[V2] net/intel/e1000: reduce the optimization level for gcc > 11

[Bruce Richardson]

On Mon, Oct 06, 2025 at 03:02:57PM +0200, Thierry Herbelot wrote:
> The e1000 PMD stopped working under Ubuntu-24.04 (using gcc-13) when
> compiled with -O3 (default level for all DPDK code). There is a crash
> when starting testpmd:
> 
> > (gdb) bt
> > #0  rte_read32_relaxed (addr=0x1100800e00) at ../sources/lib/eal/include/generic/rte_io.h:290
> > #1  rte_read32 (addr=0x1100800e00) at ../sources/lib/eal/include/generic/rte_io.h:345
> > #2  e1000_read_addr (addr=0x1100800e00) at ../sources/drivers/net/intel/e1000/base/e1000_osdep.h:106
> > #3  e1000_id_led_init_generic (hw=0x1586788c0) at ../sources/drivers/net/intel/e1000/base/e1000_mac.c:1844
> > #4  0x000062aaf653c85f in e1000_init_hw_82540 (hw=0x1586788c0)
> >     at ../sources/drivers/net/intel/e1000/base/e1000_82540.c:308
> > #5  0x000062aaf6db8227 in em_hardware_init (hw=hw at entry=0x1586788c0)
> >     at ../sources/drivers/net/intel/e1000/em_ethdev.c:920
> > #6  0x000062aaf65340ff in em_hw_init (hw=0x1586788c0) at ../sources/drivers/net/intel/e1000/em_ethdev.c:445
> > #7  eth_em_dev_init (eth_dev=eth_dev at entry=0x62aaff346000 <rte_eth_devices>)
> >     at ../sources/drivers/net/intel/e1000/em_ethdev.c:314
> > #8  0x000062aaf6db8b71 in rte_eth_dev_pci_generic_probe (private_data_size=11240,
> >     dev_init=0x62aaf6db8310 <eth_em_dev_init>, pci_dev=0x62ab2853dd90) at ../sources/lib/ethdev/ethdev_pci.h:150
> > #9  eth_em_pci_probe (pci_drv=<optimized out>, pci_dev=0x62ab2853dd90)
> >     at ../sources/drivers/net/intel/e1000/em_ethdev.c:365
> > #10 0x000062aaf646adf5 in rte_pci_probe_one_driver (dr=dr at entry=0x62aaf82d8020 <rte_em_pmd>,
> >     dev=dev at entry=0x62ab2853dd90) at ../sources/drivers/bus/pci/pci_common.c:299
> > #11 0x000062aaf6a15f7d in pci_probe_all_drivers (dev=0x62ab2853dd90) at ../sources/drivers/bus/pci/pci_common.c:383
> > #12 pci_probe () at ../sources/drivers/bus/pci/pci_common.c:410
> > #13 0x000062aaf7a485f3 in rte_bus_probe () at ../sources/lib/eal/common/eal_common_bus.c:84
> > #14 0x000062aaf670585d in rte_eal_init (argc=argc at entry=146, argv=argv at entry=0x7fffca468898)
> >     at ../sources/lib/eal/linux/eal.c:1253
> 
> The crash is linked to the use of gcc-13: under Ubuntu-24.04 testpmd
> compiled with gcc-11 from the same DPDK tree works as expected.
> 
> The perfect solution would be for someone to investigate why the
> PMD crashes. However, this depends on Maintainer availability.
> 
Hi,

can you test with [1]. It's still a workaround while we investigate more,
but a less severe one!

/Bruce

[1] https://patches.dpdk.org/project/dpdk/patch/20251010125848.965340-1-ciara.loftus@intel.com/