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From: Vladimir Davydov <vdavydov.dev@gmail.com>
To: Sahitya Tummala <stummala@codeaurora.org>
Cc: Alexander Polakov <apolyakov@beget.ru>,
	Andrew Morton <akpm@linux-foundation.org>,
	Jan Kara <jack@suse.cz>,
	viro@zeniv.linux.org.uk, linux-mm@kvack.org,
	linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH v4 2/2] fs/dcache.c: fix spin lockup issue on nlru->lock
Date: Sat, 1 Jul 2017 19:28:56 +0300	[thread overview]
Message-ID: <20170701162856.i7ysaqb5s24hqero@esperanza> (raw)
In-Reply-To: <1498707575-2472-1-git-send-email-stummala@codeaurora.org>

On Thu, Jun 29, 2017 at 09:09:35AM +0530, Sahitya Tummala wrote:
> __list_lru_walk_one() acquires nlru spin lock (nlru->lock) for
> longer duration if there are more number of items in the lru list.
> As per the current code, it can hold the spin lock for upto maximum
> UINT_MAX entries at a time. So if there are more number of items in
> the lru list, then "BUG: spinlock lockup suspected" is observed in
> the below path -
> 
> [<ffffff8eca0fb0bc>] spin_bug+0x90
> [<ffffff8eca0fb220>] do_raw_spin_lock+0xfc
> [<ffffff8ecafb7798>] _raw_spin_lock+0x28
> [<ffffff8eca1ae884>] list_lru_add+0x28
> [<ffffff8eca1f5dac>] dput+0x1c8
> [<ffffff8eca1eb46c>] path_put+0x20
> [<ffffff8eca1eb73c>] terminate_walk+0x3c
> [<ffffff8eca1eee58>] path_lookupat+0x100
> [<ffffff8eca1f00fc>] filename_lookup+0x6c
> [<ffffff8eca1f0264>] user_path_at_empty+0x54
> [<ffffff8eca1e066c>] SyS_faccessat+0xd0
> [<ffffff8eca084e30>] el0_svc_naked+0x24
> 
> This nlru->lock is acquired by another CPU in this path -
> 
> [<ffffff8eca1f5fd0>] d_lru_shrink_move+0x34
> [<ffffff8eca1f6180>] dentry_lru_isolate_shrink+0x48
> [<ffffff8eca1aeafc>] __list_lru_walk_one.isra.10+0x94
> [<ffffff8eca1aec34>] list_lru_walk_node+0x40
> [<ffffff8eca1f6620>] shrink_dcache_sb+0x60
> [<ffffff8eca1e56a8>] do_remount_sb+0xbc
> [<ffffff8eca1e583c>] do_emergency_remount+0xb0
> [<ffffff8eca0ba510>] process_one_work+0x228
> [<ffffff8eca0bb158>] worker_thread+0x2e0
> [<ffffff8eca0c040c>] kthread+0xf4
> [<ffffff8eca084dd0>] ret_from_fork+0x10
> 
> Fix this lockup by reducing the number of entries to be shrinked
> from the lru list to 1024 at once. Also, add cond_resched() before
> processing the lru list again.
> 
> Link: http://marc.info/?t=149722864900001&r=1&w=2
> Fix-suggested-by: Jan kara <jack@suse.cz>
> Fix-suggested-by: Vladimir Davydov <vdavydov.dev@gmail.com>
> Signed-off-by: Sahitya Tummala <stummala@codeaurora.org>

Acked-by: Vladimir Davydov <vdavydov.dev@gmail.com>

WARNING: multiple messages have this Message-ID (diff)
From: Vladimir Davydov <vdavydov.dev@gmail.com>
To: Sahitya Tummala <stummala@codeaurora.org>
Cc: Alexander Polakov <apolyakov@beget.ru>,
	Andrew Morton <akpm@linux-foundation.org>,
	Jan Kara <jack@suse.cz>,
	viro@zeniv.linux.org.uk, linux-mm@kvack.org,
	linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH v4 2/2] fs/dcache.c: fix spin lockup issue on nlru->lock
Date: Sat, 1 Jul 2017 19:28:56 +0300	[thread overview]
Message-ID: <20170701162856.i7ysaqb5s24hqero@esperanza> (raw)
In-Reply-To: <1498707575-2472-1-git-send-email-stummala@codeaurora.org>

