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author | Miroslav Benes <mbenes@suse.cz> | 2017-12-21 14:40:43 +0100 |
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committer | Jiri Kosina <jkosina@suse.cz> | 2018-01-11 17:36:07 +0100 |
commit | 8869016d3a58cbe7c31c70f4f008a92122b271c7 (patch) | |
tree | 02ebd2a73b91b135034353426d3430e3b28c7832 /drivers/devfreq/governor_performance.c | |
parent | livepatch: force transition to finish (diff) | |
download | linux-8869016d3a58cbe7c31c70f4f008a92122b271c7.tar.xz linux-8869016d3a58cbe7c31c70f4f008a92122b271c7.zip |
livepatch: add locking to force and signal functions
klp_send_signals() and klp_force_transition() do not acquire klp_mutex,
because it seemed to be superfluous. A potential race in
klp_send_signals() was harmless and there was nothing in
klp_force_transition() which needed to be synchronized. That changed
with the addition of klp_forced variable during the review process.
There is a small window now, when klp_complete_transition() does not see
klp_forced set to true while all tasks have been already transitioned to
the target state. module_put() is called and the module can be removed.
Acquire klp_mutex in sysfs callback to prevent it. Do the same for the
signal sending just to be sure. There is no real downside to that.
Fixes: c99a2be790b07 ("livepatch: force transition to finish")
Fixes: 43347d56c8d9d ("livepatch: send a fake signal to all blocking tasks")
Reported-by: Jason Baron <jbaron@akamai.com>
Signed-off-by: Miroslav Benes <mbenes@suse.cz>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Diffstat (limited to 'drivers/devfreq/governor_performance.c')
0 files changed, 0 insertions, 0 deletions