The patch below does not apply to the 4.19-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-4.19.y
git checkout FETCH_HEAD
git cherry-pick -x 4903fde8047a28299d1fc79c1a0dcc255e928f12
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2023072112-trustful-carmaker-90a3@gregkh' --subject-prefix 'PATCH 4.19.y' HEAD^..
Possible dependencies:
4903fde8047a ("tty: fix hang on tty device with no_room set")
947d66b68f3c ("n_tty: Rename tail to old_tail in n_tty_read()")
64d608db38ff ("tty: cumulate and document tty_struct::ctrl* members")
6e94dbc7a4e4 ("tty: cumulate and document tty_struct::flow* members")
202680c7a937 ("tty: pty: Add a blank line after declarations")
3cfade53c773 ("Merge branch 'tty-splice' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux into tty-next")
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 4903fde8047a28299d1fc79c1a0dcc255e928f12 Mon Sep 17 00:00:00 2001
From: Hui Li <caelli(a)tencent.com>
Date: Thu, 6 Apr 2023 10:44:50 +0800
Subject: [PATCH] tty: fix hang on tty device with no_room set
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
It is possible to hang pty devices in this case, the reader was
blocking at epoll on master side, the writer was sleeping at
wait_woken inside n_tty_write on slave side, and the write buffer
on tty_port was full, we found that the reader and writer would
never be woken again and blocked forever.
The problem was caused by a race between reader and kworker:
n_tty_read(reader): n_tty_receive_buf_common(kworker):
copy_from_read_buf()|
|room = N_TTY_BUF_SIZE - (ldata->read_head - tail)
|room <= 0
n_tty_kick_worker() |
|ldata->no_room = true
After writing to slave device, writer wakes up kworker to flush
data on tty_port to reader, and the kworker finds that reader
has no room to store data so room <= 0 is met. At this moment,
reader consumes all the data on reader buffer and calls
n_tty_kick_worker to check ldata->no_room which is false and
reader quits reading. Then kworker sets ldata->no_room=true
and quits too.
If write buffer is not full, writer will wake kworker to flush data
again after following writes, but if write buffer is full and writer
goes to sleep, kworker will never be woken again and tty device is
blocked.
This problem can be solved with a check for read buffer size inside
n_tty_receive_buf_common, if read buffer is empty and ldata->no_room
is true, a call to n_tty_kick_worker is necessary to keep flushing
data to reader.
Cc: <stable(a)vger.kernel.org>
Fixes: 42458f41d08f ("n_tty: Ensure reader restarts worker for next reader")
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen(a)linux.intel.com>
Signed-off-by: Hui Li <caelli(a)tencent.com>
Message-ID: <1680749090-14106-1-git-send-email-caelli(a)tencent.com>
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c
index 1c9e5d2ea7de..552e8a741562 100644
--- a/drivers/tty/n_tty.c
+++ b/drivers/tty/n_tty.c
@@ -203,8 +203,8 @@ static void n_tty_kick_worker(struct tty_struct *tty)
struct n_tty_data *ldata = tty->disc_data;
/* Did the input worker stop? Restart it */
- if (unlikely(ldata->no_room)) {
- ldata->no_room = 0;
+ if (unlikely(READ_ONCE(ldata->no_room))) {
+ WRITE_ONCE(ldata->no_room, 0);
WARN_RATELIMIT(tty->port->itty == NULL,
"scheduling with invalid itty\n");
@@ -1697,7 +1697,7 @@ n_tty_receive_buf_common(struct tty_struct *tty, const unsigned char *cp,
if (overflow && room < 0)
ldata->read_head--;
room = overflow;
- ldata->no_room = flow && !room;
+ WRITE_ONCE(ldata->no_room, flow && !room);
} else
overflow = 0;
@@ -1728,6 +1728,17 @@ n_tty_receive_buf_common(struct tty_struct *tty, const unsigned char *cp,
} else
n_tty_check_throttle(tty);
+ if (unlikely(ldata->no_room)) {
+ /*
+ * Barrier here is to ensure to read the latest read_tail in
+ * chars_in_buffer() and to make sure that read_tail is not loaded
+ * before ldata->no_room is set.
+ */
+ smp_mb();
+ if (!chars_in_buffer(tty))
+ n_tty_kick_worker(tty);
+ }
+
up_read(&tty->termios_rwsem);
return rcvd;
@@ -2281,8 +2292,14 @@ static ssize_t n_tty_read(struct tty_struct *tty, struct file *file,
if (time)
timeout = time;
}
- if (old_tail != ldata->read_tail)
+ if (old_tail != ldata->read_tail) {
+ /*
+ * Make sure no_room is not read in n_tty_kick_worker()
+ * before setting ldata->read_tail in copy_from_read_buf().
