The kernel WARNs and then crashes today if wm8994_device_init() fails
after calling devm_regulator_bulk_get().

That happens because there are multiple devices involved here and the
order in which resources are freed isn't correct.

The regulators are added as children of wm8994->dev.
devm_regulator_bulk_get() receives wm8994->dev as the device, though it
gets the same regulators which were added as children of wm8994->dev
earlier.

During failures, the children are removed first and the core eventually
calls regulator_unregister() for them. As regulator_put() was never done
for them (opposite of devm_regulator_bulk_get()), the kernel WARNs at

        WARN_ON(rdev->open_count);

And eventually it crashes from debugfs_remove_recursive().

--------x------------------x----------------

 wm8994 3-001a: Device is not a WM8994, ID is 0
 ------------[ cut here ]------------
 WARNING: CPU: 0 PID: 1 at 
/mnt/ssd/all/work/repos/devel/linux/drivers/regulator/core.c:4072 
regulator_unregister+0xc8/0xd0
 Modules linked in:
 CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.8.0-rc6-00154-g54fe84cbd50b #41
 Hardware name: SAMSUNG EXYNOS (Flattened Device Tree)
 [<c010e24c>] (unwind_backtrace) from [<c010af38>] (show_stack+0x10/0x14)
 [<c010af38>] (show_stack) from [<c032a1c4>] (dump_stack+0x88/0x9c)
 [<c032a1c4>] (dump_stack) from [<c011a98c>] (__warn+0xe8/0x100)
 [<c011a98c>] (__warn) from [<c011aa54>] (warn_slowpath_null+0x20/0x28)
 [<c011aa54>] (warn_slowpath_null) from [<c0384a0c>] 
(regulator_unregister+0xc8/0xd0)
 [<c0384a0c>] (regulator_unregister) from [<c0406434>] 
(release_nodes+0x16c/0x1dc)
 [<c0406434>] (release_nodes) from [<c04039c4>] 
(__device_release_driver+0x8c/0x110)
 [<c04039c4>] (__device_release_driver) from [<c0403a64>] 
(device_release_driver+0x1c/0x28)
 [<c0403a64>] (device_release_driver) from [<c0402b24>] 
(bus_remove_device+0xd8/0x104)
 [<c0402b24>] (bus_remove_device) from [<c03ffcd8>] (device_del+0x10c/0x218)
 [<c03ffcd8>] (device_del) from [<c0404e4c>] (platform_device_del+0x1c/0x88)
 [<c0404e4c>] (platform_device_del) from [<c0404ec4>] 
(platform_device_unregister+0xc/0x20)
 [<c0404ec4>] (platform_device_unregister) from [<c0428bc0>] 
(mfd_remove_devices_fn+0x5c/0x64)
 [<c0428bc0>] (mfd_remove_devices_fn) from [<c03ff9d8>] 
(device_for_each_child_reverse+0x4c/0x78)
 [<c03ff9d8>] (device_for_each_child_reverse) from [<c04288c4>] 
(mfd_remove_devices+0x20/0x30)
 [<c04288c4>] (mfd_remove_devices) from [<c042758c>] 
(wm8994_device_init+0x2ac/0x7f0)
 [<c042758c>] (wm8994_device_init) from [<c04f14a8>] 
(i2c_device_probe+0x178/0x1fc)
 [<c04f14a8>] (i2c_device_probe) from [<c04036fc>] 
(driver_probe_device+0x214/0x2c0)
 [<c04036fc>] (driver_probe_device) from [<c0403854>] 
(__driver_attach+0xac/0xb0)
 [<c0403854>] (__driver_attach) from [<c0401a74>] (bus_for_each_dev+0x68/0x9c)
 [<c0401a74>] (bus_for_each_dev) from [<c0402cf0>] (bus_add_driver+0x1a0/0x218)
 [<c0402cf0>] (bus_add_driver) from [<c040406c>] (driver_register+0x78/0xf8)
 [<c040406c>] (driver_register) from [<c04f20a0>] 
(i2c_register_driver+0x34/0x84)
 [<c04f20a0>] (i2c_register_driver) from [<c01017d0>] 
(do_one_initcall+0x40/0x170)
 [<c01017d0>] (do_one_initcall) from [<c0a00dbc>] 
(kernel_init_freeable+0x15c/0x1fc)
 [<c0a00dbc>] (kernel_init_freeable) from [<c06e07b0>] (kernel_init+0x8/0x114)
