Re: [PATCH 3/4] mmc: sdhci: defer probing on regulator_get_optional() failures

[Alexandre Courbot]

On Tue, Apr 15, 2014 at 10:42 AM, Andrew Bresticker
<abrestic@xxxxxxxxxxxx> wrote:
> If regulator_get_optional() returns EPROBE_DEFER, it indicates
> that the regulator may show up later (e.g. the DT property is
> present but the corresponding regulator may not have probed).
> Instead of continuing without the regulator, return EPROBE_DEFER
> from sdhci_add_host().  Also, fix regulator leaks in the error
> paths in sdhci_add_host().

I tried this series and while it seems to fix some MMC errors I was
seeing on a regular basis, I had to revert this particular patch which
is causing the following oops at boot on my Venice2 (with 3.15-rc1):

[    2.007916] sdhci-tegra 700b0400.sdhci: Got CD GPIO #170.
[    2.008197] Unable to handle kernel NULL pointer dereference at
virtual address 0000003c
[    2.008202] pgd = c0004000
[    2.008208] [0000003c] *pgd=00000000
[    2.008216] Internal error: Oops: 5 [#1] PREEMPT SMP ARM
[    2.008222] Modules linked in:
[    2.008230] CPU: 1 PID: 79 Comm: irq/362-700b040 Not tainted
3.15.0-rc1-00030-g20b0e68aa3b9 #1411
[    2.008235] task: e61ea680 ti: e5862000 task.ti: e5862000
[    2.008248] PC is at mmc_gpio_cd_irqt+0xc/0x3c
[    2.008258] LR is at irq_thread_fn+0x1c/0x40
[    2.008265] pc : [<c048d740>]    lr : [<c006ae70>]    psr: 60000113
[    2.008265] sp : e5863f18  ip : 00000000  fp : c006ae54
[    2.008268] r10: c091e4a4  r9 : e5845340  r8 : e60e31c0
[    2.008272] r7 : 00000001  r6 : 00000000  r5 : e60e31c0  r4 : e5844800
[    2.008277] r3 : 00000000  r2 : 00000000  r1 : e5844800  r0 : 0000016a
[    2.008283] Flags: nZCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM
Segment kernel
[    2.008289] Control: 10c5387d  Table: 8000406a  DAC: 00000015
[    2.008293] Process irq/362-700b040 (pid: 79, stack limit = 0xe5862240)
[    2.008298] Stack: (0xe5863f18 to 0xe5864000)
[    2.008304] 3f00:
    e5845340 c006ae70
[    2.008312] 3f20: e5845360 e5862000 00000000 c006b190 c006b058
e5862030 00000000 c006af9c
[    2.008319] 3f40: 00000000 e5845300 00000000 e5845340 c006b058
00000000 00000000 00000000
[    2.008326] 3f60: 00000000 c0040ea0 5a5a5a5a 00000000 5a5a5a5a
e5845340 00000000 00000000
[    2.008333] 3f80: e5863f80 e5863f80 00000000 00000000 e5863f90
e5863f90 e5863fac e5845300
[    2.008340] 3fa0: c0040dc8 00000000 00000000 c000e638 00000000
00000000 00000000 00000000
[    2.008346] 3fc0: 00000000 00000000 00000000 00000000 00000000
00000000 00000000 00000000
[    2.008353] 3fe0: 00000000 00000000 00000000 00000000 00000013
00000000 00000000 00000000
[    2.008369] [<c048d740>] (mmc_gpio_cd_irqt) from [<c006ae70>]
(irq_thread_fn+0x1c/0x40)
[    2.008382] [<c006ae70>] (irq_thread_fn) from [<c006b190>]
(irq_thread+0x138/0x170)
