RE: [PATCH] usb: cdnsp: fix cdnsp_decode_trb function to properly handle ret value

From: Pawel Laszczak
Date: Wed Jan 12 2022 - 02:27:34 EST

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In reply to: Greg KH: "Re: [PATCH] usb: cdnsp: fix cdnsp_decode_trb function to properly handle ret value"
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>
>
>On Wed, Jan 12, 2022 at 06:32:37AM +0100, Pawel Laszczak wrote:
>> From: Pawel Laszczak <pawell@xxxxxxxxxxx>
>>
>> Variable ret in function cdnsp_decode_trb is initialized but not
>> used. To fix this compiler warning patch adds checking whether the
>> data buffer has not been overflowed.
>>
>> Reported-by: kernel test robot <lkp@xxxxxxxxx>
>> Signed-off-by: Pawel Laszczak <pawell@xxxxxxxxxxx>
>> ---
>> drivers/usb/cdns3/cdnsp-debug.h | 305 ++++++++++++++++----------------
>> 1 file changed, 154 insertions(+), 151 deletions(-)
>>
>> diff --git a/drivers/usb/cdns3/cdnsp-debug.h b/drivers/usb/cdns3/cdnsp-debug.h
>> index a8776df2d4e0..f0ca865cce2a 100644
>> --- a/drivers/usb/cdns3/cdnsp-debug.h
>> +++ b/drivers/usb/cdns3/cdnsp-debug.h
>> @@ -182,208 +182,211 @@ static inline const char *cdnsp_decode_trb(char *str, size_t size, u32 field0,
>> int ep_id = TRB_TO_EP_INDEX(field3) - 1;
>> int type = TRB_FIELD_TO_TYPE(field3);
>> unsigned int ep_num;
>> - int ret = 0;
>> + int ret;
>> u32 temp;
>>
>> ep_num = DIV_ROUND_UP(ep_id, 2);
>>
>> switch (type) {
>> case TRB_LINK:
>> - ret += snprintf(str, size,
>> - "LINK %08x%08x intr %ld type '%s' flags %c:%c:%c:%c",
>> - field1, field0, GET_INTR_TARGET(field2),
>> - cdnsp_trb_type_string(type),
>> - field3 & TRB_IOC ? 'I' : 'i',
>> - field3 & TRB_CHAIN ? 'C' : 'c',
>> - field3 & TRB_TC ? 'T' : 't',
>> - field3 & TRB_CYCLE ? 'C' : 'c');
>> + ret = snprintf(str, size,
>> + "LINK %08x%08x intr %ld type '%s' flags %c:%c:%c:%c",
>> + field1, field0, GET_INTR_TARGET(field2),
>> + cdnsp_trb_type_string(type),
>> + field3 & TRB_IOC ? 'I' : 'i',
>> + field3 & TRB_CHAIN ? 'C' : 'c',
>> + field3 & TRB_TC ? 'T' : 't',
>> + field3 & TRB_CYCLE ? 'C' : 'c');
>> break;
>> case TRB_TRANSFER:
>> case TRB_COMPLETION:
>> case TRB_PORT_STATUS:
>> case TRB_HC_EVENT:
>> - ret += snprintf(str, size,
>> - "ep%d%s(%d) type '%s' TRB %08x%08x status '%s'"
>> - " len %ld slot %ld flags %c:%c",
>> - ep_num, ep_id % 2 ? "out" : "in",
>> - TRB_TO_EP_INDEX(field3),
>> - cdnsp_trb_type_string(type), field1, field0,
>> - cdnsp_trb_comp_code_string(GET_COMP_CODE(field2)),
>> - EVENT_TRB_LEN(field2), TRB_TO_SLOT_ID(field3),
>> - field3 & EVENT_DATA ? 'E' : 'e',
>> - field3 & TRB_CYCLE ? 'C' : 'c');
>> + ret = snprintf(str, size,
>> + "ep%d%s(%d) type '%s' TRB %08x%08x status '%s'"
>> + " len %ld slot %ld flags %c:%c",
>> + ep_num, ep_id % 2 ? "out" : "in",
>> + TRB_TO_EP_INDEX(field3),
>> + cdnsp_trb_type_string(type), field1, field0,
