Hi Jean-Philippe, FYI, the error/warning still remains. tree: https://gitee.com/openeuler/kernel.git openEuler-1.0-LTS head: 02951ceaa6d546dfa0f741f52f6d47e0fb0ac7b4 commit: 2dd8345826607c5d2d6528de872118da554015b6 [1341/1341] vfio: Add support for Shared Virtual Addressing config: arm64-randconfig-002-20241220 (https://download.01.org/0day-ci/archive/20241221/202412210041.OxTX5o7L-lkp@i...) compiler: aarch64-linux-gcc (GCC) 14.2.0 reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20241221/202412210041.OxTX5o7L-lkp@i...) If you fix the issue in a separate patch/commit (i.e. not just a new version of the same patch/commit), kindly add following tags | Reported-by: kernel test robot <lkp@intel.com> | Closes: https://lore.kernel.org/oe-kbuild-all/202412210041.OxTX5o7L-lkp@intel.com/ Note: it may well be a FALSE warning. FWIW you are at least aware of it now. http://gcc.gnu.org/wiki/Better_Uninitialized_Warnings All warnings (new ones prefixed by >>): In file included from include/linux/compat.h:19, from drivers/vfio/vfio_iommu_type1.c:27: In function '_copy_from_user', inlined from 'copy_from_user' at include/linux/uaccess.h:144:7, inlined from 'vfio_iommu_type1_bind_process' at drivers/vfio/vfio_iommu_type1.c:1933:6: include/linux/uaccess.h:112:17: warning: 'params' may be used uninitialized [-Wmaybe-uninitialized] 112 | kasan_check_write(to, n); | ^~~~~~~~~~~~~~~~~~~~~~~~ In file included from include/linux/compiler.h:251, from include/asm-generic/div64.h:25, from ./arch/arm64/include/generated/asm/div64.h:1, from include/linux/math64.h:6, from include/linux/time64.h:5, from include/linux/compat_time.h:6, from include/linux/compat.h:10: include/linux/kasan-checks.h: In function 'vfio_iommu_type1_bind_process': include/linux/kasan-checks.h:7:6: note: by argument 1 of type 'const volatile void *' to 'kasan_check_write' declared here 7 | void kasan_check_write(const volatile void *p, unsigned int size); | ^~~~~~~~~~~~~~~~~ drivers/vfio/vfio_iommu_type1.c:1920:46: note: 'params' declared here 1920 | struct vfio_iommu_type1_bind_process params; | ^~~~~~ In function '_copy_from_user', inlined from 'copy_from_user' at include/linux/uaccess.h:144:7, inlined from 'vfio_iommu_type1_unbind_process' at drivers/vfio/vfio_iommu_type1.c:2021:6: include/linux/uaccess.h:112:17: warning: 'params' may be used uninitialized [-Wmaybe-uninitialized] 112 | kasan_check_write(to, n); | ^~~~~~~~~~~~~~~~~~~~~~~~ include/linux/kasan-checks.h: In function 'vfio_iommu_type1_unbind_process': include/linux/kasan-checks.h:7:6: note: by argument 1 of type 'const volatile void *' to 'kasan_check_write' declared here 7 | void kasan_check_write(const volatile void *p, unsigned int size); | ^~~~~~~~~~~~~~~~~ drivers/vfio/vfio_iommu_type1.c:2014:46: note: 'params' declared here 2014 | struct vfio_iommu_type1_bind_process params; | ^~~~~~ In function '_copy_from_user', inlined from 'copy_from_user' at include/linux/uaccess.h:144:7, inlined from 'vfio_iommu_type1_ioctl.part.0' at drivers/vfio/vfio_iommu_type1.c:2084:7: include/linux/uaccess.h:112:17: warning: 'info' may be used uninitialized [-Wmaybe-uninitialized] 112 | kasan_check_write(to, n); | ^~~~~~~~~~~~~~~~~~~~~~~~ include/linux/kasan-checks.h: In function 'vfio_iommu_type1_ioctl.part.0': include/linux/kasan-checks.h:7:6: note: by argument 1 of type 'const volatile void *' to 'kasan_check_write' declared here 7 | void kasan_check_write(const volatile void *p, unsigned int size); | ^~~~~~~~~~~~~~~~~ drivers/vfio/vfio_iommu_type1.c:2080:46: note: 'info' declared here 2080 | struct vfio_iommu_type1_info info; | ^~~~ In function '_copy_from_user', inlined from 'copy_from_user' at include/linux/uaccess.h:144:7, inlined from 'vfio_iommu_type1_ioctl.part.0' at drivers/vfio/vfio_iommu_type1.c:2104:7: include/linux/uaccess.h:112:17: warning: 'map' may be used uninitialized [-Wmaybe-uninitialized] 112 | kasan_check_write(to, n); | ^~~~~~~~~~~~~~~~~~~~~~~~ include/linux/kasan-checks.h: In function 'vfio_iommu_type1_ioctl.part.0': include/linux/kasan-checks.h:7:6: note: by argument 1 of type 'const volatile void *' to 'kasan_check_write' declared here 7 | void kasan_check_write(const volatile void *p, unsigned int size); | ^~~~~~~~~~~~~~~~~ drivers/vfio/vfio_iommu_type1.c:2098:49: note: 'map' declared here 2098 | struct vfio_iommu_type1_dma_map map; | ^~~ In function '_copy_from_user', inlined from 'copy_from_user' at include/linux/uaccess.h:144:7, inlined from 'vfio_iommu_type1_ioctl.part.0' at drivers/vfio/vfio_iommu_type1.c:2118:7: include/linux/uaccess.h:112:17: warning: 'unmap' may be used uninitialized [-Wmaybe-uninitialized] 112 | kasan_check_write(to, n); | ^~~~~~~~~~~~~~~~~~~~~~~~ include/linux/kasan-checks.h: In function 'vfio_iommu_type1_ioctl.part.0': include/linux/kasan-checks.h:7:6: note: by argument 1 of type 'const volatile void *' to 'kasan_check_write' declared here 7 | void kasan_check_write(const volatile void *p, unsigned int size); | ^~~~~~~~~~~~~~~~~ drivers/vfio/vfio_iommu_type1.c:2113:51: note: 'unmap' declared here 2113 | struct vfio_iommu_type1_dma_unmap unmap; | ^~~~~ In function '_copy_from_user', inlined from 'copy_from_user' at include/linux/uaccess.h:144:7, inlined from 'vfio_iommu_type1_ioctl.part.0' at drivers/vfio/vfio_iommu_type1.c:2136:7:

...

include/linux/uaccess.h:112:17: warning: 'bind' may be used uninitialized [-Wmaybe-uninitialized] 112 | kasan_check_write(to, n); | ^~~~~~~~~~~~~~~~~~~~~~~~ include/linux/kasan-checks.h: In function 'vfio_iommu_type1_ioctl.part.0': include/linux/kasan-checks.h:7:6: note: by argument 1 of type 'const volatile void *' to 'kasan_check_write' declared here 7 | void kasan_check_write(const volatile void *p, unsigned int size); | ^~~~~~~~~~~~~~~~~ drivers/vfio/vfio_iommu_type1.c:2132:46: note: 'bind' declared here 2132 | struct vfio_iommu_type1_bind bind; | ^~~~ In function '_copy_from_user', inlined from 'copy_from_user' at include/linux/uaccess.h:144:7, inlined from 'vfio_iommu_type1_ioctl.part.0' at drivers/vfio/vfio_iommu_type1.c:2155:7: include/linux/uaccess.h:112:17: warning: 'bind' may be used uninitialized [-Wmaybe-uninitialized] 112 | kasan_check_write(to, n); | ^~~~~~~~~~~~~~~~~~~~~~~~ include/linux/kasan-checks.h: In function 'vfio_iommu_type1_ioctl.part.0': include/linux/kasan-checks.h:7:6: note: by argument 1 of type 'const volatile void *' to 'kasan_check_write' declared here 7 | void kasan_check_write(const volatile void *p, unsigned int size); | ^~~~~~~~~~~~~~~~~ drivers/vfio/vfio_iommu_type1.c:2151:46: note: 'bind' declared here 2151 | struct vfio_iommu_type1_bind bind; | ^~~~

vim +/bind +112 include/linux/uaccess.h d597580d373774 Al Viro 2017-03-20 104 d597580d373774 Al Viro 2017-03-20 105 #ifdef INLINE_COPY_FROM_USER d597580d373774 Al Viro 2017-03-20 106 static inline unsigned long d597580d373774 Al Viro 2017-03-20 107 _copy_from_user(void *to, const void __user *from, unsigned long n) d597580d373774 Al Viro 2017-03-20 108 { d597580d373774 Al Viro 2017-03-20 109 unsigned long res = n; 9c5f6908de03a4 Al Viro 2017-06-29 110 might_fault(); 4983cb67a383a7 Linus Torvalds 2019-02-14 111 if (likely(access_ok(from, n))) { 9c5f6908de03a4 Al Viro 2017-06-29 @112 kasan_check_write(to, n); d597580d373774 Al Viro 2017-03-20 113 res = raw_copy_from_user(to, from, n); 9c5f6908de03a4 Al Viro 2017-06-29 114 } d597580d373774 Al Viro 2017-03-20 115 if (unlikely(res)) d597580d373774 Al Viro 2017-03-20 116 memset(to + (n - res), 0, res); d597580d373774 Al Viro 2017-03-20 117 return res; d597580d373774 Al Viro 2017-03-20 118 } d597580d373774 Al Viro 2017-03-20 119 #else d597580d373774 Al Viro 2017-03-20 120 extern unsigned long d597580d373774 Al Viro 2017-03-20 121 _copy_from_user(void *, const void __user *, unsigned long); d597580d373774 Al Viro 2017-03-20 122 #endif d597580d373774 Al Viro 2017-03-20 123 :::::: The code at line 112 was first introduced by commit :::::: 9c5f6908de03a4f52ba7364b11fcd6116225480c copy_{from,to}_user(): move kasan checks and might_fault() out-of-line :::::: TO: Al Viro <viro@zeniv.linux.org.uk> :::::: CC: Al Viro <viro@zeniv.linux.org.uk> -- 0-DAY CI Kernel Test Service https://github.com/intel/lkp-tests/wiki