Messages in this thread | | | Date | Fri, 26 Jul 2019 16:54:06 +0200 | From | Michał Mirosław <> | Subject | AT91: sama5d2: lockdep splat in sama5d2_pmc_of_clk_init_driver() |
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Dear Developers
Since upgrading to v5.2.2 from v5.1.x I keep getting lockdep complaints (below) from clk initialization on SAMA5D2 board. Have you seen this? Can you help me in finding a fix?
Best Regards, Michał Mirosław
------- dmesg START ------
[ 0.000000] Booting Linux on physical CPU 0x0 [ 0.000000] Linux version 5.2.3+ (mirq@qmqm) (gcc version 8.3.0 (Debian 8.3.0-2)) #312 Fri Jul 26 15:32:06 CEST 2019 [ 0.000000] CPU: ARMv7 Processor [410fc051] revision 1 (ARMv7), cr=10c53c7d [ 0.000000] CPU: PIPT / VIPT nonaliasing data cache, VIPT aliasing instruction cache [ 0.000000] OF: fdt: Machine model: SAMA5D2 proto3 [ 0.000000] printk: bootconsole [earlycon0] enabled [ 0.000000] Memory policy: Data cache writeback [ 0.000000] On node 0 totalpages: 65536 [ 0.000000] Normal zone: 512 pages used for memmap [ 0.000000] Normal zone: 0 pages reserved [ 0.000000] Normal zone: 65536 pages, LIFO batch:15 [ 0.000000] CPU: All CPU(s) started in SVC mode. [ 0.000000] pcpu-alloc: s0 r0 d32768 u32768 alloc=1*32768 [ 0.000000] pcpu-alloc: [0] 0 [ 0.000000] Built 1 zonelists, mobility grouping on. Total pages: 65024 [ 0.000000] Kernel command line: console=ttyS0,115200 root=/dev/mmcblk0p1 rootfstype=squashfs debug loglevel=9 earlyprintk [ 0.000000] Dentry cache hash table entries: 32768 (order: 5, 131072 bytes) [ 0.000000] Inode-cache hash table entries: 16384 (order: 4, 65536 bytes) [ 0.000000] Memory: 239752K/262144K available (8192K kernel code, 578K rwdata, 2312K rodata, 1024K init, 7103K bss, 22392K reserved, 0K cma-reserved) [ 0.000000] ftrace: allocating 25429 entries in 50 pages [ 0.000000] Running RCU self tests [ 0.000000] NR_IRQS: 16, nr_irqs: 16, preallocated irqs: 16 [ 0.000000] L2C-310 ID prefetch enabled, offset 2 lines [ 0.000000] L2C-310 dynamic clock gating enabled, standby mode enabled [ 0.000000] L2C-310 cache controller enabled, 8 ways, 128 kB [ 0.000000] L2C-310: CACHE_ID 0x410000c9, AUX_CTRL 0x36020000 [ 0.000000] random: get_random_bytes called from start_kernel+0x2b8/0x450 with crng_init=0
[ 0.000000] ====================================================== [ 0.000000] WARNING: possible circular locking dependency detected [ 0.000000] 5.2.3+ #312 Not tainted [ 0.000000] ------------------------------------------------------ [ 0.000000] swapper/0 is trying to acquire lock: [ 0.000000] (ptrval) (pmc_pcr_lock){....}, at: clk_sam9x5_peripheral_enable+0x28/0xac [ 0.000000] but task is already holding lock: [ 0.000000] (ptrval) (enable_lock){....}, at: clk_enable_lock+0x38/0xf4 [ 0.000000] which lock already depends on the new lock.
[ 0.000000] the existing dependency chain (in reverse order) is: [ 0.000000] -> #2 (enable_lock){....}: [ 0.000000] clk_enable_lock+0x38/0xf4 [ 0.000000] clk_core_enable_lock+0x14/0x34 [ 0.000000] regmap_mmio_read+0x54/0x6c [ 0.000000] _regmap_read+0x68/0x160 [ 0.000000] regmap_read+0x44/0x64 [ 0.000000] at91_clk_register_sam9x5_main+0xb0/0x108 [ 0.000000] sama5d2_pmc_of_clk_init_driver+0x15c/0x654 [ 0.000000] of_clk_init+0x154/0x21c [ 0.000000] time_init+0x30/0x38 [ 0.000000] start_kernel+0x2ec/0x450 [ 0.000000] 0x0 [ 0.000000] -> #1 (syscon:113:(&syscon_config)->lock){....}: [ 0.000000] regmap_lock_spinlock+0x14/0x1c [ 0.000000] regmap_write+0x34/0x64 [ 0.000000] clk_sam9x5_peripheral_recalc_rate+0x60/0xf4 [ 0.000000] __clk_register+0x28c/0x7f4 [ 0.000000] clk_hw_register+0x20/0x2c [ 0.000000] at91_clk_register_sam9x5_peripheral+0xec/0x14c [ 0.000000] sama5d2_pmc_of_clk_init_driver+0x42c/0x654 [ 0.000000] of_clk_init+0x154/0x21c [ 0.000000] time_init+0x30/0x38 [ 0.000000] start_kernel+0x2ec/0x450 [ 0.000000] 0x0 [ 0.000000] -> #0 (pmc_pcr_lock){....}: [ 0.000000] _raw_spin_lock_irqsave+0x44/0x58 [ 0.000000] clk_sam9x5_peripheral_enable+0x28/0xac [ 0.000000] clk_core_enable+0x88/0x258 [ 0.000000] clk_core_enable_lock+0x20/0x34 [ 0.000000] clk_prepare_enable+0x1c/0x34 [ 0.000000] tcb_clksrc_init+0x13c/0x4b8 [ 0.000000] timer_probe+0x78/0xe0 [ 0.000000] start_kernel+0x2ec/0x450 [ 0.000000] 0x0 [ 0.000000] other info that might help us debug this:
