diff options
author | John Dias <joaodias@google.com> | 2016-10-10 14:44:30 -0700 |
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committer | Gerrit - the friendly Code Review server <code-review@localhost> | 2016-12-09 12:09:59 -0800 |
commit | 7ee4109d7ec74f5ed2ae10330f9d0b69b0eeb1c2 (patch) | |
tree | 336bef63c87e7817043171f874eadc2de1245292 /include/linux/perf_event.h | |
parent | 368fecd7df5b203a5ce684a0c77726a5690c1147 (diff) |
perf: protect group_leader from races that cause ctx double-free
When moving a group_leader perf event from a software-context
to a hardware-context, there's a race in checking and
updating that context. The existing locking solution
doesn't work; note that it tries to grab a lock inside
the group_leader's context object, which you can only
get at by going through a pointer that should be protected
from these races. To avoid that problem, and to produce
a simple solution, we can just use a lock per group_leader
to protect all checks on the group_leader's context.
The new lock is grabbed and released when no context locks
are held.
Bug: 30955111
Bug: 31095224
Change-Id: If37124c100ca6f4aa962559fba3bd5dbbec8e052
Git-repo: https://android.googlesource.com/kernel/msm
Git-commit: 5b87e00be9ca28ea32cab49b92c0386e4a91f730
Signed-off-by: Dennis Cagle <d-cagle@codeaurora.org>
Diffstat (limited to 'include/linux/perf_event.h')
-rw-r--r-- | include/linux/perf_event.h | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index 12d3415a3ef5..9bd7e4b2663c 100644 --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -476,6 +476,12 @@ struct perf_event { int nr_siblings; int group_flags; struct perf_event *group_leader; + + /* + * Protect the pmu, attributes and context of a group leader. + * Note: does not protect the pointer to the group_leader. + */ + struct mutex group_leader_mutex; struct pmu *pmu; enum perf_event_active_state state; |