From: Rob Clark robdclark@chromium.org
[ Upstream commit a66f1efcf748febea7758c4c3c8b5bc5294949ef ]
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 Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/gpu/drm/msm/adreno/adreno_gpu.c | 4 ++++ drivers/gpu/drm/msm/msm_gpu.c | 2 ++ 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 5a0e8491cd3a..2e7531d2a5d6 100644 --- a/drivers/gpu/drm/msm/adreno/adreno_gpu.c +++ b/drivers/gpu/drm/msm/adreno/adreno_gpu.c @@ -351,6 +351,8 @@ 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 { @@ -360,6 +362,8 @@ 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;
/**