Revision 0ace17d56824165c7f4c68785d6b58971db954dd authored by Richard Palethorpe on 21 January 2020, 13:42:58 UTC, committed by David S. Miller on 22 January 2020, 19:32:03 UTC
write_wakeup can happen in parallel with close/hangup where tty->disc_data
is set to NULL and the netdevice is freed thus also freeing
disc_data. write_wakeup accesses disc_data so we must prevent close from
freeing the netdev while write_wakeup has a non-NULL view of
tty->disc_data.
We also need to make sure that accesses to disc_data are atomic. Which can
all be done with RCU.
This problem was found by Syzkaller on SLCAN, but the same issue is
reproducible with the SLIP line discipline using an LTP test based on the
Syzkaller reproducer.
A fix which didn't use RCU was posted by Hillf Danton.
Fixes: 661f7fda21b1 ("slip: Fix deadlock in write_wakeup")
Fixes: a8e83b17536a ("slcan: Port write_wakeup deadlock fix from slip")
Reported-by: syzbot+017e491ae13c0068598a@syzkaller.appspotmail.com
Signed-off-by: Richard Palethorpe <rpalethorpe@suse.com>
Cc: Wolfgang Grandegger <wg@grandegger.com>
Cc: Marc Kleine-Budde <mkl@pengutronix.de>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Tyler Hall <tylerwhall@gmail.com>
Cc: linux-can@vger.kernel.org
Cc: netdev@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: syzkaller@googlegroups.com
Signed-off-by: David S. Miller <davem@davemloft.net>
1 parent 58c8db9
| File | Mode | Size |
|---|---|---|
| Kconfig | -rw-r--r-- | 516 bytes |
| Makefile | -rw-r--r-- | 378 bytes |
| ast.c | -rw-r--r-- | 8.1 KB |
| ast.h | -rw-r--r-- | 1.1 KB |
| config.c | -rw-r--r-- | 21.5 KB |
| config.h | -rw-r--r-- | 1.3 KB |
| debug_fs.c | -rw-r--r-- | 18.1 KB |
| dir.c | -rw-r--r-- | 7.3 KB |
| dir.h | -rw-r--r-- | 889 bytes |
| dlm_internal.h | -rw-r--r-- | 19.9 KB |
| lock.c | -rw-r--r-- | 157.4 KB |
| lock.h | -rw-r--r-- | 2.9 KB |
| lockspace.c | -rw-r--r-- | 20.4 KB |
| lockspace.h | -rw-r--r-- | 902 bytes |
| lowcomms.c | -rw-r--r-- | 43.6 KB |
| lowcomms.h | -rw-r--r-- | 973 bytes |
| lvb_table.h | -rw-r--r-- | 541 bytes |
| main.c | -rw-r--r-- | 1.8 KB |
| member.c | -rw-r--r-- | 16.1 KB |
| member.h | -rw-r--r-- | 1.3 KB |
| memory.c | -rw-r--r-- | 1.9 KB |
| memory.h | -rw-r--r-- | 904 bytes |
| midcomms.c | -rw-r--r-- | 3.6 KB |
| midcomms.h | -rw-r--r-- | 718 bytes |
| netlink.c | -rw-r--r-- | 2.8 KB |
| plock.c | -rw-r--r-- | 11.5 KB |
| rcom.c | -rw-r--r-- | 15.5 KB |
| rcom.h | -rw-r--r-- | 987 bytes |
| recover.c | -rw-r--r-- | 22.8 KB |
| recover.h | -rw-r--r-- | 1.3 KB |
| recoverd.c | -rw-r--r-- | 8.1 KB |
| recoverd.h | -rw-r--r-- | 781 bytes |
| requestqueue.c | -rw-r--r-- | 4.7 KB |
| requestqueue.h | -rw-r--r-- | 736 bytes |
| user.c | -rw-r--r-- | 24.5 KB |
| user.h | -rw-r--r-- | 440 bytes |
| util.c | -rw-r--r-- | 4.4 KB |
| util.h | -rw-r--r-- | 659 bytes |
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