Colin Ian King 5353ed8dee devpts: fix null pointer dereference on failed memory allocation ... An ENOMEM when creating a pair tty in tty_ldisc_setup causes a null pointer dereference in devpts_kill_index because tty->link->driver_data is NULL. The oops was triggered with the pty stressor in stress-ng when in a low memory condition. tty_init_dev tries to clean up a tty_ldisc_setup ENOMEM error by calling release_tty, however, this ultimately tries to clean up the NULL pair'd tty in pty_unix98_remove, triggering the Oops. Add check to pty_unix98_remove to only clean up fsi if it is not NULL. Ooops: [ 23.020961] Oops: 0000 [#1] SMP [ 23.020976] Modules linked in: ppdev snd_hda_codec_generic snd_hda_intel snd_hda_codec parport_pc snd_hda_core snd_hwdep parport snd_pcm input_leds joydev snd_timer serio_raw snd soundcore i2c_piix4 mac_hid ib_iser rdma_cm iw_cm ib_cm ib_core configfs iscsi_tcp libiscsi_tcp libiscsi scsi_transport_iscsi autofs4 btrfs raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c raid1 raid0 multipath linear crct10dif_pclmul crc32_pclmul ghash_clmulni_intel aesni_intel qxl aes_x86_64 ttm lrw gf128mul glue_helper ablk_helper drm_kms_helper cryptd syscopyarea sysfillrect psmouse sysimgblt floppy fb_sys_fops drm pata_acpi jitterentropy_rng drbg ansi_cprng [ 23.020978] CPU: 0 PID: 1452 Comm: stress-ng-pty Not tainted 4.7.0-rc4+ #2 [ 23.020978] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014 [ 23.020979] task: ffff88007ba30000 ti: ffff880078ea8000 task.ti: ffff880078ea8000 [ 23.020981] RIP: 0010:[<ffffffff813f11ff>] [<ffffffff813f11ff>] ida_remove+0x1f/0x120 [ 23.020981] RSP: 0018:ffff880078eabb60 EFLAGS: 00010a03 [ 23.020982] RAX: 4444444444444567 RBX: 0000000000000000 RCX: 000000000000001f [ 23.020982] RDX: 000000000000014c RSI: 000000000000026f RDI: 0000000000000000 [ 23.020982] RBP: ffff880078eabb70 R08: 0000000000000004 R09: 0000000000000036 [ 23.020983] R10: 000000000000026f R11: 0000000000000000 R12: 000000000000026f [ 23.020983] R13: 000000000000026f R14: ffff88007c944b40 R15: 000000000000026f [ 23.020984] FS: 00007f9a2f3cc700(0000) GS:ffff88007fc00000(0000) knlGS:0000000000000000 [ 23.020984] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 23.020985] CR2: 0000000000000010 CR3: 000000006c81b000 CR4: 00000000001406f0 [ 23.020988] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 23.020988] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 23.020988] Stack: [ 23.020989] 0000000000000000 000000000000026f ffff880078eabb90 ffffffff812a5a99 [ 23.020990] 0000000000000000 00000000fffffff4 ffff880078eabba8 ffffffff814f9cbe [ 23.020991] ffff88007965c800 ffff880078eabbc8 ffffffff814eef43 fffffffffffffff4 [ 23.020991] Call Trace: [ 23.021000] [<ffffffff812a5a99>] devpts_kill_index+0x29/0x50 [ 23.021002] [<ffffffff814f9cbe>] pty_unix98_remove+0x2e/0x50 [ 23.021006] [<ffffffff814eef43>] release_tty+0xb3/0x1b0 [ 23.021007] [<ffffffff814f18d4>] tty_init_dev+0xd4/0x1c0 [ 23.021011] [<ffffffff814f9fae>] ptmx_open+0xae/0x190 [ 23.021013] [<ffffffff812254ef>] chrdev_open+0xbf/0x1b0 [ 23.021015] [<ffffffff8121d973>] do_dentry_open+0x203/0x310 [ 23.021016] [<ffffffff81225430>] ? cdev_put+0x30/0x30 [ 23.021017] [<ffffffff8121ee44>] vfs_open+0x54/0x80 [ 23.021018] [<ffffffff8122b8fc>] ? may_open+0x8c/0x100 [ 23.021019] [<ffffffff8122f26b>] path_openat+0x2eb/0x1440 [ 23.021020] [<ffffffff81230534>] ? putname+0x54/0x60 [ 23.021022] [<ffffffff814f6f97>] ? n_tty_ioctl_helper+0x27/0x100 [ 23.021023] [<ffffffff81231651>] do_filp_open+0x91/0x100 [ 23.021024] [<ffffffff81230596>] ? getname_flags+0x56/0x1f0 [ 23.021026] [<ffffffff8123fc66>] ? __alloc_fd+0x46/0x190 [ 23.021027] [<ffffffff8121f1e4>] do_sys_open+0x124/0x210 [ 23.021028] [<ffffffff8121f2ee>] SyS_open+0x1e/0x20 [ 23.021035] [<ffffffff81845576>] entry_SYSCALL_64_fastpath+0x1e/0xa8 [ 23.021044] Code: 63 28 45 31 e4 eb dd 0f 1f 44 00 00 55 4c 63 d6 48 ba 89 88 88 88 88 88 88 88 4c 89 d0 b9 1f 00 00 00 48 f7 e2 48 89 e5 41 54 53 <8b> 47 10 48 89 fb 8d 3c c5 00 00 00 00 48 c1 ea 09 b8 01 00 00 [ 23.021045] RIP [<ffffffff813f11ff>] ida_remove+0x1f/0x120 [ 23.021045] RSP <ffff880078eabb60> [ 23.021046] CR2: 0000000000000010 Signed-off-by: Colin Ian King <colin.king@canonical.com> Cc: stable <stable@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2016-06-26 11:39:00 -07:00
..
