| Message ID | 1387796544-18209-1-git-send-email-b29396@freescale.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Mon, Dec 23, 2013 at 07:02:23PM +0800, Dong Aisheng wrote: > Sometimes we may meet the following lockdep issue. > The root cause is .set_clock callback is executed with spin_lock_irqsave > in sdhci_do_set_ios. However, the IMX set_clock callback will try to access > clk_get_rate which is using a mutex lock. > > The fix avoids access mutex in .set_clock callback by initializing the > pltfm_host->clock at probe time and use it later instead of calling > clk_get_rate again in atomic context. While I agree this is the way less intrusive, I'm also wondering why sdhci_do_set_ios() needs a spinlock at all, or at least it's questionable if the lock should necessarily be held for such a long running section. Nevertheless, as long as we can guarantee that the rate of pltfm_host->clk does not change after the driver is probed, I'm fine with the patch. Shawn
On Mon, Dec 23, 2013 at 08:47:01PM +0800, Shawn Guo wrote: > On Mon, Dec 23, 2013 at 07:02:23PM +0800, Dong Aisheng wrote: > > Sometimes we may meet the following lockdep issue. > > The root cause is .set_clock callback is executed with spin_lock_irqsave > > in sdhci_do_set_ios. However, the IMX set_clock callback will try to access > > clk_get_rate which is using a mutex lock. > > > > The fix avoids access mutex in .set_clock callback by initializing the > > pltfm_host->clock at probe time and use it later instead of calling > > clk_get_rate again in atomic context. > > While I agree this is the way less intrusive, I'm also wondering why > sdhci_do_set_ios() needs a spinlock at all, or at least it's > questionable if the lock should necessarily be held for such a long > running section. Per my understanding, it's for protecting the host structure including register r/w where can also be accessed from ISR, so we need it. > > Nevertheless, as long as we can guarantee that the rate of > pltfm_host->clk does not change after the driver is probed, I'm fine > with the patch. > We does not change the host parent clock always currently. Regards Dong Aisheng > Shawn >
diff --git a/drivers/mmc/host/sdhci-esdhc-imx.c b/drivers/mmc/host/sdhci-esdhc-imx.c index 2a04847..745ee1e 100644 --- a/drivers/mmc/host/sdhci-esdhc-imx.c +++ b/drivers/mmc/host/sdhci-esdhc-imx.c @@ -576,19 +576,17 @@ static unsigned int esdhc_pltfm_get_max_clock(struct sdhci_host *host) struct pltfm_imx_data *imx_data = pltfm_host->priv; struct esdhc_platform_data *boarddata = &imx_data->boarddata; - u32 f_host = clk_get_rate(pltfm_host->clk); - - if (boarddata->f_max && (boarddata->f_max < f_host)) + if (boarddata->f_max && (boarddata->f_max < pltfm_host->clock)) return boarddata->f_max; else - return