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author | Frederic Weisbecker <fweisbec@gmail.com> | 2008-10-31 13:08:28 +0100 |
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committer | Ingo Molnar <mingo@elte.hu> | 2008-11-04 17:14:04 +0100 |
commit | 07695fa04e8a3384b0c855398ce1f7885bd7dc3b (patch) | |
tree | 5a70702087ea1f603b69281aaa270b117f37a63f /virt | |
parent | 71566a0d161edec70361b7f90f6e54af6a6d5d05 (diff) |
tracing/ftrace: fix a race condition in sched_switch tracer
Impact: fix race condition in sched_switch tracer
This patch fixes a race condition in the sched_switch tracer. If
several tasks (IE: concurrent initcalls) are playing with
tracing_start_cmdline_record() and tracing_stop_cmdline_record(), the
following situation could happen:
_ Task A and B are using the same tracepoint probe. Task A holds it.
Task B is sleeping and doesn't hold it.
_ Task A frees the sched tracer, then sched_ref is decremented to 0.
_ Task A is preempted and hadn't yet unregistered its tracepoint
probe, then B runs.
_ B increments sched_ref, sees it's 1 and then guess it has to
register its probe. But it has not been freed by task A.
_ A lot of bad things can happen after that...
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'virt')
0 files changed, 0 insertions, 0 deletions