On (07/10/19 10:04), Vincent Whitchurch wrote: > > > [..] > > > > > > > @@ -1318,7 +1318,7 @@ static size_t msg_print_text(const struct > > > > printk_log *msg, bool syslog, > > > > } > > > > > > > > if (buf) { > > > > - if (prefix_len + text_len + 1 >= size - len) > > > > + if (prefix_len + text_len + 1 > size - len) > > > > break; > > > > > > So with this patch the last byte of the buffer is 0xA. It's a bit > > > uncomfortable that `len', which we return from msg_print_text(), > > > now points one byte beyond the buffer: > > > > > > buf[len++] = '\n'; > > > return len; > > > > > > This is not very common. Not sure what usually happens to kmsg_dump > > > buffers, but anyone who'd do a rather innocent > > > > > > kmsg_dump(buf, &len); > > > buf[len] = 0x00; > > > > > > will write to something which is not a kmsg buffer (in some cases).
[..] > arch/powerpc/xmon/xmon.c > 2836: while (kmsg_dump_get_line_nolock(&dumper, false, buf, sizeof(buf), > &len)) { > 2837- buf[len] = '\0'; > > arch/um/kernel/kmsg_dump.c > 29: while (kmsg_dump_get_line(dumper, true, line, sizeof(line), &len)) { > 30- line[len] = '\0'; > > I guess we should fix these first and leave this patch as is? We certainly need to fix something here, and I'd say that we better handle it on the msg_print_text() side. There might be more kmsg_dump_get_line() users doing `buf[len] = '\0'' in the future. -ss