From a66f1efcf748febea7758c4c3c8b5bc5294949ef Mon Sep 17 00:00:00 2001 From: Rob Clark Date: Tue, 10 Jan 2023 13:28:59 -0800 Subject: 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 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 --- drivers/gpu/drm/msm/msm_gpu.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'drivers/gpu/drm/msm/msm_gpu.c') 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); -- cgit v1.2.3