[ 0.000000] Chain exists of: pmc_pcr_lock --> syscon:113:(&syscon_config)->lock --> enable_lock
[ 0.000000] Possible unsafe locking scenario:
[ 0.000000] CPU0 CPU1 [ 0.000000] ---- ---- [ 0.000000] lock(enable_lock); [ 0.000000] lock(syscon:113:(&syscon_config)->lock); [ 0.000000] lock(enable_lock); [ 0.000000] lock(pmc_pcr_lock); [ 0.000000] *** DEADLOCK ***
[ 0.000000] 1 lock held by swapper/0: [ 0.000000] #0: (ptrval) (enable_lock){....}, at: clk_enable_lock+0x38/0xf4 [ 0.000000] stack backtrace: [ 0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 5.2.3+ #312 [ 0.000000] Hardware name: Atmel SAMA5 [ 0.000000] [<c010edc0>] (unwind_backtrace) from [<c010c1a8>] (show_stack+0x18/0x1c) [ 0.000000] [<c010c1a8>] (show_stack) from [<c01515c4>] (print_circular_bug+0x220/0x25c) [ 0.000000] [<c01515c4>] (print_circular_bug) from [<c0154264>] (__lock_acquire+0x1600/0x1a80) [ 0.000000] [<c0154264>] (__lock_acquire) from [<c0154f08>] (lock_acquire+0xc4/0x168) [ 0.000000] [<c0154f08>] (lock_acquire) from [<c08330a8>] (_raw_spin_lock_irqsave+0x44/0x58) [ 0.000000] [<c08330a8>] (_raw_spin_lock_irqsave) from [<c042fabc>] (clk_sam9x5_peripheral_enable+0x28/0xac) [ 0.000000] [<c042fabc>] (clk_sam9x5_peripheral_enable) from [<c0424990>] (clk_core_enable+0x88/0x258) [ 0.000000] [<c0424990>] (clk_core_enable) from [<c0425c4c>] (clk_core_enable_lock+0x20/0x34) [ 0.000000] [<c0425c4c>] (clk_core_enable_lock) from [<c058d788>] (clk_prepare_enable+0x1c/0x34) [ 0.000000] [<c058d788>] (clk_prepare_enable) from [<c0c358bc>] (tcb_clksrc_init+0x13c/0x4b8) [ 0.000000] [<c0c358bc>] (tcb_clksrc_init) from [<c0c35718>] (timer_probe+0x78/0xe0) [ 0.000000] [<c0c35718>] (timer_probe) from [<c0c00dc4>] (start_kernel+0x2ec/0x450) [ 0.000000] [<c0c00dc4>] (start_kernel) from [<00000000>] (0x0) [ 0.000000] clocksource: timer@f800c000: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 184217874325 ns [ 0.000021] sched_clock: 32 bits at 10MHz, resolution 96ns, wraps every 206986376143ns [ 0.009762] Lock dependency validator: Copyright (c) 2006 Red Hat, Inc., Ingo Molnar [ 0.018365] ... MAX_LOCKDEP_SUBCLASSES: 8 [ 0.022911] ... MAX_LOCK_DEPTH: 48 [ 0.027546] ... MAX_LOCKDEP_KEYS: 8191 [ 0.032367] ... CLASSHASH_SIZE: 4096 [ 0.037190] ... MAX_LOCKDEP_ENTRIES: 32768 [ 0.042109] ... MAX_LOCKDEP_CHAINS: 65536 [ 0.047028] ... CHAINHASH_SIZE: 32768 [ 0.051944] memory used by lock dependency info: 4411 kB [ 0.057913] per task-struct memory footprint: 1536 bytes [ 0.063965] Calibrating delay loop... 358.40 BogoMIPS (lpj=179200) [ 0.081133] pid_max: default: 32768 minimum: 301 [ 0.086831] Mount-cache hash table entries: 1024 (order: 0, 4096 bytes) [ 0.094201] Mountpoint-cache hash table entries: 1024 (order: 0, 4096 bytes) [ 0.104331] CPU: Testing write buffer coherency: ok [ 0.112611] Setting up static identity map for 0x20100000 - 0x20100060 [ 0.122704] devtmpfs: initialized [ 0.151047] VFP support v0.3: implementor 41 architecture 2 part 30 variant 5 rev 1 [ 0.160466] clocksource: jiffies: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 1911260446275000 ns [ 0.171341] futex hash table entries: 256 (order: 1, 11264 bytes) [ 0.178738] pinctrl core: initialized pinctrl subsystem [ 0.186405] regulator-dummy: no parameters, enabled [ 0.194206] NET: Registered protocol family 16 [ 0.207208] DMA: preallocated 256 KiB pool for atomic coherent allocations [ 0.292223] AT91: PM: standby: standby, suspend: ulp0 [ 0.300092] atmel_tcb: probe of f800c000.timer failed with error -16 [ 0.422319] random: fast init done [ 0.496218] at_xdmac f0010000.dma-controller: 16 channels, mapped at 0x(ptrval) [ 0.511573] at_xdmac f0004000.dma-controller: 16 channels, mapped at 0x(ptrval) [ 0.521731] AT91: Detected SoC family: sama5d2 [ 0.526738] AT91: Detected SoC: sama5d27, revision 2 [...]
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