 [<c06e07b0>] (kernel_init) from [<c0107978>] (ret_from_fork+0x14/0x3c)
 ---[ end trace 0919d3d0bc998260 ]---
 ------------[ cut here ]------------
 WARNING: CPU: 0 PID: 1 at 
/mnt/ssd/all/work/repos/devel/linux/drivers/regulator/core.c:4072 
regulator_unregister+0xc8/0xd0
 Modules linked in:
 CPU: 0 PID: 1 Comm: swapper/0 Tainted: G        W       
4.8.0-rc6-00154-g54fe84cbd50b #41
 Hardware name: SAMSUNG EXYNOS (Flattened Device Tree)
 [<c010e24c>] (unwind_backtrace) from [<c010af38>] (show_stack+0x10/0x14)
 [<c010af38>] (show_stack) from [<c032a1c4>] (dump_stack+0x88/0x9c)
 [<c032a1c4>] (dump_stack) from [<c011a98c>] (__warn+0xe8/0x100)
 [<c011a98c>] (__warn) from [<c011aa54>] (warn_slowpath_null+0x20/0x28)
 [<c011aa54>] (warn_slowpath_null) from [<c0384a0c>] 
(regulator_unregister+0xc8/0xd0)
 [<c0384a0c>] (regulator_unregister) from [<c0406434>] 
(release_nodes+0x16c/0x1dc)
 [<c0406434>] (release_nodes) from [<c04039c4>] 
(__device_release_driver+0x8c/0x110)
 [<c04039c4>] (__device_release_driver) from [<c0403a64>] 
(device_release_driver+0x1c/0x28)
 [<c0403a64>] (device_release_driver) from [<c0402b24>] 
(bus_remove_device+0xd8/0x104)
 [<c0402b24>] (bus_remove_device) from [<c03ffcd8>] (device_del+0x10c/0x218)
 [<c03ffcd8>] (device_del) from [<c0404e4c>] (platform_device_del+0x1c/0x88)
 wm8994 3-001a: Device is not a WM8994, ID is 0
 ------------[ cut here ]------------
 WARNING: CPU: 0 PID: 1 at 
/mnt/ssd/all/work/repos/devel/linux/drivers/regulator/core.c:4072 
regulator_unregister+0xc8/0xd0
 Modules linked in:
 CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.8.0-rc6-00154-g54fe84cbd50b #41
 Hardware name: SAMSUNG EXYNOS (Flattened Device Tree)
 [<c010e24c>] (unwind_backtrace) from [<c010af38>] (show_stack+0x10/0x14)
 [<c010af38>] (show_stack) from [<c032a1c4>] (dump_stack+0x88/0x9c)
 [<c032a1c4>] (dump_stack) from [<c011a98c>] (__warn+0xe8/0x100)
 [<c011a98c>] (__warn) from [<c011aa54>] (warn_slowpath_null+0x20/0x28)
 [<c011aa54>] (warn_slowpath_null) from [<c0384a0c>] 
(regulator_unregister+0xc8/0xd0)
 [<c0384a0c>] (regulator_unregister) from [<c0406434>] 
(release_nodes+0x16c/0x1dc)
 [<c0406434>] (release_nodes) from [<c04039c4>] 
(__device_release_driver+0x8c/0x110)
 [<c04039c4>] (__device_release_driver) from [<c0403a64>] 
(device_release_driver+0x1c/0x28)
 [<c0403a64>] (device_release_driver) from [<c0402b24>] 
(bus_remove_device+0xd8/0x104)
 [<c0402b24>] (bus_remove_device) from [<c03ffcd8>] (device_del+0x10c/0x218)
 [<c03ffcd8>] (device_del) from [<c0404e4c>] (platform_device_del+0x1c/0x88)
 [<c0404e4c>] (platform_device_del) from [<c0404ec4>] 
(platform_device_unregister+0xc/0x20)
 [<c0404ec4>] (platform_device_unregister) from [<c0428bc0>] 
(mfd_remove_devices_fn+0x5c/0x64)
 [<c0428bc0>] (mfd_remove_devices_fn) from [<c03ff9d8>] 
(device_for_each_child_reverse+0x4c/0x78)
 [<c03ff9d8>] (device_for_each_child_reverse) from [<c04288c4>] 
(mfd_remove_devices+0x20/0x30)
 [<c04288c4>] (mfd_remove_devices) from [<c042758c>] 
(wm8994_device_init+0x2ac/0x7f0)
 [<c042758c>] (wm8994_device_init) from [<c04f14a8>] 
(i2c_device_probe+0x178/0x1fc)
 [<c04f14a8>] (i2c_device_probe) from [<c04036fc>] 
(driver_probe_device+0x214/0x2c0)
 [<c04036fc>] (driver_probe_device) from [<c0403854>] 
(__driver_attach+0xac/0xb0)
 [<c0403854>] (__driver_attach) from [<c0401a74>] (bus_for_each_dev+0x68/0x9c)
