aboutsummaryrefslogtreecommitdiff
path: root/drivers/tty/tty_io.c
AgeCommit message (Collapse)AuthorFilesLines
2014-11-05tty: Serialize proc_set_tty() with tty_lockPeter Hurley1-8/+5
Setting the controlling terminal for a session occurs with either the first open of a non-pty master tty or with ioctl(TIOCSCTTY). Since only the session leader can set the controlling terminal for a session (and the session leader cannot change), it is not necessary to prevent a process from attempting to set different ttys as the controlling terminal concurrently. So it's only necessary to prevent the same tty from becoming the controlling terminal for different session leaders. The tty_lock() is sufficient to prevent concurrent proc_set_tty() for the same tty. Remove the tty_mutex lock region; add tty_lock() to tiocsctty(). While this may appear to allow a race condition between opening the controlling tty via tty_open_current_tty() and stealing the controlling tty via ioctl(TIOCSCTTY, 1), that race condition already existed. Even if the tty_mutex prevented stealing the controlling tty while tty_open_current_tty() returned the original controlling tty, it cannot prevent stealing the controlling tty before tty_open() returns. Thus, tty_open() could already return a no-longer-controlling tty when opening /dev/tty. Signed-off-by: Peter Hurley <[email protected]> Reviewed-by: Alan Cox <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>
2014-11-05tty: Move session_of_pgrp() and make staticPeter Hurley1-0/+21
tiocspgrp() is the lone caller of session_of_pgrp(); relocate and limit to file scope. Signed-off-by: Peter Hurley <[email protected]> Reviewed-by: Alan Cox <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>
2014-11-05tty: Fix multiple races when setting the controlling terminalPeter Hurley1-6/+17
Claim a read lock on the tasklist_lock while setting the controlling terminal for the session leader. This fixes multiple races: 1. task_pgrp() and task_session() cannot be safely dereferenced, such as passing to get_pid(), without holding either rcu_read_lock() or tasklist_lock 2. setsid() unwisely allows any thread in the thread group to make the thread group leader the session leader; this makes the unlocked reads of ->signal->leader and signal->tty potentially unordered, stale or even have spurious values. Signed-off-by: Peter Hurley <[email protected]> Reviewed-by: Alan Cox <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>
2014-11-05tty: Remove !tty condition from __proc_set_tty()Peter Hurley1-13/+12
The tty parameter to __proc_set_tty() cannot be NULL; all call sites have already dereferenced tty. Signed-off-by: Peter Hurley <[email protected]> Reviewed-by: Alan Cox <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>
2014-11-05tty: Replace open-coded tty_get_pgrp()Peter Hurley1-6/+2
Replace open-coded instances of tty_get_pgrp(). Signed-off-by: Peter Hurley <[email protected]> Reviewed-by: Alan Cox <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>
2014-11-05tty: Remove tsk parameter from proc_set_tty()Peter Hurley1-14/+14
Only the current task itself can set its controlling tty (other than before the task has been forked). Equivalent to existing usage. Signed-off-by: Peter Hurley <[email protected]> Reviewed-by: Alan Cox <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>
2014-11-05tty: Reorder proc_set_tty() and related fnsPeter Hurley1-63/+62
Move the controlling tty-related functions and remove forward declarations for __proc_set_tty() and proc_set_tty(). Signed-off-by: Peter Hurley <[email protected]> Reviewed-by: Alan Cox <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>
2014-11-05tty: Remove tty_pair_get_tty()/tty_pair_get_pty() apiPeter Hurley1-11/+5
tty_pair_get_pty() has no in-tree users and tty_pair_get_tty() has only one file-local user. Remove the external declarations, the export declarations, and declare tty_pair_get_tty() static. Signed-off-by: Peter Hurley <[email protected]> Reviewed-by: Alan Cox <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>
2014-11-05tty: Remove sparse lock annotations from tty_write_lock()/_unlock()Peter Hurley1-2/+0
sparse lock annotations cannot represent conditional acquire, such as mutex_lock_interruptible() or mutex_trylock(), and produce sparse warnings at _every_ correct call site. Remove lock annotations from tty_write_lock() and tty_write_unlock(). Fixes sparse warnings: drivers/tty/tty_io.c:1083:13: warning: context imbalance in 'tty_write_unlock' - wrong count at exit drivers/tty/tty_io.c:1090:12: warning: context imbalance in 'tty_write_lock' - wrong count at exit drivers/tty/tty_io.c:1211:17: warning: context imbalance in 'tty_write_message' - unexpected unlock drivers/tty/tty_io.c:1233:16: warning: context imbalance in 'tty_write' - different lock contexts for basic block drivers/tty/tty_io.c:1285:5: warning: context imbalance in 'tty_send_xchar' - different lock contexts for basic block drivers/tty/tty_io.c:2653:12: warning: context imbalance in 'send_break' - different lock contexts for basic block Signed-off-by: Peter Hurley <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>
2014-11-05tty: Prevent "read/write wait queue active!" log floodingPeter Hurley1-2/+6
Only print one warning when a task is on the read_wait or write_wait wait queue at final tty release. Cc: <[email protected]> # 3.4.x+ Signed-off-by: Peter Hurley <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>
2014-11-05tty: Fix high cpu load if tty is unreleaseablePeter Hurley1-1/+6
Kernel oops can cause the tty to be unreleaseable (for example, if n_tty_read() crashes while on the read_wait queue). This will cause tty_release() to endlessly loop without sleeping. Use a killable sleep timeout which grows by 2n+1 jiffies over the interval [0, 120 secs.) and then jumps to forever (but still killable). NB: killable just allows for the task to be rewoken manually, not to be terminated. Cc: <[email protected]> # since before 2.6.32 Signed-off-by: Peter Hurley <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>
2014-10-11Merge tag 'locks-v3.18-1' of git://git.samba.org/jlayton/linuxLinus Torvalds1-1/+2
Pull file locking related changes from Jeff Layton: "This release is a little more busy for file locking changes than the last: - a set of patches from Kinglong Mee to fix the lockowner handling in knfsd - a pile of cleanups to the internal file lease API. This should get us a bit closer to allowing for setlease methods that can block. There are some dependencies between mine and Bruce's trees this cycle, and I based my tree on top of the requisite patches in Bruce's tree" * tag 'locks-v3.18-1' of git://git.samba.org/jlayton/linux: (26 commits) locks: fix fcntl_setlease/getlease return when !CONFIG_FILE_LOCKING locks: flock_make_lock should return a struct file_lock (or PTR_ERR) locks: set fl_owner for leases to filp instead of current->files locks: give lm_break a return value locks: __break_lease cleanup in preparation of allowing direct removal of leases locks: remove i_have_this_lease check from __break_lease locks: move freeing of leases outside of i_lock locks: move i_lock acquisition into generic_*_lease handlers locks: define a lm_setup handler for leases locks: plumb a "priv" pointer into the setlease routines nfsd: don't keep a pointer to the lease in nfs4_file locks: clean up vfs_setlease kerneldoc comments locks: generic_delete_lease doesn't need a file_lock at all nfsd: fix potential lease memory leak in nfs4_setlease locks: close potential race in lease_get_mtime security: make security_file_set_fowner, f_setown and __f_setown void return locks: consolidate "nolease" routines locks: remove lock_may_read and lock_may_write lockd: rip out deferred lock handling from testlock codepath NFSD: Get reference of lockowner when coping file_lock ...
