Crash when specifying non-existent serial port in speakup / tty_kopen

From: Matthias Reichl
Date: Wed Nov 04 2020 - 09:57:46 EST


I initially noticed this oops on x86_64 running kernel 5.4.59 when
I accidentally mistyped "ttyS0" as "ttyS9":

modprobe speakup_dummy dev=ttyS9

x86_64/5.10-rc2 showed the same behaviour (see below), also
5.9.3 on RPi with the ttyAMA driver. I couldn't make the kernel
warn/crash yet by specifying non-existent ttyUSB ports yet though.

It looks like spk_ttyio or tty_dev_name_to_number() / tty_kopen()
should perform some additional validation, as the missing tty->port
is quite fatal.

Here's the I got on 5.10-rc2:

[ 49.967409] input: Speakup as /devices/virtual/input/input10
[ 49.967731] initialized device: /dev/synth, node (MAJOR 10, MINOR 61)
[ 49.968848] speakup 3.1.6: initialized
[ 49.968852] synth name on entry is: (null)
[ 49.978421] synth probe
[ 49.978477] ------------[ cut here ]------------
[ 49.978481] tty_init_dev: ttyS driver does not set tty->port. This would crash the kernel. Fix the driver!
[ 49.978522] WARNING: CPU: 1 PID: 283 at drivers/tty/tty_io.c:1351 tty_init_dev+0x17a/0x1d0
[ 49.978525] Modules linked in: speakup_dummy(+) speakup
[ 49.978538] CPU: 1 PID: 283 Comm: modprobe Not tainted 5.10.0-rc2 #5
[ 49.978541] Hardware name: /8IPE775/-G, BIOS F5 08/31/2006
[ 49.978580] RIP: 0010:tty_init_dev+0x17a/0x1d0
[ 49.978586] Code: ff ff e8 f9 a6 f5 ff 85 c0 0f 84 43 ff ff ff 49 8b 46 10 48 c7 c6 98 30 07 82 48 c7 c7 b0 c0 26 82 48 8b 50 20 e8 95 37 69 00 <0f> 0b e9 21 ff ff ff e8 da da ff ff e9 ed fe ff ff 4c 89 f7 89 45
[ 49.978591] RSP: 0018:ffffc9000029bb88 EFLAGS: 00010282
[ 49.978596] RAX: 0000000000000000 RBX: ffffffffffffffea RCX: 0000000000000027
[ 49.978599] RDX: 0000000000000027 RSI: ffff88807dc97820 RDI: ffff88807dc97828
[ 49.978603] RBP: ffffc9000029bbb0 R08: 0000000000000000 R09: c0000000ffffdfff
[ 49.978605] R10: 0000000000000001 R11: ffffc9000029b958 R12: ffff88800386df00
[ 49.978608] R13: 0000000000000009 R14: ffff88800514c000 R15: ffffffffa001e500
[ 49.978613] FS: 00007faebf8ae540(0000) GS:ffff88807dc80000(0000) knlGS:0000000000000000
[ 49.978617] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 49.978621] CR2: 00007fff4ff25ff8 CR3: 000000000529a000 CR4: 00000000000006e0
[ 49.978624] Call Trace:
[ 49.978635] tty_kopen+0x101/0x150
[ 49.978651] spk_ttyio_synth_probe+0xd5/0x230 [speakup]
[ 49.978661] ? _cond_resched+0x14/0x30
[ 49.978669] ? do_init_module+0x22/0x200
[ 49.978678] do_synth_init.cold.11+0x2d/0x15f [speakup]
[ 49.978686] synth_add+0x95/0xa0 [speakup]
[ 49.978689] ? 0xffffffffa0021000
[ 49.978696] synth_dummy_init+0x10/0x1000 [speakup_dummy]
[ 49.978702] do_one_initcall+0x45/0x1d0
[ 49.978707] ? _cond_resched+0x14/0x30
[ 49.978714] ? kmem_cache_alloc_trace+0x39/0x1b0
[ 49.978720] do_init_module+0x5b/0x200
[ 49.978726] load_module+0x25e6/0x2830
[ 49.978733] __do_sys_finit_module+0xc1/0x120
[ 49.978737] ? __do_sys_finit_module+0xc1/0x120
[ 49.978744] __x64_sys_finit_module+0x15/0x20
[ 49.978750] do_syscall_64+0x37/0x50
[ 49.978757] entry_SYSCALL_64_after_hwframe+0x44/0xa9
[ 49.978762] RIP: 0033:0x7faebf9cf919
[ 49.978767] Code: 00 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 47 55 0c 00 f7 d8 64 89 01 48
[ 49.978771] RSP: 002b:00007fffb3a03018 EFLAGS: 00000246 ORIG_RAX: 0000000000000139
[ 49.978777] RAX: ffffffffffffffda RBX: 00005620ea9c58f0 RCX: 00007faebf9cf919