+ */
+ smp_mb();
n_tty_kick_worker(tty);
+ }
up_read(&tty->termios_rwsem);
remove_wait_queue(&tty->read_wait, &wait);
The patch below does not apply to the 5.4-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.4.y
git checkout FETCH_HEAD
git cherry-pick -x 4903fde8047a28299d1fc79c1a0dcc255e928f12
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2023072110-lego-outplayed-b9d2@gregkh' --subject-prefix 'PATCH 5.4.y' HEAD^..
Possible dependencies:
4903fde8047a ("tty: fix hang on tty device with no_room set")
947d66b68f3c ("n_tty: Rename tail to old_tail in n_tty_read()")
64d608db38ff ("tty: cumulate and document tty_struct::ctrl* members")
6e94dbc7a4e4 ("tty: cumulate and document tty_struct::flow* members")
202680c7a937 ("tty: pty: Add a blank line after declarations")
3cfade53c773 ("Merge branch 'tty-splice' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux into tty-next")
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 4903fde8047a28299d1fc79c1a0dcc255e928f12 Mon Sep 17 00:00:00 2001
From: Hui Li <caelli(a)tencent.com>
Date: Thu, 6 Apr 2023 10:44:50 +0800
Subject: [PATCH] tty: fix hang on tty device with no_room set
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
It is possible to hang pty devices in this case, the reader was
blocking at epoll on master side, the writer was sleeping at
wait_woken inside n_tty_write on slave side, and the write buffer
on tty_port was full, we found that the reader and writer would
never be woken again and blocked forever.
The problem was caused by a race between reader and kworker:
n_tty_read(reader): n_tty_receive_buf_common(kworker):
copy_from_read_buf()|
|room = N_TTY_BUF_SIZE - (ldata->read_head - tail)
|room <= 0
n_tty_kick_worker() |
|ldata->no_room = true
After writing to slave device, writer wakes up kworker to flush
data on tty_port to reader, and the kworker finds that reader
has no room to store data so room <= 0 is met. At this moment,
reader consumes all the data on reader buffer and calls
n_tty_kick_worker to check ldata->no_room which is false and
reader quits reading. Then kworker sets ldata->no_room=true
and quits too.
If write buffer is not full, writer will wake kworker to flush data
again after following writes, but if write buffer is full and writer
goes to sleep, kworker will never be woken again and tty device is
blocked.
This problem can be solved with a check for read buffer size inside
n_tty_receive_buf_common, if read buffer is empty and ldata->no_room
is true, a call to n_tty_kick_worker is necessary to keep flushing
data to reader.
Cc: <stable(a)vger.kernel.org>
Fixes: 42458f41d08f ("n_tty: Ensure reader restarts worker for next reader")
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen(a)linux.intel.com>
Signed-off-by: Hui Li <caelli(a)tencent.com>
Message-ID: <1680749090-14106-1-git-send-email-caelli(a)tencent.com>
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c
index 1c9e5d2ea7de..552e8a741562 100644
--- a/drivers/tty/n_tty.c
+++ b/drivers/tty/n_tty.c
@@ -203,8 +203,8 @@ static void n_tty_kick_worker(struct tty_struct *tty)
struct n_tty_data *ldata = tty->disc_data;
/* Did the input worker stop? Restart it */
- if (unlikely(ldata->no_room)) {
- ldata->no_room = 0;
+ if (unlikely(READ_ONCE(ldata->no_room))) {
+ WRITE_ONCE(ldata->no_room, 0);
WARN_RATELIMIT(tty->port->itty == NULL,
"scheduling with invalid itty\n");
@@ -1697,7 +1697,7 @@ n_tty_receive_buf_common(struct tty_struct *tty, const unsigned char *cp,
if (overflow && room < 0)
ldata->read_head--;
room = overflow;
- ldata->no_room = flow && !room;
+ WRITE_ONCE(ldata->no_room, flow && !room);
} else
overflow = 0;
@@ -1728,6 +1728,17 @@ n_tty_receive_buf_common(struct tty_struct *tty, const unsigned char *cp,
} else
n_tty_check_throttle(tty);
+ if (unlikely(ldata->no_room)) {
+ /*
+ * Barrier here is to ensure to read the latest read_tail in
+ * chars_in_buffer() and to make sure that read_tail is not loaded
+ * before ldata->no_room is set.
+ */
+ smp_mb();
+ if (!chars_in_buffer(tty))
+ n_tty_kick_worker(tty);
+ }
+
up_read(&tty->termios_rwsem);
return rcvd;
@@ -2281,8 +2292,14 @@ static ssize_t n_tty_read(struct tty_struct *tty, struct file *file,
if (time)
timeout = time;
}
- if (old_tail != ldata->read_tail)
+ if (old_tail != ldata->read_tail) {
+ /*
+ * Make sure no_room is not read in n_tty_kick_worker()
+ * before setting ldata->read_tail in copy_from_read_buf().
