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| author | Dmitry Vyukov | 2015-09-17 17:17:08 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman | 2015-10-04 20:03:40 +0200 |
| commit | 7098296a362a96051fa120abf48f0095818b99cd (patch) | |
| tree | d5faab1ed808c7fc3d55be88d431452b43e1e63e /drivers/tty | |
| parent | tty: fix stall caused by missing memory barrier in drivers/tty/n_tty.c (diff) | |
| download | kernel-qcow2-linux-7098296a362a96051fa120abf48f0095818b99cd.tar.gz kernel-qcow2-linux-7098296a362a96051fa120abf48f0095818b99cd.tar.xz kernel-qcow2-linux-7098296a362a96051fa120abf48f0095818b99cd.zip | |
tty: fix data race in flush_to_ldisc
flush_to_ldisc reads port->itty and checks that it is not NULL,
concurrently release_tty sets port->itty to NULL. It is possible
that flush_to_ldisc loads port->itty once, ensures that it is
not NULL, but then reloads it again and uses. The second load
can already return NULL, which will cause a crash.
Use READ_ONCE to read port->itty.
The data race was found with KernelThreadSanitizer (KTSAN).
Signed-off-by: Dmitry Vyukov <dvyukov@google.com>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty')
| -rw-r--r-- | drivers/tty/tty_buffer.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/tty/tty_buffer.c b/drivers/tty/tty_buffer.c index 5a3fa8913880..23de97de09a4 100644 --- a/drivers/tty/tty_buffer.c +++ b/drivers/tty/tty_buffer.c @@ -467,7 +467,7 @@ static void flush_to_ldisc(struct work_struct *work) struct tty_struct *tty; struct tty_ldisc *disc; - tty = port->itty; + tty = READ_ONCE(port->itty); if (tty == NULL) return; |