RE: [PATCH 09/11] scsi: ufs: Fix a kernel crash during shutdown
From: Avri Altman <Avri.Altman@wdc.com>
Date: 2021-11-11 07:49:08
quoted hunk ↗ jump to hunk
Fix the following kernel crash: Unable to handle kernel paging request at virtual address ffffffc91e735000 Call trace: __queue_work+0x26c/0x624 queue_work_on+0x6c/0xf0 ufshcd_hold+0x12c/0x210 __ufshcd_wl_suspend+0xc0/0x400 ufshcd_wl_shutdown+0xb8/0xcc device_shutdown+0x184/0x224 kernel_restart+0x4c/0x124 __arm64_sys_reboot+0x194/0x264 el0_svc_common+0xc8/0x1d4 do_el0_svc+0x30/0x8c el0_svc+0x20/0x30 el0_sync_handler+0x84/0xe4 el0_sync+0x1bc/0x1c0 Fix this crash by ungating the clock before destroying the work queue on which clock gating work is queued. Signed-off-by: Bart Van Assche <bvanassche@acm.org> --- drivers/scsi/ufs/ufshcd.c | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-)diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c index1e15ed1f639f..13848e93cda8 100644--- a/drivers/scsi/ufs/ufshcd.c +++ b/drivers/scsi/ufs/ufshcd.c@@ -1666,7 +1666,8 @@ int ufshcd_hold(struct ufs_hba *hba, bool async) bool flush_result; unsigned long flags; - if (!ufshcd_is_clkgating_allowed(hba)) + if (!ufshcd_is_clkgating_allowed(hba) || + !hba->clk_gating.is_initialized) goto out; spin_lock_irqsave(hba->host->host_lock, flags); hba->clk_gating.active_reqs++;@@ -1826,7 +1827,7 @@ static void __ufshcd_release(struct ufs_hba *hba) if (hba->clk_gating.active_reqs || hba->clk_gating.is_suspended || hba->ufshcd_state != UFSHCD_STATE_OPERATIONAL || - hba->outstanding_tasks || + hba->outstanding_tasks || !hba->clk_gating.is_initialized || hba->active_uic_cmd || hba->uic_async_done || hba->clk_gating.state == CLKS_OFF) return;@@ -1961,11 +1962,15 @@ static void ufshcd_exit_clk_gating(struct ufs_hba*hba) { if (!hba->clk_gating.is_initialized) return; + ufshcd_remove_clk_gating_sysfs(hba); - cancel_work_sync(&hba->clk_gating.ungate_work); - cancel_delayed_work_sync(&hba->clk_gating.gate_work); - destroy_workqueue(hba->clk_gating.clk_gating_workq); + + /* Ungate the clock if necessary. */ + ufshcd_hold(hba, false); hba->clk_gating.is_initialized = false; + ufshcd_release(hba);
Not sure that the symmetry in calling ufshcd_release() is meaningful here? You don't really want to queue a new gate work, this is why you added !.is_initialized to release(), Or did I get it wrong? Thanks, Avri
+ + destroy_workqueue(hba->clk_gating.clk_gating_workq); } /* Must be called with host lock acquired */