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d31e31365b
Currently, srcu_get_delay() can be called concurrently, for example, by a CPU that is the first to request a new grace period and the CPU processing the current grace period. Although concurrent access is harmless, it unnecessarily expands the state space. Additionally, all calls to srcu_get_delay() are from slow paths. This commit therefore protects all calls to srcu_get_delay() with ssp->srcu_sup->lock, which is already held on the invocation from the srcu_funnel_gp_start() function. While in the area, this commit also adds a lockdep_assert_held() to srcu_get_delay() itself. Reported-by: syzbot+16a19b06125a2963eaee@syzkaller.appspotmail.com Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Andrii Nakryiko <andrii@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Kent Overstreet <kent.overstreet@linux.dev> Cc: <bpf@vger.kernel.org> Signed-off-by: Boqun Feng <boqun.feng@gmail.com>