• Stephan Gerhold's avatar
    opp: Fix use-after-free in lazy_opp_tables after probe deferral · b2a2ab03
    Stephan Gerhold authored
    
    
    When dev_pm_opp_of_find_icc_paths() in _allocate_opp_table() returns
    -EPROBE_DEFER, the opp_table is freed again, to wait until all the
    interconnect paths are available.
    
    However, if the OPP table is using required-opps then it may already
    have been added to the global lazy_opp_tables list. The error path
    does not remove the opp_table from the list again.
    
    This can cause crashes later when the provider of the required-opps
    is added, since we will iterate over OPP tables that have already been
    freed. E.g.:
    
      Unable to handle kernel NULL pointer dereference when read
      CPU: 0 PID: 7 Comm: kworker/0:0 Not tainted 6.4.0-rc3
      PC is at _of_add_opp_table_v2 (include/linux/of.h:949
      drivers/opp/of.c:98 drivers/opp/of.c:344 drivers/opp/of.c:404
      drivers/opp/of.c:1032) -> lazy_link_required_opp_table()
    
    Fix this by calling _of_clear_opp_table() to remove the opp_table from
    the list and clear other allocated resources. While at it, also add the
    missing mutex_destroy() calls in the error path.
    
    Cc: stable@vger.kernel.org
    Suggested-by: default avatarViresh Kumar <viresh.kumar@linaro.org>
    Fixes: 7eba0c76
    
     ("opp: Allow lazy-linking of required-opps")
    Signed-off-by: default avatarStephan Gerhold <stephan.gerhold@kernkonzept.com>
    Signed-off-by: default avatarViresh Kumar <viresh.kumar@linaro.org>
    b2a2ab03
core.c 81.7 KB