 [<c0401a74>] (bus_for_each_dev) from [<c0402cf0>] (bus_add_driver+0x1a0/0x218)
 [<c0402cf0>] (bus_add_driver) from [<c040406c>] (driver_register+0x78/0xf8)
 [<c040406c>] (driver_register) from [<c04f20a0>] 
(i2c_register_driver+0x34/0x84)
 [<c04f20a0>] (i2c_register_driver) from [<c01017d0>] 
(do_one_initcall+0x40/0x170)
 [<c01017d0>] (do_one_initcall) from [<c0a00dbc>] 
(kernel_init_freeable+0x15c/0x1fc)
 [<c0a00dbc>] (kernel_init_freeable) from [<c06e07b0>] (kernel_init+0x8/0x114)
 [<c06e07b0>] (kernel_init) from [<c0107978>] (ret_from_fork+0x14/0x3c)
 ---[ end trace 0919d3d0bc998260 ]---
 ------------[ cut here ]------------
 WARNING: CPU: 0 PID: 1 at 
/mnt/ssd/all/work/repos/devel/linux/drivers/regulator/core.c:4072 
regulator_unregister+0xc8/0xd0
 Modules linked in:
 CPU: 0 PID: 1 Comm: swapper/0 Tainted: G        W       
4.8.0-rc6-00154-g54fe84cbd50b #41
 Hardware name: SAMSUNG EXYNOS (Flattened Device Tree)
 [<c010e24c>] (unwind_backtrace) from [<c010af38>] (show_stack+0x10/0x14)
 [<c010af38>] (show_stack) from [<c032a1c4>] (dump_stack+0x88/0x9c)
 [<c032a1c4>] (dump_stack) from [<c011a98c>] (__warn+0xe8/0x100)
 [<c011a98c>] (__warn) from [<c011aa54>] (warn_slowpath_null+0x20/0x28)
 [<c011aa54>] (warn_slowpath_null) from [<c0384a0c>] 
(regulator_unregister+0xc8/0xd0)
 [<c0384a0c>] (regulator_unregister) from [<c0406434>] 
(release_nodes+0x16c/0x1dc)
 [<c0406434>] (release_nodes) from [<c04039c4>] 
(__device_release_driver+0x8c/0x110)
 [<c04039c4>] (__device_release_driver) from [<c0403a64>] 
(device_release_driver+0x1c/0x28)
 [<c0403a64>] (device_release_driver) from [<c0402b24>] 
(bus_remove_device+0xd8/0x104)
 [<c0402b24>] (bus_remove_device) from [<c03ffcd8>] (device_del+0x10c/0x218)
 [<c03ffcd8>] (device_del) from [<c0404e4c>] (platform_device_del+0x1c/0x88)
 [<c0404e4c>] (platform_device_del) from [<c0404ec4>] 
(platform_device_unregister+0xc/0x20)
 [<c0404ec4>] (platform_device_unregister) from [<c0428bc0>] 
(mfd_remove_devices_fn+0x5c/0x64)
 [<c0428bc0>] (mfd_remove_devices_fn) from [<c03ff9d8>] 
(device_for_each_child_reverse+0x4c/0x78)
 [<c03ff9d8>] (device_for_each_child_reverse) from [<c04288c4>] 
(mfd_remove_devices+0x20/0x30)
 [<c04288c4>] (mfd_remove_devices) from [<c042758c>] 
(wm8994_device_init+0x2ac/0x7f0)
 [<c042758c>] (wm8994_device_init) from [<c04f14a8>] 
(i2c_device_probe+0x178/0x1fc)
 [<c04f14a8>] (i2c_device_probe) from [<c04036fc>] 
(driver_probe_device+0x214/0x2c0)
 [<c04036fc>] (driver_probe_device) from [<c0403854>] 
(__driver_attach+0xac/0xb0)
 [<c0403854>] (__driver_attach) from [<c0401a74>] (bus_for_each_dev+0x68/0x9c)
 [<c0401a74>] (bus_for_each_dev) from [<c0402cf0>] (bus_add_driver+0x1a0/0x218)
 [<c0402cf0>] (bus_add_driver) from [<c040406c>] (driver_register+0x78/0xf8)
 [<c040406c>] (driver_register) from [<c04f20a0>] 
(i2c_register_driver+0x34/0x84)
 [<c04f20a0>] (i2c_register_driver) from [<c01017d0>] 
(do_one_initcall+0x40/0x170)
 [<c01017d0>] (do_one_initcall) from [<c0a00dbc>] 
(kernel_init_freeable+0x15c/0x1fc)
 [<c0a00dbc>] (kernel_init_freeable) from [<c06e07b0>] (kernel_init+0x8/0x114)
 [<c06e07b0>] (kernel_init) from [<c0107978>] (ret_from_fork+0x14/0x3c)
 ---[ end trace 0919d3d0bc998261 ]---
 Unable to handle kernel NULL pointer dereference at virtual address 00000078
 pgd = c0004000
 [00000078] *pgd=00000000