2014-09-23tty: Move and rename send_prio_char() as tty_send_xchar()Peter Hurley1-2/+31
Relocate the file-scope function, send_prio_char(), as a global helper tty_send_xchar(). Remove the global declarations for tty_write_lock()/tty_write_unlock(), as these are file-scope only now. Signed-off-by: Peter Hurley <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>
2014-09-23tty: Move packet mode flow control notifications to pty driverPeter Hurley1-27/+4
When a master pty is set to packet mode, flow control changes to the slave pty cause notifications to the master pty via reads and polls. However, these tests are occurring for all ttys, not just ptys. Implement flow control packet mode notifications in the pty driver. Only the slave side implements the flow control handlers since packet mode is asymmetric; the master pty receives notifications for slave-side changes, but not vice versa. Signed-off-by: Peter Hurley <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>
2014-09-23tty: Serialize tty flow control changes with flow_lockPeter Hurley1-11/+28
Without serialization, the flow control state can become inverted wrt. the actual hardware state. For example, CPU 0 | CPU 1 stop_tty() | lock ctrl_lock | tty->stopped = 1 | unlock ctrl_lock | | start_tty() | lock ctrl_lock | tty->stopped = 0 | unlock ctrl_lock | driver->start() driver->stop() | In this case, the flow control state now indicates the tty has been started, but the actual hardware state has actually been stopped. Introduce tty->flow_lock spinlock to serialize tty flow control changes. Split out unlocked __start_tty()/__stop_tty() flavors for use by ioctl(TCXONC) in follow-on patch. Signed-off-by: Peter Hurley <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>
2014-09-09security: make security_file_set_fowner, f_setown and __f_setown void returnJeff Layton1-1/+2
security_file_set_fowner always returns 0, so make it f_setown and __f_setown void return functions and fix up the error handling in the callers. Cc: [email protected] Signed-off-by: Jeff Layton <[email protected]> Reviewed-by: Christoph Hellwig <[email protected]>
2014-09-08tty: Fix potential use after free in release_one_ttyCyrill Gorcunov1-1/+2
In case if we're releasing the last tty reference the following call sequence is possible tty_driver_kref_put destruct_tty_driver kfree(driver); where @driver is used in next module_put call, which leads to | [ 285.964007] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 | [ 285.964007] Workqueue: events release_one_tty | [ 285.964007] task: ffff8800cc7ea5f0 ti: ffff8800cb800000 task.ti: ffff8800cb800000 | [ 285.964007] RIP: 0010:[<ffffffff810aeaf5>] [<ffffffff810aeaf5>] module_put+0x24/0xf4 | [ 285.964007] RSP: 0018:ffff8800cb801d48 EFLAGS: 00010213 | [ 285.964007] RAX: ffff8800cb801fd8 RBX: ffff8800ca3429d0 RCX: ffff8800cb1db400 | [ 285.964007] RDX: 0000000000000000 RSI: ffffffff817349c1 RDI: 0000000000000001 | [ 285.964007] RBP: ffff8800cb801d60 R08: ffff8800cd632b40 R09: 0000000000000000 | [ 285.964007] R10: 00000000ffffffff R11: ffff88011f40a000 R12: 6b6b6b6b6b6b6b6b | [ 285.964007] R13: ffff8800ca342520 R14: 0000000000000000 R15: ffff88011f5d8200 | [ 285.964007] FS: 0000000000000000(0000) GS:ffff88011f400000(0000) knlGS:0000000000000000 | [ 285.964007] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b | [ 285.964007] CR2: 00007faf5229d090 CR3: 0000000001c0b000 CR4: 00000000000006f0 | [ 285.964007] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 | [ 285.964007] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 | [ 285.964007] Stack: | [ 285.964007] ffff8800ca3429d0 ffff8800ca342a30 ffff8800ca342520 ffff8800cb801d88 | [ 285.964007] ffffffff8146554a ffff8800cc77cc78 ffff8800ca3429d0 ffff88011f5d3800 | [ 285.964007] ffff8800cb801e08 ffffffff810683c1 ffffffff810682ff 0000000000000046 | [ 285.964007] Call Trace: | [ 285.964007] [<ffffffff8146554a>] release_one_tty+0x54/0xa3 | [ 285.964007] [<ffffffff810683c1>] process_one_work+0x223/0x404 | [ 285.964007] [<ffffffff810682ff>] ? process_one_work+0x161/0x404 | [ 285.964007] [<ffffffff81068971>] worker_thread+0x136/0x205 | [ 285.964007] [<ffffffff8106883b>] ? rescuer_thread+0x26a/0x26a | [ 285.964007] [<ffffffff8106e5bf>] kthread+0xa2/0xaa | [ 285.964007] [<ffffffff810a4586>] ? trace_hardirqs_on_caller+0x16/0x1eb | [ 285.964007] [<ffffffff8106e51d>] ? __kthread_parkme+0x65/0x65 | [ 285.964007] [<ffffffff8173f59c>] ret_from_fork+0x7c/0xb0 | [ 285.964007] [<ffffffff8106e51d>] ? __kthread_parkme+0x65/0x65 | [ 285.964007] Code: 09 00 5b 41 5c 5d c3 0f 1f 44 00 00 55 48 85 ff 48 89 e5 41 55 41 54 49 89 fc 53 0f 84 d3 00 | 00 00 bf 01 00 00 00 e8 d0 a1 fc ff <49> 8b 84 24 50 02 00 00 65 48 ff 40 08 4c 8b 6d 08 0f 1f 44 00 so simply keep a local reference to the module owner and use it later. CC: Pavel Emelyanov <[email protected]> CC: Jiri Slaby <[email protected]> CC: Greg Kroah-Hartman <[email protected]> Signed-off-by: Cyrill Gorcunov <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>
