This patch was posted previously on lkml. I've updated the patch to fix another memory overrun in ucsi_unregister_altmodes The following crash occurs whilst plugging in a Thinkpad USB type C dock and appears to be affecting other users as seen below; https://bbs.archlinux.org/viewtopic.php?id=256404 https://forums.linuxmint.com/viewtopic.php?p=1826251 My specific crash is; [ 565.427757] input: USBPS2 as /devices/pci0000:00/0000:00:14.0/usb1/1-2/1-2.1/1-2.1.4/1-2.1.4:1.0/0003:0D3D:0001.0006/input/input31 [ 565.452023] BUG: kernel NULL pointer dereference, address: 00000000000002fe [ 565.452025] #PF: supervisor read access in kernel mode [ 565.452026] #PF: error_code(0x0000) - not-present page [ 565.452026] PGD 0 P4D 0 [ 565.452028] Oops: 0000 [#1] PREEMPT SMP NOPTI [ 565.452030] CPU: 0 PID: 502 Comm: kworker/0:3 Not tainted 5.8.0-rc3+ #1 [ 565.452031] Hardware name: LENOVO 20RD002VUS/20RD002VUS, BIOS R16ET25W (1.11 ) 04/21/2020 [ 565.452034] Workqueue: events ucsi_handle_connector_change [typec_ucsi] [ 565.452039] RIP: 0010:typec_altmode_update_active+0x1f/0x100 [typec] [ 565.452040] Code: 0f 1f 84 00 00 00 00 00 0f 1f 00 0f 1f 44 00 00 55 48 89 e5 41 54 53 48 83 ec 10 65 48 8b 04 25 28 00 00 00 48 89 45 e8 31 c0 <0f> b6 87 fc 02 00 00 83 e0 01 40 38 f0 0f 84 95 00 00 00 48 8b 47 [ 565.452041] RSP: 0018:ffffb729c066bdb0 EFLAGS: 00010246 [ 565.452042] RAX: 0000000000000000 RBX: ffffa067c3e64a70 RCX: 0000000000000000 [ 565.452043] RDX: ffffb729c066bd20 RSI: 0000000000000000 RDI: 0000000000000002 [ 565.452044] RBP: ffffb729c066bdd0 R08: 00000083a7910a4f R09: 0000000000000000 [ 565.452044] R10: ffffffffa106a220 R11: 0000000000000000 R12: 0000000000000000 [ 565.452045] R13: ffffa067c3e64a98 R14: ffffa067c3e64810 R15: ffffa067c3e64800 [ 565.452046] FS: 0000000000000000(0000) GS:ffffa067d1400000(0000) knlGS:0000000000000000 [ 565.452047] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 565.452048] CR2: 00000000000002fe CR3: 00000001b060a003 CR4: 00000000003606f0 [ 565.452048] Call Trace: [ 565.452052] ucsi_altmode_update_active+0x83/0xd0 [typec_ucsi] [ 565.452054] ucsi_handle_connector_change+0x1dc/0x320 [typec_ucsi] [ 565.452057] process_one_work+0x1df/0x3d0 [ 565.452059] worker_thread+0x4d/0x3d0 [ 565.452060] ? process_one_work+0x3d0/0x3d0 [ 565.452062] kthread+0x127/0x170 [ 565.452063] ? kthread_park+0x90/0x90 [ 565.452065] ret_from_fork+0x1f/0x30 The failing instruction is; 0x0000000000000380 <+0>: callq 0x385 <typec_altmode_update_active+5> 0x0000000000000385 <+5>: push %rbp 0x0000000000000386 <+6>: mov %rsp,%rbp 0x0000000000000389 <+9>: push %r12 0x000000000000038b <+11>: push %rbx 0x000000000000038c <+12>: sub $0x10,%rsp 0x0000000000000390 <+16>: mov %gs:0x28,%rax 0x0000000000000399 <+25>: mov %rax,-0x18(%rbp) 0x000000000000039d <+29>: xor %eax,%eax 0x000000000000039f <+31>: movzbl 0x2fc(%rdi),%eax <====== 0x00000000000003a6 <+38>: and $0x1,%eax (gdb) list *typec_altmode_update_active+0x1f 0x39f is in typec_altmode_update_active (drivers/usb/typec/class.c:221). 216 */ 217 void typec_altmode_update_active(struct typec_altmode *adev, bool active) 218 { 219 char dir[6]; 220 221 if (adev->active == active) 222 return; 223 224 if (!is_typec_port(adev->dev.parent) && adev->dev.driver) { 225 if (!active) (gdb) list *ucsi_altmode_update_active+0x83 0x12a3 is in ucsi_altmode_update_active (drivers/usb/typec/ucsi/ucsi.c:221). 