2.443376] tty_open: opening pts5... [ 2.447830] tty_release: ptm0 (tty count=1)... [ 2.447849] pts0 vhangup... [ 2.447865] tty_release: ptm0: final close [ 2.447876] tty_release: ptm0: freeing structure... [ 2.451634] tty_release: tty1 (tty count=1)... [ 2.451638] tty_release: tty1: final close [ 2.451654] tty_release: tty1: freeing structure... [ 2.452505] tty_release: pts5 (tty count=2)... [ 2.453029] tty_open: opening pts0... Signed-off-by:
-
Peter Hurley authored
This comment is a victim of code migration from "tty: Fix the ldisc hangup race"; re-parent it. Signed-off-by:
-
Peter Hurley authored
The tty core relies on the ldisc layer for synchronizing destruction of the tty. Instead, the final tty release must wait for any pending tty work to complete prior to tty destruction. Signed-off-by:
-
Peter Hurley authored
Waiting for buffer work to complete is not required for safely performing changes to the line discipline, once the line discipline is halted. The buffer work routine, flush_to_ldisc(), will be unable to acquire an ldisc ref and all existing references were waited until released (so it can't already have one). Ensure running buffer work which may reference the soon-to-be-gone tty completes and any buffer work running after this point retrieves a NULL tty. Also, ensure all buffer work is cancelled on port destruction. Signed-off-by:
-
Peter Hurley authored
tty_ldisc_hangup() guarantees the ldisc is enabled (or that there is no ldisc). Since __tty_hangup() was the only user, re-define tty_ldisc_enable() in file-scope. Signed-off-by:
-
Peter Hurley authored
Buffer work may already be pending when the n_tty ldisc is re-opened, eg., when setting the ldisc (via TIOCSETD ioctl) and when hanging up the tty. Since n_tty_set_room() may restart buffer work, first ensure the ldisc is completely initialized. Factor n_tty_set_room() out of reset_buffer_flags() (only 2 callers) and reorganize n_tty_open() to set termios last; buffer work will be restarted there if necessary, after the char_map is properly initialized. Fixes this WARNING: [ 549.561769] ------------[ cut here ]------------ [ 549.598755] WARNING: at drivers/tty/n_tty.c:160 n_tty_set_room+0xff/0x130() [ 549.604058] scheduling buffer work for halted ldisc [ 549.607741] Pid: 9417, comm: trinity-child28 Tainted: G D W 3.7.0-next-20121217-sasha-00023-g8689ef9 #219 [ 549.652580] Call Trace: [ 549.662754] [<ffffffff81c432cf>] ? n_tty_set_room+0xff/0x130 [ 549.665458] [<ffffffff8110cae7>] warn_slowpath_common+0x87/0xb0 [ 549.668257] [<ffffffff8110cb71>] warn_slowpath_fmt+0x41/0x50 [ 549.671007] [<ffffffff81c432cf>] n_tty_set_room+0xff/0x130 [ 549.673268] [<ffffffff81c44597>] reset_buffer_flags+0x137/0x150 [ 549.675607] [<ffffffff81c45b71>] n_tty_open+0x131/0x1c0 [ 549.677699] [<ffffffff81c47824>] tty_ldisc_open.isra.5+0x54/0x70 [ 549.680147] [<ffffffff81c482bf>] tty_ldisc_hangup+0x11f/0x1e0 [ 549.682409] [<ffffffff81c3fa17>] __tty_hangup+0x137/0x440 [ 549.684634] [<ffffffff81c3fd49>] tty_vhangup+0x9/0x10 [ 549.686443] [<ffffffff81c4a42c>] pty_close+0x14c/0x160 [ 549.688446] [<ffffffff81c41225>] tty_release+0xd5/0x490 [ 549.690460] [<ffffffff8127d8a2>] __fput+0x122/0x250 [ 549.692577] [<ffffffff8127d9d9>] ____fput+0x9/0x10 [ 549.694534] [<ffffffff811348c2>] task_work_run+0xb2/0xf0 [ 549.696349] [<ffffffff81113c6d>] do_exit+0x36d/0x580 [ 549.698286] [<ffffffff8107d964>] ? syscall_trace_enter+0x24/0x2e0 [ 549.702729] [<ffffffff81113f4a>] do_group_exit+0x8a/0xc0 [ 549.706775] [<ffffffff81113f92>] sys_exit_group+0x12/0x20 [ 549.711088] [<ffffffff83cfab18>] tracesys+0xe1/0xe6 [ 549.728001] ---[ end trace 73eb41728f11f87e ]--- Reported-by:
Sasha Levin <levinsasha928@gmail.com> Signed-off-by:
-
Peter Hurley authored