>> + cdnsp_trb_comp_code_string(GET_COMP_CODE(field2)),
>> + EVENT_TRB_LEN(field2), TRB_TO_SLOT_ID(field3),
>> + field3 & EVENT_DATA ? 'E' : 'e',
>> + field3 & TRB_CYCLE ? 'C' : 'c');
>> break;
>> case TRB_MFINDEX_WRAP:
>> - ret += snprintf(str, size, "%s: flags %c",
>> - cdnsp_trb_type_string(type),
>> - field3 & TRB_CYCLE ? 'C' : 'c');
>> + ret = snprintf(str, size, "%s: flags %c",
>> + cdnsp_trb_type_string(type),
>> + field3 & TRB_CYCLE ? 'C' : 'c');
>> break;
>> case TRB_SETUP:
>> - ret += snprintf(str, size,
>> - "type '%s' bRequestType %02x bRequest %02x "
>> - "wValue %02x%02x wIndex %02x%02x wLength %d "
>> - "length %ld TD size %ld intr %ld Setup ID %ld "
>> - "flags %c:%c:%c",
>> - cdnsp_trb_type_string(type),
>> - field0 & 0xff,
>> - (field0 & 0xff00) >> 8,
>> - (field0 & 0xff000000) >> 24,
>> - (field0 & 0xff0000) >> 16,
>> - (field1 & 0xff00) >> 8,
>> - field1 & 0xff,
>> - (field1 & 0xff000000) >> 16 |
>> - (field1 & 0xff0000) >> 16,
>> - TRB_LEN(field2), GET_TD_SIZE(field2),
>> - GET_INTR_TARGET(field2),
>> - TRB_SETUPID_TO_TYPE(field3),
>> - field3 & TRB_IDT ? 'D' : 'd',
>> - field3 & TRB_IOC ? 'I' : 'i',
>> - field3 & TRB_CYCLE ? 'C' : 'c');
>> + ret = snprintf(str, size,
>> + "type '%s' bRequestType %02x bRequest %02x "
>> + "wValue %02x%02x wIndex %02x%02x wLength %d "
>> + "length %ld TD size %ld intr %ld Setup ID %ld "
>> + "flags %c:%c:%c",
>> + cdnsp_trb_type_string(type),
>> + field0 & 0xff,
>> + (field0 & 0xff00) >> 8,
>> + (field0 & 0xff000000) >> 24,
>> + (field0 & 0xff0000) >> 16,
>> + (field1 & 0xff00) >> 8,
>> + field1 & 0xff,
>> + (field1 & 0xff000000) >> 16 |
>> + (field1 & 0xff0000) >> 16,
>> + TRB_LEN(field2), GET_TD_SIZE(field2),
>> + GET_INTR_TARGET(field2),
>> + TRB_SETUPID_TO_TYPE(field3),
>> + field3 & TRB_IDT ? 'D' : 'd',
>> + field3 & TRB_IOC ? 'I' : 'i',
>> + field3 & TRB_CYCLE ? 'C' : 'c');
>> break;
>> case TRB_DATA:
>> - ret += snprintf(str, size,
>> - "type '%s' Buffer %08x%08x length %ld TD size %ld "
>> - "intr %ld flags %c:%c:%c:%c:%c:%c:%c",
>> - cdnsp_trb_type_string(type),
>> - field1, field0, TRB_LEN(field2),
>> - GET_TD_SIZE(field2),
>> - GET_INTR_TARGET(field2),
>> - field3 & TRB_IDT ? 'D' : 'i',
>> - field3 & TRB_IOC ? 'I' : 'i',
>> - field3 & TRB_CHAIN ? 'C' : 'c',
>> - field3 & TRB_NO_SNOOP ? 'S' : 's',
>> - field3 & TRB_ISP ? 'I' : 'i',
>> - field3 & TRB_ENT ? 'E' : 'e',
>> - field3 & TRB_CYCLE ? 'C' : 'c');
>> + ret = snprintf(str, size,
>> + "type '%s' Buffer %08x%08x length %ld TD size %ld "
>> + "intr %ld flags %c:%c:%c:%c:%c:%c:%c",
>> + cdnsp_trb_type_string(type),
>> + field1, field0, TRB_LEN(field2),
>> + GET_TD_SIZE(field2),
>> + GET_INTR_TARGET(field2),
>> + field3 & TRB_IDT ? 'D' : 'i',
>> + field3 & TRB_IOC ? 'I' : 'i',
>> + field3 & TRB_CHAIN ? 'C' : 'c',
>> + field3 & TRB_NO_SNOOP ? 'S' : 's',
>> + field3 & TRB_ISP ? 'I' : 'i',
