Re: drivers/net/usb/pegasus.c:461:2: warning: Value stored to 'ret' is never read [clang-analyzer-deadcode.DeadStores]
From: Pavel Skripkin
Date: Mon Aug 09 2021 - 07:00:59 EST
On 8/9/21 1:37 PM, kernel test robot wrote:
tree:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head: 85a90500f9a1717c4e142ce92e6c1cb1a339ec78
commit: 8a160e2e9aeb8318159b48701ad8a6e22274372d net: usb: pegasus:
Check the return value of get_geristers() and friends;
date: 4 days ago
:::::: branch date: 8 hours ago
:::::: commit date: 4 days ago
config: x86_64-randconfig-c001-20210808 (attached as .config)
compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project
41a6b50c25961addc04438b567ee1f4ef9e40f98)
reproduce (this is a W=1 build):
wget
https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross
-O ~/bin/make.cross
chmod +x ~/bin/make.cross
# install x86_64 cross compiling tool for clang build
# apt-get install binutils-x86-64-linux-gnu
#
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=8a160e2e9aeb8318159b48701ad8a6e22274372d
git remote add linus
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
git fetch --no-tags linus master
git checkout 8a160e2e9aeb8318159b48701ad8a6e22274372d
# save the attached .config to linux build tree
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross
ARCH=x86_64 clang-analyzer
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@xxxxxxxxx>
[snip]
drivers/net/usb/pegasus.c:461:2: warning: Value stored to 'ret' is never read [clang-analyzer-deadcode.DeadStores]
ret = set_registers(pegasus, EthCtrl0, 3, data);
^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/net/usb/pegasus.c:461:2: note: Value stored to 'ret' is
never read
ret = set_registers(pegasus, EthCtrl0, 3, data);
^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/net/usb/pegasus.c:778:18: warning: The left operand of '>>'
is a garbage value [clang-analyzer-core.UndefinedBinaryOperatorResult]
interval = data >> 8;
^
This is fixed by commit af35fc37354c ("net: pegasus: fix uninit-value in
get_interrupt_interval")
drivers/net/usb/pegasus.c:1157:2: note: Taking false branch
if (pegasus_blacklisted(dev))
^
drivers/net/usb/pegasus.c:1161:6: note: Assuming 'net' is non-null
if (!net)
^~~~
drivers/net/usb/pegasus.c:1161:2: note: Taking false branch
if (!net)
^
drivers/net/usb/pegasus.c:1168:6: note: 'res' is >= 0
if (res < 0) {
^~~
drivers/net/usb/pegasus.c:1168:2: note: Taking false branch
if (res < 0) {
^
drivers/net/usb/pegasus.c:1175:2: note: Loop condition is false.
Exiting loop
INIT_DELAYED_WORK(&pegasus->carrier_check, check_carrier);
^
include/linux/workqueue.h:272:2: note: expanded from macro
'INIT_DELAYED_WORK'
__INIT_DELAYED_WORK(_work, _func, 0)
^
include/linux/workqueue.h:257:3: note: expanded from macro
'__INIT_DELAYED_WORK'
INIT_WORK(&(_work)->work, (_func));
\
^
include/linux/workqueue.h:250:2: note: expanded from macro 'INIT_WORK'
__INIT_WORK((_work), (_func), 0)
^
include/linux/workqueue.h:230:2: note: expanded from macro '__INIT_WORK'
do {
\
^
drivers/net/usb/pegasus.c:1175:2: note: Loop condition is false.
Exiting loop
INIT_DELAYED_WORK(&pegasus->carrier_check, check_carrier);
^
include/linux/workqueue.h:272:2: note: expanded from macro
'INIT_DELAYED_WORK'
__INIT_DELAYED_WORK(_work, _func, 0)
^
include/linux/workqueue.h:258:3: note: expanded from macro
'__INIT_DELAYED_WORK'
__init_timer(&(_work)->timer,
\
^
include/linux/timer.h:113:2: note: expanded from macro '__init_timer'
do {
\
^
drivers/net/usb/pegasus.c:1175:2: note: Loop condition is false.
