ACPI: OSL: only free map once in osl.c

acpi_os_map_cleanup checks map->refcount outside of acpi_ioremap_lock
before freeing the map. This creates a race condition the can result
in the map being freed more than once.
A panic can be caused by running

for ((i=0; i<10; i++))
do
        for ((j=0; j<100000; j++))
        do
                cat /sys/firmware/acpi/tables/data/BERT >/dev/null
        done &
done

This patch makes sure that only the process that drops the reference
to 0 does the freeing.

Fixes: b7c1fadd6c2e ("ACPI: Do not use krefs under a mutex in osl.c")
Signed-off-by: Francesco Ruggeri <[email protected]>
Reviewed-by: Dmitry Safonov <[email protected]>
Cc: All applicable <[email protected]>
Signed-off-by: Rafael J. Wysocki <[email protected]>

0 files changed, 0 insertions, 0 deletions