>> + field3 & TRB_ENT ? 'E' : 'e',
>> + field3 & TRB_CYCLE ? 'C' : 'c');
>> break;
>> case TRB_STATUS:
>> - ret += snprintf(str, size,
>> - "Buffer %08x%08x length %ld TD size %ld intr"
>> - "%ld type '%s' flags %c:%c:%c:%c",
>> - field1, field0, TRB_LEN(field2),
>> - GET_TD_SIZE(field2),
>> - GET_INTR_TARGET(field2),
>> - cdnsp_trb_type_string(type),
>> - field3 & TRB_IOC ? 'I' : 'i',
>> - field3 & TRB_CHAIN ? 'C' : 'c',
>> - field3 & TRB_ENT ? 'E' : 'e',
>> - field3 & TRB_CYCLE ? 'C' : 'c');
>> + ret = snprintf(str, size,
>> + "Buffer %08x%08x length %ld TD size %ld intr"
>> + "%ld type '%s' flags %c:%c:%c:%c",
>> + field1, field0, TRB_LEN(field2),
>> + GET_TD_SIZE(field2),
>> + GET_INTR_TARGET(field2),
>> + cdnsp_trb_type_string(type),
>> + field3 & TRB_IOC ? 'I' : 'i',
>> + field3 & TRB_CHAIN ? 'C' : 'c',
>> + field3 & TRB_ENT ? 'E' : 'e',
>> + field3 & TRB_CYCLE ? 'C' : 'c');
>> break;
>> case TRB_NORMAL:
>> case TRB_ISOC:
>> case TRB_EVENT_DATA:
>> case TRB_TR_NOOP:
>> - ret += snprintf(str, size,
>> - "type '%s' Buffer %08x%08x length %ld "
>> - "TD size %ld intr %ld "
>> - "flags %c:%c:%c:%c:%c:%c:%c:%c:%c",
>> - cdnsp_trb_type_string(type),
>> - field1, field0, TRB_LEN(field2),
>> - GET_TD_SIZE(field2),
>> - GET_INTR_TARGET(field2),
>> - field3 & TRB_BEI ? 'B' : 'b',
>> - field3 & TRB_IDT ? 'T' : 't',
>> - field3 & TRB_IOC ? 'I' : 'i',
>> - field3 & TRB_CHAIN ? 'C' : 'c',
>> - field3 & TRB_NO_SNOOP ? 'S' : 's',
>> - field3 & TRB_ISP ? 'I' : 'i',
>> - field3 & TRB_ENT ? 'E' : 'e',
>> - field3 & TRB_CYCLE ? 'C' : 'c',
>> - !(field3 & TRB_EVENT_INVALIDATE) ? 'V' : 'v');
>> + ret = snprintf(str, size,
>> + "type '%s' Buffer %08x%08x length %ld "
>> + "TD size %ld intr %ld "
>> + "flags %c:%c:%c:%c:%c:%c:%c:%c:%c",
>> + cdnsp_trb_type_string(type),
>> + field1, field0, TRB_LEN(field2),
>> + GET_TD_SIZE(field2),
>> + GET_INTR_TARGET(field2),
>> + field3 & TRB_BEI ? 'B' : 'b',
>> + field3 & TRB_IDT ? 'T' : 't',
>> + field3 & TRB_IOC ? 'I' : 'i',
>> + field3 & TRB_CHAIN ? 'C' : 'c',
>> + field3 & TRB_NO_SNOOP ? 'S' : 's',
>> + field3 & TRB_ISP ? 'I' : 'i',
>> + field3 & TRB_ENT ? 'E' : 'e',
>> + field3 & TRB_CYCLE ? 'C' : 'c',
>> + !(field3 & TRB_EVENT_INVALIDATE) ? 'V' : 'v');
>> break;
>> case TRB_CMD_NOOP:
>> case TRB_ENABLE_SLOT:
>> - ret += snprintf(str, size, "%s: flags %c",
>> - cdnsp_trb_type_string(type),
>> - field3 & TRB_CYCLE ? 'C' : 'c');
>> + ret = snprintf(str, size, "%s: flags %c",
>> + cdnsp_trb_type_string(type),
>> + field3 & TRB_CYCLE ? 'C' : 'c');
>> break;
>> case TRB_DISABLE_SLOT:
>> - ret += snprintf(str, size, "%s: slot %ld flags %c",
>> - cdnsp_trb_type_string(type),
>> - TRB_TO_SLOT_ID(field3),
>> - field3 & TRB_CYCLE ? 'C' : 'c');
>> + ret = snprintf(str, size, "%s: slot %ld flags %c",
>> + cdnsp_trb_type_string(type),
>> + TRB_TO_SLOT_ID(field3),