+ */
+ smp_mb();
n_tty_kick_worker(tty);
+ }
up_read(&tty->termios_rwsem);
remove_wait_queue(&tty->read_wait, &wait);
The patch below does not apply to the 5.10-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.10.y
git checkout FETCH_HEAD
git cherry-pick -x 4903fde8047a28299d1fc79c1a0dcc255e928f12
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2023072109-guidable-shrill-b348@gregkh' --subject-prefix 'PATCH 5.10.y' HEAD^..
Possible dependencies:
4903fde8047a ("tty: fix hang on tty device with no_room set")
947d66b68f3c ("n_tty: Rename tail to old_tail in n_tty_read()")
64d608db38ff ("tty: cumulate and document tty_struct::ctrl* members")
6e94dbc7a4e4 ("tty: cumulate and document tty_struct::flow* members")
202680c7a937 ("tty: pty: Add a blank line after declarations")
3cfade53c773 ("Merge branch 'tty-splice' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux into tty-next")
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 4903fde8047a28299d1fc79c1a0dcc255e928f12 Mon Sep 17 00:00:00 2001
From: Hui Li <caelli(a)tencent.com>
Date: Thu, 6 Apr 2023 10:44:50 +0800
Subject: [PATCH] tty: fix hang on tty device with no_room set
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
It is possible to hang pty devices in this case, the reader was
blocking at epoll on master side, the writer was sleeping at
wait_woken inside n_tty_write on slave side, and the write buffer
on tty_port was full, we found that the reader and writer would
never be woken again and blocked forever.
The problem was caused by a race between reader and kworker:
n_tty_read(reader): n_tty_receive_buf_common(kworker):
copy_from_read_buf()|
|room = N_TTY_BUF_SIZE - (ldata->read_head - tail)
|room <= 0
n_tty_kick_worker() |
|ldata->no_room = true
After writing to slave device, writer wakes up kworker to flush
data on tty_port to reader, and the kworker finds that reader
has no room to store data so room <= 0 is met. At this moment,
reader consumes all the data on reader buffer and calls
n_tty_kick_worker to check ldata->no_room which is false and
reader quits reading. Then kworker sets ldata->no_room=true
and quits too.
If write buffer is not full, writer will wake kworker to flush data
again after following writes, but if write buffer is full and writer
goes to sleep, kworker will never be woken again and tty device is
blocked.
This problem can be solved with a check for read buffer size inside
n_tty_receive_buf_common, if read buffer is empty and ldata->no_room
is true, a call to n_tty_kick_worker is necessary to keep flushing
data to reader.
Cc: <stable(a)vger.kernel.org>
Fixes: 42458f41d08f ("n_tty: Ensure reader restarts worker for next reader")
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen(a)linux.intel.com>
Signed-off-by: Hui Li <caelli(a)tencent.com>
Message-ID: <1680749090-14106-1-git-send-email-caelli(a)tencent.com>
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c
index 1c9e5d2ea7de..552e8a741562 100644
--- a/drivers/tty/n_tty.c
+++ b/drivers/tty/n_tty.c
@@ -203,8 +203,8 @@ static void n_tty_kick_worker(struct tty_struct *tty)
struct n_tty_data *ldata = tty->disc_data;
/* Did the input worker stop? Restart it */
- if (unlikely(ldata->no_room)) {
- ldata->no_room = 0;
+ if (unlikely(READ_ONCE(ldata->no_room))) {
+ WRITE_ONCE(ldata->no_room, 0);
WARN_RATELIMIT(tty->port->itty == NULL,
"scheduling with invalid itty\n");
@@ -1697,7 +1697,7 @@ n_tty_receive_buf_common(struct tty_struct *tty, const unsigned char *cp,
if (overflow && room < 0)
ldata->read_head--;
room = overflow;
- ldata->no_room = flow && !room;
+ WRITE_ONCE(ldata->no_room, flow && !room);
} else
overflow = 0;
@@ -1728,6 +1728,17 @@ n_tty_receive_buf_common(struct tty_struct *tty, const unsigned char *cp,
} else
n_tty_check_throttle(tty);
+ if (unlikely(ldata->no_room)) {
+ /*
+ * Barrier here is to ensure to read the latest read_tail in
+ * chars_in_buffer() and to make sure that read_tail is not loaded
+ * before ldata->no_room is set.
+ */
+ smp_mb();
+ if (!chars_in_buffer(tty))
+ n_tty_kick_worker(tty);
+ }
+
up_read(&tty->termios_rwsem);
return rcvd;
@@ -2281,8 +2292,14 @@ static ssize_t n_tty_read(struct tty_struct *tty, struct file *file,
if (time)
timeout = time;
}
- if (old_tail != ldata->read_tail)
+ if (old_tail != ldata->read_tail) {
+ /*
+ * Make sure no_room is not read in n_tty_kick_worker()
+ * before setting ldata->read_tail in copy_from_read_buf().
+ */
+ smp_mb();
n_tty_kick_worker(tty);
+ }
up_read(&tty->termios_rwsem);
remove_wait_queue(&tty->read_wait, &wait);
The patch below does not apply to the 5.15-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y
git checkout FETCH_HEAD
git cherry-pick -x 4903fde8047a28299d1fc79c1a0dcc255e928f12
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2023072107-washbowl-exporter-0ed3@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^..