[    2.008393] [<c006b190>] (irq_thread) from [<c0040ea0>] (kthread+0xd8/0xf0)
[    2.008404] [<c0040ea0>] (kthread) from [<c000e638>]
(ret_from_fork+0x14/0x3c)
[    2.008413] Code: eaffffea e92d4010 e1a04001 e591318c (e593303c)
[    2.008420] ---[ end trace 4e1b9273d6367aac ]---
[    2.008442] Unable to handle kernel paging request at virtual
address ffffffec
[    2.008444] pgd = c0004000
[    2.008456] [ffffffec] *pgd=a77be821, *pte=00000000, *ppte=00000000
[    2.008461] Internal error: Oops: 17 [#2] PREEMPT SMP ARM
[    2.008466] Modules linked in:
[    2.008472] CPU: 1 PID: 79 Comm: irq/362-700b040 Tainted: G      D
     3.15.0-rc1-00030-g20b0e68aa3b9 #1411
[    2.008477] task: e61ea680 ti: e5862000 task.ti: e5862000
[    2.008482] PC is at kthread_data+0x4/0xc
[    2.008489] LR is at irq_thread_dtor+0x28/0xbc
[    2.008495] pc : [<c00413d0>]    lr : [<c006afc4>]    psr: 20000113
[    2.008495] sp : e5863ca8  ip : e5863f84  fp : e61ea680
[    2.008498] r10: c048d744  r9 : 00000000  r8 : e5862010
[    2.008502] r7 : e61ea680  r6 : c0982970  r5 : 00000000  r4 : e61ea680
[    2.008505] r3 : 00000000  r2 : e5863ca8  r1 : e5863f38  r0 : e61ea680
[    2.008511] Flags: nzCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment user
[    2.008515] Control: 10c5387d  Table: 8000406a  DAC: 00000015
[    2.008520] Process irq/362-700b040 (pid: 79, stack limit = 0xe5862240)
[    2.008523] Stack: (0xe5863ca8 to 0xe5864000)
[    2.008530] 3ca0:                   c006af9c e61eab6c 00000000
c003e560 00000039 0000000b
[    2.008539] 3cc0: e5863ed0 e5862000 0000000b c002781c e5863ce0
00000001 c0980ac4 c0669b70
[    2.008546] 3ce0: c07e19d0 c0927710 00000002 c0922fc0 e5863ed0
e5862000 0000000b 00000001
[    2.008552] 3d00: c048d742 c048d744 c0980ac4 c0011d08 e5862240
0000000b 60000113 c07dd458
[    2.008559] 3d20: e5862010 00000000 00000000 00000008 65862010
66666661 20616566 64323965
[    2.008567] 3d40: 30313034 61316520 30303430 35652031 31333139
28206338 33393565 63333033
[    2.008574] 3d60: c0002029 c0669b70 c08416c8 0000003c 00000005
00000000 e5863ed0 0000003c
[    2.008581] 3d80: e61ea680 c091e4a4 c006ae54 c0669484 00000005
c001b988 25e6c000 e604bfc0
[    2.008588] 3da0: c091e478 e604aa00 00000001 e677fc00 00000530
c0056094 5a5a5a5a a55a5a5a
[    2.008595] 3dc0: 3a393731 5a003436 5a5a5a5a 5a5a5a5a 0183681b
00000000 ffff8bfa e604aa00
[    2.008602] 3de0: c091ef7c c0913c00 c0913c00 e604aa08 00000001
00000002 c091ecfc e677e4a8
[    2.008609] 3e00: c091e470 00000000 00000000 00000005 c001bc24
c0923c20 0000003c e5863ed0
[    2.008616] 3e20: e5845340 c091e4a4 c006ae54 c0008594 e677e4a8
00000000 00000000 00000020
[    2.008623] 3e40: 00000000 00000002 0183681b 00000000 00000001
00000000 ffff8bfa c091e478
[    2.008631] 3e60: e604aa00 e677fc00 ffff8b6e c0056f1c e5863ea4
