[ Upstream commit 11e7f27b79757b6586645d87b95d5b78375ecdfc ]
There is a pid leakage:
------------------------------
unreferenced object 0xffff88810c181940 (size 224):
comm "sshd", pid 8191, jiffies 4294946950 (age 524.570s)
hex dump (first 32 bytes):
01 00 00 00 00 00 00 00 00 00 00 00 ad 4e ad de .............N..
ff ff ff ff 6b 6b 6b 6b ff ff ff ff ff ff ff ff ....kkkk........
backtrace:
[<ffffffff814774e6>] kmem_cache_alloc+0x5c6/0x9b0
[<ffffffff81177342>] alloc_pid+0x72/0x570
[<ffffffff81140ac4>] copy_process+0x1374/0x2470
[<ffffffff81141d77>] kernel_clone+0xb7/0x900
[<ffffffff81142645>] __se_sys_clone+0x85/0xb0
[<ffffffff8114269b>] __x64_sys_clone+0x2b/0x30
[<ffffffff83965a72>] do_syscall_64+0x32/0x80
[<ffffffff83a00085>] entry_SYSCALL_64_after_hwframe+0x61/0xc6
It turns out that there is a race condition between disassociate_ctty() and
tty_signal_session_leader(), which caused this leakage.
The pid memleak is triggered by the following race:
task[sshd] task[bash]
----------------------- -----------------------
disassociate_ctty();
spin_lock_irq(¤t->sighand->siglock);
put_pid(current->signal->tty_old_pgrp);
current->signal->tty_old_pgrp = NULL;
tty = tty_kref_get(current->signal->tty);
spin_unlock_irq(¤t->sighand->siglock);
tty_vhangup();
tty_lock(tty);
...
tty_signal_session_leader();
spin_lock_irq(&p->sighand->siglock);
...
if (tty->ctrl.pgrp) //tty->ctrl.pgrp is not NULL
p->signal->tty_old_pgrp = get_pid(tty->ctrl.pgrp); //An extra get
spin_unlock_irq(&p->sighand->siglock);
...
tty_unlock(tty);
if (tty) {
tty_lock(tty);
...
put_pid(tty->ctrl.pgrp);
tty->ctrl.pgrp = NULL; //It's too late
...
tty_unlock(tty);
}
The issue is believed to be introduced by commit c8bcd9c5be24 ("tty:
Fix ->session locking") who moves the unlock of siglock in
disassociate_ctty() above "if (tty)", making a small window allowing
tty_signal_session_leader() to kick in. It can be easily reproduced by
adding a delay before "if (tty)" and at the entrance of
tty_signal_session_leader().
To fix this issue, we move "put_pid(current->signal->tty_old_pgrp)" after
"tty->ctrl.pgrp = NULL".
Fixes: c8bcd9c5be24 ("tty: Fix ->session locking")
Signed-off-by: Yi Yang <yiyang13@huawei.com>
Co-developed-by: GUO Zihua <guozihua@huawei.com>
Signed-off-by: GUO Zihua <guozihua@huawei.com>
Link: https://lore.kernel.org/r/20230831023329.165737-1-yiyang13@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 33092fb3af51deb80849e90a17bada44bbcde6b3 upstream.
The UC-257 is a serial + LPT card, so remove it from this driver.
A patch has been submitted to add it to parport_serial instead.
Additionaly, the UC-431 does not use this card ID, only the UC-420
does. The 431 is a 3-port card and there is no generic 3-port configuration
available, so remove reference to it from this driver.
Fixes: 152d1afa834c ("tty: Add support for Brainboxes UC cards.")
Cc: stable@vger.kernel.org
Signed-off-by: Cameron Williams <cang1@live.co.uk>
Link: https://lore.kernel.org/r/DU0PR02MB78995ADF7394C74AD4CF3357C4DBA@DU0PR02MB7899.eurprd02.prod.outlook.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 560706eff7c8e5621b0d63afe0866e0e1906e87e ]
We now get errors on system suspend if no_console_suspend is set as
reported by Thomas. The errors started with commit 20a41a62618d ("serial:
8250_omap: Use force_suspend and resume for system suspend").
Let's fix the issue by checking for console_suspend_enabled in the system
suspend and resume path.
Note that with this fix the checks for console_suspend_enabled in
omap8250_runtime_suspend() become useless. We now keep runtime PM usage
count for an attached kernel console starting with commit bedb404e91bb
("serial: 8250_port: Don't use power management for kernel console").
Fixes: 20a41a62618d ("serial: 8250_omap: Use force_suspend and resume for system suspend")
Cc: stable <stable@kernel.org>
Cc: Udit Kumar <u-kumar1@ti.com>
Reported-by: Thomas Richard <thomas.richard@bootlin.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Tested-by: Thomas Richard <thomas.richard@bootlin.com>
Reviewed-by: Dhruva Gole <d-gole@ti.com>
Link: https://lore.kernel.org/r/20230926061319.15140-1-tony@atomide.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 398cecc24846e867b9f90a0bd22730e3df6b05be ]
We must idle the uart only after serial8250_unregister_port(). Otherwise
unbinding the uart via sysfs while doing cat on the port produces an
imprecise external abort:
mem_serial_in from omap_8250_pm+0x44/0xf4
omap_8250_pm from uart_hangup+0xe0/0x194
uart_hangup from __tty_hangup.part.0+0x37c/0x3a8
__tty_hangup.part.0 from uart_remove_one_port+0x9c/0x22c
uart_remove_one_port from serial8250_unregister_port+0x60/0xe8
serial8250_unregister_port from omap8250_remove+0x6c/0xd0
omap8250_remove from platform_remove+0x28/0x54
Turns out the driver needs to have runtime PM functional before the
driver probe calls serial8250_register_8250_port(). And it needs
runtime PM after driver remove calls serial8250_unregister_port().
On probe, we need to read registers before registering the port in
omap_serial_fill_features_erratas(). We do that with custom uart_read()
already.
On remove, after serial8250_unregister_port(), we need to write to the
uart registers to idle the device. Let's add a custom uart_write() for
that.
Currently the uart register access depends on port->membase to be
initialized, which won't work after serial8250_unregister_port().
Let's use priv->membase instead, and use it for runtime PM related
functions to remove the dependency to port->membase for early and
late register access.
Note that during use, we need to check for a valid port in the runtime PM
related functions. This is needed for the optional wakeup configuration.
We now need to set the drvdata a bit earlier so it's available for the
runtime PM functions.
With the port checks in runtime PM functions, the old checks for priv in
omap8250_runtime_suspend() and omap8250_runtime_resume() functions are no
longer needed and are removed.
Signed-off-by: Tony Lindgren <tony@atomide.com>
Link: https://lore.kernel.org/r/20230508082014.23083-3-tony@atomide.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Stable-dep-of: 560706eff7c8 ("serial: 8250_omap: Fix errors with no_console_suspend")
Signed-off-by: Sasha Levin <sashal@kernel.org>
