2021-10-22 01:26:41

by He Ying

Subject: [PATCH] drm: Fix possible memleak in drm_client_modeset_probe

I got memory leak as follows when doing fault injection test:

WARNING: CPU: 0 PID: 1214 at drm_mode_config_cleanup+0x689/0x890 [drm]
RIP: 0010:drm_mode_config_cleanup+0x689/0x890 [drm]
Call Trace:
? tracer_hardirqs_on+0x33/0x520
? drm_mode_config_reset+0x3f0/0x3f0 [drm]
? trace_event_raw_event_rcu_torture_read+0x2c0/0x2c0
? __sanitizer_cov_trace_pc+0x1d/0x50
? call_rcu+0x489/0x15e0
? trace_hardirqs_on+0x63/0x2d0
? write_comp_data+0x2a/0x90
? drm_mode_config_cleanup+0x890/0x890 [drm]
drm_managed_release+0x1fa/0x4f0 [drm]
drm_dev_release+0x72/0xb0 [drm]
devm_drm_dev_init_release+0x81/0xa0 [drm]
release_nodes+0xba/0x3b0
...
entry_SYSCALL_64_after_hwframe+0x44/0xae

and then an error message:

[drm:drm_mode_config_cleanup [drm]] *ERROR* connector SPI-1 leaked!

When krealloc() in drm_client_modeset_probe() fails, it
goes to the label 'free_connectors'. However, krealloc()
is between drm_connector_list_iter_begin() and *_end().
Going to the label directly is not a good idea. Because
iter->conn is not cleaned up if so. Fix the problem by
going to the label outside drm_connector_list_iter_end().

Signed-off-by: He Ying <[email protected]>
---
drivers/gpu/drm/drm_client_modeset.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/drm_client_modeset.c b/drivers/gpu/drm/drm_client_modeset.c
index ced09c7c06f9..7ac88ae93f38 100644
--- a/drivers/gpu/drm/drm_client_modeset.c
+++ b/drivers/gpu/drm/drm_client_modeset.c
@@ -789,7 +789,7 @@ int drm_client_modeset_probe(struct drm_client_dev *client, unsigned int width,
tmp = krealloc(connectors, (connector_count + 1) * sizeof(*connectors), GFP_KERNEL);
if (!tmp) {
ret = -ENOMEM;
- goto free_connectors;
+ break;
}

connectors = tmp;
@@ -798,6 +798,9 @@ int drm_client_modeset_probe(struct drm_client_dev *client, unsigned int width,
}
drm_connector_list_iter_end(&conn_iter);

+ if (ret)
+ goto free_connectors;
+
if (!connector_count)
return 0;

--
2.17.1

2021-11-09 11:43:41

by He Ying

Subject: Re: [PATCH] drm: Fix possible memleak in drm_client_modeset_probe

kindly ping...

?? 2021/10/22 9:26, He Ying д??:
> I got memory leak as follows when doing fault injection test:
>
> WARNING: CPU: 0 PID: 1214 at drm_mode_config_cleanup+0x689/0x890 [drm]
> RIP: 0010:drm_mode_config_cleanup+0x689/0x890 [drm]
> Call Trace:
> ? tracer_hardirqs_on+0x33/0x520
> ? drm_mode_config_reset+0x3f0/0x3f0 [drm]
> ? trace_event_raw_event_rcu_torture_read+0x2c0/0x2c0
> ? __sanitizer_cov_trace_pc+0x1d/0x50
> ? call_rcu+0x489/0x15e0
> ? trace_hardirqs_on+0x63/0x2d0
> ? write_comp_data+0x2a/0x90
> ? drm_mode_config_cleanup+0x890/0x890 [drm]
> drm_managed_release+0x1fa/0x4f0 [drm]
> drm_dev_release+0x72/0xb0 [drm]
> devm_drm_dev_init_release+0x81/0xa0 [drm]
> release_nodes+0xba/0x3b0
> ...
> entry_SYSCALL_64_after_hwframe+0x44/0xae
>
> and then an error message:
>
> [drm:drm_mode_config_cleanup [drm]] *ERROR* connector SPI-1 leaked!
>
> When krealloc() in drm_client_modeset_probe() fails, it
> goes to the label 'free_connectors'. However, krealloc()
> is between drm_connector_list_iter_begin() and *_end().
> Going to the label directly is not a good idea. Because
> iter->conn is not cleaned up if so. Fix the problem by
> going to the label outside drm_connector_list_iter_end().
>
> Signed-off-by: He Ying <[email protected]>
> ---
> drivers/gpu/drm/drm_client_modeset.c | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/drm_client_modeset.c b/drivers/gpu/drm/drm_client_modeset.c
> index ced09c7c06f9..7ac88ae93f38 100644
> --- a/drivers/gpu/drm/drm_client_modeset.c
> +++ b/drivers/gpu/drm/drm_client_modeset.c
> @@ -789,7 +789,7 @@ int drm_client_modeset_probe(struct drm_client_dev *client, unsigned int width,
> tmp = krealloc(connectors, (connector_count + 1) * sizeof(*connectors), GFP_KERNEL);
> if (!tmp) {
> ret = -ENOMEM;
> - goto free_connectors;
> + break;
> }
>
> connectors = tmp;
> @@ -798,6 +798,9 @@ int drm_client_modeset_probe(struct drm_client_dev *client, unsigned int width,
> }
> drm_connector_list_iter_end(&conn_iter);
>
> + if (ret)
> + goto free_connectors;
> +
> if (!connector_count)
> return 0;
>