[ 49.978780] RDX: 0000000000000000 RSI: 00005620ea9c5e10 RDI: 0000000000000004
[ 49.978783] RBP: 0000000000040000 R08: 0000000000000000 R09: 0000000000000000
[ 49.978785] R10: 0000000000000004 R11: 0000000000000246 R12: 00005620ea9c5e10
[ 49.978788] R13: 0000000000000000 R14: 00005620ea9c5ab0 R15: 00005620ea9c58f0
[ 49.978795] CPU: 1 PID: 283 Comm: modprobe Not tainted 5.10.0-rc2 #5
[ 49.978798] Hardware name: /8IPE775/-G, BIOS F5 08/31/2006
[ 49.978800] Call Trace:
[ 49.978806] dump_stack+0x5e/0x74
[ 49.978813] __warn.cold.13+0xe/0x3f
[ 49.978819] ? tty_init_dev+0x17a/0x1d0
[ 49.978826] report_bug+0xc5/0x100
[ 49.978831] handle_bug+0x48/0x90
[ 49.978835] exc_invalid_op+0x18/0x70
[ 49.978839] asm_exc_invalid_op+0x12/0x20
[ 49.978844] RIP: 0010:tty_init_dev+0x17a/0x1d0
[ 49.978849] Code: ff ff e8 f9 a6 f5 ff 85 c0 0f 84 43 ff ff ff 49 8b 46 10 48 c7 c6 98 30 07 82 48 c7 c7 b0 c0 26 82 48 8b 50 20 e8 95 37 69 00 <0f> 0b e9 21 ff ff ff e8 da da ff ff e9 ed fe ff ff 4c 89 f7 89 45
[ 49.978852] RSP: 0018:ffffc9000029bb88 EFLAGS: 00010282
[ 49.978857] RAX: 0000000000000000 RBX: ffffffffffffffea RCX: 0000000000000027
[ 49.978860] RDX: 0000000000000027 RSI: ffff88807dc97820 RDI: ffff88807dc97828
[ 49.978863] RBP: ffffc9000029bbb0 R08: 0000000000000000 R09: c0000000ffffdfff
[ 49.978865] R10: 0000000000000001 R11: ffffc9000029b958 R12: ffff88800386df00
[ 49.978868] R13: 0000000000000009 R14: ffff88800514c000 R15: ffffffffa001e500
[ 49.978876] ? tty_init_dev+0x17a/0x1d0
[ 49.978882] tty_kopen+0x101/0x150
[ 49.978893] spk_ttyio_synth_probe+0xd5/0x230 [speakup]
[ 49.978900] ? _cond_resched+0x14/0x30
[ 49.978905] ? do_init_module+0x22/0x200
[ 49.978915] do_synth_init.cold.11+0x2d/0x15f [speakup]
[ 49.978923] synth_add+0x95/0xa0 [speakup]
[ 49.978926] ? 0xffffffffa0021000
[ 49.978932] synth_dummy_init+0x10/0x1000 [speakup_dummy]
[ 49.978936] do_one_initcall+0x45/0x1d0
[ 49.978941] ? _cond_resched+0x14/0x30
[ 49.978947] ? kmem_cache_alloc_trace+0x39/0x1b0
[ 49.978953] do_init_module+0x5b/0x200
[ 49.978959] load_module+0x25e6/0x2830
[ 49.978967] __do_sys_finit_module+0xc1/0x120
[ 49.978973] ? __do_sys_finit_module+0xc1/0x120
[ 49.978980] __x64_sys_finit_module+0x15/0x20
[ 49.978985] do_syscall_64+0x37/0x50
[ 49.978990] entry_SYSCALL_64_after_hwframe+0x44/0xa9
[ 49.978994] RIP: 0033:0x7faebf9cf919
[ 49.978998] Code: 00 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 47 55 0c 00 f7 d8 64 89 01 48
[ 49.979001] RSP: 002b:00007fffb3a03018 EFLAGS: 00000246 ORIG_RAX: 0000000000000139
[ 49.979008] RAX: ffffffffffffffda RBX: 00005620ea9c58f0 RCX: 00007faebf9cf919
[ 49.979012] RDX: 0000000000000000 RSI: 00005620ea9c5e10 RDI: 0000000000000004
[ 49.979015] RBP: 0000000000040000 R08: 0000000000000000 R09: 0000000000000000
[ 49.979020] R10: 0000000000000004 R11: 0000000000000246 R12: 00005620ea9c5e10
[ 49.979023] R13: 0000000000000000 R14: 00005620ea9c5ab0 R15: 00005620ea9c58f0
[ 49.979028] ---[ end trace 6f832dacaff58cbe ]---
[ 49.979043] BUG: kernel NULL pointer dereference, address: 0000000000000090
[ 49.986001] #PF: supervisor write access in kernel mode
[ 49.991226] #PF: error_code(0x0002) - not-present page
[ 49.996361] PGD 0 P4D 0
[ 49.998902] Oops: 0002 [#1] SMP PTI
[ 50.002393] CPU: 1 PID: 283 Comm: modprobe Tainted: G W 5.10.0-rc2 #5
[ 50.010130] Hardware name: /8IPE775/-G, BIOS F5 08/31/2006
[ 50.015697] RIP: 0010:release_tty+0x69/0x150
