Runtime warnings in powerpc code

[Scott Wood]

On Thu, 2018-12-27 at 11:05 -0800, Guenter Roeck wrote:
> ---
> CONFIG_DEBUG_ATOMIC_SLEEP
> 
> ------------[ cut here ]------------
> do not call blocking ops when !TASK_RUNNING; state=2 set at [<(ptrval)>]
> prepare_to_wait+0x54/0xe4
> WARNING: CPU: 0 PID: 1 at kernel/sched/core.c:6099 __might_sleep+0x94/0x9c
> Modules linked in:
> CPU: 0 PID: 1 Comm: init Not tainted 4.20.0-yocto-standard+ #1
> NIP:  c00667a0 LR: c00667a0 CTR: 00000000
> REGS: cf8df8c0 TRAP: 0700   Not tainted  (4.20.0-yocto-standard+)
> MSR:  00029032 <EE,ME,IR,DR,RI>  CR: 28888822  XER: 20000000
> 
> GPR00: c00667a0 cf8df970 cf8e0000 00000062 c0af15c8 00000007 fa1ae97e
> 757148e2 
> GPR08: cf8de000 00000000 00000000 00000000 1f386000 00000000 00000000
> cfd83c8c 
> GPR16: 00000004 00000004 00000004 00000000 0000060c 0000000a cf8dfdb8
> cf267804 
> GPR24: cf8dfd78 cf8dfd68 cfa88a20 cec70830 00000001 00000000 000001d3
> c0b444cc 
> NIP [c00667a0] __might_sleep+0x94/0x9c
> LR [c00667a0] __might_sleep+0x94/0x9c
> Call Trace:
> [cf8df970] [c00667a0] __might_sleep+0x94/0x9c (unreliable)
> [cf8df990] [c05beddc] do_ide_request+0x48/0x6bc
> [cf8dfa10] [c0492bcc] __blk_run_queue+0x80/0x10c
> [cf8dfa20] [c049a938] blk_flush_plug_list+0x23c/0x258
> [cf8dfa60] [c006b888] io_schedule_prepare+0x44/0x5c
> [cf8dfa70] [c006b8c0] io_schedule+0x20/0x48
> [cf8dfa80] [c095e1ac] bit_wait_io+0x24/0x74
> [cf8dfa90] [c095dd94] __wait_on_bit+0xac/0x104
> [cf8dfab0] [c095de74] out_of_line_wait_on_bit+0x88/0x98
> [cf8dfae0] [c0229094] bh_submit_read+0xf8/0x104
> [cf8dfaf0] [c028b9a8] ext4_get_branch+0xdc/0x168
> [cf8dfb20] [c028c7fc] ext4_ind_map_blocks+0x2b0/0xc08
> [cf8dfc30] [c029551c] ext4_map_blocks+0x2e0/0x65c
> [cf8dfc80] [c02b8c84] ext4_mpage_readpages+0x5e8/0x97c
> [cf8dfd60] [c016c3cc] read_pages+0x60/0x1a0
> [cf8dfdb0] [c016c6e8] __do_page_cache_readahead+0x1dc/0x208
> [cf8dfe10] [c0159768] filemap_fault+0x418/0x834
> [cf8dfe50] [c02a00fc] ext4_filemap_fault+0x40/0x64
> [cf8dfe60] [c0198d0c] __do_fault+0x34/0xb8
> [cf8dfe70] [c019e264] handle_mm_fault+0xc44/0xf88
> [cf8dfef0] [c001a218] __do_page_fault+0x158/0x7b4
> [cf8dff40] [c00143b4] handle_page_fault+0x14/0x40
> --- interrupt: 301 at 0xb7904a70
>     LR = 0xb78ef0c8
> Instruction dump:
> 7fe3fb78 bba10014 7c0803a6 38210020 4bfffd20 808a0000 3c60c0b0 39400001 
> 7cc53378 3863a558 99490001 4bfd03bd <0fe00000> 4bffffc0 7c0802a6 90010004 
> irq event stamp: 126702
> hardirqs last  enabled at (126701): [<c0091a74>] console_unlock+0x434/0x5d0
> hardirqs last disabled at (126702): [<c00140b4>] reenable_mmu+0x30/0x88
> softirqs last  enabled at (126552): [<c0964614>] __do_softirq+0x42c/0x4a0
> softirqs last disabled at (126529): [<c003cda4>] irq_exit+0x104/0x108
> ---[ end trace 4f6c84b7815474d9 ]---

This doesn't look PPC-specific, but rather IDE-specific.  Here's a similar one
on x86:
https://lkml.org/lkml/2016/12/12/596

> ---
> #if defined(CONFIG_PROVE_LOCKING) && defined(CONFIG_DEBUG_LOCKDEP) && \
>     defined(CONFIG_TRACE_IRQFLAGS)
> 
> ------------[ cut here ]------------
> DEBUG_LOCKS_WARN_ON(!current->hardirqs_enabled)
> WARNING: CPU: 0 PID: 1 at kernel/locking/lockdep.c:3762

http://patchwork.ozlabs.org/patch/1016541/ should fix this.  It should also
only be showing up on 32-bit, not all platforms.

-Scott