2014-07-11drivers: tty: Merge alloc_tty_struct and initialize_tty_structRasmus Villemoes1-24/+13
The two functions alloc_tty_struct and initialize_tty_struct are always called together. Merge them into alloc_tty_struct, updating its prototype and the only two callers of these functions. Signed-off-by: Rasmus Villemoes <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>
2014-07-10tty: Call hangup method in modern stylePeter Hurley1-1/+1
Signed-off-by: Peter Hurley <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>
2014-04-16tty: fix memleak in alloc_pidChen Tingjie1-2/+2
There is memleak in alloc_pid: ------------------------------ unreferenced object 0xd3453a80 (size 64): comm "adbd", pid 1730, jiffies 66363 (age 6586.950s) hex dump (first 32 bytes): 01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00 00 00 00 40 c2 f6 d5 00 d3 25 c1 59 28 00 00 ....@.....%.Y(.. backtrace: [<c1a6f15c>] kmemleak_alloc+0x3c/0xa0 [<c1320546>] kmem_cache_alloc+0xc6/0x190 [<c125d51e>] alloc_pid+0x1e/0x400 [<c123d344>] copy_process.part.39+0xad4/0x1120 [<c123da59>] do_fork+0x99/0x330 [<c123dd58>] sys_fork+0x28/0x30 [<c1a89a08>] syscall_call+0x7/0xb [<ffffffff>] 0xffffffff the leak is due to unreleased pid->count, which execute in function: get_pid()(pid->count++) and put_pid()(pid->count--). The race condition as following: task[dumpsys] task[adbd] in disassociate_ctty() in tty_signal_session_leader() ----------------------- ------------------------- tty = get_current_tty(); // tty is not NULL ... spin_lock_irq(&current->sighand->siglock); put_pid(current->signal->tty_old_pgrp); current->signal->tty_old_pgrp = NULL; spin_unlock_irq(&current->sighand->siglock); spin_lock_irq(&p->sighand->siglock); ... p->signal->tty = NULL; ... spin_unlock_irq(&p->sighand->siglock); tty = get_current_tty(); // tty NULL, goto else branch by accident. if (tty) { ... put_pid(tty_session); put_pid(tty_pgrp); ... } else { print msg } in task[dumpsys], in disassociate_ctty(), tty is set NULL by task[adbd], tty_signal_session_leader(), then it goto else branch and lack of put_pid(), cause memleak. move spin_unlock(sighand->siglock) after get_current_tty() can avoid the race and fix the memleak. Signed-off-by: Zhang Jun <[email protected]> Signed-off-by: Chen Tingjie <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>
2014-02-28tty: Set correct tty name in 'active' sysfs attributeHannes Reinecke1-6/+17
The 'active' sysfs attribute should refer to the currently active tty devices the console is running on, not the currently active console. The console structure doesn't refer to any device in sysfs, only the tty the console is running on has. So we need to print out the tty names in 'active', not the console names. There is one special-case, which is tty0. If the console is directed to it, we want 'tty0' to show up in the file, so user-space knows that the messages get forwarded to the active VT. The ->device() callback would resolve tty0, though. Hence, treat it special and don't call into the VT layer to resolve it (plymouth is known to depend on it). Cc: Lennart Poettering <[email protected]> Cc: Kay Sievers <[email protected]> Cc: Greg Kroah-Hartman <[email protected]> Cc: Jiri Slaby <[email protected]> Cc: stable <[email protected]> Signed-off-by: Werner Fink <[email protected]> Signed-off-by: Hannes Reinecke <[email protected]> Signed-off-by: David Herrmann <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>
2014-02-22Revert "tty: Set correct tty name in 'active' sysfs attribute"Greg Kroah-Hartman1-18/+7
This reverts commit d8a5dc3033af2fd6d16030d2ee4fbd073460fe54. This breaks plymouth installs, either because plymouth is using the file "incorrectly" or because the patch is incorrect. Either way, this needs to be reverted until it is all figured out. Reported-by: Josh Boyer <[email protected]> Reported-by: Ray Strode <[email protected]> Cc: Lennart Poettering <[email protected]> Cc: Kay Sievers <[email protected]> Cc: Jiri Slaby <[email protected]> Cc: David Herrmann <[email protected]> Cc: Werner Fink <[email protected]> Cc: Hannes Reinecke <[email protected]> Cc: stable <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>
2014-02-07tty: Set correct tty name in 'active' sysfs attributeHannes Reinecke1-7/+18
The 'active' sysfs attribute should refer to the currently active tty devices the console is running on, not the currently active console. The console structure doesn't refer to any device in sysfs, only the tty the console is running on has. So we need to print out the tty names in 'active', not the console names. This resolves an issue on s390 platforms in determining the correct console device to use. Cc: Lennart Poettering <[email protected]> Cc: Kay Sievers <[email protected]> Cc: Jiri Slaby <[email protected]> Cc: David Herrmann <[email protected]> Signed-off-by: Werner Fink <[email protected]> Signed-off-by: Hannes Reinecke <[email protected]> Cc: stable <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>