216 } 217 218 if (cur < UCSI_MAX_ALTMODES) 219 altmode = typec_altmode_get_partner(con->port_altmode[cur]); 220 221 for (i = 0; con->partner_altmode[i]; i++) 222 typec_altmode_update_active(con->partner_altmode[i], 223 con->partner_altmode[i] == altmode); 224 } con->partner_altmode[i] ends up with the value 0x2 in the call and it's because the array has been accessed out of bounds. There is also another occurence of this which shows up as the following crash; [ 4372.429633] usb 1-2.1.4: USB disconnect, device number 16 [ 4372.523235] usb 1-2.2: USB disconnect, device number 7 [ 4372.570537] usb 1-2.5: USB disconnect, device number 9 [ 4373.153246] BUG: kernel NULL pointer dereference, address: 00000000000002f2 [ 4373.153267] #PF: supervisor read access in kernel mode [ 4373.153271] #PF: error_code(0x0000) - not-present page [ 4373.153275] PGD 0 P4D 0 [ 4373.153284] Oops: 0000 [#2] PREEMPT SMP NOPTI [ 4373.153292] CPU: 0 PID: 13242 Comm: kworker/0:0 Tainted: G D 5.8.0-rc6+ #1 [ 4373.153296] Hardware name: LENOVO 20RD002VUS/20RD002VUS, BIOS R16ET25W (1.11 ) 04/21/2020 [ 4373.153308] Workqueue: events ucsi_handle_connector_change [typec_ucsi] [ 4373.153320] RIP: 0010:ucsi_unregister_altmodes+0x5f/0xa0 [typec_ucsi] [ 4373.153326] Code: 54 48 8b 3b 41 83 c4 01 e8 9e f9 0c 00 49 63 c4 48 c7 03 00 00 00 00 49 8d 5c c5 00 48 8b 3b 48 85 ff 74 31 41 80 fe 01 75 d7 <0f> b7 87 f0 02 00 00 66 3d 01 ff 74 0f 66 3d 55 09 75 c4 83 bf f8 [ 4373.153332] RSP: 0018:ffffb2ef036b3dc8 EFLAGS: 00010246 [ 4373.153338] RAX: 000000000000001e RBX: ffff94268b006a60 RCX: 0000000080800067 [ 4373.153342] RDX: 0000000080800068 RSI: 0000000000000001 RDI: 0000000000000002 [ 4373.153347] RBP: ffffb2ef036b3de8 R08: 0000000000000000 R09: ffffffff8dc65400 [ 4373.153351] R10: ffff9426678d7200 R11: 0000000000000001 R12: 000000000000001e [ 4373.153355] R13: ffff94268b006970 R14: 0000000000000001 R15: ffff94268b006800 [ 4373.153361] FS: 0000000000000000(0000) GS:ffff942691400000(0000) knlGS:0000000000000000 [ 4373.153366] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 4373.153371] CR2: 00000000000002f2 CR3: 00000004445a6005 CR4: 00000000003606f0 [ 4373.153375] Call Trace: [ 4373.153389] ucsi_unregister_partner.part.0+0x17/0x30 [typec_ucsi] [ 4373.153400] ucsi_handle_connector_change+0x25c/0x320 [typec_ucsi] [ 4373.153418] process_one_work+0x1df/0x3d0 [ 4373.153428] worker_thread+0x4a/0x3d0 [ 4373.153436] ? process_one_work+0x3d0/0x3d0 [ 4373.153444] kthread+0x127/0x170 [ 4373.153451] ? kthread_park+0x90/0x90 [ 4373.153461] ret_from_fork+0x1f/0x30 [ 4373.153661] CR2: 00000000000002f2 diff --git a/drivers/usb/typec/ucsi/ucsi.c b/drivers/usb/typec/ucsi/ucsi.c index d0c63afaf..79061705e 100644 --- a/drivers/usb/typec/ucsi/ucsi.c +++ b/drivers/usb/typec/ucsi/ucsi.c @@ -218,9 +218,10 @@ void ucsi_altmode_update_active(struct ucsi_connector *con) if (cur < UCSI_MAX_ALTMODES) altmode = typec_altmode_get_partner(con->port_altmode[cur]); - for (i = 0; con->partner_altmode[i]; i++) - typec_altmode_update_active(con->partner_altmode[i], - con->partner_altmode[i] == altmode); + for (i = 0; i < UCSI_MAX_ALTMODES; i++) + if (con->partner_altmode[i]) + typec_altmode_update_active(con->partner_altmode[i], + con->partner_altmode[i] == altmode); } static u8 ucsi_altmode_next_mode(struct typec_altmode **alt, u16 svid) @@ -479,7 +480,10 @@ static void ucsi_unregister_altmodes(struct ucsi_connector *con, u8 recipient) return; } - while (adev[i]) { + for (i = 0; i < UCSI_MAX_ALTMODES; i++) { + if (!adev[i]) + break; + if (recipient == UCSI_RECIPIENT_SOP && (adev[i]->svid == USB_TYPEC_DP_SID || (adev[i]->svid == USB_TYPEC_NVIDIA_VLINK_SID && @@ -488,7 +492,7 @@ static void ucsi_unregister_altmodes(struct ucsi_connector *con, u8 recipient) ucsi_displayport_remove_partner((void *)pdev); } typec_unregister_altmode(adev[i]); - adev[i++] = NULL; + adev[i] = NULL; } }
