BUG: drivers/usb/host/xhci: memleak in alloc from xhci_disable_usb3_lpm_timeout()

[Mathias Nyman]

On 25.3.2023 13.33, Mirsad Goran Todorovac wrote:
> On 25. 03. 2023. 12:27, Mirsad Goran Todorovac wrote:
>> Hi all!
>>
>> Here are again the good news and the bad news:
>>
>> BAD:  another kernel memory leak detected (one more to hunt down and fix)
>> GOOD: another kernel memory leak detected (one less unaccounted for)
>>
>> I tried to make some fun, but maintainers are busy folks, so let's get down
>> to business:
>>
>> ---
>> Nine (9) new systemd-udevd kernel memory leaks occurred (unable to reproduce).
>>
>> The platform is Ubuntu 22.10 with (relatively recent) systemd 251.4-1ubuntu7.1
>> on LENOVO_MT_82H8_BU_idea_FM_IdeaPad 3 15ITL6 with BIOS GGCN51WW from 11/16/2022.
>>
>> The symptom (/sys/kernel/debug/kmemleak output):
>>
>> unreferenced object 0xffff909698ff9280 (size 64):
>>    comm "systemd-udevd", pid 436, jiffies 4294893239 (age 6287.088s)
>>    hex dump (first 32 bytes):
>>      e0 51 bb 99 96 90 ff ff 00 00 00 00 00 00 00 00  .Q..............
>>      40 5b bb 99 96 90 ff ff 00 00 00 00 00 00 00 00  @[..............
>>    backtrace:
>>      [<ffffffffb29de94c>] slab_post_alloc_hook+0x8c/0x320
>>      [<ffffffffb29e5107>] __kmem_cache_alloc_node+0x1c7/0x2b0
>>      [<ffffffffb2962f3b>] kmalloc_node_trace+0x2b/0xa0
>>      [<ffffffffb31af2ec>] xhci_alloc_command+0x7c/0x1b0
>>      [<ffffffffb31af451>] xhci_alloc_command_with_ctx+0x21/0x70
>>      [<ffffffffb31a8a3e>] xhci_change_max_exit_latency+0x2e/0x1c0>>      [<ffffffffb31a8c5b>] xhci_disable_usb3_lpm_timeout+0x7b/0xb0
>>      [<ffffffffb31457a7>] usb_disable_link_state+0x57/0xe0

Thanks for the report.

I think I found the leak, and wrote a patch for it.
Any chance you could test it with the same setup?

https://git.kernel.org/pub/scm/linux/kernel/git/mnyman/xhci.git/commit/?h=for-usb-linus&id=8bacee588602ed74cc22aaf4c56b796300e5a943

Thanks
-Mathias