Messages in this thread | | | Subject | Re: [PATCH] Intel: Skylake: Fix inconsistent IS_ERR and PTR_ERR | From | Pierre-Louis Bossart <> | Date | Fri, 21 Feb 2020 09:40:13 -0600 |
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On 2/21/20 8:41 AM, Joe Perches wrote: > On Fri, 2020-02-21 at 18:11 +0800, Xu Wang wrote: >> PTR_ERR should access the value just tested by IS_ERR. >> In skl_clk_dev_probe(),it is inconsistent. > [] >> diff --git a/sound/soc/intel/skylake/skl-ssp-clk.c b/sound/soc/intel/skylake/skl-ssp-clk.c > [] >> @@ -384,7 +384,7 @@ static int skl_clk_dev_probe(struct platform_device *pdev) >> &clks[i], clk_pdata, i); >> >> if (IS_ERR(data->clk[data->avail_clk_cnt])) { >> - ret = PTR_ERR(data->clk[data->avail_clk_cnt++]); >> + ret = PTR_ERR(data->clk[data->avail_clk_cnt]); > > NAK. > > This is not inconsistent and you are removing the ++ > which is a post increment. Likely that is necessary. > > You could write the access and the increment as two > separate statements if it confuses you.
Well to be fair the code is far from clear.
the post-increment is likely needed because of the error handling in unregister_src_clk 1 data->clk[data->avail_clk_cnt] = register_skl_clk(dev, &clks[i], clk_pdata, i);
if (IS_ERR(data->clk[data->avail_clk_cnt])) { ret = PTR_ERR(data->clk[data->avail_clk_cnt++]); goto err_unreg_skl_clk; } }
platform_set_drvdata(pdev, data);
return 0;
err_unreg_skl_clk: unregister_src_clk(data);
static void unregister_src_clk(struct skl_clk_data *dclk) { while (dclk->avail_clk_cnt--) clkdev_drop(dclk->clk[dclk->avail_clk_cnt]->lookup); }
So the post-increment is cancelled in the while().
That said, the avail_clk_cnt field is never initialized or incremented in normal usages so the code looks quite suspicious indeed.
gitk tells me this patch is likely the culprit:
6ee927f2f01466 ('ASoC: Intel: Skylake: Fix NULL ptr dereference when unloading clk dev')
- data->clk[i] = register_skl_clk(dev, &clks[i], clk_pdata, i); - if (IS_ERR(data->clk[i])) { - ret = PTR_ERR(data->clk[i]); + data->clk[data->avail_clk_cnt] = register_skl_clk(dev, + &clks[i], clk_pdata, i); + + if (IS_ERR(data->clk[data->avail_clk_cnt])) { + ret = PTR_ERR(data->clk[data->avail_clk_cnt++]); goto err_unreg_skl_clk; } - - data->avail_clk_cnt++;
That last removal is probably wrong. Cezary and Amadeusz, you may want to look at this?
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