f_host; + return pltfm_host->clock; } static unsigned int esdhc_pltfm_get_min_clock(struct sdhci_host *host) { struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host); - return clk_get_rate(pltfm_host->clk) / 256 / 16; + return pltfm_host->clock / 256 / 16; } static inline void esdhc_pltfm_set_clock(struct sdhci_host *host, @@ -596,7 +594,7 @@ static inline void esdhc_pltfm_set_clock(struct sdhci_host *host, { struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host); struct pltfm_imx_data *imx_data = pltfm_host->priv; - unsigned int host_clock = clk_get_rate(pltfm_host->clk); + unsigned int host_clock = pltfm_host->clock; int pre_div = 2; int div = 1; u32 temp, val; @@ -1017,7 +1015,7 @@ static int sdhci_esdhc_imx_probe(struct platform_device *pdev) } pltfm_host->clk = imx_data->clk_per; - + pltfm_host->clock = clk_get_rate(pltfm_host->clk); clk_prepare_enable(imx_data->clk_per); clk_prepare_enable(imx_data->clk_ipg); clk_prepare_enable(imx_data->clk_ahb);
Sometimes we may meet the following lockdep issue. The root cause is .set_clock callback is executed with spin_lock_irqsave in sdhci_do_set_ios. However, the IMX set_clock callback will try to access clk_get_rate which is using a mutex lock. The fix avoids access mutex in .set_clock callback by initializing the pltfm_host->clock at probe time and use it later instead of calling clk_get_rate again in atomic context. [ INFO: HARDIRQ-safe -> HARDIRQ-unsafe lock order detected ] 3.13.0-rc1+ #285 Not tainted ------------------------------------------------------ kworker/u8:1/29 [HC0[0]:SC0[0]:HE0:SE1] is trying to acquire: (prepare_lock){+.+...}, at: [<80480b08>] clk_prepare_lock+0x44/0xe4 and this task is already holding: (&(&host->lock)->rlock#2){-.-...}, at: [<804611f4>] sdhci_do_set_ios+0x20/0x720 which would create a new lock dependency: (&(&host->lock)->rlock#2){-.-...} -> (prepare_lock){+.+...} but this new dependency connects a HARDIRQ-irq-safe lock: (&(&host->lock)->rlock#2){-.-...} ... which became HARDIRQ-irq-safe at: [<8005f030>] mark_lock+0x140/0x6ac [<80060760>] __lock_acquire+0xb30/0x1cbc [<800620d0>] lock_acquire+0x70/0x84 [<8061d2f0>] _raw_spin_lock+0x30/0x40 [<80460668>] sdhci_irq+0x24/0xa68 [<8006b1d4>] handle_irq_event_percpu+0x54/0x18c [<8006b350>] handle_irq_event+0x44/0x64 [<8006e50c>] handle_fasteoi_irq+0xa0/0x170 [<8006a8f0>] generic_handle_irq+0x30/0x44 [<8000f238>] handle_IRQ+0x54/0xbc [<8000864c>] gic_handle_irq+0x30/0x64 [<80013024>] __irq_svc+0x44/0x5c [<80614c58>] printk+0x38/0x40 [<804622a8>] sdhci_add_host+0x844/0xbcc [<80464948>] sdhci_esdhc_imx_probe+0x378/0x67c [<8032ee88>] platform_drv_probe+0x20/0x50 [<8032d48c>] driver_probe_device+0x118/0x234 [<8032d690>] __driver_attach+0x9c/0xa0 [<8032b89c>] bus_for_each_dev+0x68/0x9c [<8032cf44>] driver_attach+0x20/0x28 [<8032cbc8>] bus_add_driver+0x148/0x1f4 [<8032dce0>] driver_register+0x80/0x100 [<8032ee54>] __platform_driver_register+0x50/0x64 [<8084b094>] sdhci_esdhc_imx_driver_init+0x18/0x20 [<80008980>] do_one_initcall+0x108/0x16c [<8081cca4>] kernel_init_freeable+0x10c/0x1d0 [<80611c50>] kernel_init+0x10/0x120 [<8000e9c8>] ret_from_fork+0x14/0x2c to a HARDIRQ-irq-unsafe lock: (prepare_lock){+.+...} ... which became HARDIRQ-irq-unsafe at: ... [<8005f030>] mark_lock+0x140/0x6ac [<8005f604>] mark_held_locks+0x68/0x12c [<8005f780>] trace_hardirqs_on_caller+0xb8/0x1d8 [<8005f8b4>] trace_hardirqs_on+0x14/0x18 [<8061a130>] mutex_trylock+0x180/0x20c [<80480ad8>] clk_prepare_lock+0x14/0xe4 [<804816a4>] clk_notifier_register+0x28/0xf0 [<80015120>] twd_clk_init+0x50/0x68 [<80008980>] do_one_initcall+0x108/0x16c [<8081cca4>] kernel_init_freeable+0x10c/0x1d0 [<80611c50>] kernel_init+0x10/0x120 [<8000e9c8>] ret_from_fork+0x14/0x2c other info that might help us debug this: Possible interrupt unsafe locking scenario: CPU0 CPU1 ---- ---- lock(prepare_lock); local_irq_disable(); lock(&(&host->lock)->rlock#2); lock(prepare_lock); <Interrupt> lock(&(&host->lock)->rlock#2); *** DEADLOCK *** 3 locks held by kworker/u8:1/29: #0: (kmmcd){.+.+.+}, at: [<8003db18>] process_one_work+0x128/0x468 #1: ((&(&host->detect)->work)){+.+.+.}, at: [<8003db18>] process_one_work+0x128/0x468 #2: (&(&host->lock)->rlock#2){-.-...}, at: [<804611f4>] sdhci_do_set_ios+0x20/0x720 the dependencies between HARDIRQ-irq-safe lock and the holding lock: -> (&(&host->lock)->rlock#2){-.-...} ops: 330 { IN-HARDIRQ-W at: [<8005f030>] mark_lock+0x140/0x6ac [<80060760>] __lock_acquire+0xb30/0x1cbc [<800620d0>] lock_acquire+0x70/0x84 [<8061d2f0>] _raw_spin_lock+0x30/0x40 [<80460668>] sdhci_irq+0x24/0xa68 [<8006b1d4>] handle_irq_event_percpu+0x54/0x18c [<8006b350>] handle_irq_event+0x44/0x64 [<8006e50c>] handle_fasteoi_irq+0xa0/0x170 [<8006a8f0>] generic_handle_irq+0x30/0x44 [<8000f238>] handle_IRQ+0x54/0xbc [<8000864c>] gic_handle_irq+0x30/0x64 [<80013024>] __irq_svc+0x44/0x5c [<80614c58>] printk+0x38/0x40 [<804622a8>] sdhci_add_host+0x844/0xbcc [<80464948>] sdhci_esdhc_imx_probe+0x378/0x67c [<8032ee88>] platform_drv_probe+0x20/0x50 [<8032d48c>] driver_probe_device+0x118/0x234 [<8032d690>] __driver_attach+0x9c/0xa0 [<8032b89c>] bus_for_each_dev+0x68/0x9c [<8032cf44>] driver_attach+0x20/0x28 [<8032cbc8>] bus_add_driver+0x148/0x1f4 [<8032dce0>] driver_register+0x80/0x100 [<8032ee54>] __platform_driver_register+0x50/0x64 [<8084b094>] sdhci_esdhc_imx_driver_init+0x18/0x20 [<80008980>] do_one_initcall+0x108/0x16c [<8081cca4>] kernel_init_freeable+0x10c/0x1d0 [<80611c50>] kernel_init+0x10/0x120 [<8000e9c8>] ret_from_fork+0x14/0x2c IN-SOFTIRQ-W at: [<8005f030>] mark_lock+0x140/0x6ac [<80060204>] __lock_acquire+0x5d4/0x1cbc [<800620d0>] lock_acquire+0x70/0x84 [<8061d40c>] _raw_spin_lock_irqsave+0x40/0x54 [<8045e4a4>] sdhci_tasklet_finish+0x1c/0x120 [<8002b538>] tasklet_action+0xa0/0x15c [<8002b778>] __do_softirq+0x118/0x290 [<8002bcf4>] irq_exit+0xb4/0x10c [<8000f240>] handle_IRQ+0x5c/0xbc [<8000864c>] gic_handle_irq+0x30/0x64 [<80013024>] __irq_svc+0x44/0x5c [<80614c58>] printk+0x38/0x40 [<804622a8>] sdhci_add_host+0x844/0xbcc [<80464948>] sdhci_esdhc_imx_probe+0x378/0x67c [<8032ee88>] platform_drv_probe+0x20/0x50 [<8032d48c>] driver_probe_device+0x118/0x234 [<8032d690>] __driver_attach+0x9c/0xa0 [<8032b89c>] bus_for_each_dev+0x68/0x9c [<8032cf44>] driver_attach+0x20/0x28 [<8032cbc8>] bus_add_driver+0x148/0x1f4 [<8032dce0>] driver_register+0x80/0x100 [<8032ee54>] __platform_driver_register+0x50/0x64 [<8084b094>] sdhci_esdhc_imx_driver_init+0x18/0x20 [<80008980>] do_one_initcall+0x108/0x16c [<8081cca4>] kernel_init_freeable+0x10c/0x1d0 [<80611c50>] kernel_init+0x10/0x120 [<8000e9c8>] ret_from_fork+0x14/0x2c INITIAL USE at: [<8005f030>] mark_lock+0x140/0x6ac [<8005ff0c>] __lock_acquire+0x2dc/0x1cbc [<800620d0>] lock_acquire+0x70/0x84 [<8061d40c>] _raw_spin_lock_irqsave+0x40/0x54 [<804611f4>] sdhci_do_set_ios+0x20/0x720 [<80461924>] sdhci_set_ios+0x30/0x3c [<8044cea0>] mmc_power_up+0x6c/0xd0 [<8044dac4>] mmc_start_host+0x60/0x70 [<8044eb3c>] mmc_add_host+0x60/0x88 [<8046225c>] sdhci_add_host+0x7f8/0xbcc [<80464948>] sdhci_esdhc_imx_probe+0x378/0x67c [<8032ee88>] platform_drv_probe+0x20/0x50 [<8032d48c>] driver_probe_device+0x118/0x234 [<8032d690>] __driver_attach+0x9c/0xa0 [<8032b89c>] bus_for_each_dev+0x68/0x9c [<8032cf44>] driver_attach+0x20/0x28 [<8032cbc8>] bus_add_driver+0x148/0x1f4 [<8032dce0>] driver_register+0x80/0x100 [<8032ee54>] __platform_driver_register+0x50/0x64 [<8084b094>] sdhci_esdhc_imx_driver_init+0x18/0x20 [<80008980>] do_one_initcall+0x108/0x16c [<8081cca4>] kernel_init_freeable+0x10c/0x1d0 [<80611c50>] kernel_init+0x10/0x120 [<8000e9c8>] ret_from_fork+0x14/0x2c } ... key at: [<80e040e8>] __key.26952+0x0/0x8 ... acquired at: [<8005eb60>] check_usage+0x3d0/0x5c0 [<8005edac>] check_irq_usage+0x5c/0xb8 [<80060d38>] __lock_acquire+0x1108/0x1cbc [<800620d0>] lock_acquire+0x70/0x84 [<8061a210>] mutex_lock_nested+0x54/0x3c0 [<80480b08>] clk_prepare_lock+0x44/0xe4 [<8048188c>] clk_get_rate+0x14/0x64 [<8046374c>] esdhc_pltfm_set_clock+0x20/0x2a4 [<8045d70c>] sdhci_set_clock+0x4c/0x498 [<80461518>] sdhci_do_set_ios+0x344/0x720 [<80461924>] sdhci_set_ios+0x30/0x3c [<8044c390>] __mmc_set_clock+0x44/0x60 [<8044cd4c>] mmc_set_clock+0x10/0x14 [<8044f8f4>] mmc_init_card+0x1b4/0x1520 [<80450f00>] mmc_attach_mmc+0xb4/0x194 [<8044da08>] mmc_rescan+0x294/0x2f0 [<8003db94>] process_one_work+0x1a4/0x468 [<8003e850>] worker_thread+0x118/0x3e0 [<80044de0>] kthread+0xd4/0xf0 [<8000e9c8>] ret_from_fork+0x14/0x2c the dependencies between the lock to be acquired and HARDIRQ-irq-unsafe lock: -> (prepare_lock){+.