2013-11-25tty: Reset hupped state on openPeter Hurley1-0/+1
A common security idiom is to hangup the current tty (via vhangup()) after forking but before execing a root shell. This hangs up any existing opens which other processes may have and ensures subsequent opens have the necessary permissions to open the root shell tty/pty. Reset the TTY_HUPPED state after the driver has successfully returned the opened tty (perform the reset while the tty is locked to avoid racing with concurrent hangups). Reported-by: Heorhi Valakhanovich <[email protected]> Signed-off-by: Peter Hurley <[email protected]> Cc: stable <[email protected]> # 3.12 Tested-by: Heorhi Valakhanovich <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>
2013-09-17tty: disassociate_ctty() sends the extra SIGCONTOleg Nesterov1-1/+2
Starting from v3.10 (probably commit f91e2590410b: "tty: Signal foreground group processes in hangup") disassociate_ctty() sends SIGCONT if tty && on_exit. This breaks LSB test-suite, in particular test8 in _exit.c and test40 in sigcon5.c. Put the "!on_exit" check back to restore the old behaviour. Review by Peter Hurley: "Yes, this regression was introduced by me in that commit. The effect of the regression is that ptys will receive a SIGCONT when, in similar circumstances, ttys would not. The fact that two test vectors accidentally tripped over this regression suggests that some other apps may as well. Thanks for catching this" Cc: [email protected] # v3.10+ Signed-off-by: Oleg Nesterov <[email protected]> Reported-by: Karel Srot <[email protected]> Reviewed-by: Peter Hurley <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
2013-08-02tty: Only hangup oncePeter Hurley1-0/+5
Instrumented testing shows a tty can be hungup multiple times [1]. Although concurrent hangups are properly serialized, multiple hangups for the same tty should be prevented. If tty has already been HUPPED, abort hangup. Note it is not necessary to cleanup file *redirect on subsequent hangups, as only TIOCCONS can set that value and ioctls are disabled after hangup. [1] Test performed by simulating a concurrent async hangup via tty_hangup() with a sync hangup via tty_vhangup(), while __tty_hangup() was instrumented with: diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c index 26bb78c..fe8b061 100644 --- a/drivers/tty/tty_io.c +++ b/drivers/tty/tty_io.c @@ -629,6 +629,8 @@ static void __tty_hangup(struct tty_struct *tty, int exit_session) tty_lock(tty); + WARN_ON(test_bit(TTY_HUPPED, &tty->flags)); + /* some functions below drop BTM, so we need this bit */ set_bit(TTY_HUPPING, &tty->flags); Test result: WARNING: at /home/peter/src/kernels/mainline/drivers/tty/tty_io.c:632 __tty_hangup+0x459/0x460() Modules linked in: ip6table_filter ip6_tables ebtable_nat <...snip...> CPU: 6 PID: 1197 Comm: kworker/6:2 Not tainted 3.10.0-0+rfcomm-xeon #0+rfcomm Hardware name: Dell Inc. Precision WorkStation T5400 /0RW203, BIOS A11 04/30/2012 Workqueue: events do_tty_hangup 0000000000000009 ffff8802b16d7d18 ffffffff816b553e ffff8802b16d7d58 ffffffff810407e0 ffff880254f95c00 ffff880254f95c00 ffff8802bfd92b00 ffff8802bfd96b00 ffff880254f95e40 0000000000000180 ffff8802b16d7d68 Call Trace: [<ffffffff816b553e>] dump_stack+0x19/0x1b [<ffffffff810407e0>] warn_slowpath_common+0x70/0xa0 [<ffffffff8104082a>] warn_slowpath_null+0x1a/0x20 [<ffffffff813fb279>] __tty_hangup+0x459/0x460 [<ffffffff8107409c>] ? finish_task_switch+0xbc/0xe0 [<ffffffff813fb297>] do_tty_hangup+0x17/0x20 [<ffffffff8105fd6f>] process_one_work+0x16f/0x450 [<ffffffff8106007c>] process_scheduled_works+0x2c/0x40 [<ffffffff8106060a>] worker_thread+0x26a/0x380 [<ffffffff810603a0>] ? rescuer_thread+0x310/0x310 [<ffffffff810698a0>] kthread+0xc0/0xd0 [<ffffffff816b0000>] ? destroy_compound_page+0x65/0x92 [<ffffffff810697e0>] ? kthread_create_on_node+0x130/0x130 [<ffffffff816c495c>] ret_from_fork+0x7c/0xb0 [<ffffffff810697e0>] ? kthread_create_on_node+0x130/0x130 ---[ end trace 98d9f01536cf411e ]--- Signed-off-by: Peter Hurley <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>
2013-07-24tty: Fix lock order in tty_do_resize()Peter Hurley1-5/+6
Commits 6a1c0680cf3ba94356ecd58833e1540c93472a57 and 9356b535fcb71db494fc434acceb79f56d15bda2, respectively 'tty: Convert termios_mutex to termios_rwsem' and 'n_tty: Access termios values safely' introduced a circular lock dependency with console_lock and termios_rwsem. The lockdep report [1] shows that n_tty_write() will attempt to claim console_lock while holding the termios_rwsem, whereas tty_do_resize() may already hold the console_lock while claiming the termios_rwsem. Since n_tty_write() and tty_do_resize() do not contend over the same data -- the tty->winsize structure -- correct the lock dependency by introducing a new lock which specifically serializes access to tty->winsize only. [1] Lockdep report ====================================================== [ INFO: possible circular locking dependency detected ] 3.10.0-0+tip-xeon+lockdep #0+tip Not tainted ------------------------------------------------------- modprobe/277 is trying to acquire lock: (&tty->termios_rwsem){++++..