 Internal error: Oops: 5 [#1] PREEMPT SMP ARM
 Modules linked in:
 CPU: 0 PID: 1 Comm: swapper/0 Tainted: G        W       
4.8.0-rc6-00154-g54fe84cbd50b #41
 Hardware name: SAMSUNG EXYNOS (Flattened Device Tree)
 task: ee874000 task.stack: ee878000
 PC is at down_write+0x14/0x54
 LR is at debugfs_remove_recursive+0x30/0x150
 pc : [<c06e489c>]    lr : [<c02e9954>]    psr: 80000013
 sp : ee879e18  ip : 2e575000  fp : 00000000
 r10: 00000000  r9 : c0406004  r8 : ee46f428
 r7 : ee46f4ac  r6 : ee46f478  r5 : ee46f428  r4 : 00000078
 r3 : ffff0001  r2 : 00000000  r1 : 00000001  r0 : 00000078
 Flags: Nzcv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment none
 Control: 10c5387d  Table: 4000406a  DAC: 00000051
 Process swapper/0 (pid: 1, stack limit = 0xee878210)
 Stack: (0xee879e18 to 0xee87a000)
 9e00:                                                       ee216340 c02e9954
 9e20: ee216340 ee12bc00 0000000d eea22220 ee879e58 c0382b78 c0b1505c ee216340
 9e40: 0000000d c0382c1c ee216300 ee216200 0000000d c0406434 ee1e7c00 ee216700
 9e60: eea22220 c0b81c0c c0b81c14 c0b22320 ffffffea 00000000 00000000 c04035d4
 9e80: eea22220 c0b22320 eea22254 c0b2a950 c0b44000 000000d8 00000000 c0403854
 9ea0: 00000000 c0b22320 c04037a8 c0401a74 ee97be74 eea153c0 c0b22320 ee16f480
 9ec0: 00000000 c0402cf0 c08a5174 c0a1d3cc c0a34840 c0b22320 c0a1d3cc c0a34840
 9ee0: c0b44000 c040406c c0b22304 c0a1d3cc c0a34840 c04f20a0 c0a5ff58 c0a1d3cc
 9f00: c0a34840 c01017d0 c0b0ac18 ee879f18 c0b45fe8 c06e3f40 60000000 c0b095a0
 9f20: 00000000 c0b095a0 efffca46 c0716b00 efffca42 c01350dc 0000cccd 00000000
 9f40: c08cdb2c 00000000 00000006 00000006 c0b0957c efffc940 c0a5ff58 00000006
 9f60: c0a34840 c0b44000 c0b44000 000000d8 c0a34848 c0a00dbc 00000006 00000006
 9f80: 00000000 c0a005a0 00000000 c06e07a8 00000000 00000000 00000000 00000000
 9fa0: 00000000 c06e07b0 00000000 c0107978 00000000 00000000 00000000 00000000
 9fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
 9fe0: 00000000 00000000 00000000 00000000 00000013 00000000 ffffffff ffffffff
 [<c06e489c>] (down_write) from [<c02e9954>] 
(debugfs_remove_recursive+0x30/0x150)
 [<c02e9954>] (debugfs_remove_recursive) from [<c0382b78>] 
(_regulator_put+0x24/0xac)
 [<c0382b78>] (_regulator_put) from [<c0382c1c>] (regulator_put+0x1c/0x2c)
 [<c0382c1c>] (regulator_put) from [<c0406434>] (release_nodes+0x16c/0x1dc)
 [<c0406434>] (release_nodes) from [<c04035d4>] (driver_probe_device+0xec/0x2c0)
 [<c04035d4>] (driver_probe_device) from [<c0403854>] 
(__driver_attach+0xac/0xb0)
 [<c0403854>] (__driver_attach) from [<c0401a74>] (bus_for_each_dev+0x68/0x9c)
 [<c0401a74>] (bus_for_each_dev) from [<c0402cf0>] (bus_add_driver+0x1a0/0x218)
 [<c0402cf0>] (bus_add_driver) from [<c040406c>] (driver_register+0x78/0xf8)
 [<c040406c>] (driver_register) from [<c04f20a0>] 
(i2c_register_driver+0x34/0x84)
 [<c04f20a0>] (i2c_register_driver) from [<c01017d0>] 
(do_one_initcall+0x40/0x170)
 [<c01017d0>] (do_one_initcall) from [<c0a00dbc>] 
(kernel_init_freeable+0x15c/0x1fc)
 [<c0a00dbc>] (kernel_init_freeable) from [<c06e07b0>] (kernel_init+0x8/0x114)
 [<c06e07b0>] (kernel_init) from [<c0107978>] (ret_from_fork+0x14/0x3c)
 Code: e1a04000 f590f000 e3a03001 e34f3fff (e1902f9f)
 ---[ end trace 0919d3d0bc998262 ]---
 Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b

