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    SubjectRe: [3.16.1 BISECTED REGRESSION]: Simtec Entropy Key (cdc-acm) broken in 3.16
    Date
    On 14 Oct 2014, Johan Hovold verbalised:

    > On Sun, Oct 12, 2014 at 10:36:30PM +0100, Nix wrote:
    >> I have checked: this code is being executed against a symlink that
    >> points to /dev/ttyACM0, and the tcsetattr() succeeds. (At least, it's
    >> succeeding on the kernel I'm running now, but of course that's 3.16.5
    >> with this commit reverted...)
    >
    > You could verify that by enabling debugging in the cdc-acm driver and
    > making sure that the corresponding control messages are indeed sent on
    > close.

    I have a debugging dump at
    <http://www.esperi.org.uk/~nix/temporary/cdc-acm.log>; it's fairly
    voluminous because the ekeyd is constantly doing USB reads, but the end
    says

    Oct 22 10:19:13 fold kern debug: : [ 88.423970] cdc_acm 2-1:1.0: acm_tty_close
    Oct 22 10:19:13 fold kern debug: : [ 88.424012] cdc_acm 2-1:1.0: acm_port_shutdown
    Oct 22 10:19:13 fold kern debug: : [ 88.440038] cdc_acm 2-1:1.0: acm_ctrl_msg - rq 0x22, val 0x0, len 0x0, result 0
    Oct 22 10:19:13 fold kern debug: : [ 88.440038] cdc_acm 2-1:1.0: acm_ctrl_irq - urb shutting down with status: -2
    Oct 22 10:19:13 fold kern debug: : [ 88.440038] cdc_acm 2-1:1.1: acm_read_bulk_callback - urb 0, len 0
    Oct 22 10:19:13 fold kern debug: : [ 88.440038] cdc_acm 2-1:1.1: acm_read_bulk_callback - non-zero urb status: -2
    Oct 22 10:19:13 fold kern debug: : [ 88.447588] cdc_acm 2-1:1.1: acm_read_bulk_callback - urb 1, len 0
    Oct 22 10:19:13 fold kern debug: : [ 88.447613] cdc_acm 2-1:1.1: acm_read_bulk_callback - non-zero urb status: -2
    Oct 22 10:19:13 fold kern debug: : [ 88.448575] cdc_acm 2-1:1.1: acm_read_bulk_callback - urb 2, len 0
    Oct 22 10:19:13 fold kern debug: : [ 88.448599] cdc_acm 2-1:1.1: acm_read_bulk_callback - non-zero urb status: -2
    Oct 22 10:19:13 fold kern debug: : [ 88.449576] cdc_acm 2-1:1.1: acm_read_bulk_callback - urb 3, len 0
    Oct 22 10:19:13 fold kern debug: : [ 88.449599] cdc_acm 2-1:1.1: acm_read_bulk_callback - non-zero urb status: -2
    Oct 22 10:19:13 fold kern debug: : [ 88.450578] cdc_acm 2-1:1.1: acm_read_bulk_callback - urb 4, len 0
    Oct 22 10:19:13 fold kern debug: : [ 88.450602] cdc_acm 2-1:1.1: acm_read_bulk_callback - non-zero urb status: -2
    Oct 22 10:19:13 fold kern debug: : [ 88.451573] cdc_acm 2-1:1.1: acm_read_bulk_callback - urb 5, len 0
    Oct 22 10:19:13 fold kern debug: : [ 88.451596] cdc_acm 2-1:1.1: acm_read_bulk_callback - non-zero urb status: -2
    Oct 22 10:19:13 fold kern debug: : [ 88.452574] cdc_acm 2-1:1.1: acm_read_bulk_callback - urb 6, len 0
    Oct 22 10:19:13 fold kern debug: : [ 88.452597] cdc_acm 2-1:1.1: acm_read_bulk_callback - non-zero urb status: -2
    Oct 22 10:19:13 fold kern debug: : [ 88.453567] cdc_acm 2-1:1.1: acm_read_bulk_callback - urb 7, len 0
    Oct 22 10:19:13 fold kern debug: : [ 88.453588] cdc_acm 2-1:1.1: acm_read_bulk_callback - non-zero urb status: -2
    Oct 22 10:19:13 fold kern debug: : [ 88.454570] cdc_acm 2-1:1.1: acm_read_bulk_callback - urb 8, len 0
    Oct 22 10:19:13 fold kern debug: : [ 88.454592] cdc_acm 2-1:1.1: acm_read_bulk_callback - non-zero urb status: -2
    Oct 22 10:19:13 fold kern debug: : [ 88.462591] cdc_acm 2-1:1.1: acm_read_bulk_callback - urb 9, len 0
    Oct 22 10:19:13 fold kern debug: : [ 88.462619] cdc_acm 2-1:1.1: acm_read_bulk_callback - non-zero urb status: -2
    Oct 22 10:19:13 fold kern debug: : [ 88.463568] cdc_acm 2-1:1.1: acm_read_bulk_callback - urb 10, len 0
    Oct 22 10:19:13 fold kern debug: : [ 88.463590] cdc_acm 2-1:1.1: acm_read_bulk_callback - non-zero urb status: -2
    Oct 22 10:19:13 fold kern debug: : [ 88.464564] cdc_acm 2-1:1.1: acm_read_bulk_callback - urb 11, len 0
    Oct 22 10:19:13 fold kern debug: : [ 88.464585] cdc_acm 2-1:1.1: acm_read_bulk_callback - non-zero urb status: -2
    Oct 22 10:19:13 fold kern debug: : [ 88.465578] cdc_acm 2-1:1.1: acm_read_bulk_callback - urb 12, len 0
    Oct 22 10:19:13 fold kern debug: : [ 88.465602] cdc_acm 2-1:1.1: acm_read_bulk_callback - non-zero urb status: -2
    Oct 22 10:19:13 fold kern debug: : [ 88.466566] cdc_acm 2-1:1.1: acm_read_bulk_callback - urb 13, len 0
    Oct 22 10:19:13 fold kern debug: : [ 88.466587] cdc_acm 2-1:1.1: acm_read_bulk_callback - non-zero urb status: -2

    which looks, hm, a bit suspicious to me.

    > But you haven't seen any fw crashes since you reverted the commit in
    > question?

    Not a one.

    > Another thing you could try is to add back the
    >
    > acm_set_control(acm, 0);
    >
    > just after the dev_info message in probe.

    Tried that (with, obviously, the commit not reverted) -- rebooted, and

    BytesRead=0
    BytesWritten=0
    ConnectionNonces=0
    ConnectionPackets=0
    ConnectionRekeys=0
    ConnectionResets=0
    ConnectionTime=46
    EntropyRate=0
    FipsFrameRate=0
    FrameByteLast=0
    FramesOk=0
    FramingErrors=0
    KeyDbsdShannonPerByteL=0
    KeyDbsdShannonPerByteR=0
    KeyEnglishBadness=No failure
    KeyRawBadness=0
    KeyRawShannonPerByteL=0
    KeyRawShannonPerByteR=0
    KeyRawShannonPerByteX=0
    KeyShortBadness=efm_ok
    KeyTemperatureC=-273.15
    KeyTemperatureF=-459.67
    KeyTemperatureK=0
    KeyVoltage=0
    PacketErrors=0
    PacketOK=0
    ReadRate=0
    TotalEntropy=0
    WriteRate=0

    So that doesn't help.

    --
    NULL && (void)


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