tracing: Remove comparing of NULL to va_list in trace_array_vprintk() (f2942487) · Commits · 戴 / test

Olof Johansson stated the following: Comparing a va_list with NULL is bogus. It's supposed to be treated like an opaque type and only be manipulated with va_* accessors. Olof noticed that this code broke the ARM builds: kernel/trace/trace.c: In function 'trace_array_vprintk': kernel/trace/trace.c:1364: error: invalid operands to binary == (have 'va_list' and 'void *') kernel/trace/trace.c: In function 'tracing_mark_write': kernel/trace/trace.c:3349: error: incompatible type for argument 3 of 'trace_vprintk' This patch partly reverts and re-installs the original mark_printk() mechanism. Reported-by:

Olof Johansson <olof@lixom.net> Signed-off-by:

Carsten Emde <C.Emde@osadl.org> LKML-Reference: <4B1BAB74.104@osadl.org> Signed-off-by:

Steven Rostedt <rostedt@goodmis.org>

kernel/trace/trace.c

+12 −6

Original line number	Diff line number	Diff line
		@@ -1361,10 +1361,6 @@ int trace_array_vprintk(struct trace_array *tr,
		pause_graph_tracing();
		raw_local_irq_save(irq_flags);
		__raw_spin_lock(&trace_buf_lock);
		if (args == NULL) {
		strncpy(trace_buf, fmt, TRACE_BUF_SIZE);
		len = strlen(trace_buf);
		} else
		len = vsnprintf(trace_buf, TRACE_BUF_SIZE, fmt, args);

		size = sizeof(*entry) + len + 1;
		@@ -3353,6 +3349,16 @@ tracing_entries_write(struct file filp, const char __user ubuf,
		return cnt;
		}

		static int mark_printk(const char *fmt, ...)
		{
		int ret;
		va_list args;
		va_start(args, fmt);
		ret = trace_vprintk(0, fmt, args);
		va_end(args);
		return ret;
		}

		static ssize_t
		tracing_mark_write(struct file filp, const char __user ubuf,
		size_t cnt, loff_t *fpos)
		@@ -3379,7 +3385,7 @@ tracing_mark_write(struct file filp, const char __user ubuf,
		} else
		buf[cnt] = '\0';

		cnt = trace_vprintk(0, buf, NULL);
		cnt = mark_printk("%s", buf);
		kfree(buf);
		*fpos += cnt;

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