>> + field3 & TRB_CYCLE ? 'C' : 'c');
>> break;
>> case TRB_ADDR_DEV:
>> - ret += snprintf(str, size,
>> - "%s: ctx %08x%08x slot %ld flags %c:%c",
>> - cdnsp_trb_type_string(type), field1, field0,
>> - TRB_TO_SLOT_ID(field3),
>> - field3 & TRB_BSR ? 'B' : 'b',
>> - field3 & TRB_CYCLE ? 'C' : 'c');
>> + ret = snprintf(str, size,
>> + "%s: ctx %08x%08x slot %ld flags %c:%c",
>> + cdnsp_trb_type_string(type), field1, field0,
>> + TRB_TO_SLOT_ID(field3),
>> + field3 & TRB_BSR ? 'B' : 'b',
>> + field3 & TRB_CYCLE ? 'C' : 'c');
>> break;
>> case TRB_CONFIG_EP:
>> - ret += snprintf(str, size,
>> - "%s: ctx %08x%08x slot %ld flags %c:%c",
>> - cdnsp_trb_type_string(type), field1, field0,
>> - TRB_TO_SLOT_ID(field3),
>> - field3 & TRB_DC ? 'D' : 'd',
>> - field3 & TRB_CYCLE ? 'C' : 'c');
>> + ret = snprintf(str, size,
>> + "%s: ctx %08x%08x slot %ld flags %c:%c",
>> + cdnsp_trb_type_string(type), field1, field0,
>> + TRB_TO_SLOT_ID(field3),
>> + field3 & TRB_DC ? 'D' : 'd',
>> + field3 & TRB_CYCLE ? 'C' : 'c');
>> break;
>> case TRB_EVAL_CONTEXT:
>> - ret += snprintf(str, size,
>> - "%s: ctx %08x%08x slot %ld flags %c",
>> - cdnsp_trb_type_string(type), field1, field0,
>> - TRB_TO_SLOT_ID(field3),
>> - field3 & TRB_CYCLE ? 'C' : 'c');
>> + ret = snprintf(str, size,
>> + "%s: ctx %08x%08x slot %ld flags %c",
>> + cdnsp_trb_type_string(type), field1, field0,
>> + TRB_TO_SLOT_ID(field3),
>> + field3 & TRB_CYCLE ? 'C' : 'c');
>> break;
>> case TRB_RESET_EP:
>> case TRB_HALT_ENDPOINT:
>> case TRB_FLUSH_ENDPOINT:
>> - ret += snprintf(str, size,
>> - "%s: ep%d%s(%d) ctx %08x%08x slot %ld flags %c",
>> - cdnsp_trb_type_string(type),
>> - ep_num, ep_id % 2 ? "out" : "in",
>> - TRB_TO_EP_INDEX(field3), field1, field0,
>> - TRB_TO_SLOT_ID(field3),
>> - field3 & TRB_CYCLE ? 'C' : 'c');
>> + ret = snprintf(str, size,
>> + "%s: ep%d%s(%d) ctx %08x%08x slot %ld flags %c",
>> + cdnsp_trb_type_string(type),
>> + ep_num, ep_id % 2 ? "out" : "in",
>> + TRB_TO_EP_INDEX(field3), field1, field0,
>> + TRB_TO_SLOT_ID(field3),
>> + field3 & TRB_CYCLE ? 'C' : 'c');
>> break;
>> case TRB_STOP_RING:
>> - ret += snprintf(str, size,
>> - "%s: ep%d%s(%d) slot %ld sp %d flags %c",
>> - cdnsp_trb_type_string(type),
>> - ep_num, ep_id % 2 ? "out" : "in",
>> - TRB_TO_EP_INDEX(field3),
>> - TRB_TO_SLOT_ID(field3),
>> - TRB_TO_SUSPEND_PORT(field3),
>> - field3 & TRB_CYCLE ? 'C' : 'c');
>> + ret = snprintf(str, size,
>> + "%s: ep%d%s(%d) slot %ld sp %d flags %c",
>> + cdnsp_trb_type_string(type),
>> + ep_num, ep_id % 2 ? "out" : "in",
>> + TRB_TO_EP_INDEX(field3),
>> + TRB_TO_SLOT_ID(field3),
>> + TRB_TO_SUSPEND_PORT(field3),
>> + field3 & TRB_CYCLE ? 'C' : 'c');
>> break;
>> case TRB_SET_DEQ:
>> - ret += snprintf(str, size,
>> - "%s: ep%d%s(%d) deq %08x%08x stream %ld slot %ld flags %c",
>> - cdnsp_trb_type_string(type),
