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| author | Rob Clark <robdclark@chromium.org> | 2023-01-10 13:28:59 -0800 |
|---|---|---|
| committer | Rob Clark <robdclark@chromium.org> | 2023-01-11 09:00:14 -0800 |
| commit | a66f1efcf748febea7758c4c3c8b5bc5294949ef (patch) | |
| tree | 8cfa9a3f9d163b01f92cc2cc398f14e1d957e5ce | |
| parent | e752e5454e6417da3f40ec1306a041ea96c56423 (diff) | |
| download | linux-a66f1efcf748febea7758c4c3c8b5bc5294949ef.tar.bz2 | |
drm/msm/gpu: Fix potential double-free
If userspace was calling the MSM_SET_PARAM ioctl on multiple threads to
set the COMM or CMDLINE param, it could trigger a race causing the
previous value to be kfree'd multiple times. Fix this by serializing on
the gpu lock.
Signed-off-by: Rob Clark <robdclark@chromium.org>
Fixes: d4726d770068 ("drm/msm: Add a way to override processes comm/cmdline")
Patchwork: https://patchwork.freedesktop.org/patch/517778/
Link: https://lore.kernel.org/r/20230110212903.1925878-1-robdclark@gmail.com
| -rw-r--r-- | drivers/gpu/drm/msm/adreno/adreno_gpu.c | 4 | ||||
| -rw-r--r-- | drivers/gpu/drm/msm/msm_gpu.c | 2 | ||||
| -rw-r--r-- | drivers/gpu/drm/msm/msm_gpu.h | 12 |
3 files changed, 16 insertions, 2 deletions
diff --git a/drivers/gpu/drm/msm/adreno/adreno_gpu.c b/drivers/gpu/drm/msm/adreno/adreno_gpu.c index 57586c794b84..3605f095b2de 100644 --- a/drivers/gpu/drm/msm/adreno/adreno_gpu.c +++ b/drivers/gpu/drm/msm/adreno/adreno_gpu.c @@ -352,6 +352,8 @@ int adreno_set_param(struct msm_gpu *gpu, struct msm_file_private *ctx, /* Ensure string is null terminated: */ str[len] = '\0'; + mutex_lock(&gpu->lock); + if (param == MSM_PARAM_COMM) { paramp = &ctx->comm; } else { @@ -361,6 +363,8 @@ int adreno_set_param(struct msm_gpu *gpu, struct msm_file_private *ctx, kfree(*paramp); *paramp = str; + mutex_unlock(&gpu->lock); + return 0; } case MSM_PARAM_SYSPROF: diff --git a/drivers/gpu/drm/msm/msm_gpu.c b/drivers/gpu/drm/msm/msm_gpu.c index 021f4e29b613..4f495eecc34b 100644 --- a/drivers/gpu/drm/msm/msm_gpu.c +++ b/drivers/gpu/drm/msm/msm_gpu.c @@ -335,6 +335,8 @@ static void get_comm_cmdline(struct msm_gem_submit *submit, char **comm, char ** struct msm_file_private *ctx = submit->queue->ctx; struct task_struct *task; + WARN_ON(!mutex_is_locked(&submit->gpu->lock)); + /* Note that kstrdup will return NULL if argument is NULL: */ *comm = kstrdup(ctx->comm, GFP_KERNEL); *cmd = kstrdup(ctx->cmdline, GFP_KERNEL); diff --git a/drivers/gpu/drm/msm/msm_gpu.h b/drivers/gpu/drm/msm/msm_gpu.h index 58a72e6b1400..a89bfdc3d7f9 100644 --- a/drivers/gpu/drm/msm/msm_gpu.h +++ b/drivers/gpu/drm/msm/msm_gpu.h @@ -366,10 +366,18 @@ struct msm_file_private { */ int sysprof; - /** comm: Overridden task comm, see MSM_PARAM_COMM */ + /** + * comm: Overridden task comm, see MSM_PARAM_COMM + * + * Accessed under msm_gpu::lock + */ char *comm; - /** cmdline: Overridden task cmdline, see MSM_PARAM_CMDLINE */ + /** + * cmdline: Overridden task cmdline, see MSM_PARAM_CMDLINE + * + * Accessed under msm_gpu::lock + */ char *cmdline; /** |