Possible dependencies:
4903fde8047a ("tty: fix hang on tty device with no_room set")
947d66b68f3c ("n_tty: Rename tail to old_tail in n_tty_read()")
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 4903fde8047a28299d1fc79c1a0dcc255e928f12 Mon Sep 17 00:00:00 2001
From: Hui Li <caelli(a)tencent.com>
Date: Thu, 6 Apr 2023 10:44:50 +0800
Subject: [PATCH] tty: fix hang on tty device with no_room set
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
It is possible to hang pty devices in this case, the reader was
blocking at epoll on master side, the writer was sleeping at
wait_woken inside n_tty_write on slave side, and the write buffer
on tty_port was full, we found that the reader and writer would
never be woken again and blocked forever.
The problem was caused by a race between reader and kworker:
n_tty_read(reader): n_tty_receive_buf_common(kworker):
copy_from_read_buf()|
|room = N_TTY_BUF_SIZE - (ldata->read_head - tail)
|room <= 0
n_tty_kick_worker() |
|ldata->no_room = true
After writing to slave device, writer wakes up kworker to flush
data on tty_port to reader, and the kworker finds that reader
has no room to store data so room <= 0 is met. At this moment,
reader consumes all the data on reader buffer and calls
n_tty_kick_worker to check ldata->no_room which is false and
reader quits reading. Then kworker sets ldata->no_room=true
and quits too.
If write buffer is not full, writer will wake kworker to flush data
again after following writes, but if write buffer is full and writer
goes to sleep, kworker will never be woken again and tty device is
blocked.
This problem can be solved with a check for read buffer size inside
n_tty_receive_buf_common, if read buffer is empty and ldata->no_room
is true, a call to n_tty_kick_worker is necessary to keep flushing
data to reader.
Cc: <stable(a)vger.kernel.org>
Fixes: 42458f41d08f ("n_tty: Ensure reader restarts worker for next reader")
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen(a)linux.intel.com>
Signed-off-by: Hui Li <caelli(a)tencent.com>
Message-ID: <1680749090-14106-1-git-send-email-caelli(a)tencent.com>
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c
index 1c9e5d2ea7de..552e8a741562 100644
--- a/drivers/tty/n_tty.c
+++ b/drivers/tty/n_tty.c
@@ -203,8 +203,8 @@ static void n_tty_kick_worker(struct tty_struct *tty)
struct n_tty_data *ldata = tty->disc_data;
/* Did the input worker stop? Restart it */
- if (unlikely(ldata->no_room)) {
- ldata->no_room = 0;
+ if (unlikely(READ_ONCE(ldata->no_room))) {
+ WRITE_ONCE(ldata->no_room, 0);
WARN_RATELIMIT(tty->port->itty == NULL,
"scheduling with invalid itty\n");
@@ -1697,7 +1697,7 @@ n_tty_receive_buf_common(struct tty_struct *tty, const unsigned char *cp,
if (overflow && room < 0)
ldata->read_head--;
room = overflow;
- ldata->no_room = flow && !room;
+ WRITE_ONCE(ldata->no_room, flow && !room);
} else
overflow = 0;
@@ -1728,6 +1728,17 @@ n_tty_receive_buf_common(struct tty_struct *tty, const unsigned char *cp,
} else
n_tty_check_throttle(tty);
+ if (unlikely(ldata->no_room)) {
+ /*
+ * Barrier here is to ensure to read the latest read_tail in
+ * chars_in_buffer() and to make sure that read_tail is not loaded
+ * before ldata->no_room is set.
+ */
+ smp_mb();
+ if (!chars_in_buffer(tty))
+ n_tty_kick_worker(tty);
+ }
+
up_read(&tty->termios_rwsem);
return rcvd;
@@ -2281,8 +2292,14 @@ static ssize_t n_tty_read(struct tty_struct *tty, struct file *file,
if (time)
timeout = time;
}
- if (old_tail != ldata->read_tail)
+ if (old_tail != ldata->read_tail) {
+ /*
+ * Make sure no_room is not read in n_tty_kick_worker()
+ * before setting ldata->read_tail in copy_from_read_buf().
+ */
+ smp_mb();
n_tty_kick_worker(tty);
+ }
up_read(&tty->termios_rwsem);
remove_wait_queue(&tty->read_wait, &wait);
The patch below does not apply to the 6.1-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.1.y
git checkout FETCH_HEAD
git cherry-pick -x 4903fde8047a28299d1fc79c1a0dcc255e928f12
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2023072106-ripening-magician-6a5e@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^..
