Paul E. McKenney 1dcaa3b462 context_tracking: Use arch_atomic_read() in __ct_state for KASAN ...

Context tracking's __ct_state() function can be invoked from noinstr state
where RCU is not watching.  This means that its use of atomic_read()
causes KASAN to invoke the non-noinstr __kasan_check_read() function
from the noinstr function __ct_state().  This is problematic because
someone tracing the __kasan_check_read() function could get a nasty
surprise because of RCU not watching.

This commit therefore replaces the __ct_state() function's use of
atomic_read() with arch_atomic_read(), which KASAN does not attempt to
add instrumention to.

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Cc: Frederic Weisbecker <frederic@kernel.org>
Cc: Marco Elver <elver@google.com>
Reviewed-by: Marco Elver <elver@google.com>

2022-07-05 13:33:00 -07:00

3.8 KiB

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