CC: kbuild-all(a)lists.01.org CC: linux-kernel(a)vger.kernel.org TO: Andrew Lunn <andrew(a)lunn.ch&gt; CC: Jakub Kicinski <kuba(a)kernel.org&gt; Hi Andrew, First bad commit (maybe != root cause): tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master head: 5e46d1b78a03d52306f21f77a4e4a144b6d31486 commit: 7958ba7e6273a02f49432a2506958d0f59b5b8da drivers: net: smsc: Add COMPILE_TEST support date: 5 months ago :::::: branch date: 20 hours ago :::::: commit date: 5 months ago config: microblaze-randconfig-m031-20210331 (attached as .config) compiler: microblaze-linux-gcc (GCC) 9.3.0 If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; Reported-by: Dan Carpenter <dan.carpenter(a)oracle.com&gt; smatch warnings: drivers/net/ethernet/smsc/smc91x.c:550 smc_hardware_send_pkt() error: uninitialized symbol 'flags'. vim +/flags +550 drivers/net/ethernet/smsc/smc91x.c ^1da177e4c3f41 drivers/net/smc91x.c Linus Torvalds 2005-04-16 534 ^1da177e4c3f41 drivers/net/smc91x.c Linus Torvalds 2005-04-16 535 /* ^1da177e4c3f41 drivers/net/smc91x.c Linus Torvalds 2005-04-16 536 * This is called to actually send a packet to the chip. ^1da177e4c3f41 drivers/net/smc91x.c Linus Torvalds 2005-04-16 537 */ 7961fb1089f826 drivers/net/ethernet/smsc/smc91x.c Allen Pais 2020-09-14 538 static void smc_hardware_send_pkt(struct tasklet_struct *t) ^1da177e4c3f41 drivers/net/smc91x.c Linus Torvalds 2005-04-16 539 { 7961fb1089f826 drivers/net/ethernet/smsc/smc91x.c Allen Pais 2020-09-14 540 struct smc_local *lp = from_tasklet(lp, t, tx_task); 7961fb1089f826 drivers/net/ethernet/smsc/smc91x.c Allen Pais 2020-09-14 541 struct net_device *dev = lp->dev; ^1da177e4c3f41 drivers/net/smc91x.c Linus Torvalds 2005-04-16 542 void __iomem *ioaddr = lp->base; ^1da177e4c3f41 drivers/net/smc91x.c Linus Torvalds 2005-04-16 543 struct sk_buff *skb; ^1da177e4c3f41 drivers/net/smc91x.c Linus Torvalds 2005-04-16 544 unsigned int packet_no, len; ^1da177e4c3f41 drivers/net/smc91x.c Linus Torvalds 2005-04-16 545 unsigned char *buf; 8ff499e43c5376 drivers/net/smc91x.c Dongdong Deng 2009-08-23 546 unsigned long flags; ^1da177e4c3f41 drivers/net/smc91x.c Linus Torvalds 2005-04-16 547 6389aa458ed995 drivers/net/ethernet/smsc/smc91x.c Ben Boeckel 2013-11-01 548 DBG(3, dev, "%s\n", __func__); ^1da177e4c3f41 drivers/net/smc91x.c Linus Torvalds 2005-04-16 549 8ff499e43c5376 drivers/net/smc91x.c Dongdong Deng 2009-08-23 @550 if (!smc_special_trylock(&lp->lock, flags)) { ^1da177e4c3f41 drivers/net/smc91x.c Linus Torvalds 2005-04-16 551 netif_stop_queue(dev); ^1da177e4c3f41 drivers/net/smc91x.c Linus Torvalds 2005-04-16 552 tasklet_schedule(&lp->tx_task); ^1da177e4c3f41 drivers/net/smc91x.c Linus Torvalds 2005-04-16 553 return; ^1da177e4c3f41 drivers/net/smc91x.c Linus Torvalds 2005-04-16 554 } ^1da177e4c3f41 drivers/net/smc91x.c Linus Torvalds 2005-04-16 555 ^1da177e4c3f41 drivers/net/smc91x.c Linus Torvalds 