+...} ops: 395 { HARDIRQ-ON-W at: [<8005f030>] mark_lock+0x140/0x6ac [<8005f604>] mark_held_locks+0x68/0x12c [<8005f780>] trace_hardirqs_on_caller+0xb8/0x1d8 [<8005f8b4>] trace_hardirqs_on+0x14/0x18 [<8061a130>] mutex_trylock+0x180/0x20c [<80480ad8>] clk_prepare_lock+0x14/0xe4 [<804816a4>] clk_notifier_register+0x28/0xf0 [<80015120>] twd_clk_init+0x50/0x68 [<80008980>] do_one_initcall+0x108/0x16c [<8081cca4>] kernel_init_freeable+0x10c/0x1d0 [<80611c50>] kernel_init+0x10/0x120 [<8000e9c8>] ret_from_fork+0x14/0x2c SOFTIRQ-ON-W at: [<8005f030>] mark_lock+0x140/0x6ac [<8005f604>] mark_held_locks+0x68/0x12c [<8005f7c8>] trace_hardirqs_on_caller+0x100/0x1d8 [<8005f8b4>] trace_hardirqs_on+0x14/0x18 [<8061a130>] mutex_trylock+0x180/0x20c [<80480ad8>] clk_prepare_lock+0x14/0xe4 [<804816a4>] clk_notifier_register+0x28/0xf0 [<80015120>] twd_clk_init+0x50/0x68 [<80008980>] do_one_initcall+0x108/0x16c [<8081cca4>] kernel_init_freeable+0x10c/0x1d0 [<80611c50>] kernel_init+0x10/0x120 [<8000e9c8>] ret_from_fork+0x14/0x2c INITIAL USE at: [<8005f030>] mark_lock+0x140/0x6ac [<8005ff0c>] __lock_acquire+0x2dc/0x1cbc [<800620d0>] lock_acquire+0x70/0x84 [<8061a0c8>] mutex_trylock+0x118/0x20c [<80480ad8>] clk_prepare_lock+0x14/0xe4 [<80482af8>] __clk_init+0x1c/0x45c [<8048306c>] _clk_register+0xd0/0x170 [<80483148>] clk_register+0x3c/0x7c [<80483b4c>] clk_register_fixed_rate+0x88/0xd8 [<80483c04>] of_fixed_clk_setup+0x68/0x94 [<8084c6fc>] of_clk_init+0x44/0x68 [<808202b0>] time_init+0x2c/0x38 [<8081ca14>] start_kernel+0x1e4/0x368 [<10008074>] 0x10008074 } ... key at: [<808afebc>] prepare_lock+0x38/0x48 ... acquired at: [<8005eb94>] check_usage+0x404/0x5c0 [<8005edac>] check_irq_usage+0x5c/0xb8 [<80060d38>] __lock_acquire+0x1108/0x1cbc [<800620d0>] lock_acquire+0x70/0x84 [<8061a210>] mutex_lock_nested+0x54/0x3c0 [<80480b08>] clk_prepare_lock+0x44/0xe4 [<8048188c>] clk_get_rate+0x14/0x64 [<8046374c>] esdhc_pltfm_set_clock+0x20/0x2a4 [<8045d70c>] sdhci_set_clock+0x4c/0x498 [<80461518>] sdhci_do_set_ios+0x344/0x720 [<80461924>] sdhci_set_ios+0x30/0x3c [<8044c390>] __mmc_set_clock+0x44/0x60 [<8044cd4c>] mmc_set_clock+0x10/0x14 [<8044f8f4>] mmc_init_card+0x1b4/0x1520 [<80450f00>] mmc_attach_mmc+0xb4/0x194 [<8044da08>] mmc_rescan+0x294/0x2f0 [<8003db94>] process_one_work+0x1a4/0x468 [<8003e850>] worker_thread+0x118/0x3e0 [<80044de0>] kthread+0xd4/0xf0 [<8000e9c8>] ret_from_fork+0x14/0x2c stack backtrace: CPU: 2 PID: 29 Comm: kworker/u8:1 Not tainted 3.13.0-rc1+ #285 Workqueue: kmmcd mmc_rescan Backtrace: [<80012160>] (dump_backtrace+0x0/0x10c) from [<80012438>] (show_stack+0x18/0x1c) r6:00000000 r5:00000000 r4:8088ecc8 r3:bfa11200 [<80012420>] (show_stack+0x0/0x1c) from [<80616b14>] (dump_stack+0x84/0x9c) [<80616a90>] (dump_stack+0x0/0x9c) from [<8005ebb4>] (check_usage+0x424/0x5c0) r5:80979940 r4:bfa29b44 [<8005e790>] (check_usage+0x0/0x5c0) from [<8005edac>] (check_irq_usage+0x5c/0xb8) [<8005ed50>] (check_irq_usage+0x0/0xb8) from [<80060d38>] (__lock_acquire+0x1108/0x1cbc) r8:bfa115e8 r7:80df9884 r6:80dafa9c r5:00000003 r4:bfa115d0 [<8005fc30>] (__lock_acquire+0x0/0x1cbc) from [<800620d0>] (lock_acquire+0x70/0x84) [<80062060>] (lock_acquire+0x0/0x84) from [<8061a210>] (mutex_lock_nested+0x54/0x3c0) r7:bfa11200 r6:80dafa9c r5:00000000 r4:80480b08 [<8061a1bc>] (mutex_lock_nested+0x0/0x3c0) from [<80480b08>] (clk_prepare_lock+0x44/0xe4) [<80480ac4>] (clk_prepare_lock+0x0/0xe4) from [<8048188c>] (clk_get_rate+0x14/0x64) r6:03197500 r5:bf0e9aa8 r4:bf827400 r3:808ae128 [<80481878>] (clk_get_rate+0x0/0x64) from [<8046374c>] (esdhc_pltfm_set_clock+0x20/0x2a4) r5:bf0e9aa8 r4:bf0e9c40 [<8046372c>] (esdhc_pltfm_set_clock+0x0/0x2a4) from [<8045d70c>] (sdhci_set_clock+0x4c/0x498) [<8045d6c0>] (sdhci_set_clock+0x0/0x498) from [<80461518>] (sdhci_do_set_ios+0x344/0x720) r8:0000003b r7:20000113 r6:bf0e9d68 r5:bf0e9aa8 r4:bf0e9c40 r3:00000000 [<804611d4>] (sdhci_do_set_ios+0x0/0x720) from [<80461924>] (sdhci_set_ios+0x30/0x3c) r9:00000004 r8:bf131000 r7:bf131048 r6:00000000 r5:bf0e9aa8 r4:bf0e9800 [<804618f4>] (sdhci_set_ios+0x0/0x3c) from [<8044c390>] (__mmc_set_clock+0x44/0x60) r5:03197500 r4:bf0e9800 [<8044c34c>] (__mmc_set_clock+0x0/0x60) from [<8044cd4c>] (mmc_set_clock+0x10/0x14) r5:00000000 r4:bf0e9800 [<8044cd3c>] (mmc_set_clock+0x0/0x14) from [<8044f8f4>] (mmc_init_card+0x1b4/0x1520) [<8044f740>] (mmc_init_card+0x0/0x1520) from [<80450f00>] (mmc_attach_mmc+0xb4/0x194) [<80450e4c>] (mmc_attach_mmc+0x0/0x194) from [<8044da08>] (mmc_rescan+0x294/0x2f0) r5:8065f358 r4:bf0e9af8 [<8044d774>] (mmc_rescan+0x0/0x2f0) from [<8003db94>] (process_one_work+0x1a4/0x468) r8:00000000 r7:bfa29eb0 r6:bf80dc00 r5:bf0e9af8 r4:bf9e3f00 r3:8044d774 [<8003d9f0>] (process_one_work+0x0/0x468) from [<8003e850>] (worker_thread+0x118/0x3e0) [<8003e738>] (worker_thread+0x0/0x3e0) from [<80044de0>] (kthread+0xd4/0xf0) [<80044d0c>] (kthread+0x0/0xf0) from [<8000e9c8>] (ret_from_fork+0x14/0x2c) r7:00000000 r6:00000000 r5:80044d0c r4:bf9e7f00 Cc: Chris Ball <cjb@laptop.org> Cc: Fabio Estevam <fabio.estevam@freescale.com> Cc: Shawn Guo <shawn.guo@linaro.org> Fixes: 0ddf03c mmc: esdhc-imx: parse max-frequency from devicetree Signed-off-by: Dong Aisheng <b29396@freescale.com> --- drivers/mmc/host/sdhci-esdhc-imx.c | 12 +++++------- 1 files changed, 5 insertions(+), 7 deletions(-)