From 5778ace04e6f07043f1564bc9b47b1098608cfdd Mon Sep 17 00:00:00 2001 From: Brahmajit Das Date: Sat, 5 Oct 2024 12:07:00 +0530 Subject: fs/proc: fix build with GCC 15 due to -Werror=unterminated-string-initialization show show_smap_vma_flags() has been a using misspelled initializer in mnemonics[] - it needed to initialize 2 element array of char and it used NUL-padded 2 character string literals (i.e. 3-element initializer). This has been spotted by gcc-15[*]; prior to that gcc quietly dropped the 3rd eleemnt of initializers. To fix this we are increasing the size of mnemonics[] (from mnemonics[BITS_PER_LONG][2] to mnemonics[BITS_PER_LONG][3]) to accomodate the NUL-padded string literals. This also helps us in simplyfying the logic for printing of the flags as instead of printing each character from the mnemonics[], we can just print the mnemonics[] using seq_printf. [*]: fs/proc/task_mmu.c:917:49: error: initializer-string for array of `char' is too long [-Werror=unterminate d-string-initialization] 917 | [0 ... (BITS_PER_LONG-1)] = "??", | ^~~~ fs/proc/task_mmu.c:917:49: error: initializer-string for array of `char' is too long [-Werror=unterminate d-string-initialization] fs/proc/task_mmu.c:917:49: error: initializer-string for array of `char' is too long [-Werror=unterminate d-string-initialization] fs/proc/task_mmu.c:917:49: error: initializer-string for array of `char' is too long [-Werror=unterminate d-string-initialization] fs/proc/task_mmu.c:917:49: error: initializer-string for array of `char' is too long [-Werror=unterminate d-string-initialization] fs/proc/task_mmu.c:917:49: error: initializer-string for array of `char' is too long [-Werror=unterminate d-string-initialization] ... Stephen pointed out: : The C standard explicitly allows for a string initializer to be too long : due to the NUL byte at the end ... so this warning may be overzealous. but let's make the warning go away anwyay. Link: https://lkml.kernel.org/r/20241005063700.2241027-1-brahmajit.xyz@gmail.com Link: https://lkml.kernel.org/r/20241003093040.47c08382@canb.auug.org.au Signed-off-by: Brahmajit Das Cc: Cyrill Gorcunov Cc: David Hildenbrand Cc: Stephen Rothwell Signed-off-by: Andrew Morton --- fs/proc/task_mmu.c | 16 ++++++++++------ 1 file changed, 10 insertions(+), 6 deletions(-) diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index 72f14fd59c2d..e52bd96137a6 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -909,8 +909,15 @@ static void show_smap_vma_flags(struct seq_file *m, struct vm_area_struct *vma) { /* * Don't forget to update Documentation/ on changes. + * + * The length of the second argument of mnemonics[] + * needs to be 3 instead of previously set 2 + * (i.e. from [BITS_PER_LONG][2] to [BITS_PER_LONG][3]) + * to avoid spurious + * -Werror=unterminated-string-initialization warning + * with GCC 15 */ - static const char mnemonics[BITS_PER_LONG][2] = { + static const char mnemonics[BITS_PER_LONG][3] = { /* * In case if we meet a flag we don't know about. */ @@ -987,11 +994,8 @@ static void show_smap_vma_flags(struct seq_file *m, struct vm_area_struct *vma) for (i = 0; i < BITS_PER_LONG; i++) { if (!mnemonics[i][0]) continue; - if (vma->vm_flags & (1UL << i)) { - seq_putc(m, mnemonics[i][0]); - seq_putc(m, mnemonics[i][1]); - seq_putc(m, ' '); - } + if (vma->vm_flags & (1UL << i)) + seq_printf(m, "%s ", mnemonics[i]); } seq_putc(m, '\n'); } -- cgit v1.2.3