Messages in this thread | | | Date | Sat, 02 Jan 2021 20:29:56 +0800 | From | Can Guo <> | Subject | Re: [PATCH v2 1/2] scsi: ufs: Fix a possible NULL pointer issue |
| |
On 2021-01-02 00:05, Bart Van Assche wrote: > On 12/31/20 9:44 PM, Can Guo wrote: >> During system resume/suspend, hba could be NULL. In this case, do not >> touch >> eh_sem. >> >> Fixes: 88a92d6ae4fe ("scsi: ufs: Serialize eh_work with system PM >> events and async scan") >> >> Signed-off-by: Can Guo <cang@codeaurora.org> >> --- >> drivers/scsi/ufs/ufshcd.c | 9 +++++---- >> 1 file changed, 5 insertions(+), 4 deletions(-) >> >> diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c >> index e221add..34e2541 100644 >> --- a/drivers/scsi/ufs/ufshcd.c >> +++ b/drivers/scsi/ufs/ufshcd.c >> @@ -8896,8 +8896,11 @@ int ufshcd_system_suspend(struct ufs_hba *hba) >> int ret = 0; >> ktime_t start = ktime_get(); >> >> + if (!hba) >> + return 0; >> + >> down(&hba->eh_sem); >> - if (!hba || !hba->is_powered) >> + if (!hba->is_powered) >> return 0; >> >> if ((ufs_get_pm_lvl_to_dev_pwr_mode(hba->spm_lvl) == >> @@ -8945,10 +8948,8 @@ int ufshcd_system_resume(struct ufs_hba *hba) >> int ret = 0; >> ktime_t start = ktime_get(); >> >> - if (!hba) { >> - up(&hba->eh_sem); >> + if (!hba) >> return -EINVAL; >> - } >> >> if (!hba->is_powered || pm_runtime_suspended(hba->dev)) >> /* > > Hi Can, > > How can ufshcd_system_suspend() or ufshcd_system_resume() be called > with a > NULL argument? In ufshcd_pci_probe() I see that pci_set_drvdata() is > called > before pm_runtime_allow(). ufshcd_pci_remove() calls > pm_runtime_forbid(). > > Thanks, > > Bart.
Hi Bart,
You are right about ufshcd_RUNTIME_suspend/resume() - platform_set_drvdata() is called before pm_runtime_enable(), so runtime suspend/resume cannot happen before pm_runtime_enable() is called. We can remove the sanity checks of !hba there, they are outdated.
But for ufshcd_SYSTEM_suspend/resume() callbacks (not runtime ones), my understanding is that system suspend/resume may happen after probe (vendor driver probe calls ufshcd_pltfrm_init()) starts but before platform_set_drvdata() is called, in this case hba is NULL.
int ufshcd_pltfrm_init(struct platform_device *pdev, const struct ufs_hba_variant_ops *vops) { ... platform_set_drvdata(pdev, hba);
pm_runtime_set_active(&pdev->dev); pm_runtime_enable(&pdev->dev); }
Thanks,
Can Guo.
| |