[tone] [kagura] MTP: Crashes when transferring files with Windows

[ix5]

Platform: Tone
Device: Kagura
Kernel version: 4.9.182
Android version: 9.0 Pie

Description
Device crashes when attempting to transfer files via MTP from a Windows host.
Possibly related:
[loire] mtp is broken for large files [2/2]
[loire] mtp is broken for large files [1/2]
Discovery: copying files using MTP or PTP reboots phone #273

Symptoms
Hard crash from kernel panic

dwc3 6a00000.dwc3: swiotlb buffer is full (sz: 1048576 bytes)
DMA: Out of SW-IOMMU space for 1048576 bytes at device 6a00000.dwc3
Kernel panic - not syncing: DMA: Random memory could be DMA written
ipa ipa2_active_clients_panic_notifier:309 
---- Active Clients Table ----
IPA_CLIENT_APPS_WAN_CONS                 1378 ENDPOINT
SPS_RESOURCE                             -1378 SPECIAL
Total active clients count: 0
Kernel Offset: disabled
CPU features: 0x112008
Memory Limit: none
Rebooting in 5 seconds..
Going down for restart now
qcom,qpnp-power-on 400f000.qcom,spmi:pmi8994@2:qcom,power-on@800: PMIC@SID2: configuring PON for reset
msm_restart_prepare : cmd is NULL, set to reboot mode

How to reproduce
Attempt to transfer files from a Windows host via MTP. You will have to transfer a large amount of files, crashes seem to happen with large files as well.

---

Unrelated: We might need to investigate our init.rc files for adb/functionfs stuff, maybe some wrong attrs/ids?

[oshmoun]

a bit impractical not having a call trace don't you think? :)
https://github.com/sonyxperiadev/kernel/blob/aosp/LE.UM.2.3.2.r1.4/lib/swiotlb.c#L735-L740
changing these to BUG should give us that

[chris42]

Could it be, that the MTP overall is a bit whacky?
Using it during system time, always (since I own Xperia X Compact) ends for me in libmtp error: Could not get file from device. under Linux. Windows just stops copying.
I always hat to switch to TWRP to copy files from the device. Maybe this is also a hint on solving the configuration?

[oshmoun]

applying the linked patch works around the issue by limiting the mtp request length
https://del.dog/ugayaselar.cc
I am not familiar enough with these things to deem this solution passable. however, should that be the case, we could simply adjust the sizes in init by writing to /sys/module/usb_f_mtp/parameters/{mtp_rx_req_len,mtp_tx_req_len}

[Haxk20]

This is issue on ganges as well and on Linux host too.

[Haxk20]

@ix5 I will limit rx/tx on my build on ganges and if it fixes the issue as well could you make PR with the changes ? Thank you

[bartcubbins]

@Haxk20 please test with this PR sonyxperiadev/kernel@aa5ff38
I see that this problem is common for at least three platforms and I think that we should fix this at the kernel level

[Haxk20]

I have made a new build. Cant test at this point due to laptop fastboot issues. Will do once i get on PC

[bartcubbins]

Don't test it, we will fix this in userspace

[Haxk20]

Don't test it, we will fix this in userspace

Yes i read the PR. I mean i will test the userspace fix (limiting rx/tx)