drivers/net/usb/pegasus.c:461:2: warning: Value stored to 'ret' is never read [clang-analyzer-deadcode.DeadStores]

From: kernel test robot
Date: Mon Aug 09 2021 - 06:37:54 EST

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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>

clang-analyzer warnings: (new ones prefixed by >>)
^~~~
drivers/net/dsa/microchip/ksz_common.h:208:2: note: Taking false branch
if (!ret) {
^
drivers/net/dsa/microchip/ksz_common.h:215:2: note: Returning without writing to '*val'
return ret;
^
drivers/net/dsa/microchip/ksz8795.c:464:2: note: Returning from 'ksz_read64'
ksz_read64(dev, regs[REG_IND_DATA_HI], data);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/net/dsa/microchip/ksz8795.c:466:1: note: Returning without writing to '*data'
}
^
drivers/net/dsa/microchip/ksz8795.c:588:2: note: Returning from 'ksz8_r_table'
ksz8_r_table(dev, TABLE_STATIC_MAC, addr, &data);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/net/dsa/microchip/ksz8795.c:589:17: note: The left operand of '>>' is a garbage value
data_hi = data >> 32;
~~~~ ^
drivers/net/dsa/microchip/ksz8795.c:692:38: warning: Assigned value is garbage or undefined [clang-analyzer-core.uninitialized.Assign]
dev->vlan_cache[addr + i].table[0] = (u16)data;
^
drivers/net/dsa/microchip/ksz8795.c:1404:6: note: Assuming field 'vlan_cache' is non-null
if (!dev->vlan_cache)
^~~~~~~~~~~~~~~~
drivers/net/dsa/microchip/ksz8795.c:1404:2: note: Taking false branch
if (!dev->vlan_cache)
^
drivers/net/dsa/microchip/ksz8795.c:1408:6: note: 'ret' is 0
if (ret) {
^~~
drivers/net/dsa/microchip/ksz8795.c:1408:2: note: Taking false branch
if (ret) {
^
drivers/net/dsa/microchip/ksz8795.c:1444:14: note: Assuming the condition is true
for (i = 0; i < (dev->num_vlans / 4); i++)
^~~~~~~~~~~~~~~~~~~~~~~~
drivers/net/dsa/microchip/ksz8795.c:1444:2: note: Loop condition is true. Entering loop body
for (i = 0; i < (dev->num_vlans / 4); i++)
^
drivers/net/dsa/microchip/ksz8795.c:1445:3: note: Calling 'ksz8_r_vlan_entries'
ksz8_r_vlan_entries(dev, i);
^~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/net/dsa/microchip/ksz8795.c:684:2: note: 'data' declared without an initial value
u64 data;
^~~~~~~~
drivers/net/dsa/microchip/ksz8795.c:689:2: note: Calling 'ksz8_r_table'
ksz8_r_table(dev, TABLE_VLAN, addr, &data);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/net/dsa/microchip/ksz8795.c:464:2: note: Calling 'ksz_read64'
ksz_read64(dev, regs[REG_IND_DATA_HI], data);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/net/dsa/microchip/ksz_common.h:208:6: note: Assuming 'ret' is not equal to 0
if (!ret) {
^~~~
drivers/net/dsa/microchip/ksz_common.h:208:2: note: Taking false branch
if (!ret) {
^
drivers/net/dsa/microchip/ksz_common.h:215:2: note: Returning without writing to '*val'
return ret;
^
drivers/net/dsa/microchip/ksz8795.c:464:2: note: Returning from 'ksz_read64'
ksz_read64(dev, regs[REG_IND_DATA_HI], data);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/net/dsa/microchip/ksz8795.c:466:1: note: Returning without writing to '*data'
}
^
drivers/net/dsa/microchip/ksz8795.c:689:2: note: Returning from 'ksz8_r_table'
ksz8_r_table(dev, TABLE_VLAN, addr, &data);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/net/dsa/microchip/ksz8795.c:691:14: note: Assuming 'i' is < field 'phy_port_cnt'
for (i = 0; i < dev->phy_port_cnt; i++) {
^~~~~~~~~~~~~~~~~~~~~
drivers/net/dsa/microchip/ksz8795.c:691:2: note: Loop condition is true. Entering loop body
for (i = 0; i < dev->phy_port_cnt; i++) {
^
drivers/net/dsa/microchip/ksz8795.c:692:38: note: Assigned value is garbage or undefined
dev->vlan_cache[addr + i].table[0] = (u16)data;
^ ~~~~~~~~~
drivers/net/dsa/microchip/ksz8795.c:1592:8: warning: Excessive padding in 'struct ksz_chip_data' (10 padding bytes, where 2 is optimal). Optimal fields order: dev_name, num_vlans, num_alus, num_statics, cpu_ports, port_cnt, chip_id, consider reordering the fields or adding explicit padding members [clang-analyzer-optin.performance.Padding]
struct ksz_chip_data {
~~~~~~~^~~~~~~~~~~~~~~
drivers/net/dsa/microchip/ksz8795.c:1592:8: note: Excessive padding in 'struct ksz_chip_data' (10 padding bytes, where 2 is optimal). Optimal fields order: dev_name, num_vlans, num_alus, num_statics, cpu_ports, port_cnt, chip_id, consider reordering the fields or adding explicit padding members
struct ksz_chip_data {
~~~~~~~^~~~~~~~~~~~~~~
Suppressed 11 warnings (11 in non-user code).
Use -header-filter=.* to display errors from all non-system headers. Use -system-headers to display errors from system headers as well.
10 warnings generated.
Suppressed 10 warnings (10 in non-user code).
Use -header-filter=.* to display errors from all non-system headers. Use -system-headers to display errors from system headers as well.
12 warnings generated.

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;
^
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);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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;

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
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Next message: Krzysztof Kozlowski: "Re: [PATCH] arm64: dts: exynos: correct GIC CPU interfaces address range on Exynos7"
Previous message: Bodo Stroesser: "Re: [PATCH] scsi: target: pscsi: Fix possible null-pointer dereference in pscsi_complete_cmd()"
Next in thread: Pavel Skripkin: "Re: drivers/net/usb/pegasus.c:461:2: warning: Value stored to 'ret' is never read [clang-analyzer-deadcode.DeadStores]"
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