Possible dependencies:
4903fde8047a ("tty: fix hang on tty device with no_room set")
947d66b68f3c ("n_tty: Rename tail to old_tail in n_tty_read()")
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 4903fde8047a28299d1fc79c1a0dcc255e928f12 Mon Sep 17 00:00:00 2001
From: Hui Li <caelli(a)tencent.com>
Date: Thu, 6 Apr 2023 10:44:50 +0800
Subject: [PATCH] tty: fix hang on tty device with no_room set
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
It is possible to hang pty devices in this case, the reader was
blocking at epoll on master side, the writer was sleeping at
wait_woken inside n_tty_write on slave side, and the write buffer
on tty_port was full, we found that the reader and writer would
never be woken again and blocked forever.
The problem was caused by a race between reader and kworker:
n_tty_read(reader): n_tty_receive_buf_common(kworker):
copy_from_read_buf()|
|room = N_TTY_BUF_SIZE - (ldata->read_head - tail)
|room <= 0
n_tty_kick_worker() |
|ldata->no_room = true
After writing to slave device, writer wakes up kworker to flush
data on tty_port to reader, and the kworker finds that reader
has no room to store data so room <= 0 is met. At this moment,
reader consumes all the data on reader buffer and calls
n_tty_kick_worker to check ldata->no_room which is false and
reader quits reading. Then kworker sets ldata->no_room=true
and quits too.
If write buffer is not full, writer will wake kworker to flush data
again after following writes, but if write buffer is full and writer
goes to sleep, kworker will never be woken again and tty device is
blocked.
This problem can be solved with a check for read buffer size inside
n_tty_receive_buf_common, if read buffer is empty and ldata->no_room
is true, a call to n_tty_kick_worker is necessary to keep flushing
data to reader.
Cc: <stable(a)vger.kernel.org>
Fixes: 42458f41d08f ("n_tty: Ensure reader restarts worker for next reader")
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen(a)linux.intel.com>
Signed-off-by: Hui Li <caelli(a)tencent.com>
Message-ID: <1680749090-14106-1-git-send-email-caelli(a)tencent.com>
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c
index 1c9e5d2ea7de..552e8a741562 100644
--- a/drivers/tty/n_tty.c
+++ b/drivers/tty/n_tty.c
@@ -203,8 +203,8 @@ static void n_tty_kick_worker(struct tty_struct *tty)
struct n_tty_data *ldata = tty->disc_data;
/* Did the input worker stop? Restart it */
- if (unlikely(ldata->no_room)) {
- ldata->no_room = 0;
+ if (unlikely(READ_ONCE(ldata->no_room))) {
+ WRITE_ONCE(ldata->no_room, 0);
WARN_RATELIMIT(tty->port->itty == NULL,
"scheduling with invalid itty\n");
@@ -1697,7 +1697,7 @@ n_tty_receive_buf_common(struct tty_struct *tty, const unsigned char *cp,
if (overflow && room < 0)
ldata->read_head--;
room = overflow;
- ldata->no_room = flow && !room;
+ WRITE_ONCE(ldata->no_room, flow && !room);
} else
overflow = 0;
@@ -1728,6 +1728,17 @@ n_tty_receive_buf_common(struct tty_struct *tty, const unsigned char *cp,
} else
n_tty_check_throttle(tty);
+ if (unlikely(ldata->no_room)) {
+ /*
+ * Barrier here is to ensure to read the latest read_tail in
+ * chars_in_buffer() and to make sure that read_tail is not loaded
+ * before ldata->no_room is set.
+ */
+ smp_mb();
+ if (!chars_in_buffer(tty))
+ n_tty_kick_worker(tty);
+ }
+
up_read(&tty->termios_rwsem);
return rcvd;
@@ -2281,8 +2292,14 @@ static ssize_t n_tty_read(struct tty_struct *tty, struct file *file,
if (time)
timeout = time;
}
- if (old_tail != ldata->read_tail)
+ if (old_tail != ldata->read_tail) {
+ /*
+ * Make sure no_room is not read in n_tty_kick_worker()
+ * before setting ldata->read_tail in copy_from_read_buf().
+ */
+ smp_mb();
n_tty_kick_worker(tty);
+ }
up_read(&tty->termios_rwsem);
remove_wait_queue(&tty->read_wait, &wait);
The patch below does not apply to the 5.15-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y
git checkout FETCH_HEAD
git cherry-pick -x e8188c461ee015ba0b9ab2fc82dbd5ebca5a5532
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2023072126-altitude-coexist-08f2@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^..
Possible dependencies:
e8188c461ee0 ("drm/ttm: Don't leak a resource on eviction error")
8ab3b0663e27 ("drm/ttm: Don't print error message if eviction was interrupted")
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From e8188c461ee015ba0b9ab2fc82dbd5ebca5a5532 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Thomas=20Hellstr=C3=B6m?= <thomas.hellstrom(a)linux.intel.com>
Date: Mon, 26 Jun 2023 11:14:49 +0200
Subject: [PATCH] drm/ttm: Don't leak a resource on eviction error
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
On eviction errors other than -EMULTIHOP we were leaking a resource.