Exiting loop
INIT_DELAYED_WORK(&pegasus->carrier_check, check_carrier);
^
include/linux/workqueue.h:272:2: note: expanded from macro
'INIT_DELAYED_WORK'
__INIT_DELAYED_WORK(_work, _func, 0)
^
include/linux/workqueue.h:256:2: note: expanded from macro
'__INIT_DELAYED_WORK'
do {
\
^
drivers/net/usb/pegasus.c:1194:2: note: Calling 'get_interrupt_interval'
get_interrupt_interval(pegasus);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/net/usb/pegasus.c:774:2: note: 'data' declared without an
initial value
u16 data;
^~~~~~~~
drivers/net/usb/pegasus.c:777:2: note: Calling 'read_eprom_word'
read_eprom_word(pegasus, 4, &data);
This is fixed by commit af35fc37354c ("net: pegasus: fix uninit-value in
get_interrupt_interval")
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/net/usb/pegasus.c:279:2: note: Loop condition is true.
Entering loop body
for (i = 0; i < REG_TIMEOUT; i++) {
^
drivers/net/usb/pegasus.c:281:7: note: Assuming 'ret' is < 0
if (ret < 0)
^~~~~~~
drivers/net/usb/pegasus.c:281:3: note: Taking true branch
if (ret < 0)
^
drivers/net/usb/pegasus.c:282:4: note: Control jumps to line 298
goto fail;
^
drivers/net/usb/pegasus.c:298:2: note: Taking false branch
netif_dbg(pegasus, drv, pegasus->net, "%s failed\n", __func__);
^
include/linux/netdevice.h:5352:2: note: expanded from macro 'netif_dbg'
if (netif_msg_##type(priv)) \
^
drivers/net/usb/pegasus.c:298:2: note: Loop condition is false.
Exiting loop
netif_dbg(pegasus, drv, pegasus->net, "%s failed\n", __func__);
^
include/linux/netdevice.h:5350:57: note: expanded from macro 'netif_dbg'
#define netif_dbg(priv, type, netdev, format, args...) \
^
drivers/net/usb/pegasus.c:299:2: note: Returning without writing to
'*retdata'
return ret;
^
drivers/net/usb/pegasus.c:777:2: note: Returning from 'read_eprom_word'
read_eprom_word(pegasus, 4, &data);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/net/usb/pegasus.c:778:18: note: The left operand of '>>' is
a garbage value
interval = data >> 8;
This is fixed by commit af35fc37354c ("net: pegasus: fix uninit-value in
get_interrupt_interval")
vim +/ret +461 drivers/net/usb/pegasus.c
^1da177e4c3f41 drivers/usb/net/pegasus.c Linus Torvalds 2005-04-16 439
^1da177e4c3f41 drivers/usb/net/pegasus.c Linus Torvalds 2005-04-16
440 static int enable_net_traffic(struct net_device *dev, struct
usb_device *usb)
^1da177e4c3f41 drivers/usb/net/pegasus.c Linus Torvalds 2005-04-16 441 {
^1da177e4c3f41 drivers/usb/net/pegasus.c Linus Torvalds 2005-04-16
442 pegasus_t *pegasus = netdev_priv(dev);
^1da177e4c3f41 drivers/usb/net/pegasus.c Linus Torvalds 2005-04-16
443 int ret;
8a160e2e9aeb83 drivers/net/usb/pegasus.c Petko Manolov 2021-08-03
444 __u16 linkpart;
8a160e2e9aeb83 drivers/net/usb/pegasus.c Petko Manolov 2021-08-03
445 __u8 data[4];
^1da177e4c3f41 drivers/usb/net/pegasus.c Linus Torvalds 2005-04-16 446
8a160e2e9aeb83 drivers/net/usb/pegasus.c Petko Manolov 2021-08-03
447 ret = read_mii_word(pegasus, pegasus->phy, MII_LPA, &linkpart);
8a160e2e9aeb83 drivers/net/usb/pegasus.c Petko Manolov 2021-08-03
448 if (ret < 0)
8a160e2e9aeb83 drivers/net/usb/pegasus.c Petko Manolov 2021-08-03
449 goto fail;
1a8deec09d12c1 drivers/net/usb/pegasus.c Petko Manolov 2016-04-27