[ 50.019966] Code: ea ff ff 48 8b 7b 10 48 8b 87 a0 00 00 00 48 8b 40 10 48 85 c0 0f 84 9e 00 00 00 48 89 de e8 1e 19 92 00 48 8b 83 b8 02 00 00 <48> c7 80 90 00 00 00 00 00 00 00 48 8b 83 f8 01 00 00 48 85 c0 74
[ 50.038707] RSP: 0018:ffffc9000029bb70 EFLAGS: 00010246
[ 50.043933] RAX: 0000000000000000 RBX: ffff88800514c000 RCX: 00000000000015cb
[ 50.051055] RDX: 0000000000000009 RSI: ffffffff814e0923 RDI: ffff88800386df00
[ 50.058177] RBP: ffffc9000029bb78 R08: 0000000000000040 R09: c0000000ffffdfff
[ 50.065300] R10: ffff888005f1cac0 R11: ffffc9000029b958 R12: ffff88800386df00
[ 50.072424] R13: 0000000000000009 R14: ffff88800514c000 R15: ffffffffa001e500
[ 50.079548] FS: 00007faebf8ae540(0000) GS:ffff88807dc80000(0000) knlGS:0000000000000000
[ 50.087632] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 50.093367] CR2: 0000000000000090 CR3: 000000000529a000 CR4: 00000000000006e0
[ 50.100489] Call Trace:
[ 50.102938] tty_init_dev+0xb5/0x1d0
[ 50.106515] tty_kopen+0x101/0x150
[ 50.109925] spk_ttyio_synth_probe+0xd5/0x230 [speakup]
[ 50.115147] ? _cond_resched+0x14/0x30
[ 50.118898] ? do_init_module+0x22/0x200
[ 50.122824] do_synth_init.cold.11+0x2d/0x15f [speakup]
[ 50.128050] synth_add+0x95/0xa0 [speakup]
[ 50.132144] ? 0xffffffffa0021000
[ 50.135457] synth_dummy_init+0x10/0x1000 [speakup_dummy]
[ 50.140855] do_one_initcall+0x45/0x1d0
[ 50.144694] ? _cond_resched+0x14/0x30
[ 50.148445] ? kmem_cache_alloc_trace+0x39/0x1b0
[ 50.153065] do_init_module+0x5b/0x200
[ 50.156815] load_module+0x25e6/0x2830
[ 50.160560] __do_sys_finit_module+0xc1/0x120
[ 50.164918] ? __do_sys_finit_module+0xc1/0x120
[ 50.169450] __x64_sys_finit_module+0x15/0x20
[ 50.173808] do_syscall_64+0x37/0x50
[ 50.177388] entry_SYSCALL_64_after_hwframe+0x44/0xa9
[ 50.182438] RIP: 0033:0x7faebf9cf919
[ 50.186007] Code: 00 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 47 55 0c 00 f7 d8 64 89 01 48
[ 50.204741] RSP: 002b:00007fffb3a03018 EFLAGS: 00000246 ORIG_RAX: 0000000000000139
[ 50.212306] RAX: ffffffffffffffda RBX: 00005620ea9c58f0 RCX: 00007faebf9cf919
[ 50.219428] RDX: 0000000000000000 RSI: 00005620ea9c5e10 RDI: 0000000000000004
[ 50.226551] RBP: 0000000000040000 R08: 0000000000000000 R09: 0000000000000000
[ 50.233674] R10: 0000000000000004 R11: 0000000000000246 R12: 00005620ea9c5e10
[ 50.240797] R13: 0000000000000000 R14: 00005620ea9c5ab0 R15: 00005620ea9c58f0
[ 50.247920] Modules linked in: speakup_dummy(+) speakup
[ 50.253146] CR2: 0000000000000090
[ 50.256538] ---[ end trace 6f832dacaff58cbf ]---
[ 50.261173] RIP: 0010:release_tty+0x69/0x150
[ 50.265464] Code: ea ff ff 48 8b 7b 10 48 8b 87 a0 00 00 00 48 8b 40 10 48 85 c0 0f 84 9e 00 00 00 48 89 de e8 1e 19 92 00 48 8b 83 b8 02 00 00 <48> c7 80 90 00 00 00 00 00 00 00 48 8b 83 f8 01 00 00 48 85 c0 74
[ 50.284221] RSP: 0018:ffffc9000029bb70 EFLAGS: 00010246
[ 50.289462] RAX: 0000000000000000 RBX: ffff88800514c000 RCX: 00000000000015cb
[ 50.296609] RDX: 0000000000000009 RSI: ffffffff814e0923 RDI: ffff88800386df00
[ 50.303750] RBP: ffffc9000029bb78 R08: 0000000000000040 R09: c0000000ffffdfff
[ 50.310900] R10: ffff888005f1cac0 R11: ffffc9000029b958 R12: ffff88800386df00
[ 50.318048] R13: 0000000000000009 R14: ffff88800514c000 R15: ffffffffa001e500
[ 50.325197] FS: 00007faebf8ae540(0000) GS:ffff88807dc80000(0000) knlGS:0000000000000000
[ 50.333297] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 50.339052] CR2: 0000000000000090 CR3: 000000000529a000 CR4: 00000000000006e0

so long,

Hias