The driver is no longer unthrottled on buffer reset, so remove comments that claim it is. Signed-off-by:
-
Peter Hurley authored
SAK work may schedule hangup work (if TTY_SOFT_SAK is defined), thus SAK work must be flushed before hangup work. Signed-off-by:
-
Peter Hurley authored
The pty driver does not obtain an ldisc reference to the linked tty when writing. When the ldiscs are sequentially halted, it is possible for one ldisc to be halted, and before the second ldisc can be halted, a concurrent write schedules buffer work on the first ldisc. This can lead to an access-after-free error when the scheduled buffer work starts on the closed ldisc. Prevent subsequent use after halt by performing each stage of the halt on both ttys. Signed-off-by:
-
Peter Hurley authored
In preparation for destructing and freeing the tty, the line discipline must first be brought to an inactive state before it can be destructed. This line discipline shutdown must: - disallow new users of the ldisc - wait for existing ldisc users to finish - only then, cancel/flush their pending/running work Factor tty_ldisc_wait_idle() from tty_set_ldisc() and tty_ldisc_kill() to ensure this shutdown order. Failure to provide this guarantee can result in scheduled work running after the tty has already been freed, as indicated in the following log message: [ 88.331234] WARNING: at drivers/tty/tty_buffer.c:435 flush_to_ldisc+0x194/0x1d0() [ 88.334505] Hardware name: Bochs [ 88.335618] tty is bad=-1 [ 88.335703] Modules linked in: netconsole configfs bnep rfcomm bluetooth ...... [ 88.345272] Pid: 39, comm: kworker/1:1 Tainted: G W 3.7.0-next-20121129+ttydebug-xeon #20121129+ttydebug [ 88.347736] Call Trace: [ 88.349024] [<ffffffff81058aff>] warn_slowpath_common+0x7f/0xc0 [ 88.350383] [<ffffffff81058bf6>] warn_slowpath_fmt+0x46/0x50 [ 88.351745] [<ffffffff81432bd4>] flush_to_ldisc+0x194/0x1d0 [ 88.353047] [<ffffffff816f7fe1>] ? _raw_spin_unlock_irq+0x21/0x50 [ 88.354190] [<ffffffff8108a809>] ? finish_task_switch+0x49/0xe0 [ 88.355436] [<ffffffff81077ad1>] process_one_work+0x121/0x490 [ 88.357674] [<ffffffff81432a40>] ? __tty_buffer_flush+0x90/0x90 [ 88.358954] [<ffffffff81078c84>] worker_thread+0x164/0x3e0 [ 88.360247] [<ffffffff81078b20>] ? manage_workers+0x120/0x120 [ 88.361282] [<ffffffff8107e230>] kthread+0xc0/0xd0 [ 88.362284] [<ffffffff816f0000>] ? cmos_do_probe+0x2eb/0x3bf [ 88.363391] [<ffffffff8107e170>] ? flush_kthread_worker+0xb0/0xb0 [ 88.364797] [<ffffffff816fff6c>] ret_from_fork+0x7c/0xb0 [ 88.366087] [<ffffffff8107e170>] ? flush_kthread_worker+0xb0/0xb0 [ 88.367266] ---[ end trace 453a7c9f38fbfec0 ]--- Signed-off-by:
-
Peter Hurley authored
tty_ldisc_halt() will use the file-scoped function, tty_ldisc_wait_idle(), in the following patch. Signed-off-by:
-
Peter Hurley authored
Flip buffer work cannot be cancelled until all outstanding ldisc references have been released. Convert the ldisc ref wait into a full ldisc halt with buffer work cancellation. Note that the legacy mutex is not held while cancelling. Signed-off-by:
-
Peter Hurley authored
Since the tty->ldisc is prevented from being changed by tty_set_ldisc() when a tty is being hung up, re-testing the ldisc user count is unnecessary -- ie, it cannot be a different ldisc and the user count cannot have increased (assuming the caller meets the precondition that TTY_LDISC flag is cleared) Removal of the 'early-out' locking optimization is necessary for the subsequent patch 'tty: Fix ldisc halt sequence on hangup'. Signed-off-by:
-
Peter Hurley authored
Refactor tty_ldisc_hangup() to extract standalone function, tty_ldisc_hangup_wait_idle(), to wait for ldisc references to be released. Signed-off-by:
-
Peter Hurley authored