c091ef7c 0000077d 00000000
[    2.008638] 3e80: 77ad1fda 00000000 00000000 c09180c0 c00099f0
ffffffff 00000000 c0044cd4
[    2.008645] 3ea0: e6084000 00000002 c0980910 00000000 00000000
c0044f60 c048d740 60000113
[    2.008652] 3ec0: ffffffff e5863f04 e60e31c0 c0012418 0000016a
e5844800 00000000 00000000
[    2.008659] 3ee0: e5844800 e60e31c0 00000000 00000001 e60e31c0
e5845340 c091e4a4 c006ae54
[    2.008666] 3f00: 00000000 e5863f18 c006ae70 c048d740 60000113
ffffffff e5845340 c006ae70
[    2.008673] 3f20: e5845360 e5862000 00000000 c006b190 c006b058
e5862030 00000000 c006af9c
[    2.008680] 3f40: 00000000 e5845300 00000000 e5845340 c006b058
00000000 00000000 00000000
[    2.008687] 3f60: 00000000 c0040ea0 5a5a5a5a 00000000 5a5a5a5a
e5845340 00000000 00000000
[    2.008695] 3f80: e5863f80 e5863f80 00000001 00010001 e5863f90
e5863f90 e5863fac e5845300
[    2.008701] 3fa0: c0040dc8 00000000 00000000 c000e638 00000000
00000000 00000000 00000000
[    2.008707] 3fc0: 00000000 00000000 00000000 00000000 00000000
00000000 00000000 00000000
[    2.008714] 3fe0: 00000000 00000000 00000000 00000000 00000013
00000000 00000000 00000000
[    2.008725] [<c00413d0>] (kthread_data) from [<c006afc4>]
(irq_thread_dtor+0x28/0xbc)
[    2.008740] [<c006afc4>] (irq_thread_dtor) from [<c003e560>]
(task_work_run+0xb4/0xe4)
[    2.008754] [<c003e560>] (task_work_run) from [<c002781c>]
(do_exit+0x2b8/0x8cc)
[    2.008768] [<c002781c>] (do_exit) from [<c0011d08>] (die+0x400/0x418)
[    2.008783] [<c0011d08>] (die) from [<c0669484>]
(__do_kernel_fault.part.11+0x64/0x74)
[    2.008795] [<c0669484>] (__do_kernel_fault.part.11) from
[<c001b988>] (do_page_fault+0x1c8/0x3d0)
[    2.008804] [<c001b988>] (do_page_fault) from [<c0008594>]
(do_DataAbort+0x38/0x98)
[    2.008814] [<c0008594>] (do_DataAbort) from [<c0012418>]
(__dabt_svc+0x38/0x60)
[    2.008818] Exception stack(0xe5863ed0 to 0xe5863f18)
[    2.008824] 3ec0:                                     0000016a
e5844800 00000000 00000000
[    2.008831] 3ee0: e5844800 e60e31c0 00000000 00000001 e60e31c0
e5845340 c091e4a4 c006ae54
[    2.008838] 3f00: 00000000 e5863f18 c006ae70 c048d740 60000113 ffffffff
[    2.008851] [<c0012418>] (__dabt_svc) from [<c048d740>]
(mmc_gpio_cd_irqt+0xc/0x3c)
[    2.008864] [<c048d740>] (mmc_gpio_cd_irqt) from [<c006ae70>]
(irq_thread_fn+0x1c/0x40)
[    2.008876] [<c006ae70>] (irq_thread_fn) from [<c006b190>]
(irq_thread+0x138/0x170)
[    2.008885] [<c006b190>] (irq_thread) from [<c0040ea0>] (kthread+0xd8/0xf0)
[    2.008895] [<c0040ea0>] (kthread) from [<c000e638>]
(ret_from_fork+0x14/0x3c)
[    2.008903] Code: e513001c e7e00150 e12fff1e e5903374 (e5130014)
[    2.008907] ---[ end trace 4e1b9273d6367aad ]---
[    2.008910] Fixing recursive fault but reboot is needed!
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