0-day reported the strncpy error below: ../kernel/trace/trace_events_synth.c: In function 'last_cmd_set': ../kernel/trace/trace_events_synth.c:65:9: warning: 'strncpy' specified bound depends on the length o\ f the source argument [-Wstringop-truncation] 65 | strncpy(last_cmd, str, strlen(str) + 1); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ../kernel/trace/trace_events_synth.c:65:32: note: length computed here 65 | strncpy(last_cmd, str, strlen(str) + 1); | ^~~~~~~~~~~ There's no reason to use strncpy here, in fact there's no reason to do anything but a simple kstrdup() (note we don't even need to check for failure since last_cmod is expected to be either the last cmd string or NULL, and the containing function is a void return). Link: https://lkml.kernel.org/r/77deca8cbfd226981b3f1eab203967381e9b5bd9.camel@kernel.org Fixes: 27c888da9867 ("tracing: Remove size restriction on synthetic event cmd error logging")
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| @@ -58,11 +58,8 @@ static void last_cmd_set(const char *str) · 57 unmodified lines | |||
| 58 | return; | 58 | return; |
| 59 | 59 | ||
| 60 | kfree(last_cmd); | 60 | kfree(last_cmd); |
| 61 | last_cmd = kzalloc(strlen(str) + 1, GFP_KERNEL); | ||
| 62 | if (!last_cmd) | ||
| 63 | return; | ||
| 64 | 61 | ||
| 65 | strncpy(last_cmd, str, strlen(str) + 1); | 62 | last_cmd = kstrdup(str, GFP_KERNEL); |
| 66 | } | 63 | } |
| 67 | 64 | ||
| 68 | static void synth_err(u8 err_type, u16 err_pos) | 65 | static void synth_err(u8 err_type, u16 err_pos) |