Re: rtsx_pci_sdmmc lockdep splat

From: micky
Date: Tue Apr 15 2014 - 21:47:26 EST


Hi Borislav,

On 04/16/2014 01:49 AM, Borislav Petkov wrote:
Hi all,

I'm seeing the following when I insert an sd card. Kernel is 3.15-rc1+.

Thanks.
The patch below may fix this problem.

From: Micky Ching<micky_ching@xxxxxxxxxxxxxx>

To avoid dead lock, we need make sure host->lock is always acquire
before pcr->lock. But in irq handler, we acquired pcr->lock in rtsx mfd
driver, and sd_isr_done_transfer() is called during pcr->lock already
acquired. Since in sd_isr_done_transfer() the only work we do is schdule
tasklet, the cmd_tasklet and data_tasklet never conflict, so it is safe
to remove spin_lock() here.

Signed-off-by: Micky Ching<micky_ching@xxxxxxxxxxxxxx>
---
drivers/mmc/host/rtsx_pci_sdmmc.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/drivers/mmc/host/rtsx_pci_sdmmc.c b/drivers/mmc/host/rtsx_pci_sdmmc.c
index 453e1d4..40695e0 100644
--- a/drivers/mmc/host/rtsx_pci_sdmmc.c
+++ b/drivers/mmc/host/rtsx_pci_sdmmc.c
@@ -108,12 +108,10 @@ static void sd_isr_done_transfer(struct platform_device *pdev)
{
struct realtek_pci_sdmmc *host = platform_get_drvdata(pdev);
- spin_lock(&host->lock);
if (host->cmd)
tasklet_schedule(&host->cmd_tasklet);
- if (host->data)
+ else if (host->data)
tasklet_schedule(&host->data_tasklet);
- spin_unlock(&host->lock);
}
static void sd_request_timeout(unsigned long host_addr)
--
1.7.9.5

I have send out this patch, Thanks.
Best Regards.
micky.