Fix.
v2:
- Avoid yet another goto (Andi Shyti)
Fixes: 403797925768 ("drm/ttm: Fix multihop assert on eviction.")
Cc: Andrey Grodzovsky <andrey.grodzovsky(a)amd.com>
Cc: Christian König <christian.koenig(a)amd.com>
Cc: Christian Koenig <christian.koenig(a)amd.com>
Cc: Huang Rui <ray.huang(a)amd.com>
Cc: dri-devel(a)lists.freedesktop.org
Cc: <stable(a)vger.kernel.org> # v5.15+
Signed-off-by: Thomas Hellström <thomas.hellstrom(a)linux.intel.com>
Reviewed-by: Nirmoy Das <nirmoy.das(a)intel.com> #v1
Reviewed-by: Andi Shyti <andi.shyti(a)linux.intel.com>
Reviewed-by: Christian König <christian.koenig(a)amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230626091450.14757-4-thomas…
diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
index bd5dae4d1624..d364639a2752 100644
--- a/drivers/gpu/drm/ttm/ttm_bo.c
+++ b/drivers/gpu/drm/ttm/ttm_bo.c
@@ -458,18 +458,18 @@ static int ttm_bo_evict(struct ttm_buffer_object *bo,
goto out;
}
-bounce:
- ret = ttm_bo_handle_move_mem(bo, evict_mem, true, ctx, &hop);
- if (ret == -EMULTIHOP) {
+ do {
+ ret = ttm_bo_handle_move_mem(bo, evict_mem, true, ctx, &hop);
+ if (ret != -EMULTIHOP)
+ break;
+
ret = ttm_bo_bounce_temp_buffer(bo, &evict_mem, ctx, &hop);
- if (ret) {
- if (ret != -ERESTARTSYS && ret != -EINTR)
- pr_err("Buffer eviction failed\n");
- ttm_resource_free(bo, &evict_mem);
- goto out;
- }
- /* try and move to final place now. */
- goto bounce;
+ } while (!ret);
+
+ if (ret) {
+ ttm_resource_free(bo, &evict_mem);
+ if (ret != -ERESTARTSYS && ret != -EINTR)
+ pr_err("Buffer eviction failed\n");
}
out:
return ret;
The patch below does not apply to the 6.1-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.1.y
git checkout FETCH_HEAD
git cherry-pick -x e8188c461ee015ba0b9ab2fc82dbd5ebca5a5532
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2023072125-simple-gents-c119@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^..
Possible dependencies:
e8188c461ee0 ("drm/ttm: Don't leak a resource on eviction error")
8ab3b0663e27 ("drm/ttm: Don't print error message if eviction was interrupted")
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From e8188c461ee015ba0b9ab2fc82dbd5ebca5a5532 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Thomas=20Hellstr=C3=B6m?= <thomas.hellstrom(a)linux.intel.com>
Date: Mon, 26 Jun 2023 11:14:49 +0200
Subject: [PATCH] drm/ttm: Don't leak a resource on eviction error
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
On eviction errors other than -EMULTIHOP we were leaking a resource.
Fix.
v2:
- Avoid yet another goto (Andi Shyti)
Fixes: 403797925768 ("drm/ttm: Fix multihop assert on eviction.")
Cc: Andrey Grodzovsky <andrey.grodzovsky(a)amd.com>
Cc: Christian König <christian.koenig(a)amd.com>
Cc: Christian Koenig <christian.koenig(a)amd.com>
Cc: Huang Rui <ray.huang(a)amd.com>
Cc: dri-devel(a)lists.freedesktop.org
Cc: <stable(a)vger.kernel.org> # v5.15+
Signed-off-by: Thomas Hellström <thomas.hellstrom(a)linux.intel.com>
Reviewed-by: Nirmoy Das <nirmoy.das(a)intel.com> #v1
Reviewed-by: Andi Shyti <andi.shyti(a)linux.intel.com>
Reviewed-by: Christian König <christian.koenig(a)amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230626091450.14757-4-thomas…
diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
index bd5dae4d1624..d364639a2752 100644
--- a/drivers/gpu/drm/ttm/ttm_bo.c
+++ b/drivers/gpu/drm/ttm/ttm_bo.c
@@ -458,18 +458,18 @@ static int ttm_bo_evict(struct ttm_buffer_object *bo,
goto out;
}
-bounce:
- ret = ttm_bo_handle_move_mem(bo, evict_mem, true, ctx, &hop);
- if (ret == -EMULTIHOP) {
+ do {
+ ret = ttm_bo_handle_move_mem(bo, evict_mem, true, ctx, &hop);
+ if (ret != -EMULTIHOP)
+ break;
+
ret = ttm_bo_bounce_temp_buffer(bo, &evict_mem, ctx, &hop);
- if (ret) {
- if (ret != -ERESTARTSYS && ret != -EINTR)
- pr_err("Buffer eviction failed\n");
- ttm_resource_free(bo, &evict_mem);
- goto out;
- }
- /* try and move to final place now. */
- goto bounce;
+ } while (!ret);
+
+ if (ret) {
+ ttm_resource_free(bo, &evict_mem);
+ if (ret != -ERESTARTSYS && ret != -EINTR)
+ pr_err("Buffer eviction failed\n");
}
out:
return ret;
The patch below does not apply to the 6.4-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.4.y
git checkout FETCH_HEAD
git cherry-pick -x 188623076d0f1a500583d392b6187056bf7cc71a
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2023072156-winking-doornail-c9cc@gregkh' --subject-prefix 'PATCH 6.4.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 188623076d0f1a500583d392b6187056bf7cc71a Mon Sep 17 00:00:00 2001
From: Mario Limonciello <mario.limonciello(a)amd.com>
Date: Fri, 7 Jul 2023 21:26:08 -0500
Subject: [PATCH] drm/amd: Move helper for dynamic speed switch check out of
smu13
This helper is used for checking if the connected host supports
the feature, it can be moved into generic code to be used by other
smu implementations as well.