}, at: [<ffffffff81452656>] tty_do_resize+0x36/0xe0 but task is already holding lock: ((fb_notifier_list).rwsem){.+.+.+}, at: [<ffffffff8107aac6>] __blocking_notifier_call_chain+0x56/0xc0 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 ((fb_notifier_list).rwsem){.+.+.+}: [<ffffffff810b6d62>] lock_acquire+0x92/0x1f0 [<ffffffff8175b797>] down_read+0x47/0x5c [<ffffffff8107aac6>] __blocking_notifier_call_chain+0x56/0xc0 [<ffffffff8107ab46>] blocking_notifier_call_chain+0x16/0x20 [<ffffffff813d7c0b>] fb_notifier_call_chain+0x1b/0x20 [<ffffffff813d95b2>] register_framebuffer+0x1e2/0x320 [<ffffffffa01043e1>] drm_fb_helper_initial_config+0x371/0x540 [drm_kms_helper] [<ffffffffa01bcb05>] nouveau_fbcon_init+0x105/0x140 [nouveau] [<ffffffffa01ad0af>] nouveau_drm_load+0x43f/0x610 [nouveau] [<ffffffffa008a79e>] drm_get_pci_dev+0x17e/0x2a0 [drm] [<ffffffffa01ad4da>] nouveau_drm_probe+0x25a/0x2a0 [nouveau] [<ffffffff813b13db>] local_pci_probe+0x4b/0x80 [<ffffffff813b1701>] pci_device_probe+0x111/0x120 [<ffffffff814977eb>] driver_probe_device+0x8b/0x3a0 [<ffffffff81497bab>] __driver_attach+0xab/0xb0 [<ffffffff814956ad>] bus_for_each_dev+0x5d/0xa0 [<ffffffff814971fe>] driver_attach+0x1e/0x20 [<ffffffff81496cc1>] bus_add_driver+0x111/0x290 [<ffffffff814982b7>] driver_register+0x77/0x170 [<ffffffff813b0454>] __pci_register_driver+0x64/0x70 [<ffffffffa008a9da>] drm_pci_init+0x11a/0x130 [drm] [<ffffffffa022a04d>] nouveau_drm_init+0x4d/0x1000 [nouveau] [<ffffffff810002ea>] do_one_initcall+0xea/0x1a0 [<ffffffff810c54cb>] load_module+0x123b/0x1bf0 [<ffffffff810c5f57>] SyS_init_module+0xd7/0x120 [<ffffffff817677c2>] system_call_fastpath+0x16/0x1b -> #1 (console_lock){+.+.+.}: [<ffffffff810b6d62>] lock_acquire+0x92/0x1f0 [<ffffffff810430a7>] console_lock+0x77/0x80 [<ffffffff8146b2a1>] con_flush_chars+0x31/0x50 [<ffffffff8145780c>] n_tty_write+0x1ec/0x4d0 [<ffffffff814541b9>] tty_write+0x159/0x2e0 [<ffffffff814543f5>] redirected_tty_write+0xb5/0xc0 [<ffffffff811ab9d5>] vfs_write+0xc5/0x1f0 [<ffffffff811abec5>] SyS_write+0x55/0xa0 [<ffffffff817677c2>] system_call_fastpath+0x16/0x1b -> #0 (&tty->termios_rwsem){++++..}: [<ffffffff810b65c3>] __lock_acquire+0x1c43/0x1d30 [<ffffffff810b6d62>] lock_acquire+0x92/0x1f0 [<ffffffff8175b724>] down_write+0x44/0x70 [<ffffffff81452656>] tty_do_resize+0x36/0xe0 [<ffffffff8146c841>] vc_do_resize+0x3e1/0x4c0 [<ffffffff8146c99f>] vc_resize+0x1f/0x30 [<ffffffff813e4535>] fbcon_init+0x385/0x5a0 [<ffffffff8146a4bc>] visual_init+0xbc/0x120 [<ffffffff8146cd13>] do_bind_con_driver+0x163/0x320 [<ffffffff8146cfa1>] do_take_over_console+0x61/0x70 [<ffffffff813e2b93>] do_fbcon_takeover+0x63/0xc0 [<ffffffff813e67a5>] fbcon_event_notify+0x715/0x820 [<ffffffff81762f9d>] notifier_call_chain+0x5d/0x110 [<ffffffff8107aadc>] __blocking_notifier_call_chain+0x6c/0xc0 [<ffffffff8107ab46>] blocking_notifier_call_chain+0x16/0x20 [<ffffffff813d7c0b>] fb_notifier_call_chain+0x1b/0x20 [<ffffffff813d95b2>] register_framebuffer+0x1e2/0x320 [<ffffffffa01043e1>] drm_fb_helper_initial_config+0x371/0x540 [drm_kms_helper] [<ffffffffa01bcb05>] nouveau_fbcon_init+0x105/0x140 [nouveau] [<ffffffffa01ad0af>] nouveau_drm_load+0x43f/0x610 [nouveau] [<ffffffffa008a79e>] drm_get_pci_dev+0x17e/0x2a0 [drm] [<ffffffffa01ad4da>] nouveau_drm_probe+0x25a/0x2a0 [nouveau] [<ffffffff813b13db>] local_pci_probe+0x4b/0x80 [<ffffffff813b1701>] pci_device_probe+0x111/0x120 [<ffffffff814977eb>] driver_probe_device+0x8b/0x3a0 [<ffffffff81497bab>] __driver_attach+0xab/0xb0 [<ffffffff814956ad>] bus_for_each_dev+0x5d/0xa0 [<ffffffff814971fe>] driver_attach+0x1e/0x20 [<ffffffff81496cc1>] bus_add_driver+0x111/0x290 [<ffffffff814982b7>] driver_register+0x77/0x170 [<ffffffff813b0454>] __pci_register_driver+0x64/0x70 [<ffffffffa008a9da>] drm_pci_init+0x11a/0x130 [drm] [<ffffffffa022a04d>] nouveau_drm_init+0x4d/0x1000 [nouveau] [<ffffffff810002ea>] do_one_initcall+0xea/0x1a0 [<ffffffff810c54cb>] load_module+0x123b/0x1bf0 [<ffffffff810c5f57>] SyS_init_module+0xd7/0x120 [<ffffffff817677c2>] system_call_fastpath+0x16/0x1b other info that might help us debug this: Chain exists of: &tty->termios_rwsem --> console_lock --> (fb_notifier_list).rwsem Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock((fb_notifier_list).rwsem); lock(console_lock); lock((fb_notifier_list).rwsem); lock(&tty->termios_rwsem); *** DEADLOCK *** 7 locks held by modprobe/277: #0: (&__lockdep_no_validate__){......}, at: [<ffffffff81497b5b>] __driver_attach+0x5b/0xb0 #1: (&__lockdep_no_validate__){......}, at: [<ffffffff81497b69>] __driver_attach+0x69/0xb0 #2: (drm_global_mutex){+.+.+.}, at: [<ffffffffa008a6dd>] drm_get_pci_dev+0xbd/0x2a0 [drm] #3: (registration_lock){+.+.+.}, at: [<ffffffff813d93f5>] register_framebuffer+0x25/0x320 #4: (&fb_info->lock){+.