tracing: kdb: Fix kernel livelock with empty buffers

Currently kdb's ftdump command will livelock by constantly printk'ing
the empty string at KERN_EMERG level if it run when the ftrace system is
not in use. This occurs because trace_empty() never returns false when
the ring buffers are left at the start of a non-consuming read [launched
by ring_buffer_read_start()].

This patch changes the loop exit condition to use the result of
trace_find_next_entry_inc(). Effectively this switches the non-consuming
kdb dumper to follow the approach of the non-consuming userspace
interface [s_next()] rather than the consuming ftrace_dump().

Link: http://lkml.kernel.org/r/[email protected]

Cc: Ingo Molnar <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: John Stultz <[email protected]>
Cc: Sumit Semwal <[email protected]>
Cc: Jason Wessel <[email protected]>
Signed-off-by: Daniel Thompson <[email protected]>
Signed-off-by: Steven Rostedt <[email protected]>

0 files changed, 0 insertions, 0 deletions