450 data[0] = 0xc8; /* TX & RX enable, append status, no CRC */
^1da177e4c3f41 drivers/usb/net/pegasus.c Linus Torvalds 2005-04-16
451 data[1] = 0;
^1da177e4c3f41 drivers/usb/net/pegasus.c Linus Torvalds 2005-04-16
452 if (linkpart & (ADVERTISE_100FULL | ADVERTISE_10FULL))
^1da177e4c3f41 drivers/usb/net/pegasus.c Linus Torvalds 2005-04-16
453 data[1] |= 0x20; /* set full duplex */
^1da177e4c3f41 drivers/usb/net/pegasus.c Linus Torvalds 2005-04-16
454 if (linkpart & (ADVERTISE_100FULL | ADVERTISE_100HALF))
^1da177e4c3f41 drivers/usb/net/pegasus.c Linus Torvalds 2005-04-16
455 data[1] |= 0x10; /* set 100 Mbps */
^1da177e4c3f41 drivers/usb/net/pegasus.c Linus Torvalds 2005-04-16
456 if (mii_mode)
^1da177e4c3f41 drivers/usb/net/pegasus.c Linus Torvalds 2005-04-16
457 data[1] = 0;
681f16232c49de drivers/net/usb/pegasus.c Dan Carpenter 2011-12-23
458 data[2] = loopback ? 0x09 : 0x01;
^1da177e4c3f41 drivers/usb/net/pegasus.c Linus Torvalds 2005-04-16 459
^1da177e4c3f41 drivers/usb/net/pegasus.c Linus Torvalds 2005-04-16
460 memcpy(pegasus->eth_regs, data, sizeof(data));
^1da177e4c3f41 drivers/usb/net/pegasus.c Linus Torvalds 2005-04-16
@461 ret = set_registers(pegasus, EthCtrl0, 3, data);
^1da177e4c3f41 drivers/usb/net/pegasus.c Linus Torvalds 2005-04-16 462
^1da177e4c3f41 drivers/usb/net/pegasus.c Linus Torvalds 2005-04-16
463 if (usb_dev_id[pegasus->dev_index].vendor == VENDOR_LINKSYS ||
efafe6fb72b2bb drivers/usb/net/pegasus.c Malte Doersam 2006-01-28
464 usb_dev_id[pegasus->dev_index].vendor == VENDOR_LINKSYS2 ||
^1da177e4c3f41 drivers/usb/net/pegasus.c Linus Torvalds 2005-04-16
465 usb_dev_id[pegasus->dev_index].vendor == VENDOR_DLINK) {
^1da177e4c3f41 drivers/usb/net/pegasus.c Linus Torvalds 2005-04-16
466 u16 auxmode;
8a160e2e9aeb83 drivers/net/usb/pegasus.c Petko Manolov 2021-08-03
467 ret = read_mii_word(pegasus, 0, 0x1b, &auxmode);
8a160e2e9aeb83 drivers/net/usb/pegasus.c Petko Manolov 2021-08-03
468 if (ret < 0)
8a160e2e9aeb83 drivers/net/usb/pegasus.c Petko Manolov 2021-08-03
469 goto fail;
2bd647018fe1b2 drivers/net/usb/pegasus.c Petko Manolov 2013-04-25
470 auxmode |= 4;
2bd647018fe1b2 drivers/net/usb/pegasus.c Petko Manolov 2013-04-25
471 write_mii_word(pegasus, 0, 0x1b, &auxmode);
^1da177e4c3f41 drivers/usb/net/pegasus.c Linus Torvalds 2005-04-16 472 }
^1da177e4c3f41 drivers/usb/net/pegasus.c Linus Torvalds 2005-04-16 473
8a160e2e9aeb83 drivers/net/usb/pegasus.c Petko Manolov 2021-08-03
474 return 0;
8a160e2e9aeb83 drivers/net/usb/pegasus.c Petko Manolov 2021-08-03 475
fail:
8a160e2e9aeb83 drivers/net/usb/pegasus.c Petko Manolov 2021-08-03
476 netif_dbg(pegasus, drv, pegasus->net, "%s failed\n", __func__);
4a1728a28a193a drivers/usb/net/pegasus.c Petko Manolov 2005-11-15
477 return ret;
^1da177e4c3f41 drivers/usb/net/pegasus.c Linus Torvalds 2005-04-16 478 }
^1da177e4c3f41 drivers/usb/net/pegasus.c Linus Torvalds 2005-04-16 479
:::::: The code at line 461 was first introduced by commit
:::::: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 Linux-2.6.12-rc2
:::::: TO: Linus Torvalds <torvalds@xxxxxxxxxxxxxxx>
:::::: CC: Linus Torvalds <torvalds@xxxxxxxxxxxxxxx>
---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@xxxxxxxxxxxx
With regards,
Pavel Skripkin