mm/vmalloc: Add a safer inlined version of find_vm_area() for debug
It is unsafe to dump vmalloc area information when trying to do so from
some contexts such as PREEMPT_RT or from an IRQ handler that interrupted
a vmap_area_lock-held region. Add a safer and inlined trylock version of
find_vm_area() to do a best-effort VMA finding and use it from
vmalloc_dump_obj().
While the vmap_area_lock is held, copy interesting attributes from the
vm_struct before unlocking.
[applied test robot feedback on unused function fix.]
[applied Uladzislau feedback on locking.]
[applied Vlastimil and Lorenzo feedback on changelog and comment
improvements]
Reported-by: Zhen Lei <thunder.leizhen@huaweicloud.com>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: rcu@vger.kernel.org
Cc: Zqiang <qiang.zhang1211@gmail.com>
Reviewed-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Fixes: 98f180837a89 ("mm: Make mem_dump_obj() handle vmalloc() memory")
Cc: stable@vger.kernel.org
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
1 file changed
