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author | Daniel Thompson <daniel.thompson@linaro.org> | 2014-11-06 12:41:56 (GMT) |
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committer | Steven Rostedt <rostedt@goodmis.org> | 2014-11-14 02:27:25 (GMT) |
commit | 8520dedbbf7578a397ecdfcf6ab83f775f914cfe (patch) | |
tree | fd60f0d3d8775a623ad5ac31042cd8ae4ba337c0 /kernel/trace/trace_events.c | |
parent | c270cc75cd22b606c901e606fbb93b002c2a655f (diff) | |
download | linux-8520dedbbf7578a397ecdfcf6ab83f775f914cfe.tar.xz |
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/1415277716-19419-3-git-send-email-daniel.thompson@linaro.org
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: Jason Wessel <jason.wessel@windriver.com>
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'kernel/trace/trace_events.c')
0 files changed, 0 insertions, 0 deletions