On Wed, May 29, 2024 at 02:19:47AM +0800, kernel test robot wrote: > tree/branch: > https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master > branch HEAD: 6dc544b66971c7f9909ff038b62149105272d26a Add linux-next > specific files for 20240528 > > Error/Warning reports: > > https://lore.kernel.org/oe-kbuild-all/202405282036.maedo54q-...@intel.com > https://lore.kernel.org/oe-kbuild-all/202405282148.jaf0flhu-...@intel.com > https://lore.kernel.org/oe-kbuild-all/202405282308.uezt6hqc-...@intel.com > > Error/Warning: (recently discovered and may have been fixed) > > drivers/dma-buf/udmabuf.c:45:(.text+0x140): undefined reference to > `vmf_insert_pfn' > fs/btrfs/fiemap.c:822:26: warning: 'last_extent_end' may be used > uninitialized [-Wmaybe-uninitialized]
The report says it's gcc 13.2, that one I use (and expect others as well as it's a recent one) and we also have -Wmaybe-uninitialized enabled in fs/btrfs/ to catch such warnings. Yet this is reported on mips64, is there something special about that compiler+architecture? The warning is IMO a false positive, the maybe-uninitialized variable is passed as pointer but initialized on success and never used on failure. We can safely silence the warning by initializing the variable to 0 but this may be pointing to a problem with mips64+gcc namely because other compiler+host combinations do not warn abou that.