+.+.}, at: [<ffffffff813d8116>] lock_fb_info+0x26/0x60 #5: (console_lock){+.+.+.}, at: [<ffffffff813d95a4>] register_framebuffer+0x1d4/0x320 #6: ((fb_notifier_list).rwsem){.+.+.+}, at: [<ffffffff8107aac6>] __blocking_notifier_call_chain+0x56/0xc0 stack backtrace: CPU: 0 PID: 277 Comm: modprobe Not tainted 3.10.0-0+tip-xeon+lockdep #0+tip Hardware name: Dell Inc. Precision WorkStation T5400 /0RW203, BIOS A11 04/30/2012 ffffffff8213e5e0 ffff8802aa2fb298 ffffffff81755f19 ffff8802aa2fb2e8 ffffffff8174f506 ffff8802aa2fa000 ffff8802aa2fb378 ffff8802aa2ea8e8 ffff8802aa2ea910 ffff8802aa2ea8e8 0000000000000006 0000000000000007 Call Trace: [<ffffffff81755f19>] dump_stack+0x19/0x1b [<ffffffff8174f506>] print_circular_bug+0x1fb/0x20c [<ffffffff810b65c3>] __lock_acquire+0x1c43/0x1d30 [<ffffffff810b775e>] ? mark_held_locks+0xae/0x120 [<ffffffff810b78d5>] ? trace_hardirqs_on_caller+0x105/0x1d0 [<ffffffff810b6d62>] lock_acquire+0x92/0x1f0 [<ffffffff81452656>] ? tty_do_resize+0x36/0xe0 [<ffffffff8175b724>] down_write+0x44/0x70 [<ffffffff81452656>] ? tty_do_resize+0x36/0xe0 [<ffffffff81452656>] tty_do_resize+0x36/0xe0 [<ffffffff8146c841>] vc_do_resize+0x3e1/0x4c0 [<ffffffff8146c99f>] vc_resize+0x1f/0x30 [<ffffffff813e4535>] fbcon_init+0x385/0x5a0 [<ffffffff8146a4bc>] visual_init+0xbc/0x120 [<ffffffff8146cd13>] do_bind_con_driver+0x163/0x320 [<ffffffff8146cfa1>] do_take_over_console+0x61/0x70 [<ffffffff813e2b93>] do_fbcon_takeover+0x63/0xc0 [<ffffffff813e67a5>] fbcon_event_notify+0x715/0x820 [<ffffffff81762f9d>] notifier_call_chain+0x5d/0x110 [<ffffffff8107aadc>] __blocking_notifier_call_chain+0x6c/0xc0 [<ffffffff8107ab46>] blocking_notifier_call_chain+0x16/0x20 [<ffffffff813d7c0b>] fb_notifier_call_chain+0x1b/0x20 [<ffffffff813d95b2>] register_framebuffer+0x1e2/0x320 [<ffffffffa01043e1>] drm_fb_helper_initial_config+0x371/0x540 [drm_kms_helper] [<ffffffff8173cbcb>] ? kmemleak_alloc+0x5b/0xc0 [<ffffffff81198874>] ? kmem_cache_alloc_trace+0x104/0x290 [<ffffffffa01035e1>] ? drm_fb_helper_single_add_all_connectors+0x81/0xf0 [drm_kms_helper] [<ffffffffa01bcb05>] nouveau_fbcon_init+0x105/0x140 [nouveau] [<ffffffffa01ad0af>] nouveau_drm_load+0x43f/0x610 [nouveau] [<ffffffffa008a79e>] drm_get_pci_dev+0x17e/0x2a0 [drm] [<ffffffffa01ad4da>] nouveau_drm_probe+0x25a/0x2a0 [nouveau] [<ffffffff8175f162>] ? _raw_spin_unlock_irqrestore+0x42/0x80 [<ffffffff813b13db>] local_pci_probe+0x4b/0x80 [<ffffffff813b1701>] pci_device_probe+0x111/0x120 [<ffffffff814977eb>] driver_probe_device+0x8b/0x3a0 [<ffffffff81497bab>] __driver_attach+0xab/0xb0 [<ffffffff81497b00>] ? driver_probe_device+0x3a0/0x3a0 [<ffffffff814956ad>] bus_for_each_dev+0x5d/0xa0 [<ffffffff814971fe>] driver_attach+0x1e/0x20 [<ffffffff81496cc1>] bus_add_driver+0x111/0x290 [<ffffffffa022a000>] ? 0xffffffffa0229fff [<ffffffff814982b7>] driver_register+0x77/0x170 [<ffffffffa022a000>] ? 0xffffffffa0229fff [<ffffffff813b0454>] __pci_register_driver+0x64/0x70 [<ffffffffa008a9da>] drm_pci_init+0x11a/0x130 [drm] [<ffffffffa022a000>] ? 0xffffffffa0229fff [<ffffffffa022a000>] ? 0xffffffffa0229fff [<ffffffffa022a04d>] nouveau_drm_init+0x4d/0x1000 [nouveau] [<ffffffff810002ea>] do_one_initcall+0xea/0x1a0 [<ffffffff810c54cb>] load_module+0x123b/0x1bf0 [<ffffffff81399a50>] ? ddebug_proc_open+0xb0/0xb0 [<ffffffff813855ae>] ? trace_hardirqs_on_thunk+0x3a/0x3f [<ffffffff810c5f57>] SyS_init_module+0xd7/0x120 [<ffffffff817677c2>] system_call_fastpath+0x16/0x1b Signed-off-by: Peter Hurley <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>
2013-07-23n_tty: Fix EOF push handlingPeter Hurley1-1/+0
In canonical mode, an EOF which is not the first character of the line causes read() to complete and return the number of characters read so far (commonly referred to as EOF push). However, if the previous read() returned because the user buffer was full _and_ the next character is an EOF not at the beginning of the line, read() must not return 0, thus mistakenly indicating the end-of-file condition. The TTY_PUSH flag is used to indicate an EOF was received which is not at the beginning of the line. Because the EOF push condition is evaluated by a thread other than the read(), multiple EOF pushes can cause a premature end-of-file to be indicated. Instead, discover the 'EOF push as first read character' condition from the read() thread itself, and restart the i/o loop if detected. Signed-off-by: Peter Hurley <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>
2013-07-23tty: Only guarantee termios read safety for throttle/unthrottlePeter Hurley1-0/+1
No tty driver modifies termios during throttle() or unthrottle(). Therefore, only read safety is required. However, tty_throttle_safe and tty_unthrottle_safe must still be mutually exclusive; introduce throttle_mutex for that purpose. Signed-off-by: Peter Hurley <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>
2013-07-23tty: Convert termios_mutex to termios_rwsemPeter Hurley1-7/+7
