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>
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Kconfig | -rw-r--r-- | 1.8 KB |
Makefile | -rw-r--r-- | 260 bytes |
balloc.c | -rw-r--r-- | 27.7 KB |
cylinder.c | -rw-r--r-- | 5.7 KB |
dir.c | -rw-r--r-- | 15.7 KB |
file.c | -rw-r--r-- | 998 bytes |
ialloc.c | -rw-r--r-- | 9.3 KB |
inode.c | -rw-r--r-- | 32.8 KB |
namei.c | -rw-r--r-- | 7.2 KB |
super.c | -rw-r--r-- | 44.2 KB |
swab.h | -rw-r--r-- | 2.5 KB |
ufs.h | -rw-r--r-- | 5.0 KB |
ufs_fs.h | -rw-r--r-- | 34.6 KB |
util.c | -rw-r--r-- | 6.1 KB |
util.h | -rw-r--r-- | 16.8 KB |
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