 CPU1: stopping
 CPU: 1 PID: 0 Comm: swapper/1 Tainted: G      D W       
4.8.0-rc6-00154-g54fe84cbd50b #41
 Hardware name: SAMSUNG EXYNOS (Flattened Device Tree)
 [<c010e24c>] (unwind_backtrace) from [<c010af38>] (show_stack+0x10/0x14)
 [<c010af38>] (show_stack) from [<c032a1c4>] (dump_stack+0x88/0x9c)
 [<c032a1c4>] (dump_stack) from [<c010d4f8>] (handle_IPI+0x198/0x1ac)
 [<c010d4f8>] (handle_IPI) from [<c01014e4>] (gic_handle_irq+0x94/0x98)
 [<c01014e4>] (gic_handle_irq) from [<c010ba0c>] (__irq_svc+0x6c/0xa8)
 Exception stack(0xee89ff88 to 0xee89ffd0)
 ff80:                   00000001 00000000 00000000 c0113f40 ee89e000 c0b02454
 ffa0: 00000002 00000000 00000000 c0a65f88 c0b024c0 c0b024b8 00000000 ee89ffd8
 ffc0: c01083b8 c01083bc 60000013 ffffffff
 [<c010ba0c>] (__irq_svc) from [<c01083bc>] (arch_cpu_idle+0x38/0x3c)
 [<c01083bc>] (arch_cpu_idle) from [<c01531f0>] (cpu_startup_entry+0x1cc/0x250)
 [<c01531f0>] (cpu_startup_entry) from [<4010158c>] (0x4010158c)
 ---[ end Kernel panic - not syncing: Attempted to kill init! 
exitcode=0x0000000b
 [<c0404e4c>] (platform_device_del) from [<c0404ec4>] 
(platform_device_unregister+0xc/0x20)
 [<c0404ec4>] (platform_device_unregister) from [<c0428bc0>] 
(mfd_remove_devices_fn+0x5c/0x64)
 [<c0428bc0>] (mfd_remove_devices_fn) from [<c03ff9d8>] 
(device_for_each_child_reverse+0x4c/0x78)
 [<c03ff9d8>] (device_for_each_child_reverse) from [<c04288c4>] 
(mfd_remove_devices+0x20/0x30)
 [<c04288c4>] (mfd_remove_devices) from [<c042758c>] 
(wm8994_device_init+0x2ac/0x7f0)
 [<c042758c>] (wm8994_device_init) from [<c04f14a8>] 
(i2c_device_probe+0x178/0x1fc)
 [<c04f14a8>] (i2c_device_probe) from [<c04036fc>] 
(driver_probe_device+0x214/0x2c0)
 [<c04036fc>] (driver_probe_device) from [<c0403854>] 
(__driver_attach+0xac/0xb0)
 [<c0403854>] (__driver_attach) from [<c0401a74>] (bus_for_each_dev+0x68/0x9c)
 [<c0401a74>] (bus_for_each_dev) from [<c0402cf0>] (bus_add_driver+0x1a0/0x218)
 [<c0402cf0>] (bus_add_driver) from [<c040406c>] (driver_register+0x78/0xf8)
 [<c040406c>] (driver_register) from [<c04f20a0>] 
(i2c_register_driver+0x34/0x84)
 [<c04f20a0>] (i2c_register_driver) from [<c01017d0>] 
(do_one_initcall+0x40/0x170)
 [<c01017d0>] (do_one_initcall) from [<c0a00dbc>] 
(kernel_init_freeable+0x15c/0x1fc)
 [<c0a00dbc>] (kernel_init_freeable) from [<c06e07b0>] (kernel_init+0x8/0x114)
 [<c06e07b0>] (kernel_init) from [<c0107978>] (ret_from_fork+0x14/0x3c)
 ---[ end trace 0919d3d0bc998261 ]---
 Unable to handle kernel NULL pointer dereference at virtual address 00000078
 pgd = c0004000
 [00000078] *pgd=00000000
 Internal error: Oops: 5 [#1] PREEMPT SMP ARM
 Modules linked in:
 CPU: 0 PID: 1 Comm: swapper/0 Tainted: G        W       
4.8.0-rc6-00154-g54fe84cbd50b #41
 Hardware name: SAMSUNG EXYNOS (Flattened Device Tree)
 task: ee874000 task.stack: ee878000
 PC is at down_write+0x14/0x54
 LR is at debugfs_remove_recursive+0x30/0x150
 pc : [<c06e489c>]    lr : [<c02e9954>]    psr: 80000013
