tree: https://git.kernel.org/pub/scm/linux/kernel/git/tglx/devel.git devicemsi head: 67d94e5e316843b1af2b0c4cf5d4f8e9a91d97b4 commit: c788f3e806861afdef54db59dc5be9afb5bc906f [18/38] x86/irq: Initialize PCI/MSI domain at PCI init time config: x86_64-randconfig-a002-20200820 (attached as .config) compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project b587ca93be114d07ec3bf654add97d7872325281) 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 git checkout c788f3e806861afdef54db59dc5be9afb5bc906f # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=x86_64 If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All warnings (new ones prefixed by >>): if (fn) { ^~ arch/x86/kernel/apic/msi.c:251:7: note: uninitialized use occurs here if (!d) { ^ arch/x86/kernel/apic/msi.c:247:2: note: remove the 'if' if its condition is always true if (fn) { ^~~~~~~~ arch/x86/kernel/apic/msi.c:241:22: note: initialize the variable 'd' to silence this warning struct irq_domain *d; ^ = NULL 1 warning generated. # https://git.kernel.org/pub/scm/linux/kernel/git/tglx/devel.git/commit/?id... git remote add tglx-devel https://git.kernel.org/pub/scm/linux/kernel/git/tglx/devel.git git fetch --no-tags tglx-devel devicemsi git checkout c788f3e806861afdef54db59dc5be9afb5bc906f vim +247 arch/x86/kernel/apic/msi.c 443809828cb5ee0 Jiang Liu 2014-10-27 237 c788f3e806861af Thomas Gleixner 2020-08-21 238 struct irq_domain * __init native_create_pci_msi_domain(void) 52f518a3a7c2f80 Jiang Liu 2015-04-13 239 { f8f37ca78915b51 Thomas Gleixner 2017-06-20 240 struct fwnode_handle *fn; c788f3e806861af Thomas Gleixner 2020-08-21 241 struct irq_domain *d; f8f37ca78915b51 Thomas Gleixner 2017-06-20 242 52f518a3a7c2f80 Jiang Liu 2015-04-13 243 if (disable_apic) c788f3e806861af Thomas Gleixner 2020-08-21 244 return NULL; 443809828cb5ee0 Jiang Liu 2014-10-27 245 f8f37ca78915b51 Thomas Gleixner 2017-06-20 246 fn = irq_domain_alloc_named_fwnode("PCI-MSI"); f8f37ca78915b51 Thomas Gleixner 2017-06-20 @247 if (fn) { c788f3e806861af Thomas Gleixner 2020-08-21 248 d = pci_msi_create_irq_domain(fn, &pci_msi_domain_info, c788f3e806861af Thomas Gleixner 2020-08-21 249 x86_vector_domain); f8f37ca78915b51 Thomas Gleixner 2017-06-20 250 } c788f3e806861af Thomas Gleixner 2020-08-21 251 if (!d) { e3beca48a45b5e0 Thomas Gleixner 2020-07-09 252 irq_domain_free_fwnode(fn); c788f3e806861af Thomas Gleixner 2020-08-21 253 pr_warn("Failed to initialize PCI-MSI irqdomain.\n"); e3beca48a45b5e0 Thomas Gleixner 2020-07-09 254 } else { c788f3e806861af Thomas Gleixner 2020-08-21 255 d->flags |= IRQ_DOMAIN_MSI_NOMASK_QUIRK; c788f3e806861af Thomas Gleixner 2020-08-21 256 } c788f3e806861af Thomas Gleixner 2020-08-21 257 return d; 443809828cb5ee0 Jiang Liu 2014-10-27 258 } c788f3e806861af Thomas Gleixner 2020-08-21 259 :::::: The code at line 247 was first introduced by commit :::::: f8f37ca78915b51a73bf240409fcda30d811b76b x86/msi: Create named irq domains :::::: TO: Thomas Gleixner <tglx(a)linutronix.de&gt; :::::: CC: Thomas Gleixner <tglx(a)linutronix.de&gt; --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org