termios is commonly accessed unsafely (especially by N_TTY) because the existing mutex forces exclusive access. Convert existing usage. Signed-off-by: Peter Hurley <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>
2013-07-23tty: Replace ldisc locking with ldisc_semPeter Hurley1-4/+3
Line discipline locking was performed with a combination of a mutex, a status bit, a count, and a waitqueue -- basically, a rw semaphore. Replace the existing combination with an ld_semaphore. Fixes: 1) the 'reference acquire after ldisc locked' bug 2) the over-complicated halt mechanism 3) lock order wrt. tty_lock() 4) dropping locks while changing ldisc 5) previously unidentified deadlock while locking ldisc from both linked ttys concurrently 6) previously unidentified recursive deadlocks Adds much-needed lockdep diagnostics. Signed-off-by: Peter Hurley <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>
2013-07-23tty: Fix tty_ldisc_lock name collisionPeter Hurley1-2/+2
The file scope spinlock identifier, tty_ldisc_lock, will collide with the file scope lock function tty_ldisc_lock() so rename it. Signed-off-by: Peter Hurley <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>
2013-06-17tty: Reset itty for other ptyPeter Hurley1-0/+2
Commit 19ffd68f816878aed456d5e87697f43bd9e3bd2b ('pty: Remove redundant itty reset') introduced a regression whereby the other pty's linkage is not cleared on teardown. This triggers a false positive diagnostic in testing. Properly reset the itty linkage. Signed-off-by: Peter Hurley <[email protected]> Cc: stable <[email protected]> # 3.10 Signed-off-by: Greg Kroah-Hartman <[email protected]>
2013-06-17n_tty: Encapsulate minimum_to_wake within N_TTYPeter Hurley1-8/+9
minimum_to_wake is unique to N_TTY processing, and belongs in per-ldisc data. Add the ldisc method, ldisc_ops::fasync(), to notify line disciplines when signal-driven I/O is enabled or disabled. When enabled for N_TTY (by fcntl(F_SETFL, O_ASYNC)), blocking reader/polls will be woken for any readable input. When disabled, blocking reader/polls are not woken until the read buffer is full. Canonical mode (L_ICANON(tty), n_tty_data::icanon) is not affected by the minimum_to_wake setting. Signed-off-by: Peter Hurley <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>
2013-05-01tty: fix up atime/mtime mess, take threeLinus Torvalds1-2/+2
We first tried to avoid updating atime/mtime entirely (commit b0de59b5733d: "TTY: do not update atime/mtime on read/write"), and then limited it to only update it occasionally (commit 37b7f3c76595: "TTY: fix atime/mtime regression"), but it turns out that this was both insufficient and overkill. It was insufficient because we let people attach to the shared ptmx node to see activity without even reading atime/mtime, and it was overkill because the "only once a minute" means that you can't really tell an idle person from an active one with 'w'. So this tries to fix the problem properly. It marks the shared ptmx node as un-notifiable, and it lowers the "only once a minute" to a few seconds instead - still long enough that you can't time individual keystrokes, but short enough that you can tell whether somebody is active or not. Reported-by: Simon Kirby <[email protected]> Acked-by: Jiri Slaby <[email protected]> Cc: Greg Kroah-Hartman <[email protected]> Cc: [email protected] Signed-off-by: Linus Torvalds <[email protected]>
2013-04-29Merge tag 'tty-3.10-rc1' of ↵Linus Torvalds1-52/+118
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty Pull tty/serial driver update from Greg Kroah-Hartman: "Here's the big tty/serial driver merge request for 3.10-rc1 Once again, Jiri has a number of TTY driver fixes and cleanups, and Peter Hurley came through with a bunch of ldisc fixes that resolve a number of reported issues. There are some other serial driver cleanups as well. All of these have been in the linux-next tree for a while" * tag 'tty-3.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (117 commits) tty/serial/sirf: fix MODULE_DEVICE_TABLE serial: mxs: drop superfluous {get|put}_device serial: mxs: fix buffer overflow ARM: PL011: add support for extended FIFO-size of PL011-r1p5 serial_core.c: add put_device() after device_find_child() tty: Fix unsafe bit ops in tty_throttle_safe/unthrottle_safe serial: sccnxp: Replace pdata.init/exit with regulator API serial: sccnxp: Do not override device name TTY: pty, fix compilation warning TTY: rocket, fix compilation warning TTY: ircomm: fix DTR being raised on hang up TTY: synclinkmp: fix DTR being raised on hang up TTY: synclink_gt: fix DTR being raised on hang up TTY: synclink: fix DTR being raised on hang up serial: 8250_dw: Fix the stub for dw8250_probe_acpi() serial: 8250_dw: Convert to devm_ioremap() serial: 8250_dw: Set port capabilities based on CPR register serial: 8250_dw: Let ACPI code extract the DMA client info serial: 8250_dw: Support clk framework also with ACPI serial: 8250_dw: Enable runtime PM ...
