On Tue, Jul 12, 2022 at 12:14:27PM -0300, André Almeida wrote: > Hi Sebin, > > Às 10:29 de 10/07/22, Sebin Sebastian escreveu: > > Fix two coverity warning's double free and and an uninitialized pointer > > read. Both tmp and new are pointing at same address and both are freed > > which leads to double free. Freeing tmp in the condition after new is > > assigned with new address fixes the double free issue. new is not > > initialized to null which also leads to a free on an uninitialized > > pointer. > > Coverity issue: 1518665 (uninitialized pointer read) > > 1518679 (double free) > > What are those numbers? > These numbers are the issue ID's for the errors that are being reported by the coverity static analyzer tool. > > > > Signed-off-by: Sebin Sebastian <mailmesebin00@xxxxxxxxx> > > --- > > drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c | 8 +++++--- > > 1 file changed, 5 insertions(+), 3 deletions(-) > > > > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c > > index f3b3c688e4e7..d82fe0e1b06b 100644 > > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c > > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c > > @@ -1660,7 +1660,7 @@ static ssize_t amdgpu_reset_dump_register_list_write(struct file *f, > > { > > struct amdgpu_device *adev = (struct amdgpu_device *)file_inode(f)->i_private; > > char reg_offset[11]; > > - uint32_t *new, *tmp = NULL; > > + uint32_t *new = NULL, *tmp = NULL; > > int ret, i = 0, len = 0; > > > > do { > > @@ -1692,17 +1692,19 @@ static ssize_t amdgpu_reset_dump_register_list_write(struct file *f, > > goto error_free; > > } > > If the `if (!new) {` above this line is true, will be tmp freed? > Yes, It doesn't seem to free tmp here. Should I free tmp immediately after the do while loop and remove `kfree(tmp)` from the `if (ret)` block? Thanks for pointing out the errors. > > ret = down_write_killable(&adev->reset_domain->sem); > > - if (ret) > > + if (ret) { > > + kfree(tmp); > > goto error_free; > > + } > > > > swap(adev->reset_dump_reg_list, tmp); > > swap(adev->reset_dump_reg_value, new); > > adev->num_regs = i; > > up_write(&adev->reset_domain->sem); > > + kfree(tmp); > > ret = size; > > > > error_free: > > - kfree(tmp); > > kfree(new); > > return ret; > > }