[PATCH 6.18 177/752] drm/atmel-hlcdc: fix memory leak from the atomic_destroy_state callback

Sasha Levin
2026-02-28T17:50:39Z

From: Ludovic Desroches <ludovic.desroches@microchip.com>

[ Upstream commit f12352471061df83a36edf54bbb16284793284e4 ]

After several commits, the slab memory increases. Some drm_crtc_commit
objects are not freed. The atomic_destroy_state callback only put the
framebuffer. Use the __drm_atomic_helper_plane_destroy_state() function
to put all the objects that are no longer needed.

It has been seen after hours of usage of a graphics application or using
kmemleak:

unreferenced object 0xc63a6580 (size 64):
comm "egt_basic", pid 171, jiffies 4294940784
hex dump (first 32 bytes):
40 50 34 c5 01 00 00 00 ff ff ff ff 8c 65 3a c6 @P4..........e:.
8c 65 3a c6 ff ff ff ff 98 65 3a c6 98 65 3a c6 .e:......e:..e:.
backtrace (crc c25aa925):
kmemleak_alloc+0x34/0x3c
__kmalloc_cache_noprof+0x150/0x1a4
drm_atomic_helper_setup_commit+0x1e8/0x7bc
drm_atomic_helper_commit+0x3c/0x15c
drm_atomic_commit+0xc0/0xf4
drm_atomic_helper_set_config+0x84/0xb8
drm_mode_setcrtc+0x32c/0x810
drm_ioctl+0x20c/0x488
sys_ioctl+0x14c/0xc20
ret_fast_syscall+0x0/0x54

Signed-off-by: Ludovic Desroches <ludovic.desroches@microchip.com>
Reviewed-by: Manikandan Muralidharan <manikandan.m@microchip.com>
Link: https://patch.msgid.link/20251024-lcd_fixes_mainlining-v1-1-79b615130dc3@microchip.com
Signed-off-by: Manikandan Muralidharan <manikandan.m@microchip.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_plane.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_plane.c b/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_plane.c
index 3787db014501e..410ec747cc7e0 100644
--- a/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_plane.c
+++ b/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_plane.c
@@ -1204,8 +1204,7 @@ static void atmel_hlcdc_plane_atomic_destroy_state(struct drm_plane *p,
state->dscrs[i]->self);
}

- if (s->fb)
- drm_framebuffer_put(s->fb);
+ __drm_atomic_helper_plane_destroy_state(s);

kfree(state);
}
--
2.51.0