On Tue, Jan 25, 2022 at 12:55:51AM +0800, Zhou Qingyang wrote:

In calculate_bandwidth(), the tag free_sclk and free_yclk are reversed, which could lead to a memory leak of yclk.

Fix this bug by changing the location of free_sclk and free_yclk.

This bug was found by a static analyzer.

Builds with 'make allyesconfig' show no new warnings, and our static analyzer no longer warns about this code.

Fixes: 2be8989d0fc2 ("drm/amd/display/dc/calcs/dce_calcs: Move some large variables from the stack to the heap") Signed-off-by: Zhou Qingyang zhou1615@umn.edu

---

The analysis employs differential checking to identify inconsistent security operations (e.g., checks or kfrees) between two code paths and confirms that the inconsistent operations are not recovered in the current function or the callers, so they constitute bugs.

Note that, as a bug found by static analysis, it can be a false positive or hard to trigger. Multiple researchers have cross-reviewed the bug.

drivers/gpu/drm/amd/display/dc/calcs/dce_calcs.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/dc/calcs/dce_calcs.c b/drivers/gpu/drm/amd/display/dc/calcs/dce_calcs.c index ff5bb152ef49..e6ef36de0825 100644 --- a/drivers/gpu/drm/amd/display/dc/calcs/dce_calcs.c +++ b/drivers/gpu/drm/amd/display/dc/calcs/dce_calcs.c @@ -2033,10 +2033,10 @@ static void calculate_bandwidth( kfree(surface_type); free_tiling_mode: kfree(tiling_mode); -free_yclk:

• kfree(yclk);

free_sclk: kfree(sclk); +free_yclk:

• kfree(yclk);

}

/*******************************************************************************

2.25.1

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