A buffer flush is both undesirable and unnecessary when the ldisc is closing. A buffer flush performs the following: 1. resets ldisc data fields to their initial state 2. resets tty->receive_room to indicate more data can be sent 3. schedules buffer work to receive more data 4. signals a buffer flush has happened to linked pty in packet mode Since the ldisc has been halted and the tty may soon be destructed, buffer work must not be scheduled as that work might access an invalid tty and ldisc state. Also, the ldisc read buffer is about to be freed, so that's pointless. Resetting the ldisc data fields is pointless as well since that structure is about to be freed. Resetting tty->receive_room is unnecessary, as it will be properly reset if a new ldisc is reopened. Besides, resetting the original receive_room value would be wrong since the read buffer will be gone. Since the packet mode flush is observable from userspace, this behavior has been preserved. The test jig originally authored by Ilya Zykov <ilya@ilyx.ru> and signed off by him is included below. The test jig prompts the following warnings which this patch fixes. [ 38.051111] ------------[ cut here ]------------ [ 38.052113] WARNING: at drivers/tty/n_tty.c:160 n_tty_set_room.part.6+0x8b/0xa0() [ 38.053916] Hardware name: Bochs [ 38.054819] Modules linked in: netconsole configfs bnep rfcomm bluetooth parport_pc ppdev snd_hda_intel snd_hda_codec snd_hwdep snd_pcm snd_seq_midi snd_rawmidi snd_seq_midi_event snd_seq psmouse snd_timer serio_raw mac_hid snd_seq_device snd microcode lp parport virtio_balloon soundcore i2c_piix4 snd_page_alloc floppy 8139too 8139cp [ 38.059704] Pid: 1564, comm: pty_kill Tainted: G W 3.7.0-next-20121130+ttydebug-xeon #20121130+ttydebug [ 38.061578] Call Trace: [ 38.062491] [<ffffffff81058b4f>] warn_slowpath_common+0x7f/0xc0 [ 38.063448] [<ffffffff81058baa>] warn_slowpath_null+0x1a/0x20 [ 38.064439] [<ffffffff8142dc2b>] n_tty_set_room.part.6+0x8b/0xa0 [ 38.065381] [<ffffffff8142dc82>] n_tty_set_room+0x42/0x80 [ 38.066323] [<ffffffff8142e6f2>] reset_buffer_flags+0x102/0x160 [ 38.077508] [<ffffffff8142e76d>] n_tty_flush_buffer+0x1d/0x90 [ 38.078782] [<ffffffff81046569>] ? default_spin_lock_flags+0x9/0x10 [ 38.079734] [<ffffffff8142e804>] n_tty_close+0x24/0x60 [ 38.080730] [<ffffffff81431b61>] tty_ldisc_close.isra.2+0x41/0x60 [ 38.081680] [<ffffffff81431bbb>] tty_ldisc_kill+0x3b/0x80 [ 38.082618] [<ffffffff81432a07>] tty_ldisc_release+0x77/0xe0 [ 38.083549] [<ffffffff8142b781>] tty_release+0x451/0x4d0 [ 38.084525] [<ffffffff811950be>] __fput+0xae/0x230 [ 38.085472] [<ffffffff8119524e>] ____fput+0xe/0x10 [ 38.086401] [<ffffffff8107aa88>] task_work_run+0xc8/0xf0 [ 38.087334] [<ffffffff8105ea56>] do_exit+0x196/0x4b0 [ 38.088304] [<ffffffff8106c77b>] ? __dequeue_signal+0x6b/0xb0 [ 38.089240] [<ffffffff8105ef34>] do_group_exit+0x44/0xa0 [ 38.090182] [<ffffffff8106f43d>] get_signal_to_deliver+0x20d/0x4e0 [ 38.091125] [<ffffffff81016979>] do_signal+0x29/0x130 [ 38.092096] [<ffffffff81431a9e>] ? tty_ldisc_deref+0xe/0x10 [ 38.093030] [<ffffffff8142a317>] ? tty_write+0xb7/0xf0 [ 38.093976] [<ffffffff81193f53>] ? vfs_write+0xb3/0x180 [ 38.094904] [<ffffffff81016b20>] do_notify_resume+0x80/0xc0 [ 38.095830] [<ffffffff81700492>] int_signal+0x12/0x17 [ 38.096788] ---[ end trace 5f6f7a9651cd999b ]--- [ 2730.570602] ------------[ cut here ]------------ [ 2730.572130] WARNING: at drivers/tty/n_tty.c:160 n_tty_set_room+0x107/0x140() [ 2730.574904] scheduling buffer work for halted ldisc [ 2730.578303] Pid: 9691, comm: trinity-child15 Tainted: G W 3.7.0-rc8-next-20121205-sasha-00023-g59f0d85 #207 [ 2730.588694] Call Trace: [ 2730.590486] [<ffffffff81c41d77>] ? n_tty_set_room+0x107/0x140 [ 2730.592559] [<ffffffff8110c827>] warn_slowpath_common+0x87/0xb0 [ 2730.595317] [<ffffffff8110c8b1>] warn_slowpath_fmt+0x41/0x50 [ 2730.599186] [<ffffffff81c41d77>] n_tty_set_room+0x107/0x140 [ 2730.603141] [<ffffffff81c42fe7>] reset_buffer_flags+0x137/0x150 [ 2730.607166] [<ffffffff81c43018>] n_tty_flush_buffer+0x18/0x90 [ 2730.610123] [<ffffffff81c430af>] n_tty_close+0x1f/0x60 [ 2730.612068] [<ffffffff81c461f2>] tty_ldisc_close.isra.4+0x52/0x60 [ 2730.614078] [<ffffffff81c462ab>] tty_ldisc_reinit+0x3b/0x70 [ 2730.615891] [<ffffffff81c46db2>] tty_ldisc_hangup+0x102/0x1e0 [ 2730.617780] [<ffffffff81c3e537>] __tty_hangup+0x137/0x440 [ 2730.619547] [<ffffffff81c3e869>] tty_vhangup+0x9/0x10 [ 2730.621266] [<ffffffff81c48f1c>] pty_close+0x14c/0x160 [ 2730.622952] [<ffffffff81c3fd45>] tty_release+0xd5/0x490 [ 2730.624674] [<ffffffff8127fbe2>] __fput+0x122/0x250 [ 2730.626195] [<ffffffff8127fd19>] ____fput+0x9/0x10 [ 2730.627758] [<ffffffff81134602>] task_work_run+0xb2/0xf0 [ 2730.629491] [<ffffffff811139ad>] do_exit+0x36d/0x580 [ 2730.631159] [<ffffffff81113c8a>] do_group_exit+0x8a/0xc0 [ 2730.632819] [<ffffffff81127351>] get_signal_to_deliver+0x501/0x5b0 [ 2730.634758] [<ffffffff8106de34>] do_signal+0x24/0x100 [ 2730.636412] [<ffffffff81204865>] ? user_exit+0xa5/0xd0 [ 2730.638078] [<ffffffff81183cd8>] ? trace_hardirqs_on_caller+0x118/0x140 [ 2730.640279] [<ffffffff81183d0d>] ? trace_hardirqs_on+0xd/0x10 [ 2730.642164] [<ffffffff8106df78>] do_notify_resume+0x48/0xa0 [ 2730.643966] [<ffffffff83cdff6a>] int_signal+0x12/0x17 [ 2730.645672] ---[ end trace a40d53149c07fce0 ]--- /* * pty_thrash.c * * Based on original test jig by Ilya Zykov <ilya@ilyx.ru> * * Signed-off-by: Peter Hurley <peter@hurleysoftware.com> * Signed-off-by: Ilya Zykov <ilya@ilyx.ru> */ static int fd; static void error_exit(char *f, ...) { va_list va; va_start(va, f); vprintf(f, va); printf(": %s\n", strerror(errno)); va_end(va); if (fd >= 0) close(fd); exit(EXIT_FAILURE); } int main(int argc, char *argv[]) { int parent; char pts_name[24]; int ptn, unlock; while (1) { fd = open("/dev/ptmx", O_RDWR); if (fd < 0) error_exit("opening pty master"); unlock = 0; if (ioctl(fd, TIOCSPTLCK, &unlock) < 0) error_exit("unlocking pty pair"); if (ioctl(fd, TIOCGPTN, &ptn) < 0) error_exit("getting pty #"); snprintf(pts_name, sizeof(pts_name), "/dev/pts/%d", ptn); child_id = fork(); if (child_id == -1) error_exit("forking child"); if (parent) { int err, id, status; char buf[128]; int n; n = read(fd, buf, sizeof(buf)); if (n < 0) error_exit("master reading"); printf("%.*s\n", n-1, buf); close(fd); err = kill(child_id, SIGKILL); if (err < 0) error_exit("killing child"); id = waitpid(child_id, &status, 0); if (id < 0 || id != child_id) error_exit("waiting for child"); } else { /* Child */ close(fd); printf("Test cycle on slave pty %s\n", pts_name); fd = open(pts_name, O_RDWR); if (fd < 0) error_exit("opening pty slave"); while (1) { char pattern[] = "test\n"; if (write(fd, pattern, strlen(pattern)) < 0) error_exit("slave writing"); } } } /* never gets here */ return 0; } Reported-by: -
Peter Hurley authored
Factor the packet mode status change from n_tty_flush_buffer for use by follow-on patch. Signed-off-by:
-
Peter Hurley authored
Flip buffer work must not be scheduled by the line discipline after the line discipline has been halted; issue warning. Note: drivers can still schedule flip buffer work. Signed-off-by:
-
Lars-Peter Clausen authored
The ifx6x60 driver implements both legacy suspend/resume callbacks and dev_pm_ops. The SPI core is going to ignore legacy suspend/resume callbacks if a driver implements dev_pm_ops. Since the legacy suspend/resume callbacks are empty in this case it is safe to just remove them. Cc: Bi Chao <chao.bi@intel.com> Cc: Chen Jun <jun.d.chen@intel.com> Signed-off-by:
