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authorGrygorii Strashko <grygorii.strashko@ti.com>2015-08-17 15:35:23 +0300
committerLinus Walleij <linus.walleij@linaro.org>2015-08-17 15:32:03 +0200
commita0a8bcf4670c2c696e6e83742539a5e0dd7a62d6 (patch)
tree05c95939cd0fc66f3a3a5bd20a55d234de3513fe /net
parent7fa25937542358bfa01ef5c5a1e9a00bd164c000 (diff)
downloadlinux-a0a8bcf4670c2c696e6e83742539a5e0dd7a62d6.tar.gz
gpiolib: irqchip: use different lockdep class for each gpio irqchip
Since IRQ chip helpers were introduced drivers lose ability to register separate lockdep classes for each registered GPIO IRQ chip and the gpiolib now is using shared lockdep class for all GPIO IRQ chips (gpiochip_irq_lock_class). As result, lockdep will produce warning when there are min two stacked GPIO chips and all of them are interrupt controllers. HW configuration which generates lockdep warning (TI dra7-evm): [SOC GPIO bankA.gpioX] <- irq - [pcf875x.gpioY] <- irq - DevZ.enable_irq_wake(pcf_gpioY_irq); The issue was reported in [1] and discussed [2]. ============================================= [ INFO: possible recursive locking detected ] 4.2.0-rc6-00013-g5d050ed-dirty #55 Not tainted --------------------------------------------- sh/63 is trying to acquire lock: (class){......}, at: [<c009b91c>] __irq_get_desc_lock+0x50/0x94 but task is already holding lock: (class){......}, at: [<c009b91c>] __irq_get_desc_lock+0x50/0x94 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(class); lock(class); *** DEADLOCK *** May be due to missing lock nesting notation 7 locks held by sh/63: #0: (sb_writers#4){.+.+.+}, at: [<c016bbb8>] vfs_write+0x13c/0x164 #1: (&of->mutex){+.+.+.}, at: [<c01debf4>] kernfs_fop_write+0x4c/0x1a0 #2: (s_active#36){.+.+.+}, at: [<c01debfc>] kernfs_fop_write+0x54/0x1a0 #3: (pm_mutex){+.+.+.}, at: [<c009758c>] pm_suspend+0xec/0x4c4 #4: (&dev->mutex){......}, at: [<c03f77f8>] __device_suspend+0xd4/0x398 #5: (&gpio->lock){+.+.+.}, at: [<c009b940>] __irq_get_desc_lock+0x74/0x94 #6: (class){......}, at: [<c009b91c>] __irq_get_desc_lock+0x50/0x94 stack backtrace: CPU: 0 PID: 63 Comm: sh Not tainted 4.2.0-rc6-00013-g5d050ed-dirty #55 Hardware name: Generic DRA74X (Flattened Device Tree) [<c0016e24>] (unwind_backtrace) from [<c0013338>] (show_stack+0x10/0x14) [<c0013338>] (show_stack) from [<c05f6b24>] (dump_stack+0x84/0x9c) [<c05f6b24>] (dump_stack) from [<c00903f4>] (__lock_acquire+0x19c0/0x1e20) [<c00903f4>] (__lock_acquire) from [<c0091098>] (lock_acquire+0xa8/0x128) [<c0091098>] (lock_acquire) from [<c05fd61c>] (_raw_spin_lock_irqsave+0x38/0x4c) [<c05fd61c>] (_raw_spin_lock_irqsave) from [<c009b91c>] (__irq_get_desc_lock+0x50/0x94) [<c009b91c>] (__irq_get_desc_lock) from [<c009c4f4>] (irq_set_irq_wake+0x20/0xfc) [<c009c4f4>] (irq_set_irq_wake) from [<c0393ac4>] (pcf857x_irq_set_wake+0x24/0x54) [<c0393ac4>] (pcf857x_irq_set_wake) from [<c009c560>] (irq_set_irq_wake+0x8c/0xfc) [<c009c560>] (irq_set_irq_wake) from [<c04a02ac>] (gpio_keys_suspend+0x70/0xd4) [<c04a02ac>] (gpio_keys_suspend) from [<c03f6a00>] (dpm_run_callback+0x50/0x124) [<c03f6a00>] (dpm_run_callback) from [<c03f7830>] (__device_suspend+0x10c/0x398) [<c03f7830>] (__device_suspend) from [<c03f90f0>] (dpm_suspend+0x134/0x2f4) [<c03f90f0>] (dpm_suspend) from [<c0096e20>] (suspend_devices_and_enter+0xa8/0x728) [<c0096e20>] (suspend_devices_and_enter) from [<c00977cc>] (pm_suspend+0x32c/0x4c4) [<c00977cc>] (pm_suspend) from [<c0096060>] (state_store+0x64/0xb8) [<c0096060>] (state_store) from [<c01dec64>] (kernfs_fop_write+0xbc/0x1a0) [<c01dec64>] (kernfs_fop_write) from [<c016b280>] (__vfs_write+0x20/0xd8) [<c016b280>] (__vfs_write) from [<c016bb0c>] (vfs_write+0x90/0x164) [<c016bb0c>] (vfs_write) from [<c016c330>] (SyS_write+0x44/0x9c) [<c016c330>] (SyS_write) from [<c000f500>] (ret_fast_syscall+0x0/0x54) Lets fix it by using separate lockdep class for each registered GPIO IRQ Chip. This is done by wrapping gpiochip_irqchip_add call into macros. The implementation of this patch inspired by solution done by Nicolas Boichat for regmap [3] [1] http://www.spinics.net/lists/linux-gpio/msg05844.html [2] http://www.spinics.net/lists/linux-gpio/msg06021.html [3] http://www.spinics.net/lists/arm-kernel/msg429834.html Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Roger Quadros <rogerq@ti.com> Reported-by: Roger Quadros <rogerq@ti.com> Tested-by: Roger Quadros <rogerq@ti.com> Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Diffstat (limited to 'net')
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