 sp : ee879e18  ip : 2e575000  fp : 00000000
 r10: 00000000  r9 : c0406004  r8 : ee46f428
 r7 : ee46f4ac  r6 : ee46f478  r5 : ee46f428  r4 : 00000078
 r3 : ffff0001  r2 : 00000000  r1 : 00000001  r0 : 00000078
 Flags: Nzcv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment none
 Control: 10c5387d  Table: 4000406a  DAC: 00000051
 Process swapper/0 (pid: 1, stack limit = 0xee878210)
 Stack: (0xee879e18 to 0xee87a000)
 9e00:                                                       ee216340 c02e9954
 9e20: ee216340 ee12bc00 0000000d eea22220 ee879e58 c0382b78 c0b1505c ee216340
 9e40: 0000000d c0382c1c ee216300 ee216200 0000000d c0406434 ee1e7c00 ee216700
 9e60: eea22220 c0b81c0c c0b81c14 c0b22320 ffffffea 00000000 00000000 c04035d4
 9e80: eea22220 c0b22320 eea22254 c0b2a950 c0b44000 000000d8 00000000 c0403854
 9ea0: 00000000 c0b22320 c04037a8 c0401a74 ee97be74 eea153c0 c0b22320 ee16f480
 9ec0: 00000000 c0402cf0 c08a5174 c0a1d3cc c0a34840 c0b22320 c0a1d3cc c0a34840
 9ee0: c0b44000 c040406c c0b22304 c0a1d3cc c0a34840 c04f20a0 c0a5ff58 c0a1d3cc
 9f00: c0a34840 c01017d0 c0b0ac18 ee879f18 c0b45fe8 c06e3f40 60000000 c0b095a0
 9f20: 00000000 c0b095a0 efffca46 c0716b00 efffca42 c01350dc 0000cccd 00000000
 9f40: c08cdb2c 00000000 00000006 00000006 c0b0957c efffc940 c0a5ff58 00000006
 9f60: c0a34840 c0b44000 c0b44000 000000d8 c0a34848 c0a00dbc 00000006 00000006
 9f80: 00000000 c0a005a0 00000000 c06e07a8 00000000 00000000 00000000 00000000
 9fa0: 00000000 c06e07b0 00000000 c0107978 00000000 00000000 00000000 00000000
 9fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
 9fe0: 00000000 00000000 00000000 00000000 00000013 00000000 ffffffff ffffffff
 [<c06e489c>] (down_write) from [<c02e9954>] 
(debugfs_remove_recursive+0x30/0x150)
 [<c02e9954>] (debugfs_remove_recursive) from [<c0382b78>] 
(_regulator_put+0x24/0xac)
 [<c0382b78>] (_regulator_put) from [<c0382c1c>] (regulator_put+0x1c/0x2c)
 [<c0382c1c>] (regulator_put) from [<c0406434>] (release_nodes+0x16c/0x1dc)
 [<c0406434>] (release_nodes) from [<c04035d4>] (driver_probe_device+0xec/0x2c0)
 [<c04035d4>] (driver_probe_device) from [<c0403854>] 
(__driver_attach+0xac/0xb0)
 [<c0403854>] (__driver_attach) from [<c0401a74>] (bus_for_each_dev+0x68/0x9c)
 [<c0401a74>] (bus_for_each_dev) from [<c0402cf0>] (bus_add_driver+0x1a0/0x218)
 [<c0402cf0>] (bus_add_driver) from [<c040406c>] (driver_register+0x78/0xf8)
 [<c040406c>] (driver_register) from [<c04f20a0>] 
(i2c_register_driver+0x34/0x84)
 [<c04f20a0>] (i2c_register_driver) from [<c01017d0>] 
(do_one_initcall+0x40/0x170)
 [<c01017d0>] (do_one_initcall) from [<c0a00dbc>] 
(kernel_init_freeable+0x15c/0x1fc)
 [<c0a00dbc>] (kernel_init_freeable) from [<c06e07b0>] (kernel_init+0x8/0x114)
 [<c06e07b0>] (kernel_init) from [<c0107978>] (ret_from_fork+0x14/0x3c)
 Code: e1a04000 f590f000 e3a03001 e34f3fff (e1902f9f)
 ---[ end trace 0919d3d0bc998262 ]---
 Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b

