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authorMasami Hiramatsu <mhiramat@kernel.org>2017-02-10 22:21:55 +0900
committerSteven Rostedt (VMware) <rostedt@goodmis.org>2017-02-15 10:32:48 -0500
commitbef5da60595f5706232e2502876f8545743b9b41 (patch)
treec2a46613ed750c5a84b8404219cafbc8f14ad413 /kernel/trace
parent8f0994bb8cbde5452e58ce0cacdbf6cb58079d01 (diff)
tracing/probes: Fix a warning message to show correct maximum length
Since tracing/*probe_events will accept a probe definition up to 4096 - 2 ('\n' and '\0') bytes, it must show 4094 instead of 4096 in warning message. Note that there is one possible case of exceed 4094. If user prepare 4096 bytes null-terminated string and syscall write it with the count == 4095, then it can be accepted. However, if user puts a '\n' after that, it must rejected. So IMHO, the warning message should indicate shorter one, since it is safer. Link: http://lkml.kernel.org/r/148673290462.2579.7966778294009665632.stgit@devbox Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Diffstat (limited to 'kernel/trace')
-rw-r--r--kernel/trace/trace_probe.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c
index 11b63328d6fb..52478f033f88 100644
--- a/kernel/trace/trace_probe.c
+++ b/kernel/trace/trace_probe.c
@@ -679,8 +679,9 @@ ssize_t traceprobe_probes_write(struct file *file, const char __user *buffer,
if (done + size < count) {
if (buf != kbuf)
break;
+ /* This can accept WRITE_BUFSIZE - 2 ('\n' + '\0') */
pr_warn("Line length is too long: Should be less than %d\n",
- WRITE_BUFSIZE);
+ WRITE_BUFSIZE - 2);
ret = -EINVAL;
goto out;
}