[ 682.675345] rtsx_pci_sdmmc rtsx_pci_sdmmc.0: sdmmc_get_cd: RTSX_BIPR = 0x00010000
[ 682.679723] mmc0: mmc_rescan_try_freq: trying to init card at 400000 Hz
[ 682.683778] mmc0: clock 0Hz busmode 2 powermode 1 cs 0 Vdd 21 width 0 timing 0
[ 682.689135] rtsx_pci_sdmmc rtsx_pci_sdmmc.0: sdmmc_switch_voltage: signal_voltage = 0
[ 682.701892] mmc0: clock 400000Hz busmode 2 powermode 2 cs 0 Vdd 21 width 0 timing 0
[ 682.718034] mmc0: starting CMD52 arg 00000c00 flags 00000195
[ 682.720975] rtsx_pci_sdmmc rtsx_pci_sdmmc.0: sd_send_cmd: SD/MMC CMD 52, arg = 0x00000c00
[ 682.723749]
[ 682.726488] ======================================================
[ 682.729295] [ INFO: possible circular locking dependency detected ]
[ 682.732138] 3.15.0-rc1+ #3 Not tainted
[ 682.734989] -------------------------------------------------------
[ 682.737905] kworker/u4:0/6 is trying to acquire lock:
[ 682.740853] (&(&pcr->lock)->rlock){-.-...}, at: [<ffffffffa0004387>] rtsx_pci_add_cmd+0x47/0xb0 [rtsx_pci]
[ 682.743945]
[ 682.743945] but task is already holding lock:
[ 682.749951] (&(&host->lock)->rlock#3){-.....}, at: [<ffffffffa00bc577>] sdmmc_request+0x57/0x579 [rtsx_pci_sdmmc]
[ 682.753076]
[ 682.753076] which lock already depends on the new lock.
[ 682.753076]
[ 682.762208]
[ 682.762208] the existing dependency chain (in reverse order) is:
[ 682.768191]
[ 682.768191] -> #1 (&(&host->lock)->rlock#3){-.....}:
[ 682.774134] [<ffffffff810bdfd6>] lock_acquire+0x96/0x130
[ 682.777063] [<ffffffff8153729b>] _raw_spin_lock+0x3b/0x50
[ 682.779959] [<ffffffffa00bb91d>] sd_isr_done_transfer+0x2d/0x80 [rtsx_pci_sdmmc]
[ 682.782861] [<ffffffffa0005679>] rtsx_pci_isr+0x119/0x220 [rtsx_pci]
[ 682.785736] [<ffffffff810cdea7>] handle_irq_event_percpu+0x47/0x1e0
[ 682.788584] [<ffffffff810ce088>] handle_irq_event+0x48/0x70
[ 682.791387] [<ffffffff810d0a9f>] handle_edge_irq+0x8f/0x150
[ 682.794195] [<ffffffff81004cee>] handle_irq+0x1e/0x30
[ 682.797026] [<ffffffff8153a8da>] do_IRQ+0x6a/0x110
[ 682.799831] [<ffffffff8153812f>] ret_from_intr+0x0/0x13
[ 682.802645] [<ffffffff81099ea8>] __atomic_notifier_call_chain+0x88/0xb0
[ 682.805465] [<ffffffff81099ee6>] atomic_notifier_call_chain+0x16/0x20
[ 682.808246] [<ffffffff8133af46>] do_con_write.part.18+0x176/0xa10
[ 682.811028] [<ffffffff8133b895>] con_write+0x75/0x80
[ 682.813758] [<ffffffff81324ac5>] n_tty_write+0x325/0x4d0
[ 682.816497] [<ffffffff81321540>] tty_write+0x150/0x2b0
[ 682.819195] [<ffffffff8118d571>] do_loop_readv_writev+0x61/0x90
[ 682.821901] [<ffffffff8118ef25>] do_readv_writev+0x205/0x210
[ 682.824583] [<ffffffff8118efb0>] vfs_writev+0x30/0x60
[ 682.827226] [<ffffffff8118f0f2>] SyS_writev+0x52/0xc0
[ 682.829821] [<ffffffff81538c92>] system_call_fastpath+0x16/0x1b
[ 682.832383]
[ 682.832383] -> #0 (&(&pcr->lock)->rlock){-.-...}:
[ 682.837324] [<ffffffff810bd570>] __lock_acquire+0x1690/0x1950
[ 682.839790] [<ffffffff810bdfd6>] lock_acquire+0x96/0x130
[ 682.842229] [<ffffffff815373f6>] _raw_spin_lock_irqsave+0x46/0x60
[ 682.844650] [<ffffffffa0004387>] rtsx_pci_add_cmd+0x47/0xb0 [rtsx_pci]
[ 682.847029] [<ffffffffa00bbc0b>] sd_send_cmd+0xcb/0x3c0 [rtsx_pci_sdmmc]
[ 682.849359] [<ffffffffa00bc7c0>] sdmmc_request+0x2a0/0x579 [rtsx_pci_sdmmc]
[ 682.851649] [<ffffffffa009082f>] mmc_start_request+0x16f/0x280 [mmc_core]
[ 682.853921] [<ffffffffa00909ca>] __mmc_start_req+0x6a/0xa0 [mmc_core]
[ 682.856162] [<ffffffffa0090f7a>] mmc_wait_for_cmd+0x7a/0xd0 [mmc_core]
[ 682.858387] [<ffffffffa009bed0>] mmc_io_rw_direct_host+0x90/0x120 [mmc_core]
[ 682.860608] [<ffffffffa009c416>] sdio_reset+0x26/0x70 [mmc_core]
[ 682.862815] [<ffffffffa009399d>] mmc_rescan+0x29d/0x350 [mmc_core]
[ 682.865007] [<ffffffff8108deba>] process_one_work+0x21a/0x560
