[PATCH AUTOSEL 3.18 1/4] Input: mousedev - add a schedule point in mousedev_write()

[PATCH AUTOSEL 3.18 1/4] Input: mousedev - add a schedule point in mousedev_write()

[Sasha Levin]

From: Eric Dumazet <edumazet@google.com>

[ Upstream commit f74c371fe72a4f820d287db8067683fb533e4ede ]

syzbot was able to trigger rcu stalls by calling write()
with large number of bytes.

Add a cond_resched() in the loop to avoid this.

Link: https://lkml.org/lkml/2018/8/23/1106
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot+9436b02171ac0894d33e@syzkaller.appspotmail.com
Reviewed-by: Paul E. McKenney <paulmck@linux.ibm.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/input/mousedev.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/input/mousedev.c b/drivers/input/mousedev.c
index b604564dec5c..036acf861496 100644
--- a/drivers/input/mousedev.c
+++ b/drivers/input/mousedev.c
@@ -701,6 +701,7 @@ static ssize_t mousedev_write(struct file *file, const char __user *buffer,
 		mousedev_generate_response(client, c);
 
 		spin_unlock_irq(&client->packet_lock);
+		cond_resched();
 	}
 
 	kill_fasync(&client->fasync, SIGIO, POLL_IN);
-- 
2.17.1

[PATCH AUTOSEL 3.18 2/4] Input: evdev - add a schedule point in evdev_write()

[Sasha Levin]

From: Dmitry Torokhov <dmitry.torokhov@gmail.com>

[ Upstream commit 36d2582ff235b4e01ad64a734c877a52dc762d9c ]

Large writes to evdev interface may cause rcu stalls. Let's add
cond_resched() to the loop to avoid this.

Reviewed-by: Paul E. McKenney <paulmck@linux.ibm.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/input/evdev.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/input/evdev.c b/drivers/input/evdev.c
index 928dec311c2b..6e054aae1f50 100644
--- a/drivers/input/evdev.c
+++ b/drivers/input/evdev.c
@@ -450,6 +450,7 @@ static ssize_t evdev_write(struct file *file, const char __user *buffer,
 
 		input_inject_event(&evdev->handle,
 				   event.type, event.code, event.value);
+		cond_resched();
 	}
 
  out:
-- 
2.17.1

[PATCH AUTOSEL 3.18 3/4] Input: uinput - add a schedule point in uinput_inject_events()

[Sasha Levin]

From: Dmitry Torokhov <dmitry.torokhov@gmail.com>

[ Upstream commit cecf10704899467a787975e3d94a1f0129b9688e ]

Large writes to uinput interface may cause rcu stalls. Let's add
cond_resched() to the loop to avoid this.

Reviewed-by: Paul E. McKenney <paulmck@linux.ibm.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/input/misc/uinput.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/input/misc/uinput.c b/drivers/input/misc/uinput.c
index 5221450f9b57..0cc05a4cf685 100644
--- a/drivers/input/misc/uinput.c
+++ b/drivers/input/misc/uinput.c
@@ -456,6 +456,7 @@ static ssize_t uinput_inject_events(struct uinput_device *udev,
 
 		input_event(udev->dev, ev.type, ev.code, ev.value);
 		bytes += input_event_size();
+		cond_resched();
 	}
 
 	return bytes;
-- 
2.17.1

[PATCH AUTOSEL 3.18 4/4] fs/fat/fatent.c: add cond_resched() to fat_count_free_clusters()

[Sasha Levin]

From: Khazhismel Kumykov <khazhy@google.com>

[ Upstream commit ac081c3be3fae6d0cc3e1862507fca3862d30b67 ]

On non-preempt kernels this loop can take a long time (more than 50 ticks)
processing through entries.

Link: http://lkml.kernel.org/r/20181010172623.57033-1-khazhy@google.com
Signed-off-by: Khazhismel Kumykov <khazhy@google.com>
Acked-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/fat/fatent.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/fs/fat/fatent.c b/fs/fat/fatent.c
index 08b3db146888..83550ac31f49 100644
--- a/fs/fat/fatent.c
+++ b/fs/fat/fatent.c
@@ -684,6 +684,7 @@ int fat_count_free_clusters(struct super_block *sb)
 			if (ops->ent_get(&fatent) == FAT_ENT_FREE)
 				free++;
 		} while (fat_ent_next(sbi, &fatent));
+		cond_resched();
 	}
 	sbi->free_clusters = free;
 	sbi->free_clus_valid = 1;
-- 
2.17.1