2005-04-16 556 skb = lp->pending_tx_skb; be83668a253149 drivers/net/smc91x.c Nicolas Pitre 2005-06-19 557 if (unlikely(!skb)) { 8ff499e43c5376 drivers/net/smc91x.c Dongdong Deng 2009-08-23 558 smc_special_unlock(&lp->lock, flags); be83668a253149 drivers/net/smc91x.c Nicolas Pitre 2005-06-19 559 return; be83668a253149 drivers/net/smc91x.c Nicolas Pitre 2005-06-19 560 } ^1da177e4c3f41 drivers/net/smc91x.c Linus Torvalds 2005-04-16 561 lp->pending_tx_skb = NULL; be83668a253149 drivers/net/smc91x.c Nicolas Pitre 2005-06-19 562 cfdfa86536d2fb drivers/net/smc91x.c Magnus Damm 2008-02-22 563 packet_no = SMC_GET_AR(lp); ^1da177e4c3f41 drivers/net/smc91x.c Linus Torvalds 2005-04-16 564 if (unlikely(packet_no & AR_FAILED)) { 6389aa458ed995 drivers/net/ethernet/smsc/smc91x.c Ben Boeckel 2013-11-01 565 netdev_err(dev, "Memory allocation failed.\n"); 09f75cd7bf1372 drivers/net/smc91x.c Jeff Garzik 2007-10-03 566 dev->stats.tx_errors++; 09f75cd7bf1372 drivers/net/smc91x.c Jeff Garzik 2007-10-03 567 dev->stats.tx_fifo_errors++; 8ff499e43c5376 drivers/net/smc91x.c Dongdong Deng 2009-08-23 568 smc_special_unlock(&lp->lock, flags); ^1da177e4c3f41 drivers/net/smc91x.c Linus Torvalds 2005-04-16 569 goto done; ^1da177e4c3f41 drivers/net/smc91x.c Linus Torvalds 2005-04-16 570 } ^1da177e4c3f41 drivers/net/smc91x.c Linus Torvalds 2005-04-16 571 ^1da177e4c3f41 drivers/net/smc91x.c Linus Torvalds 2005-04-16 572 /* point to the beginning of the packet */ cfdfa86536d2fb drivers/net/smc91x.c Magnus Damm 2008-02-22 573 SMC_SET_PN(lp, packet_no); cfdfa86536d2fb drivers/net/smc91x.c Magnus Damm 2008-02-22 574 SMC_SET_PTR(lp, PTR_AUTOINC); ^1da177e4c3f41 drivers/net/smc91x.c Linus Torvalds 2005-04-16 575 ^1da177e4c3f41 drivers/net/smc91x.c Linus Torvalds 2005-04-16 576 buf = skb->data; ^1da177e4c3f41 drivers/net/smc91x.c Linus Torvalds 2005-04-16 577 len = skb->len; 6389aa458ed995 drivers/net/ethernet/smsc/smc91x.c Ben Boeckel 2013-11-01 578 DBG(2, dev, "TX PNR 0x%x LENGTH 0x%04x (%d) BUF 0x%p\n", 6389aa458ed995 drivers/net/ethernet/smsc/smc91x.c Ben Boeckel 2013-11-01 579 packet_no, len, len, buf); ^1da177e4c3f41 drivers/net/smc91x.c Linus Torvalds 2005-04-16 580 PRINT_PKT(buf, len); ^1da177e4c3f41 drivers/net/smc91x.c Linus Torvalds 2005-04-16 581 ^1da177e4c3f41 drivers/net/smc91x.c Linus Torvalds 2005-04-16 582 /* ^1da177e4c3f41 drivers/net/smc91x.c Linus Torvalds 2005-04-16 583 * Send the packet length (+6 for status words, length, and ctl. ^1da177e4c3f41 drivers/net/smc91x.c Linus Torvalds 2005-04-16 584 * The card will pad to 64 bytes with zeroes if packet is too small. ^1da177e4c3f41 drivers/net/smc91x.c Linus Torvalds 2005-04-16 585 */ cfdfa86536d2fb drivers/net/smc91x.c Magnus Damm 2008-02-22 586 SMC_PUT_PKT_HDR(lp, 0, len + 6); ^1da177e4c3f41 drivers/net/smc91x.c Linus Torvalds 2005-04-16 587 ^1da177e4c3f41 drivers/net/smc91x.c Linus Torvalds 2005-04-16 588 /* send the actual data */ cfdfa86536d2fb drivers/net/smc91x.c Magnus Damm 2008-02-22 589 SMC_PUSH_DATA(lp, buf, len & ~1); ^1da177e4c3f41 drivers/net/smc91x.c Linus Torvalds 2005-04-16 590 ^1da177e4c3f41 drivers/net/smc91x.c Linus Torvalds 2005-04-16 591 /* Send final ctl word with the last byte if there is one */ d09d747ae4c25a drivers/net/ethernet/smsc/smc91x.c Robert Jarzmik 2016-10-17 592 SMC_outw(lp, ((len & 1) ? (0x2000 | buf[len - 1]) : 0), ioaddr, d09d747ae4c25a drivers/net/ethernet/smsc/smc91x.c Robert Jarzmik 2016-10-17 593 DATA_REG(lp)); ^1da177e4c3f41 drivers/net/smc91x.c Linus Torvalds 2005-04-16 594 ^1da177e4c3f41 drivers/net/smc91x.c Linus Torvalds 2005-04-16 595 /* ea9375607f8b31 drivers/net/smc91x.c Nicolas Pitre 2005-04-12 596 * If THROTTLE_TX_PKTS is set, we stop the queue here. This will ea9375607f8b31 drivers/net/smc91x.c Nicolas Pitre 2005-04-12 597 * have the effect of having at most one packet queued for TX ea9375607f8b31 drivers/net/smc91x.c Nicolas Pitre 2005-04-12 598 * in the chip's memory at all time. ea9375607f8b31 drivers/net/smc91x.c Nicolas Pitre 2005-04-12 599 * ea9375607f8b31 drivers/net/smc91x.c Nicolas Pitre 2005-04-12 600 * If THROTTLE_TX_PKTS is not set then the queue is stopped only ea9375607f8b31 drivers/net/smc91x.c Nicolas Pitre 2005-04-12 601 * when memory allocation (MC_ALLOC) does not succeed right away. ^1da177e4c3f41 drivers/net/smc91x.c Linus Torvalds 2005-04-16 602 */ ea9375607f8b31 drivers/net/smc91x.c Nicolas Pitre 2005-04-12 603 if (THROTTLE_TX_PKTS) ^1da177e4c3f41 drivers/net/smc91x.c Linus Torvalds 2005-04-16 604 netif_stop_queue(dev); ^1da177e4c3f41 drivers/net/smc91x.c Linus Torvalds 2005-04-16 605 ^1da177e4c3f41 drivers/net/smc91x.c Linus Torvalds 2005-04-16 606 /* queue the packet for TX */ cfdfa86536d2fb drivers/net/smc91x.c Magnus Damm 2008-02-22 607 SMC_SET_MMU_CMD(lp, MC_ENQUEUE); 8ff499e43c5376 drivers/net/smc91x.c Dongdong Deng 2009-08-23 608 smc_special_unlock(&lp->lock, flags); ^1da177e4c3f41 drivers/net/smc91x.c Linus Torvalds 2005-04-16 609 860e9538a9482b drivers/net/ethernet/smsc/smc91x.c Florian Westphal 2016-05-03 610 netif_trans_update(dev); 09f75cd7bf1372 drivers/net/smc91x.c Jeff Garzik 2007-10-03 611 dev->stats.tx_packets++; 09f75cd7bf1372 drivers/net/smc91x.c Jeff Garzik 2007-10-03 612 dev->stats.tx_bytes += len; ^1da177e4c3f41 drivers/net/smc91x.c Linus Torvalds 2005-04-16 613 cfdfa86536d2fb drivers/net/smc91x.c Magnus Damm 2008-02-22 614 SMC_ENABLE_INT(lp, IM_TX_INT | IM_TX_EMPTY_INT); ^1da177e4c3f41 drivers/net/smc91x.c Linus Torvalds 2005-04-16 615 :::::: The code at line 550 was first introduced by commit :::::: 8ff499e43c537648399fca8ba39d24c0768b3fab smc91x: let smc91x work well under netpoll :::::: TO: Dongdong Deng <dongdong.deng(a)windriver.com&gt; :::::: CC: David S. Miller <davem(a)davemloft.net&gt; --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org