On Mon, Jan 30, 2023 at 03:30:12PM +0800, Hongyu Xie wrote: > 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. I think it's similar to this one I reported two years ago, that others also faced, and was apparently only fixed in later versions: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98503 Most likely the workaround in 5a41237ad1d4 should be extended to gcc-10. Willy
