6.12-stable review patch. If anyone has any objections, please let me know.
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From: Brahmajit Das brahmajit.xyz@gmail.com
[ Upstream commit 989e0cdc0f18a594b25cabc60426d29659aeaf58 ]
qnx6_checkroot() had been using weirdly spelled initializer - it needed to initialize 3-element arrays of char and it used NUL-padded 3-character string literals (i.e. 4-element initializers, with completely pointless zeroes at the end).
That had been spotted by gcc-15[*]; prior to that gcc quietly dropped the 4th element of initializers.
However, none of that had been needed in the first place - all this array is used for is checking that the first directory entry in root directory is "." and the second - "..". The check had been expressed as a loop, using that match_root[] array. Since there is no chance that we ever want to extend that list of entries, the entire thing is much too fancy for its own good; what we need is just a couple of explicit memcmp() and that's it.
[*]: fs/qnx6/inode.c: In function ‘qnx6_checkroot’: fs/qnx6/inode.c:182:41: error: initializer-string for array of ‘char’ is too long [-Werror=unterminated-string-initialization] 182 | static char match_root[2][3] = {".\0\0", "..\0"}; | ^~~~~~~ fs/qnx6/inode.c:182:50: error: initializer-string for array of ‘char’ is too long [-Werror=unterminated-string-initialization] 182 | static char match_root[2][3] = {".\0\0", "..\0"}; | ^~~~~~
Signed-off-by: Brahmajit Das brahmajit.xyz@gmail.com Link: https://lore.kernel.org/r/20241004195132.1393968-1-brahmajit.xyz@gmail.com Acked-by: Al Viro viro@zeniv.linux.org.uk Signed-off-by: Christian Brauner brauner@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- fs/qnx6/inode.c | 11 ++++------- 1 file changed, 4 insertions(+), 7 deletions(-)
diff --git a/fs/qnx6/inode.c b/fs/qnx6/inode.c index 85925ec0051a9..3310d1ad4d0e9 100644 --- a/fs/qnx6/inode.c +++ b/fs/qnx6/inode.c @@ -179,8 +179,7 @@ static int qnx6_statfs(struct dentry *dentry, struct kstatfs *buf) */ static const char *qnx6_checkroot(struct super_block *s) { - static char match_root[2][3] = {".\0\0", "..\0"}; - int i, error = 0; + int error = 0; struct qnx6_dir_entry *dir_entry; struct inode *root = d_inode(s->s_root); struct address_space *mapping = root->i_mapping; @@ -189,11 +188,9 @@ static const char *qnx6_checkroot(struct super_block *s) if (IS_ERR(folio)) return "error reading root directory"; dir_entry = kmap_local_folio(folio, 0); - for (i = 0; i < 2; i++) { - /* maximum 3 bytes - due to match_root limitation */ - if (strncmp(dir_entry[i].de_fname, match_root[i], 3)) - error = 1; - } + if (memcmp(dir_entry[0].de_fname, ".", 2) || + memcmp(dir_entry[1].de_fname, "..", 3)) + error = 1; folio_release_kmap(folio, dir_entry); if (error) return "error reading root directory.";