Using gcc and W=1 option, there are some warning like these: fs/dlm/debug_fs.c: In function ‘dlm_create_debug_file’: fs/dlm/debug_fs.c:1020:51: error: ‘snprintf’ output may be truncated before the last format character [-Werror=format-truncation=] 1020 | snprintf(name, DLM_LOCKSPACE_LEN + 8, "%s_waiters", ls->ls_name); | ^ fs/dlm/debug_fs.c:1020:2: note: 'snprintf' output between 9 and 73 bytes into a destination of size 72 1020 | snprintf(name, DLM_LOCKSPACE_LEN + 8, "%s_waiters", ls->ls_name); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ fs/dlm/debug_fs.c:1031:43: error: '_queued_asts' directive output may be truncated writing 12 bytes into a region of size between 8 and 72 [-Werror=format-truncation=] 1031 | snprintf(name, DLM_LOCKSPACE_LEN + 8, "%s_queued_asts", ls->ls_name); | ^~~~~~~~~~~~ The length of 'ls->ls_name' is 'DLM_LOCKSPACE_LEN + 1'. So string "%s_waiters" can up to 'DLM_LOCKSPACE_LEN + 9' and string "%s_queued_asts" can up to 'DLM_LOCKSPACE_LEN + 13'. Signed-off-by: Su Hui <suhui@xxxxxxxxxxxx> --- fs/dlm/debug_fs.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/fs/dlm/debug_fs.c b/fs/dlm/debug_fs.c index 5aabcb6f0f15..d0b34b9fbdaf 100644 --- a/fs/dlm/debug_fs.c +++ b/fs/dlm/debug_fs.c @@ -973,7 +973,7 @@ void dlm_delete_debug_comms_file(void *ctx) void dlm_create_debug_file(struct dlm_ls *ls) { - char name[DLM_LOCKSPACE_LEN + 8]; + char name[DLM_LOCKSPACE_LEN + 13]; /* format 1 */ @@ -1017,7 +1017,7 @@ void dlm_create_debug_file(struct dlm_ls *ls) &format4_fops); memset(name, 0, sizeof(name)); - snprintf(name, DLM_LOCKSPACE_LEN + 8, "%s_waiters", ls->ls_name); + snprintf(name, DLM_LOCKSPACE_LEN + 9, "%s_waiters", ls->ls_name); ls->ls_debug_waiters_dentry = debugfs_create_file(name, 0644, @@ -1028,7 +1028,7 @@ void dlm_create_debug_file(struct dlm_ls *ls) /* format 5 */ memset(name, 0, sizeof(name)); - snprintf(name, DLM_LOCKSPACE_LEN + 8, "%s_queued_asts", ls->ls_name); + snprintf(name, DLM_LOCKSPACE_LEN + 13, "%s_queued_asts", ls->ls_name); ls->ls_debug_queued_asts_dentry = debugfs_create_file(name, 0644, -- 2.30.2