source code: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git base: ae0c77e1bc6963c67c6c09e8c72959fcb1ed8d5f config tested: x86_64_defconfig defconfig(arm64) toolchain: gcc version 10.4.0 (Ubuntu 10.4.0-4ubuntu1~22.04) cross compile toolchain: gcc version 10.4.0 (Ubuntu 10.4.0-4ubuntu1~22.04) reproduce compile err: CONFIG_WERROR=y && CONFIG_PRINTK=n && CONFIG_UBSAN_ALIGNMENT=y && CONFIG_UBSAN_SANITIZE_ALL=y compile err log: kernel/printk/printk.c: In function ‘console_flush_all’: kernel/printk/printk.c:2845:17: error: array subscript 0 is outside array bounds of ‘char[0]’ [-Werror=array-bounds] 2845 | char *outbuf = &pbufs.outbuf[0]; | ^~~~~~~~~~~~~~~~ In file included from kernel/printk/printk.c:61: kernel/printk/internal.h:87:7: note: while referencing ‘outbuf’ 87 | char outbuf[PRINTK_MESSAGE_MAX]; | ^~~~~~ kernel/printk/printk.c:2842:31: note: defined here ‘pbufs’ 2842 | static struct printk_buffers pbufs; | ^~~~~ I applied the way 5a41237ad1d4 in mainline did for gcc 10, problem goes away. I'm guessing this is a gcc bug.