Signed-off-by: Mario Limonciello <mario.limonciello(a)amd.com>
Reviewed-by: Evan Quan <evan.quan(a)amd.com>
Signed-off-by: Alex Deucher <alexander.deucher(a)amd.com>
Cc: stable(a)vger.kernel.org # 6.1.x
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
index 2f9c14aca73c..a3b86b86dc47 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
@@ -1296,6 +1296,7 @@ int amdgpu_device_gpu_recover(struct amdgpu_device *adev,
void amdgpu_device_pci_config_reset(struct amdgpu_device *adev);
int amdgpu_device_pci_reset(struct amdgpu_device *adev);
bool amdgpu_device_need_post(struct amdgpu_device *adev);
+bool amdgpu_device_pcie_dynamic_switching_supported(void);
bool amdgpu_device_should_use_aspm(struct amdgpu_device *adev);
bool amdgpu_device_aspm_support_quirk(void);
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
index a92c6189b4b6..a2cdde0ca0a7 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
@@ -1458,6 +1458,25 @@ bool amdgpu_device_need_post(struct amdgpu_device *adev)
return true;
}
+/*
+ * Intel hosts such as Raptor Lake and Sapphire Rapids don't support dynamic
+ * speed switching. Until we have confirmation from Intel that a specific host
+ * supports it, it's safer that we keep it disabled for all.
+ *
+ * https://edc.intel.com/content/www/us/en/design/products/platforms/details/r…
+ * https://gitlab.freedesktop.org/drm/amd/-/issues/2663
+ */
+bool amdgpu_device_pcie_dynamic_switching_supported(void)
+{
+#if IS_ENABLED(CONFIG_X86)
+ struct cpuinfo_x86 *c = &cpu_data(0);
+
+ if (c->x86_vendor == X86_VENDOR_INTEL)
+ return false;
+#endif
+ return true;
+}
+
/**
* amdgpu_device_should_use_aspm - check if the device should program ASPM
*
diff --git a/drivers/gpu/drm/amd/pm/swsmu/smu13/smu_v13_0.c b/drivers/gpu/drm/amd/pm/swsmu/smu13/smu_v13_0.c
index cf7e729020ab..9b62b45ebb7f 100644
--- a/drivers/gpu/drm/amd/pm/swsmu/smu13/smu_v13_0.c
+++ b/drivers/gpu/drm/amd/pm/swsmu/smu13/smu_v13_0.c
@@ -2425,25 +2425,6 @@ int smu_v13_0_mode1_reset(struct smu_context *smu)
return ret;
}
-/*
- * Intel hosts such as Raptor Lake and Sapphire Rapids don't support dynamic
- * speed switching. Until we have confirmation from Intel that a specific host
- * supports it, it's safer that we keep it disabled for all.
- *
- * https://edc.intel.com/content/www/us/en/design/products/platforms/details/r…
- * https://gitlab.freedesktop.org/drm/amd/-/issues/2663
- */
-static bool smu_v13_0_is_pcie_dynamic_switching_supported(void)
-{
-#if IS_ENABLED(CONFIG_X86)
- struct cpuinfo_x86 *c = &cpu_data(0);
-
- if (c->x86_vendor == X86_VENDOR_INTEL)
- return false;
-#endif
- return true;
-}
-
int smu_v13_0_update_pcie_parameters(struct smu_context *smu,
uint32_t pcie_gen_cap,
uint32_t pcie_width_cap)
@@ -2455,7 +2436,7 @@ int smu_v13_0_update_pcie_parameters(struct smu_context *smu,
uint32_t smu_pcie_arg;
int ret, i;
- if (!smu_v13_0_is_pcie_dynamic_switching_supported()) {
+ if (!amdgpu_device_pcie_dynamic_switching_supported()) {
if (pcie_table->pcie_gen[num_of_levels - 1] < pcie_gen_cap)
pcie_gen_cap = pcie_table->pcie_gen[num_of_levels - 1];
The patch below does not apply to the 6.1-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.1.y
git checkout FETCH_HEAD
git cherry-pick -x 188623076d0f1a500583d392b6187056bf7cc71a
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2023072155-sculptor-untoasted-d8ce@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^..
