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Petersen" Cc: linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org, Manivannan Sadhasivam , Bart Van Assche , Geert Uytterhoeven , Avri Altman Subject: [PATCH v3 2/2] scsi: ufs: Fix toggling of clk_gating.state when clock gating is not allowed Date: Sun, 26 Jan 2025 08:45:21 +0200 Message-Id: <20250126064521.3857557-3-avri.altman@wdc.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20250126064521.3857557-1-avri.altman@wdc.com> References: <20250126064521.3857557-1-avri.altman@wdc.com> Precedence: bulk X-Mailing-List: linux-scsi@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 This commit addresses an issue where `clk_gating.state` is being toggled in `ufshcd_setup_clocks` even if clock gating is not allowed. This can lead to a crash with the following error: BUG: spinlock bad magic on CPU#6, swapper/0/1 lock: 0xffffff84443014e8, .magic: 00000000, .owner: /-1, .owner_cpu: 0 CPU: 6 UID: 0 PID: 1 Comm: swapper/0 Not tainted 6.13.0-rcar3-initrd-08318-g75abbef32a94 #896 Hardware name: R-Car S4 Starter Kit board (DT) Call trace: show_stack+0x18/0x24 (C) dump_stack_lvl+0x60/0x80 dump_stack+0x18/0x24 spin_bug+0x7c/0xa0 do_raw_spin_lock+0x34/0xb4 _raw_spin_lock_irqsave+0x1c/0x30 class_spinlock_irqsave_constructor+0x18/0x30 ufshcd_setup_clocks+0x98/0x23c ufshcd_init+0x288/0xd38 ufshcd_pltfrm_init+0x618/0x738 ufs_renesas_probe+0x18/0x24 platform_probe+0x68/0xb8 really_probe+0x138/0x268 __driver_probe_device+0xf4/0x10c driver_probe_device+0x3c/0xf8 __driver_attach+0xf0/0x100 bus_for_each_dev+0x84/0xdc driver_attach+0x24/0x30 bus_add_driver+0xe8/0x1dc driver_register+0xbc/0xf8 __platform_driver_register+0x24/0x30 ufs_renesas_platform_init+0x1c/0x28 do_one_initcall+0x84/0x1f4 kernel_init_freeable+0x238/0x23c kernel_init+0x20/0x120 ret_from_fork+0x10/0x20 The root cause of the issue is that `clk_gating.state` is being toggled even if clock gating is not allowed. This can lead to the spinlock being used before it is properly initialized. The fix is to add a check for `hba->clk_gating.is_initialized` before toggling `clk_gating.state` in `ufshcd_setup_clocks`. Since `clk_gating.lock` is now initialized unconditionally, this is for documentation purposes, to ensure clarity in the code. The primary fix remains to prevent toggling the `clk_gating.state` if clock gating is not allowed. Fixes: 1ab27c9cf8b6 ("ufs: Add support for clock gating") Reported-by: Geert Uytterhoeven Signed-off-by: Avri Altman Tested-by: Geert Uytterhoeven --- drivers/ufs/core/ufshcd.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c index b73c87da383d..abe0774133f5 100644 --- a/drivers/ufs/core/ufshcd.c +++ b/drivers/ufs/core/ufshcd.c @@ -9140,7 +9140,7 @@ static int ufshcd_setup_clocks(struct ufs_hba *hba, bool on) if (!IS_ERR_OR_NULL(clki->clk) && clki->enabled) clk_disable_unprepare(clki->clk); } - } else if (!ret && on) { + } else if (!ret && on && hba->clk_gating.is_initialized) { scoped_guard(spinlock_irqsave, &hba->clk_gating.lock) hba->clk_gating.state = CLKS_ON; trace_ufshcd_clk_gating(dev_name(hba->dev),