Re: [PATCH] raid5: Using slow_path to release stripe when mmdev->threand is null

[NeilBrown <neilb@suse.de>]

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On Thu, 7 Nov 2013 09:58:42 +0800 majianpeng <majianpeng@gmail.com> wrote:

> Starting a failed raid5,kernel print those messages:
> [    7.085934] md/raid:md127: not enough operational devices (3/4 failed)
> [    7.085941] RAID conf printout:
> [    7.085942]  --- level:5 rd:4 wd:1
> [    7.085944]  disk 0, o:1, dev:sdb
> [    7.085948]
> =============================================================================
> [    7.085950] BUG raid5-md127 (Not tainted): Objects remaining in raid5-md127 on kmem_cache_close()
> [    7.085951]
> -----------------------------------------------------------------------------
> [    7.085951]
> [    7.085952] Disabling lock debugging due to kernel taint
> [    7.085955] INFO: Slab 0xffffea0002e44800 objects=24 used=16 fp=0xffff8800b9127698 flags=0x100000000004080
> [    7.085958] CPU: 0 PID: 2176 Comm: mdadm Tainted: G    B 3.12.0+ #2
> [    7.085959] Hardware name: To Be Filled By O.E.M. To Be Filled By
> O.E.M./To be filled by O.E.M., BIOS 080015  11/09/2011
> [    7.085961]  ffff88013aa38600 ffff8800b8f71b58 ffffffff81704891 ffff8800b9127698
> [    7.085963]  ffffea0002e44800 ffff8800b8f71c48 ffffffff8113c7c7 20737463656a624f
> [    7.085966]  6e696e69616d6572 696172206e692067 373231646d2d3564 6d656d6b206e6f20
> [    7.085968] Call Trace:
> [    7.085974]  [<ffffffff81704891>] dump_stack+0x49/0x60
> [    7.085977]  [<ffffffff8113c7c7>] slab_err+0x97/0xb0
> [    7.085980]  [<ffffffff8113ee90>] ? slab_cpuup_callback+0xd0/0xd0
> [    7.085982]  [<ffffffff8113eeeb>] ? flush_cpu_slab+0x5b/0x70
> [    7.085984]  [<ffffffff8113fc64>] ? __kmalloc+0xf4/0x170
> [    7.085986]  [<ffffffff811421cb>]
> list_slab_objects.clone.0+0x5b/0x160
> [    7.085988]  [<ffffffff811429cb>] __kmem_cache_shutdown+0xdb/0x1b0
> [    7.085992]  [<ffffffff8111853d>] kmem_cache_destroy+0x5d/0x100
> [    7.085996]  [<ffffffffa008dd1d>] free_conf+0x5d/0x120 [raid456]
> [    7.085999]  [<ffffffffa0090cf9>] run+0x8d9/0xa71 [raid456]
> [    7.086015]  [<ffffffff81516a97>] md_run+0x377/0x8b0
> [    7.086023]  [<ffffffff81516fe9>] do_md_run+0x19/0xc0
> [    7.086025]  [<ffffffff815172d8>] array_state_store+0x248/0x260
> [    7.086027]  [<ffffffff815102ef>] md_attr_store+0xdf/0x120
> [    7.086031]  [<ffffffff811b73ed>] sysfs_write_file+0xdd/0x160
> [    7.086033]  [<ffffffff81146f58>] vfs_write+0xc8/0x170
> [    7.086036]  [<ffffffff8114753a>] SyS_write+0x5a/0xa0
> [    7.086038]  [<ffffffff817105e2>] system_call_fastpath+0x16/0x1b
> [    7.086040] INFO: Object 0xffff8800b9120000 @offset=0
> [    7.086042] INFO: Object 0xffff8800b9120528 @offset=1320
> [    7.086043] INFO: Object 0xffff8800b9120a50 @offset=2640
> [    7.086044] INFO: Object 0xffff8800b9120f78 @offset=3960
> [    7.086045] INFO: Object 0xffff8800b91214a0 @offset=5280
> [    7.086046] INFO: Object 0xffff8800b91219c8 @offset=6600
