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| author | Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> | 2018-04-25 14:12:31 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-04-25 16:03:44 +0300 |
| commit | bcdd0ca8cb8730573afebcaae4138f8f4c8eaa20 (patch) | |
| tree | b022d1770f2ab76607c0071636e2012daa678cdb | |
| parent | 66dd99c2033684169f04068f66c7f83f7da229b8 (diff) | |
| download | linux-bcdd0ca8cb8730573afebcaae4138f8f4c8eaa20.tar.xz | |
tty: Use __GFP_NOFAIL for tty_ldisc_get()
syzbot is reporting crashes triggered by memory allocation fault injection
at tty_ldisc_get() [1]. As an attempt to handle OOM in a graceful way, we
have tried commit 5362544bebe85071 ("tty: don't panic on OOM in
tty_set_ldisc()"). But we reverted that attempt by commit a8983d01f9b7d600
("Revert "tty: don't panic on OOM in tty_set_ldisc()"") due to reproducible
crash. We should spend resource for finding and fixing race condition bugs
rather than complicate error paths for 2 * sizeof(void *) bytes allocation
failure.
[1] https://syzkaller.appspot.com/bug?id=489d33fa386453859ead58ff5171d43772b13aa3
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Reported-by: syzbot <syzbot+40b7287c2dc987c48c81@syzkaller.appspotmail.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Vegard Nossum <vegard.nossum@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: Peter Hurley <peter@hurleysoftware.com>
Cc: One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/tty/tty_ldisc.c | 11 |
1 files changed, 5 insertions, 6 deletions
diff --git a/drivers/tty/tty_ldisc.c b/drivers/tty/tty_ldisc.c index 8a88a7787cfe..fb7329ab2b37 100644 --- a/drivers/tty/tty_ldisc.c +++ b/drivers/tty/tty_ldisc.c @@ -176,12 +176,11 @@ static struct tty_ldisc *tty_ldisc_get(struct tty_struct *tty, int disc) return ERR_CAST(ldops); } - ld = kmalloc(sizeof(struct tty_ldisc), GFP_KERNEL); - if (ld == NULL) { - put_ldops(ldops); - return ERR_PTR(-ENOMEM); - } - + /* + * There is no way to handle allocation failure of only 16 bytes. + * Let's simplify error handling and save more memory. + */ + ld = kmalloc(sizeof(struct tty_ldisc), GFP_KERNEL | __GFP_NOFAIL); ld->ops = ldops; ld->tty = tty; |