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    Subject[PATCH 4.9 23/86] drm/radeon: fix double free
    Date
    From: Tom Rix <trix@redhat.com>

    commit 41855a898650803e24b284173354cc3e44d07725 upstream.

    clang static analysis flags this error

    drivers/gpu/drm/radeon/ci_dpm.c:5652:9: warning: Use of memory after it is freed [unix.Malloc]
    kfree(rdev->pm.dpm.ps[i].ps_priv);
    ^~~~~~~~~~~~~~~~~~~~~~~~~~
    drivers/gpu/drm/radeon/ci_dpm.c:5654:2: warning: Attempt to free released memory [unix.Malloc]
    kfree(rdev->pm.dpm.ps);
    ^~~~~~~~~~~~~~~~~~~~~~

    problem is reported in ci_dpm_fini, with these code blocks.

    for (i = 0; i < rdev->pm.dpm.num_ps; i++) {
    kfree(rdev->pm.dpm.ps[i].ps_priv);
    }
    kfree(rdev->pm.dpm.ps);

    The first free happens in ci_parse_power_table where it cleans up locally
    on a failure. ci_dpm_fini also does a cleanup.

    ret = ci_parse_power_table(rdev);
    if (ret) {
    ci_dpm_fini(rdev);
    return ret;
    }

    So remove the cleanup in ci_parse_power_table and
    move the num_ps calculation to inside the loop so ci_dpm_fini
    will know how many array elements to free.

    Fixes: cc8dbbb4f62a ("drm/radeon: add dpm support for CI dGPUs (v2)")

    Signed-off-by: Tom Rix <trix@redhat.com>
    Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
    Cc: stable@vger.kernel.org
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

    ---
    drivers/gpu/drm/radeon/ci_dpm.c | 7 +++----
    1 file changed, 3 insertions(+), 4 deletions(-)

    --- a/drivers/gpu/drm/radeon/ci_dpm.c
    +++ b/drivers/gpu/drm/radeon/ci_dpm.c
    @@ -5557,6 +5557,7 @@ static int ci_parse_power_table(struct r
    if (!rdev->pm.dpm.ps)
    return -ENOMEM;
    power_state_offset = (u8 *)state_array->states;
    + rdev->pm.dpm.num_ps = 0;
    for (i = 0; i < state_array->ucNumEntries; i++) {
    u8 *idx;
    power_state = (union pplib_power_state *)power_state_offset;
    @@ -5566,10 +5567,8 @@ static int ci_parse_power_table(struct r
    if (!rdev->pm.power_state[i].clock_info)
    return -EINVAL;
    ps = kzalloc(sizeof(struct ci_ps), GFP_KERNEL);
    - if (ps == NULL) {
    - kfree(rdev->pm.dpm.ps);
    + if (ps == NULL)
    return -ENOMEM;
    - }
    rdev->pm.dpm.ps[i].ps_priv = ps;
    ci_parse_pplib_non_clock_info(rdev, &rdev->pm.dpm.ps[i],
    non_clock_info,
    @@ -5591,8 +5590,8 @@ static int ci_parse_power_table(struct r
    k++;
    }
    power_state_offset += 2 + power_state->v2.ucNumDPMLevels;
    + rdev->pm.dpm.num_ps = i + 1;
    }
    - rdev->pm.dpm.num_ps = state_array->ucNumEntries;

    /* fill in the vce power states */
    for (i = 0; i < RADEON_MAX_VCE_LEVELS; i++) {

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