From: Zheyu Ma zheyuma97@gmail.com
stable inclusion from stable-v5.10.150 commit 877e92e9b1bdeb580b31a46061005936be902cd4 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I6D0XA
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
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[ Upstream commit 1ff673333d46d2c1b053ebd0c1c7c7c79e36943e ]
When removing the module we will get the following warning:
[ 31.911505] i2c-core: driver [stdp2690-ge-b850v3-fw] unregistered [ 31.912484] general protection fault, probably for non-canonical address 0xdffffc0000000001: 0000 [#1] PREEMPT SMP KASAN PTI [ 31.913338] KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f] [ 31.915280] RIP: 0010:drm_bridge_remove+0x97/0x130 [ 31.921825] Call Trace: [ 31.922533] stdp4028_ge_b850v3_fw_remove+0x34/0x60 [megachips_stdpxxxx_ge_b850v3_fw] [ 31.923139] i2c_device_remove+0x181/0x1f0
The two bridges (stdp2690, stdp4028) do not probe at the same time, so the driver does not call ge_b850v3_resgiter() when probing, causing the driver to try to remove the object that has not been initialized.
Fix this by checking whether both the bridges are probed.
Fixes: 11632d4aa2b3 ("drm/bridge: megachips: Ensure both bridges are probed before registration") Signed-off-by: Zheyu Ma zheyuma97@gmail.com Signed-off-by: Robert Foss robert.foss@linaro.org Link: https://patchwork.freedesktop.org/patch/msgid/20220830073450.1897020-1-zheyu... Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: Jialin Zhang zhangjialin11@huawei.com --- drivers/gpu/drm/bridge/megachips-stdpxxxx-ge-b850v3-fw.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/bridge/megachips-stdpxxxx-ge-b850v3-fw.c b/drivers/gpu/drm/bridge/megachips-stdpxxxx-ge-b850v3-fw.c index cce98bf2a4e7..72248a565579 100644 --- a/drivers/gpu/drm/bridge/megachips-stdpxxxx-ge-b850v3-fw.c +++ b/drivers/gpu/drm/bridge/megachips-stdpxxxx-ge-b850v3-fw.c @@ -296,7 +296,9 @@ static void ge_b850v3_lvds_remove(void) * This check is to avoid both the drivers * removing the bridge in their remove() function */ - if (!ge_b850v3_lvds_ptr) + if (!ge_b850v3_lvds_ptr || + !ge_b850v3_lvds_ptr->stdp2690_i2c || + !ge_b850v3_lvds_ptr->stdp4028_i2c) goto out;
drm_bridge_remove(&ge_b850v3_lvds_ptr->bridge);