On Thu, Jun 29, 2017 at 09:09:35AM +0530, Sahitya Tummala wrote:
> __list_lru_walk_one() acquires nlru spin lock (nlru->lock) for
> longer duration if there are more number of items in the lru list.
> As per the current code, it can hold the spin lock for upto maximum
> UINT_MAX entries at a time. So if there are more number of items in
> the lru list, then "BUG: spinlock lockup suspected" is observed in
> the below path -
> 
> [<ffffff8eca0fb0bc>] spin_bug+0x90
> [<ffffff8eca0fb220>] do_raw_spin_lock+0xfc
> [<ffffff8ecafb7798>] _raw_spin_lock+0x28
> [<ffffff8eca1ae884>] list_lru_add+0x28
> [<ffffff8eca1f5dac>] dput+0x1c8
> [<ffffff8eca1eb46c>] path_put+0x20
> [<ffffff8eca1eb73c>] terminate_walk+0x3c
> [<ffffff8eca1eee58>] path_lookupat+0x100
> [<ffffff8eca1f00fc>] filename_lookup+0x6c
> [<ffffff8eca1f0264>] user_path_at_empty+0x54
> [<ffffff8eca1e066c>] SyS_faccessat+0xd0
> [<ffffff8eca084e30>] el0_svc_naked+0x24
> 
> This nlru->lock is acquired by another CPU in this path -
> 
> [<ffffff8eca1f5fd0>] d_lru_shrink_move+0x34
> [<ffffff8eca1f6180>] dentry_lru_isolate_shrink+0x48
> [<ffffff8eca1aeafc>] __list_lru_walk_one.isra.10+0x94
> [<ffffff8eca1aec34>] list_lru_walk_node+0x40
> [<ffffff8eca1f6620>] shrink_dcache_sb+0x60
> [<ffffff8eca1e56a8>] do_remount_sb+0xbc
> [<ffffff8eca1e583c>] do_emergency_remount+0xb0
> [<ffffff8eca0ba510>] process_one_work+0x228
> [<ffffff8eca0bb158>] worker_thread+0x2e0
> [<ffffff8eca0c040c>] kthread+0xf4
> [<ffffff8eca084dd0>] ret_from_fork+0x10
> 
> Fix this lockup by reducing the number of entries to be shrinked
> from the lru list to 1024 at once. Also, add cond_resched() before
> processing the lru list again.
> 
> Link: http://marc.info/?t=149722864900001&r=1&w=2
> Fix-suggested-by: Jan kara <jack@suse.cz>
> Fix-suggested-by: Vladimir Davydov <vdavydov.dev@gmail.com>
> Signed-off-by: Sahitya Tummala <stummala@codeaurora.org>

Acked-by: Vladimir Davydov <vdavydov.dev@gmail.com>

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  parent reply	other threads:[~2017-07-01 16:29 UTC|newest]

Thread overview: 38+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-06-12  0:47 [PATCH] mm/list_lru.c: use cond_resched_lock() for nlru->lock Sahitya Tummala
2017-06-12  0:47 ` Sahitya Tummala
2017-06-12 13:11 ` Jan Kara
2017-06-12 13:11   ` Jan Kara
2017-06-15 21:05 ` Andrew Morton
2017-06-15 21:05   ` Andrew Morton
2017-06-16 14:44   ` Sahitya Tummala
2017-06-16 14:44     ` Sahitya Tummala
2017-06-17 11:14   ` Vladimir Davydov
2017-06-17 11:14     ` Vladimir Davydov
2017-06-20  2:52     ` Sahitya Tummala
2017-06-20  2:52       ` Sahitya Tummala
2017-06-21  6:39       ` [PATCH v2] fs/dcache.c: fix spin lockup issue on nlru->lock Sahitya Tummala
2017-06-21  6:39         ` Sahitya Tummala
2017-06-21 16:31         ` Vladimir Davydov
2017-06-21 16:31           ` Vladimir Davydov
2017-06-22 16:31           ` Sahitya Tummala
2017-06-22 16:31             ` Sahitya Tummala
2017-06-22 17:49             ` Vladimir Davydov
2017-06-22 17:49               ` Vladimir Davydov
2017-06-28  6:07               ` [PATCH v3 1/2] mm/list_lru.c: fix list_lru_count_node() to be race free Sahitya Tummala
2017-06-28  6:07                 ` Sahitya Tummala
2017-06-28  6:07                 ` [PATCH v3 2/2] fs/dcache.c: fix spin lockup issue on nlru->lock Sahitya Tummala
2017-06-28  6:07                   ` Sahitya Tummala
2017-06-28 17:18                 ` [PATCH v3 1/2] mm/list_lru.c: fix list_lru_count_node() to be race free Vladimir Davydov
2017-06-28 17:18                   ` Vladimir Davydov
2017-06-29  3:39                   ` [PATCH v4 " Sahitya Tummala
2017-06-29  3:39                     ` Sahitya Tummala
2017-07-01 16:28                     ` Vladimir Davydov
2017-07-01 16:28                       ` Vladimir Davydov
2017-06-29  3:39                   ` [PATCH v4 2/2] fs/dcache.c: fix spin lockup issue on nlru->lock Sahitya Tummala
2017-06-29  3:39                     ` Sahitya Tummala
2017-06-29 22:48                     ` Andrew Morton
2017-06-29 22:48                       ` Andrew Morton
2017-06-30  3:16                       ` Sahitya Tummala
2017-06-30  3:16                         ` Sahitya Tummala
2017-07-01 16:28                     ` Vladimir Davydov [this message]
2017-07-01 16:28                       ` Vladimir Davydov

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