> [    7.086048] INFO: Object 0xffff8800b9121ef0 @offset=7920
> [    7.086049] INFO: Object 0xffff8800b9122418 @offset=9240
> [    7.086050] INFO: Object 0xffff8800b9122940 @offset=10560
> [    7.086051] INFO: Object 0xffff8800b9122e68 @offset=11880
> [    7.086052] INFO: Object 0xffff8800b9123390 @offset=13200
> [    7.086054] INFO: Object 0xffff8800b91238b8 @offset=14520
> [    7.086055] INFO: Object 0xffff8800b9123de0 @offset=15840
> [    7.086057] INFO: Object 0xffff8800b9124308 @offset=17160
> [    7.086058] INFO: Object 0xffff8800b9124830 @offset=18480
> [    7.086059] INFO: Object 0xffff8800b9124d58 @offset=19800
> [    7.086061] kmem_cache_destroy raid5-md127: Slab cache still has bjects
> [    7.086063] CPU: 0 PID: 2176 Comm: mdadm Tainted: G    B 3.12.0+ #2
> [    7.086064] Hardware name: To Be Filled By O.E.M. To Be Filled By
> O.E.M./To be filled by O.E.M., BIOS 080015  11/09/2011
> [    7.086065]  ffff8800b92eaa00 ffff8800b8f71cd8 ffffffff81704891 0000000000015740
> [    7.086068]  ffff88013aa38600 ffff8800b8f71cf8 ffffffff811185dd 0000000000000000
> [    7.086070]  ffff8800b92eaa00 ffff8800b8f71d28 ffffffffa008dd1d ffff88013a16d800
> [    7.086072] Call Trace:
> [    7.086074]  [<ffffffff81704891>] dump_stack+0x49/0x60
> [    7.086077]  [<ffffffff811185dd>] kmem_cache_destroy+0xfd/0x100
> [    7.086080]  [<ffffffffa008dd1d>] free_conf+0x5d/0x120 [raid456]
> [    7.086082]  [<ffffffffa0090cf9>] run+0x8d9/0xa71 [raid456]
> [    7.086085]  [<ffffffff81516a97>] md_run+0x377/0x8b0
> [    7.086087]  [<ffffffff81516fe9>] do_md_run+0x19/0xc0
> [    7.086089]  [<ffffffff815172d8>] array_state_store+0x248/0x260
> [    7.086091]  [<ffffffff815102ef>] md_attr_store+0xdf/0x120
> [    7.086094]  [<ffffffff811b73ed>] sysfs_write_file+0xdd/0x160
> [    7.086096]  [<ffffffff81146f58>] vfs_write+0xc8/0x170
> [    7.086098]  [<ffffffff8114753a>] SyS_write+0x5a/0xa0
> [    7.086100]  [<ffffffff817105e2>] system_call_fastpath+0x16/0x1b
> [    7.086104] md/raid:md127: failed to run raid set.
> [    7.086105] md: pers->run() failed ...
> 
> This is because when called release_stripe() in grow_one_stripe(), the
> mddev->thread is null.So it will omit one wakeup this thread to release
> stripe.
> For this condition, using slow_path to release stripe.
> 
> Signed-off-by: Jianpeng Ma <majianpeng@gmail.com>
> ---
>  drivers/md/raid5.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
> index f8b9068..e93eb7b 100644
> --- a/drivers/md/raid5.c
> +++ b/drivers/md/raid5.c
> @@ -340,7 +340,11 @@ static void release_stripe(struct stripe_head *sh)
>  	unsigned long flags;
>  	bool wakeup;
>  
> -	if (test_and_set_bit(STRIPE_ON_RELEASE_LIST, &sh->state))
> +	/*
> +	 * Before creating mmdev->thread,this func willbe called.
> +	 */
> +	if (unlikely(!conf->mddev->thread) ||
> +		test_and_set_bit(STRIPE_ON_RELEASE_LIST, &sh->state))
>  		goto slow_path;
>  	wakeup = llist_add(&sh->release_list, &conf->released_stripes);
>  	if (wakeup)



applied, thanks.

NeilBrown

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