[PATCH] md/raid5: init batch_xxx for new sh at resize_stripes
From: Yuanhan Liu
Date: Mon May 04 2015 - 01:49:13 EST
This is to fix a kernel NULL dereference oops introduced by commit
59fc630b("RAID5: batch adjacent full stripe write"), which introduced
several batch_xxx fields, and did initiation for them at grow_one_stripes(),
but forgot to do same at resize_stripes().
This oops can be easily triggered by following steps:
__create RAID5 /dev/md0
__grow /dev/md0
mdadm --wait /dev/md0
dd if=/dev/zero of=/dev/md0
Here is the detailed oops log:
[ 32.384499] BUG: unable to handle kernel NULL pointer dereference at (null)
[ 32.385366] IP: [<ffffffff81844082>] add_stripe_bio+0x48d/0x544
[ 32.385955] PGD 373f3067 PUD 36e34067 PMD 0
[ 32.386404] Oops: 0002 [#1] SMP
[ 32.386740] Modules linked in:
[ 32.387040] CPU: 0 PID: 1059 Comm: kworker/u2:2 Not tainted 4.0.0-next-20150427+ #107
[ 32.387762] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.7.5-0-ge51488c-20140602_164612-nilsson.home.kraxel.org 04/01/2014
[ 32.388044] Workqueue: writeback bdi_writeback_workfn (flush-9:0)
[ 32.388044] task: ffff88003d038000 ti: ffff88003d40c000 task.ti: ffff88003d40c000
[ 32.388044] RIP: 0010:[<ffffffff81844082>] [<ffffffff81844082>] add_stripe_bio+0x48d/0x544
[ 32.388044] RSP: 0000:ffff88003d40f6f8 EFLAGS: 00010046
[ 32.388044] RAX: 0000000000000000 RBX: ffff880037168cd0 RCX: ffff880037179a28
[ 32.388044] RDX: ffff880037168d58 RSI: 0000000000000000 RDI: ffff880037179a20
[ 32.388044] RBP: ffff88003d40f738 R08: 0000000000000410 R09: 0000000000000410
[ 32.388044] R10: 0000000000000410 R11: 0000000000000002 R12: ffff8800371799a0
[ 32.388044] R13: ffff88003c3d0800 R14: 0000000000000001 R15: ffff880037179a08
[ 32.388044] FS: 0000000000000000(0000) GS:ffff88003fc00000(0000) knlGS:0000000000000000
[ 32.388044] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[ 32.388044] CR2: 0000000000000000 CR3: 0000000036e33000 CR4: 00000000000006f0
[ 32.388044] Stack:
[ 32.388044] 0000000200000000 ffff880037168d38 ffff88003d40f738 ffff88003c3abd00
[ 32.388044] ffff88003c2df800 ffff88003c3d0800 0000000000000408 ffff88003c3d0b54
[ 32.388044] ffff88003d40f828 ffffffff8184b9ea ffffffff3d40f7e8 0000000000000292
[ 32.388044] Call Trace:
[ 32.388044] [<ffffffff8184b9ea>] make_request+0x7a8/0xaee
[ 32.388044] [<ffffffff81120387>] ? wait_woken+0x79/0x79
[ 32.388044] [<ffffffff811e9a85>] ? kmem_cache_alloc+0x95/0x1b6
[ 32.388044] [<ffffffff8186b944>] md_make_request+0xeb/0x1c3
[ 32.388044] [<ffffffff811a3025>] ? mempool_alloc+0x64/0x127
[ 32.388044] [<ffffffff81481575>] generic_make_request+0x9c/0xdb
[ 32.388044] [<ffffffff814816aa>] submit_bio+0xf6/0x134
[ 32.388044] [<ffffffff8122a1f7>] _submit_bh+0x119/0x141
[ 32.388044] [<ffffffff8122a22f>] submit_bh+0x10/0x12
[ 32.388044] [<ffffffff8122bbb9>] __block_write_full_page.constprop.30+0x1a3/0x2a4
[ 32.388044] [<ffffffff8122bead>] ? I_BDEV+0xd/0xd
[ 32.388044] [<ffffffff8122bd65>] block_write_full_page+0xab/0xaf
[ 32.388044] [<ffffffff8122c657>] blkdev_writepage+0x18/0x1a
[ 32.388044] [<ffffffff811a9853>] __writepage+0x14/0x2d
[ 32.388044] [<ffffffff811a9ef3>] write_cache_pages+0x29a/0x3a7
[ 32.388044] [<ffffffff811a983f>] ? mapping_tagged+0x14/0x14
[ 32.388044] [<ffffffff811aa03e>] generic_writepages+0x3e/0x56
[ 32.388044] [<ffffffff811ab638>] do_writepages+0x1e/0x2c
[ 32.388044] [<ffffffff812229ed>] __writeback_single_inode+0x5b/0x27e
[ 32.388044] [<ffffffff81222ec7>] writeback_sb_inodes+0x1dc/0x358
[ 32.388044] [<ffffffff812230c2>] __writeback_inodes_wb+0x7f/0xb8
[ 32.388044] [<ffffffff812232b9>] wb_writeback+0x11a/0x271
[ 32.388044] [<ffffffff811aa483>] ? global_dirty_limits+0x1b/0xfd
[ 32.388044] [<ffffffff8122399c>] bdi_writeback_workfn+0x1ae/0x360
[ 32.388044] [<ffffffff81101bab>] process_one_work+0x1c2/0x340
[ 32.388044] [<ffffffff81102571>] worker_thread+0x28b/0x389
[ 32.388044] [<ffffffff811022e6>] ? cancel_delayed_work_sync+0x15/0x15
[ 32.388044] [<ffffffff81106936>] kthread+0xd2/0xda
[ 32.388044] [<ffffffff81106864>] ? kthread_create_on_node+0x17c/0x17c
[ 32.388044] [<ffffffff81a16682>] ret_from_fork+0x42/0x70
[ 32.388044] [<ffffffff81106864>] ? kthread_create_on_node+0x17c/0x17c
[ 32.388044] Code: 84 24 90 00 00 00 48 8d 93 88 00 00 00 49 8d 8c 24 88 00 00 00 49 89 94 24 90 00 00 00 48 89 8b 88 00 00 00 48 89 83 90 00 00 00 <48> 89 10 66 41 83 84 24 80 00 00 00 01 3e 0f ba 73 48 06 72 02
[ 32.388044] RIP [<ffffffff81844082>] add_stripe_bio+0x48d/0x544
[ 32.388044] RSP <ffff88003d40f6f8>
[ 32.388044] CR2: 0000000000000000
[ 32.388044] ---[ end trace 2b255d3f55be9eb3 ]---
Cc: Shaohua Li <shli@xxxxxxxxxx>
Signed-off-by: Yuanhan Liu <yuanhan.liu@xxxxxxxxxxxxxxx>
---
drivers/md/raid5.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 697d77a..7b074f7 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -2217,6 +2217,10 @@ static int resize_stripes(struct r5conf *conf, int newsize)
if (!p)
err = -ENOMEM;
}
+
+ spin_lock_init(&nsh->batch_lock);
+ INIT_LIST_HEAD(&nsh->batch_list);
+ nsh->batch_head = NULL;
release_stripe(nsh);
}
/* critical section pass, GFP_NOIO no longer needed */
--
1.9.0
--
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