Hey Mika, On 12-02-2024 12:51, Mika Westerberg wrote:
Olliver reported that his system crashes when plugging in Thunderbolt 1 device: BUG: kernel NULL pointer dereference, address: 0000000000000020 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 0 P4D 0 Oops: 0000 [#1] PREEMPT SMP NOPTI RIP: 0010:tb_port_do_update_credits+0x1b/0x130 [thunderbolt] Call Trace: <TASK> ? __die+0x23/0x70 ? page_fault_oops+0x171/0x4e0 ? exc_page_fault+0x7f/0x180 ? asm_exc_page_fault+0x26/0x30 ? tb_port_do_update_credits+0x1b/0x130 ? tb_switch_update_link_attributes+0x83/0xd0 tb_switch_add+0x7a2/0xfe0 tb_scan_port+0x236/0x6f0 tb_handle_hotplug+0x6db/0x900 process_one_work+0x171/0x340 worker_thread+0x27b/0x3a0 ? __pfx_worker_thread+0x10/0x10 kthread+0xe5/0x120 ? __pfx_kthread+0x10/0x10 ret_from_fork+0x31/0x50 ? __pfx_kthread+0x10/0x10 ret_from_fork_asm+0x1b/0x30 </TASK> This is due the fact that some Thunderbolt 1 devices only have one lane adapter. Fix this by checking for the lane 1 before we read its credits. Reported-by: Olliver Schinagl <oliver@xxxxxxxxxxx> Closes: https://lore.kernel.org/linux-usb/c24c7882-6254-4e68-8f22-f3e8f65dc84f@xxxxxxxxxxx/ Fixes: 81af2952e606 ("thunderbolt: Add support for asymmetric link") Cc: stable@xxxxxxxxxxxxxxx Cc: Gil Fine <gil.fine@xxxxxxxxxxxxxxx> Signed-off-by: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx> --- Hi Olliver, I managed to reproduce this with a Thunderbolt 1 device. I wonder if you can try this patch and see if it fixes your issue too?
That sounds reasonable, as it's an old Macbook (Should be TB2) with an old ethernet dongle (probably TB1?) or simply because it doesn't need that much speed (gbit adapter only). Sadly patching my kernel is not something I can do at the moment.
Olliver
drivers/thunderbolt/switch.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/thunderbolt/switch.c b/drivers/thunderbolt/switch.c index bca6f28c553b..72ebde0e34d7 100644 --- a/drivers/thunderbolt/switch.c +++ b/drivers/thunderbolt/switch.c @@ -1256,6 +1256,9 @@ int tb_port_update_credits(struct tb_port *port) ret = tb_port_do_update_credits(port); if (ret) return ret; + + if (!port->dual_link_port) + return 0; return tb_port_do_update_credits(port->dual_link_port); }
