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authorBrahmajit Das <brahmajit.xyz@gmail.com>2024-10-05 12:07:00 +0530
committerAndrew Morton <akpm@linux-foundation.org>2024-10-17 00:28:07 -0700
commit5778ace04e6f07043f1564bc9b47b1098608cfdd (patch)
tree299114a4b409ca6067f21af20deedf242bca3e23
parentdc783ba4b9df3fb3e76e968b2cbeb9960069263c (diff)
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 <brahmajit.xyz@gmail.com> Cc: Cyrill Gorcunov <gorcunov@openvz.org> Cc: David Hildenbrand <david@redhat.com> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
-rw-r--r--fs/proc/task_mmu.c16
1 files 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');
}