Possible dependencies:
188623076d0f ("drm/amd: Move helper for dynamic speed switch check out of smu13")
31c7a3b378a1 ("drm/amd/pm: conditionally disable pcie lane/speed switching for SMU13")
dcb489bae65d ("drm/amd/pm: share the code around SMU13 pcie parameters update")
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 188623076d0f1a500583d392b6187056bf7cc71a Mon Sep 17 00:00:00 2001
From: Mario Limonciello <mario.limonciello(a)amd.com>
Date: Fri, 7 Jul 2023 21:26:08 -0500
Subject: [PATCH] drm/amd: Move helper for dynamic speed switch check out of
smu13
This helper is used for checking if the connected host supports
the feature, it can be moved into generic code to be used by other
smu implementations as well.
Signed-off-by: Mario Limonciello <mario.limonciello(a)amd.com>
Reviewed-by: Evan Quan <evan.quan(a)amd.com>
Signed-off-by: Alex Deucher <alexander.deucher(a)amd.com>
Cc: stable(a)vger.kernel.org # 6.1.x
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
index 2f9c14aca73c..a3b86b86dc47 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
@@ -1296,6 +1296,7 @@ int amdgpu_device_gpu_recover(struct amdgpu_device *adev,
void amdgpu_device_pci_config_reset(struct amdgpu_device *adev);
int amdgpu_device_pci_reset(struct amdgpu_device *adev);
bool amdgpu_device_need_post(struct amdgpu_device *adev);
+bool amdgpu_device_pcie_dynamic_switching_supported(void);
bool amdgpu_device_should_use_aspm(struct amdgpu_device *adev);
bool amdgpu_device_aspm_support_quirk(void);
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
index a92c6189b4b6..a2cdde0ca0a7 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
@@ -1458,6 +1458,25 @@ bool amdgpu_device_need_post(struct amdgpu_device *adev)
return true;
}
+/*
+ * Intel hosts such as Raptor Lake and Sapphire Rapids don't support dynamic
+ * speed switching. Until we have confirmation from Intel that a specific host
+ * supports it, it's safer that we keep it disabled for all.
+ *
+ * https://edc.intel.com/content/www/us/en/design/products/platforms/details/r…
+ * https://gitlab.freedesktop.org/drm/amd/-/issues/2663
+ */
+bool amdgpu_device_pcie_dynamic_switching_supported(void)
+{
+#if IS_ENABLED(CONFIG_X86)
+ struct cpuinfo_x86 *c = &cpu_data(0);
+
+ if (c->x86_vendor == X86_VENDOR_INTEL)
+ return false;
+#endif
+ return true;
+}
+
/**
* amdgpu_device_should_use_aspm - check if the device should program ASPM
*
diff --git a/drivers/gpu/drm/amd/pm/swsmu/smu13/smu_v13_0.c b/drivers/gpu/drm/amd/pm/swsmu/smu13/smu_v13_0.c
index cf7e729020ab..9b62b45ebb7f 100644
--- a/drivers/gpu/drm/amd/pm/swsmu/smu13/smu_v13_0.c
+++ b/drivers/gpu/drm/amd/pm/swsmu/smu13/smu_v13_0.c
@@ -2425,25 +2425,6 @@ int smu_v13_0_mode1_reset(struct smu_context *smu)
return ret;
}
-/*
- * Intel hosts such as Raptor Lake and Sapphire Rapids don't support dynamic
- * speed switching. Until we have confirmation from Intel that a specific host
- * supports it, it's safer that we keep it disabled for all.
- *
- * https://edc.intel.com/content/www/us/en/design/products/platforms/details/r…
- * https://gitlab.freedesktop.org/drm/amd/-/issues/2663
- */
-static bool smu_v13_0_is_pcie_dynamic_switching_supported(void)
-{
-#if IS_ENABLED(CONFIG_X86)
- struct cpuinfo_x86 *c = &cpu_data(0);
-
- if (c->x86_vendor == X86_VENDOR_INTEL)
- return false;
-#endif
- return true;
-}
-
int smu_v13_0_update_pcie_parameters(struct smu_context *smu,
uint32_t pcie_gen_cap,
uint32_t pcie_width_cap)
@@ -2455,7 +2436,7 @@ int smu_v13_0_update_pcie_parameters(struct smu_context *smu,
uint32_t smu_pcie_arg;
int ret, i;
- if (!smu_v13_0_is_pcie_dynamic_switching_supported()) {
+ if (!amdgpu_device_pcie_dynamic_switching_supported()) {
if (pcie_table->pcie_gen[num_of_levels - 1] < pcie_gen_cap)
pcie_gen_cap = pcie_table->pcie_gen[num_of_levels - 1];