[ 682.867175] [<ffffffff8108e320>] worker_thread+0x120/0x390
[ 682.869286] [<ffffffff81094aac>] kthread+0xfc/0x120
[ 682.871341] [<ffffffff81538bec>] ret_from_fork+0x7c/0xb0
[ 682.873404]
[ 682.873404] other info that might help us debug this:
[ 682.873404]
[ 682.879197] Possible unsafe locking scenario:
[ 682.879197]
[ 682.883048] CPU0 CPU1
[ 682.884972] ---- ----
[ 682.886860] lock(&(&host->lock)->rlock#3);
[ 682.888763] lock(&(&pcr->lock)->rlock);
[ 682.890686] lock(&(&host->lock)->rlock#3);
[ 682.892608] lock(&(&pcr->lock)->rlock);
[ 682.894492]
[ 682.894492] *** DEADLOCK ***
[ 682.894492]
[ 682.899913] 4 locks held by kworker/u4:0/6:
[ 682.901735] #0: ("kmmcd"){.+.+..}, at: [<ffffffff8108de45>] process_one_work+0x1a5/0x560
[ 682.903677] #1: ((&(&host->detect)->work)){+.+...}, at: [<ffffffff8108de45>] process_one_work+0x1a5/0x560
[ 682.905678] #2: (&pcr->pcr_mutex){+.+...}, at: [<ffffffffa00bc56f>] sdmmc_request+0x4f/0x579 [rtsx_pci_sdmmc]
[ 682.907737] #3: (&(&host->lock)->rlock#3){-.....}, at: [<ffffffffa00bc577>] sdmmc_request+0x57/0x579 [rtsx_pci_sdmmc]
[ 682.909851]
[ 682.909851] stack backtrace:
[ 682.913909] CPU: 1 PID: 6 Comm: kworker/u4:0 Not tainted 3.15.0-rc1+ #3
[ 682.915987] Hardware name: LENOVO 30515QG/30515QG, BIOS 8RET30WW (1.12 ) 09/15/2011
[ 682.918124] Workqueue: kmmcd mmc_rescan [mmc_core]
[ 682.920264] ffffffff8202f4f0 ffff880119949940 ffffffff8152f1c5 ffffffff81ff6fd0
[ 682.922471] ffff880119949980 ffffffff8152c20e ffff8801199499d0 ffff8801198e59a8
[ 682.924690] 0000000000000003 ffff8801198e51e0 0000000000000004 ffff8801198e59a8
[ 682.926923] Call Trace:
[ 682.929136] [<ffffffff8152f1c5>] dump_stack+0x4e/0x7a
[ 682.931384] [<ffffffff8152c20e>] print_circular_bug+0x203/0x211
[ 682.933625] [<ffffffff810bd570>] __lock_acquire+0x1690/0x1950
[ 682.935869] [<ffffffff81537591>] ? _raw_spin_unlock_irqrestore+0x41/0x80
[ 682.938106] [<ffffffffa0004387>] ? rtsx_pci_add_cmd+0x47/0xb0 [rtsx_pci]
[ 682.940345] [<ffffffff810bdfd6>] lock_acquire+0x96/0x130
[ 682.942585] [<ffffffffa0004387>] ? rtsx_pci_add_cmd+0x47/0xb0 [rtsx_pci]
[ 682.944835] [<ffffffff815373f6>] _raw_spin_lock_irqsave+0x46/0x60
[ 682.947089] [<ffffffffa0004387>] ? rtsx_pci_add_cmd+0x47/0xb0 [rtsx_pci]
[ 682.949350] [<ffffffffa0004387>] rtsx_pci_add_cmd+0x47/0xb0 [rtsx_pci]
[ 682.951601] [<ffffffffa00bbc0b>] sd_send_cmd+0xcb/0x3c0 [rtsx_pci_sdmmc]
[ 682.953849] [<ffffffffa00bc7c0>] sdmmc_request+0x2a0/0x579 [rtsx_pci_sdmmc]
[ 682.956116] [<ffffffffa009082f>] mmc_start_request+0x16f/0x280 [mmc_core]
[ 682.958382] [<ffffffffa00909ca>] __mmc_start_req+0x6a/0xa0 [mmc_core]
[ 682.960642] [<ffffffffa0090f7a>] mmc_wait_for_cmd+0x7a/0xd0 [mmc_core]
[ 682.962906] [<ffffffffa0090940>] ? mmc_start_request+0x280/0x280 [mmc_core]
[ 682.965183] [<ffffffffa009bed0>] mmc_io_rw_direct_host+0x90/0x120 [mmc_core]
[ 682.967471] [<ffffffffa009c416>] sdio_reset+0x26/0x70 [mmc_core]
[ 682.969765] [<ffffffffa009399d>] mmc_rescan+0x29d/0x350 [mmc_core]
[ 682.972056] [<ffffffff8108deba>] process_one_work+0x21a/0x560
[ 682.974342] [<ffffffff8108de45>] ? process_one_work+0x1a5/0x560
[ 682.976634] [<ffffffff8108e320>] worker_thread+0x120/0x390
[ 682.978916] [<ffffffff8108e200>] ? process_one_work+0x560/0x560
[ 682.981209] [<ffffffff81094aac>] kthread+0xfc/0x120
[ 682.983499] [<ffffffff815375fc>] ? _raw_spin_unlock_irq+0x2c/0x60
[ 682.985826] [<ffffffff810949b0>] ? kthread_create_on_node+0x1f0/0x1f0
[ 682.988182] [<ffffffff81538bec>] ret_from_fork+0x7c/0xb0
[ 682.990534] [<ffffffff810949b0>] ? kthread_create_on_node+0x1f0/0x1f0
[ 683.033350] rtsx_pci_sdmmc rtsx_pci_sdmmc.0: timeout for request


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