2013-04-26TTY: fix atime/mtime regressionJiri Slaby1-2/+16
In commit b0de59b5733d ("TTY: do not update atime/mtime on read/write") we removed timestamps from tty inodes to fix a security issue and waited if something breaks. Well, 'w', the utility to find out logged users and their inactivity time broke. It shows that users are inactive since the time they logged in. To revert to the old behaviour while still preventing attackers to guess the password length, we update the timestamps in one-minute intervals by this patch. Signed-off-by: Jiri Slaby <[email protected]> Cc: Greg Kroah-Hartman <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
2013-03-25tty: tty_vhangup_session can be staticChanglong Xie1-1/+1
Reported-by: Fengguang Wu <[email protected]> Acked-by: Peter Hurley <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>
2013-03-18tty: Don't protect atomic operation with mutexPeter Hurley1-2/+0
test_bit() is already atomic; drop mutex lock/unlock. Signed-off-by: Peter Hurley <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>
2013-03-18tty: Bracket ldisc release with TTY_DEBUG_HANGUP messagesPeter Hurley1-1/+4
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 <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>
2013-03-18tty: Make core responsible for synchronizing its workPeter Hurley1-0/+17
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 <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>
2013-03-18tty: Complete ownership transfer of flip buffersPeter Hurley1-0/+1
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 <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>
2013-03-18tty: Don't reenable already enabled ldiscPeter Hurley1-1/+0
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 <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>
2013-03-15tty: Signal SIGHUP before hanging up ldiscPeter Hurley1-5/+5
An exiting session leader can hang if a foreground process is blocking for line discipline i/o, eg. in n_tty_read(). This happens because the blocking reader is holding an ldisc reference (indicating the line discipline is in-use) which prevents __tty_hangup() from recycling the line discipline. Although waiters are woken before attempting to gain exclusive access for changing the ldisc, the blocking reader in this case will not exit the i/o loop since it has not yet received SIGHUP (because it has not been sent). Instead, perform signalling first, then recycle the line discipline. Fixes: INFO: task init:1 blocked for more than 120 seconds. "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. init D 00000000001d7180 2688 1 0 0x00000002 ffff8800b9acfba8 0000000000000002 00000000001d7180 ffff8800b9b10048 ffff8800b94cb000 ffff8800b9b10000 00000000001d7180 00000000001d7180 ffff8800b9b10000 ffff8800b9acffd8 00000000001d7180 00000000001d7180 Call Trace: [<ffffffff83db9909>] __schedule+0x2e9/0x3b0 [<ffffffff83db9b35>] schedule+0x55/0x60 [<ffffffff83db74ba>] schedule_timeout+0x3a/0x370 [<ffffffff81182349>] ? mark_held_locks+0xf9/0x130 [<ffffffff83dbab38>] ? down_failed+0x108/0x200 [<ffffffff83dbb7ab>] ? _raw_spin_unlock_irq+0x2b/0x80 [<ffffffff81182608>] ? trace_hardirqs_on_caller+0x128/0x160 [<ffffffff83dbab61>] down_failed+0x131/0x200 [<ffffffff83dbbfad>] ? tty_ldisc_lock_pair_timeout+0xcd/0x120 [<ffffffff83dbae03>] ldsem_down_write+0xd3/0x113 [<ffffffff83dbbfad>] ? tty_ldisc_lock_pair_timeout+0xcd/0x120 [<ffffffff8118264d>] ? trace_hardirqs_on+0xd/0x10 [<ffffffff83dbbfad>] tty_ldisc_lock_pair_timeout+0xcd/0x120 [<ffffffff81c3df60>] tty_ldisc_hangup+0xd0/0x220 [<ffffffff81c35bd7>] __tty_hangup+0x137/0x4f0 [<ffffffff81c37c7c>] disassociate_ctty+0x6c/0x230 [<ffffffff8111290c>] do_exit+0x41c/0x590 [<ffffffff8107ad34>] ? syscall_trace_enter+0x24/0x2e0 [<ffffffff81112b4a>] do_group_exit+0x8a/0xc0 [<ffffffff81112b92>] sys_exit_group+0x12/0x20 [<ffffffff83dc49d8>] tracesys+0xe1/0xe6 1 lock held by init/1: #0: (&tty->ldisc_sem){++++++}, at: [<ffffffff83dbbfad>] tty_ldisc_lock_pair_timeout+0xcd/0x120 Reported-by: Sasha Levin <[email protected]> Signed-off-by: Peter Hurley <[email protected]> Acked-by: Jiri Slaby <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>
2013-03-15tty: Signal foreground group processes in hangupPeter Hurley1-17/+48
When the session leader is exiting, signal the foreground group processes as part of the hangup sequence, instead of after the hangup is complete. This prepares for hanging up the line discipline _after_ signalling processes which may be blocking on ldisc i/o. Parameterize __tty_hangup() to distinguish between when the session leader is exiting and all other hangups; signal the foreground group after signalling the session leader and its process group, which preserves the original signal order. Signed-off-by: Peter Hurley <[email protected]> Acked-by: Jiri Slaby <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>
2013-03-15tty: Use spin_lock() inside existing critical regionPeter Hurley1-3/+2
The interrupt state does not need to be saved, disabled and restored here; interrupts are already off because this lock is bracketed by spin_lock_irq/spin_unlock_irq. Signed-off-by: Peter Hurley <[email protected]> Acked-by: Jiri Slaby <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>
2013-03-15tty: Fix spinlock flavor in non-atomic __tty_hangup()Peter Hurley1-3/+2
__tty_hangup() and tty_vhangup() cannot be called from atomic context, so locks do not need to preserve the interrupt state (although, still disable interrupts). Signed-off-by: Peter Hurley <[email protected]> Acked-by: Jiri Slaby <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>
2013-03-15tty: Refactor session leader SIGHUP from __tty_hangup()Peter Hurley1-31/+50
Reduce complexity of __tty_hangup(); separate SIGHUP signalling into tty_signal_session_leader(). Signed-off-by: Peter Hurley <[email protected]> Acked-by: Jiri Slaby <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>
2013-02-27more file_inode() open-coded instancesAl Viro1-10/+6
Signed-off-by: Al Viro <[email protected]>
2013-02-21Merge branch 'for-linus' of ↵Linus Torvalds1-0/+1
git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux Pull s390 update from Martin Schwidefsky: "The most prominent change in this patch set is the software dirty bit patch for s390. It removes __HAVE_ARCH_PAGE_TEST_AND_CLEAR_DIRTY and the page_test_and_clear_dirty primitive which makes the common memory management code a bit less obscure. Heiko fixed most of the PCI related fallout, more often than not missing GENERIC_HARDIRQS dependencies. Notable is one of the 3270 patches which adds an export to tty_io to be able to resize a tty. The rest is the usual bunch of cleanups and bug fixes." * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (42 commits) s390/module: Add missing R_390_NONE relocation type drivers/gpio: add missing GENERIC_HARDIRQ dependency drivers/input: add couple of missing GENERIC_HARDIRQS dependencies s390/cleanup: rename SPP to LPP s390/mm: implement software dirty bits s390/mm: Fix crst upgrade of mmap with MAP_FIXED s390/linker skript: discard exit.data at runtime drivers/media: add missing GENERIC_HARDIRQS dependency s390/bpf,jit: add vlan tag support drivers/net,AT91RM9200: add missing GENERIC_HARDIRQS dependency iucv: fix kernel panic at reboot s390/Kconfig: sort list of arch selected config options phylib: remove !S390 dependeny from Kconfig uio: remove !S390 dependency from Kconfig dasd: fix sysfs cleanup in dasd_generic_remove s390/pci: fix hotplug module init s390/pci: cleanup clp page allocation s390/pci: cleanup clp inline assembly s390/perf: cpum_cf: fallback to software sampling events s390/mm: provide PAGE_SHARED define ...
Powered by cgit, Gruvboxed by Blaster4385.