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| author | Jiri Slaby <jslaby@suse.cz> | 2016-03-22 18:09:51 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2016-04-28 20:07:10 -0700 |
| commit | d175feca89a1c162f60f4e3560ca7bc9437c65eb (patch) | |
| tree | a6dca7f533dbfef9ca45f0b81f31f3d68a278eaf /drivers/tty/n_gsm.c | |
| parent | 6f210c18c1c0f016772c8cd51ae12a02bfb9e7ef (diff) | |
| download | lwn-d175feca89a1c162f60f4e3560ca7bc9437c65eb.tar.gz lwn-d175feca89a1c162f60f4e3560ca7bc9437c65eb.zip | |
TTY: n_gsm, fix false positive WARN_ON
Dmitry reported, that the current cleanup code in n_gsm can trigger a
warning:
WARNING: CPU: 2 PID: 24238 at drivers/tty/n_gsm.c:2048 gsm_cleanup_mux+0x166/0x6b0()
...
Call Trace:
...
[<ffffffff81247ab9>] warn_slowpath_null+0x29/0x30 kernel/panic.c:490
[<ffffffff828d0456>] gsm_cleanup_mux+0x166/0x6b0 drivers/tty/n_gsm.c:2048
[<ffffffff828d4d87>] gsmld_open+0x5b7/0x7a0 drivers/tty/n_gsm.c:2386
[<ffffffff828b9078>] tty_ldisc_open.isra.2+0x78/0xd0 drivers/tty/tty_ldisc.c:447
[<ffffffff828b973a>] tty_set_ldisc+0x1ca/0xa70 drivers/tty/tty_ldisc.c:567
[< inline >] tiocsetd drivers/tty/tty_io.c:2650
[<ffffffff828a14ea>] tty_ioctl+0xb2a/0x2140 drivers/tty/tty_io.c:2883
...
But this is a legal path when open fails to find a space in the
gsm_mux array and tries to clean up. So make it a standard test
instead of a warning.
Reported-by: "Dmitry Vyukov" <dvyukov@google.com>
Cc: Alan Cox <alan@linux.intel.com>
Link: http://lkml.kernel.org/r/CACT4Y+bHQbAB68VFi7Romcs-Z9ZW3kQRvcq+BvHH1oa5NcAdLA@mail.gmail.com
Fixes: 5a640967 ("tty/n_gsm.c: fix a memory leak in gsmld_open()")
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty/n_gsm.c')
| -rw-r--r-- | drivers/tty/n_gsm.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c index c01620780f5b..365dfd8bc42b 100644 --- a/drivers/tty/n_gsm.c +++ b/drivers/tty/n_gsm.c @@ -2045,7 +2045,9 @@ static void gsm_cleanup_mux(struct gsm_mux *gsm) } } spin_unlock(&gsm_mux_lock); - WARN_ON(i == MAX_MUX); + /* open failed before registering => nothing to do */ + if (i == MAX_MUX) + return; /* In theory disconnecting DLCI 0 is sufficient but for some modems this is apparently not the case. */ |