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authorTetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>2014-07-22 21:20:01 +0900
committerJames Morris <james.l.morris@oracle.com>2014-07-24 21:12:30 +1000
commit6d6f3328422a3bc56b0d8dd026a5de845d2abfa7 (patch)
tree51c24037355a91d098568a88f7dd9715dee8008c /fs
parentfd33c43677a7965624b46352a686a7c1e72ae4aa (diff)
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commoncap: don't alloc the credential unless needed in cap_task_prctl
In function cap_task_prctl(), we would allocate a credential unconditionally and then check if we support the requested function. If not we would release this credential with abort_creds() by using RCU method. But on some archs such as powerpc, the sys_prctl is heavily used to get/set the floating point exception mode. So the unnecessary allocating/releasing of credential not only introduce runtime overhead but also do cause OOM due to the RCU implementation. This patch removes abort_creds() from cap_task_prctl() by calling prepare_creds() only when we need to modify it. Reported-by: Kevin Hao <haokexin@gmail.com> Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Reviewed-by: Paul Moore <paul@paul-moore.com> Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com> Reviewed-by: Kees Cook <keescook@chromium.org> Signed-off-by: James Morris <james.l.morris@oracle.com>
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