Lars-Peter Clausen <lars@metafoo.de> Signed-off-by:
-
Lars-Peter Clausen authored
Use dev_pm_ops instead of the deprecated legacy suspend/resume for the mrst_max3110 driver. Cc: Alan Cox <alan@linux.intel.com> Signed-off-by:
-
Lars-Peter Clausen authored
Use dev_pm_ops instead of the deprecated legacy suspend/resume for the max310x driver. Cc: Alexander Shiyan <shc_work@mail.ru> Signed-off-by:
-
Lars-Peter Clausen authored
Use dev_pm_ops instead of the deprecated legacy suspend/resume for the max3100 driver. Signed-off-by:
-
Johan Hovold authored
Make sure we do not make tty-driver callbacks or wait for port to drain on uninitialised ports (e.g. when open failed) in tty_port_close_start(). No callback, such as flush_buffer or wait_until_sent, needs to be made on a port that has never been opened. Neither does it make much sense to add drain delay for an uninitialised port. Currently a drain delay of up to two seconds could be added when a tty fails to open. Signed-off-by:
Johan Hovold <jhovold@gmail.com> Signed-off-by:
-
Johan Hovold authored
Move port drain-delay handling to a separate function. Signed-off-by:
-
Johan Hovold authored
Move HUPCL handling to port shutdown so that DTR is dropped also on hang up (tty_port_close is a noop for hung-up ports). Also do not try to drop DTR for uninitialised ports where it has never been raised (e.g. after a failed open). Note that this is also the current behaviour of serial-core. Nine drivers currently call tty_port_close_start directly (rather than through tty_port_close) and seven of them lower DTR as part of their close (if the port has been initialised). Fixup the remaining two drivers so that it continues to be lowered also on normal (non-HUP) close. [ Note that most of those other seven drivers did not expect DTR to have been dropped by tty_port_close_start in the first place. ] Signed-off-by:
-
Johan Hovold authored
Make sure to check ASYNC_INITIALISED before raising DTR when waking up from blocked open in tty_port_block_til_ready. Currently DTR could get raised at hang up as a blocked process would raise DTR unconditionally before checking for hang up and returning. Signed-off-by:
-
Johan Hovold authored
Move wake up of processes on blocked-open and modem-status wait queues to after port shutdown at hangup. This way the woken up processes can use the ASYNC_INITIALIZED flag to detect port shutdown. Note that this is the order currently used by serial-core. Signed-off-by:
-
Johan Hovold authored
Untangle port-shutdown logic and make sure the initialised flag is always cleared for non-console ports. Signed-off-by:
-
Jiri Slaby authored
The same as flags, convert to using open/close counts from tty_port. Signed-off-by:
Jiri Slaby <jslaby@suse.cz> Signed-off-by:
-
Jiri Slaby authored
The same as flags, convert to using *_wait queues from tty_port. Signed-off-by:
-
Jiri Slaby authored
The same as flags, convert to using close delays from tty_port. Signed-off-by:
-
Jiri Slaby authored
Well, all those are unused. They were perhaps copied from generic serial structure ages ago. Remove them for good. Signed-off-by:
-
Jiri Slaby authored
The return value is not used anywhere, so no need to return anything. Signed-off-by:
-
Jiri Slaby authored
First, remove STD_FLAGS as the value, or its subvalues (ASYNC_BOOT_AUTOCONF | ASYNC_SKIP_TEST) is not tested anywhere -- there is no point to initialize flags to that. Second, use flags member from tty_port when we have it now. So that we do not waste space. Signed-off-by:
-
Jiri Slaby authored
tty->hw_stopped is set only by drivers to remember HW state. If it is never set to 1 in a particular driver, there is no need to check it in the driver at all. Remove such checks. Signed-off-by:
-