--------x------------------x----------------

Fix the kernel warnings and crashes by moving away from managed
regulator bulk get API by using regulator_bulk_get() and explicitly
calling regulator_put() for all the supplies in exit paths.

Tested on Exynos 5250, dual core ARM A15 machine.

Signed-off-by: Viresh Kumar <viresh.ku...@linaro.org>
---
 drivers/mfd/wm8994-core.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/mfd/wm8994-core.c b/drivers/mfd/wm8994-core.c
index 1e644aa53a2d..a232387b7783 100644
--- a/drivers/mfd/wm8994-core.c
+++ b/drivers/mfd/wm8994-core.c
@@ -394,7 +394,7 @@ static int wm8994_device_init(struct wm8994 *wm8994, int 
irq)
                goto err;
        }
                
-       ret = devm_regulator_bulk_get(wm8994->dev, wm8994->num_supplies,
+       ret = regulator_bulk_get(wm8994->dev, wm8994->num_supplies,
                                 wm8994->supplies);
        if (ret != 0) {
                dev_err(wm8994->dev, "Failed to get supplies: %d\n", ret);
@@ -405,7 +405,7 @@ static int wm8994_device_init(struct wm8994 *wm8994, int 
irq)
                                    wm8994->supplies);
        if (ret != 0) {
                dev_err(wm8994->dev, "Failed to enable supplies: %d\n", ret);
-               goto err;
+               goto err_regulator_put;
        }
 
        ret = wm8994_reg_read(wm8994, WM8994_SOFTWARE_RESET);
@@ -596,6 +596,9 @@ static int wm8994_device_init(struct wm8994 *wm8994, int 
irq)
 err_enable:
        regulator_bulk_disable(wm8994->num_supplies,
                               wm8994->supplies);
+err_regulator_put:
+       for (i = wm8994->num_supplies - 1; i >= 0; i--)
+               regulator_put(wm8994->supplies[i].consumer);
 err:
        mfd_remove_devices(wm8994->dev);
        return ret;
@@ -603,10 +606,13 @@ static int wm8994_device_init(struct wm8994 *wm8994, int 
irq)
 
 static void wm8994_device_exit(struct wm8994 *wm8994)
 {
+       int i;
        pm_runtime_disable(wm8994->dev);
        wm8994_irq_exit(wm8994);
        regulator_bulk_disable(wm8994->num_supplies,
                               wm8994->supplies);
+       for (i = wm8994->num_supplies - 1; i >= 0; i--)
+               regulator_put(wm8994->supplies[i].consumer);
        mfd_remove_devices(wm8994->dev);
 }
 
-- 
2.7.1.410.g6faf27b

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