>> - ep_num, ep_id % 2 ? "out" : "in",
>> - TRB_TO_EP_INDEX(field3), field1, field0,
>> - TRB_TO_STREAM_ID(field2),
>> - TRB_TO_SLOT_ID(field3),
>> - field3 & TRB_CYCLE ? 'C' : 'c');
>> + ret = snprintf(str, size,
>> + "%s: ep%d%s(%d) deq %08x%08x stream %ld slot %ld flags %c",
>> + cdnsp_trb_type_string(type),
>> + ep_num, ep_id % 2 ? "out" : "in",
>> + TRB_TO_EP_INDEX(field3), field1, field0,
>> + TRB_TO_STREAM_ID(field2),
>> + TRB_TO_SLOT_ID(field3),
>> + field3 & TRB_CYCLE ? 'C' : 'c');
>> break;
>> case TRB_RESET_DEV:
>> - ret += snprintf(str, size, "%s: slot %ld flags %c",
>> - cdnsp_trb_type_string(type),
>> - TRB_TO_SLOT_ID(field3),
>> - field3 & TRB_CYCLE ? 'C' : 'c');
>> + ret = snprintf(str, size, "%s: slot %ld flags %c",
>> + cdnsp_trb_type_string(type),
>> + TRB_TO_SLOT_ID(field3),
>> + field3 & TRB_CYCLE ? 'C' : 'c');
>> break;
>> case TRB_ENDPOINT_NRDY:
>> - temp = TRB_TO_HOST_STREAM(field2);
>> -
>> - ret += snprintf(str, size,
>> - "%s: ep%d%s(%d) H_SID %x%s%s D_SID %lx flags %c:%c",
>> - cdnsp_trb_type_string(type),
>> - ep_num, ep_id % 2 ? "out" : "in",
>> - TRB_TO_EP_INDEX(field3), temp,
>> - temp == STREAM_PRIME_ACK ? "(PRIME)" : "",
>> - temp == STREAM_REJECTED ? "(REJECTED)" : "",
>> - TRB_TO_DEV_STREAM(field0),
>> - field3 & TRB_STAT ? 'S' : 's',
>> - field3 & TRB_CYCLE ? 'C' : 'c');
>> + temp = TRB_TO_HOST_STREAM(field2);
>> +
>> + ret = snprintf(str, size,
>> + "%s: ep%d%s(%d) H_SID %x%s%s D_SID %lx flags %c:%c",
>> + cdnsp_trb_type_string(type),
>> + ep_num, ep_id % 2 ? "out" : "in",
>> + TRB_TO_EP_INDEX(field3), temp,
>> + temp == STREAM_PRIME_ACK ? "(PRIME)" : "",
>> + temp == STREAM_REJECTED ? "(REJECTED)" : "",
>> + TRB_TO_DEV_STREAM(field0),
>> + field3 & TRB_STAT ? 'S' : 's',
>> + field3 & TRB_CYCLE ? 'C' : 'c');
>> break;
>> default:
>> - ret += snprintf(str, size,
>> - "type '%s' -> raw %08x %08x %08x %08x",
>> - cdnsp_trb_type_string(type),
>> - field0, field1, field2, field3);
>> + ret = snprintf(str, size,
>> + "type '%s' -> raw %08x %08x %08x %08x",
>> + cdnsp_trb_type_string(type),
>> + field0, field1, field2, field3);
>> }
>>
>> + if (ret >= size)
>> + pr_info("CDNSP: buffer overflowed.\n");
>
>"info"?
>
>If the buffer overflows, was it properly truncated? Or did we just
>crash something else by passing on an overflowed buffer?

Yes, data will be properly truncated. Driver and kernel will not crash.
So, I added only information that some debug date may have been truncated.

Thanks,

Pawel Laszczak

Next message: Yao Hongbo: "Re: [RFC PATCH v2] PCI: Waiting command completed in get_port_device_capability()"
Previous message: Jagan Teki: "Re: [PATCH 6/6] drm/meson: add support for MIPI-DSI transceiver"
In reply to: Greg KH: "Re: [PATCH] usb: cdnsp: fix cdnsp_decode_trb function to properly handle ret value"
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