hvc	tty: hvc_console: silence unintialized variable warning	2016-04-30 09:26:55 -07:00
ipwireless	tty: ipwireless: fix possible NULL dereference	2016-04-30 09:26:55 -07:00
serial	remove lots of IS_ERR_VALUE abuses	2016-05-27 15:26:11 -07:00
vt	tty: vt: Fix soft lockup in fbcon cursor blink timer.	2016-06-25 10:41:13 -07:00
amiserial.c	tty: Replace ASYNC_INITIALIZED bit and update atomically	2016-04-30 09:26:55 -07:00
bfin_jtag_comm.c
cyclades.c	tty: Replace ASYNC_INITIALIZED bit and update atomically	2016-04-30 09:26:55 -07:00
ehv_bytechan.c	drivers/tty: make ehv_bytechan.c explicitly non-modular	2016-02-06 23:26:43 -08:00
goldfish.c	tty: goldfish: support platform_device with id -1	2016-03-07 16:11:14 -08:00
isicom.c	tty: Replace ASYNC_INITIALIZED bit and update atomically	2016-04-30 09:26:55 -07:00
Kconfig	devpts: Make each mount of devpts an independent filesystem.	2016-06-05 10:36:01 -07:00
Makefile	TTY: Add MIPS EJTAG Fast Debug Channel TTY driver	2015-03-31 12:04:12 +02:00
metag_da.c	tty/metag_da: Avoid module_init/module_exit in non-modular code	2015-06-16 14:12:31 -04:00
mips_ejtag_fdc.c	ttyFDC: Fix build problems due to use of module_{init,exit}	2015-10-17 21:29:21 -07:00
moxa.c	tty: Replace ASYNC_INITIALIZED bit and update atomically	2016-04-30 09:26:55 -07:00
moxa.h
mxser.c	tty: mxser: Remove unused ASYNC_SHARE_IRQ flag	2016-04-30 09:26:55 -07:00
mxser.h
n_gsm.c	TTY and Serial driver update for 4.7-rc1	2016-05-20 20:57:27 -07:00
n_hdlc.c	Fix OpenSSH pty regression on close	2016-05-01 13:22:54 -07:00
n_r3964.c	tty: r3964: Replace/remove bogus tty lock use	2015-10-17 21:11:29 -07:00
n_tracerouter.c	n_tracerouter: stop including <asm-generic/bug>	2015-10-15 00:21:10 +02:00
n_tracesink.c	n_tracesink: stop including <asm-generic/bug>	2015-10-15 00:21:11 +02:00
n_tracesink.h
n_tty.c	Fix OpenSSH pty regression on close	2016-05-01 13:22:54 -07:00
nozomi.c	tty: Replace TTY_THROTTLED bit tests with tty_throttled()	2016-04-30 09:26:55 -07:00
pty.c	devpts: fix null pointer dereference on failed memory allocation	2016-06-26 11:39:00 -07:00
rocket_int.h	tty: rocket: Remove private close_wait	2016-01-28 14:13:44 -08:00
rocket.c	TTY: add __init attribute	2016-04-30 09:26:55 -07:00
rocket.h	tty: rocket: fix comment of ROCKET_SPD_HI	2015-05-24 12:49:16 -07:00
synclink_gt.c	TTY and Serial driver update for 4.7-rc1	2016-05-20 20:57:27 -07:00
synclink.c	TTY and Serial driver update for 4.7-rc1	2016-05-20 20:57:27 -07:00
synclinkmp.c	TTY and Serial driver update for 4.7-rc1	2016-05-20 20:57:27 -07:00
sysrq.c	sysrq: Fix warning in sysrq generated crash.	2015-12-29 16:29:18 -08:00
tty_audit.c	tty: audit: remove unused variable	2016-03-07 16:11:14 -08:00
tty_buffer.c	Fix OpenSSH pty regression on close	2016-05-01 13:22:54 -07:00
tty_io.c	Merge 4.6-rc7 into tty-next	2016-05-09 09:39:13 +02:00
tty_ioctl.c	tty: Replace TTY_THROTTLED bit tests with tty_throttled()	2016-04-30 09:26:55 -07:00
tty_ldisc.c	tty: Eliminate global symbol tty_ldisc_N_TTY	2016-01-27 15:13:28 -08:00
tty_ldsem.c	tty: Deinline __ldsem_down_write_nested, save 128 bytes	2015-12-13 19:59:48 -08:00
tty_mutex.c	Merge 4.5-rc4 into tty-next	2016-02-14 14:36:04 -08:00
tty_port.c	tty: Replace ASYNC_INITIALIZED bit and update atomically	2016-04-30 09:26:55 -07:00