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SubjectRe: drivers/staging/greybus/bootrom.c:298:35-39: ERROR: fw is NULL but dereferenced.
On Sun, Nov 27, 2016 at 12:06:33PM +0100, Greg KH wrote:
>On Sun, Nov 27, 2016 at 07:11:46AM +0800, kbuild test robot wrote:
>> tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
>> head: a0d60e62ea5c88a9823410e9d0929a513e29dea2
>> commit: f44dd184634d401f5cf88a6d8b4a60d5ff4f417f Merge greybus driver tree into 4.8-rc6
>> date: 10 weeks ago
>
>This is a false-positive, sorry.

Yes it's a false warning: ret != 0, so fw->size in the if test won't be dereferenced.
Relevant code:

if (!fw) {
dev_err(dev, "%s: firmware not available\n", __func__);
ret = -EINVAL;
goto unlock;
}
...
unlock:
mutex_unlock(&bootrom->mutex);

queue_work:
/* Refresh timeout */
if (!ret && (offset + size == fw->size))
next_request = NEXT_REQ_READY_TO_BOOT;
else
next_request = NEXT_REQ_GET_FIRMWARE;

CC Julia for possible improvements to the coccinelle script. If it's
not convenient to fix there I'll teach the robot to ignore this
particular false warning.

Thanks,
Fengguang

>> coccinelle warnings: (new ones prefixed by >>)
>>
>> >> drivers/staging/greybus/bootrom.c:298:35-39: ERROR: fw is NULL but dereferenced.
>>
>> vim +298 drivers/staging/greybus/bootrom.c
>>
>> 90f1b617 drivers/staging/greybus/firmware.c Viresh Kumar 2015-08-12 282 dev_err(dev, "%s: error allocating response\n", __func__);
>> a956d939 drivers/staging/greybus/bootrom.c Viresh Kumar 2016-05-09 283 ret = -ENOMEM;
>> a956d939 drivers/staging/greybus/bootrom.c Viresh Kumar 2016-05-09 284 goto unlock;
>> 90f1b617 drivers/staging/greybus/firmware.c Viresh Kumar 2015-08-12 285 }
>> 90f1b617 drivers/staging/greybus/firmware.c Viresh Kumar 2015-08-12 286
>> 90f1b617 drivers/staging/greybus/firmware.c Viresh Kumar 2015-08-12 287 firmware_response = op->response->payload;
>> 98645a9c drivers/staging/greybus/firmware.c Johan Hovold 2015-11-19 288 memcpy(firmware_response->data, fw->data + offset, size);
>> 90f1b617 drivers/staging/greybus/firmware.c Viresh Kumar 2015-08-12 289
>> fc41c2da drivers/staging/greybus/firmware.c Eli Sennesh 2016-01-08 290 dev_dbg(dev, "responding with firmware (offs = %u, size = %u)\n", offset,
>> fc41c2da drivers/staging/greybus/firmware.c Eli Sennesh 2016-01-08 291 size);
>> fc41c2da drivers/staging/greybus/firmware.c Eli Sennesh 2016-01-08 292
>> a956d939 drivers/staging/greybus/bootrom.c Viresh Kumar 2016-05-09 293 unlock:
>> a956d939 drivers/staging/greybus/bootrom.c Viresh Kumar 2016-05-09 294 mutex_unlock(&bootrom->mutex);
>> a956d939 drivers/staging/greybus/bootrom.c Viresh Kumar 2016-05-09 295
>> a956d939 drivers/staging/greybus/bootrom.c Viresh Kumar 2016-05-09 296 queue_work:
>> a956d939 drivers/staging/greybus/bootrom.c Viresh Kumar 2016-05-09 297 /* Refresh timeout */
>> a4293e1d drivers/staging/greybus/bootrom.c Viresh Kumar 2016-06-22 @298 if (!ret && (offset + size == fw->size))
>> a4293e1d drivers/staging/greybus/bootrom.c Viresh Kumar 2016-06-22 299 next_request = NEXT_REQ_READY_TO_BOOT;
>> a4293e1d drivers/staging/greybus/bootrom.c Viresh Kumar 2016-06-22 300 else
>> a4293e1d drivers/staging/greybus/bootrom.c Viresh Kumar 2016-06-22 301 next_request = NEXT_REQ_GET_FIRMWARE;
>> a4293e1d drivers/staging/greybus/bootrom.c Viresh Kumar 2016-06-22 302
>> dbb8cfeb drivers/staging/greybus/bootrom.c Viresh Kumar 2016-06-22 303 gb_bootrom_set_timeout(bootrom, next_request, NEXT_REQ_TIMEOUT_MS);
>> a956d939 drivers/staging/greybus/bootrom.c Viresh Kumar 2016-05-09 304
>> a956d939 drivers/staging/greybus/bootrom.c Viresh Kumar 2016-05-09 305 return ret;
>> 90f1b617 drivers/staging/greybus/firmware.c Viresh Kumar 2015-08-12 306 }
>>
>> :::::: The code at line 298 was first introduced by commit
>> :::::: a4293e1d4e6416477976ee3bd248589d3fc4bb19 greybus: bootrom: Enhance timeout error message
>>
>> :::::: TO: Viresh Kumar <viresh.kumar@linaro.org>
>> :::::: CC: Greg Kroah-Hartman <gregkh@google.com>
>>
>> ---
>> 0-DAY kernel test infrastructure Open Source Technology Center
>> https://lists.01.org/pipermail/kbuild-all Intel Corporation

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