From: Song Liu <song@kernel.org>
To: Yu Kuai <yukuai1@huaweicloud.com>
Cc: yukuai3@huawei.com, linan122@huawei.com,
linux-raid@vger.kernel.org, linux-kernel@vger.kernel.org,
yi.zhang@huawei.com, yangerkun@huawei.com
Subject: Re: [PATCH -next] md: fix resync softlockup when bitmap size is less than array size
Date: Tue, 23 Apr 2024 15:29:25 -0700 [thread overview]
Message-ID: <CAPhsuW59dA2y9vLdJMzMpP_NcDRR_TUFz6Jk8mZLziWs94vaTQ@mail.gmail.com> (raw)
In-Reply-To: <20240422065824.2516-1-yukuai1@huaweicloud.com>
On Mon, Apr 22, 2024 at 12:07 AM Yu Kuai <yukuai1@huaweicloud.com> wrote:
>
> From: Yu Kuai <yukuai3@huawei.com>
>
> Is is reported that for dm-raid10, lvextend + lvchange --syncaction will
> trigger following softlockup:
>
> kernel:watchdog: BUG: soft lockup - CPU#3 stuck for 26s! [mdX_resync:6976]
> CPU: 7 PID: 3588 Comm: mdX_resync Kdump: loaded Not tainted 6.9.0-rc4-next-20240419 #1
> RIP: 0010:_raw_spin_unlock_irq+0x13/0x30
> Call Trace:
> <TASK>
> md_bitmap_start_sync+0x6b/0xf0
> raid10_sync_request+0x25c/0x1b40 [raid10]
> md_do_sync+0x64b/0x1020
> md_thread+0xa7/0x170
> kthread+0xcf/0x100
> ret_from_fork+0x30/0x50
> ret_from_fork_asm+0x1a/0x30
>
> And the detailed process is as follows:
>
> md_do_sync
> j = mddev->resync_min
> while (j < max_sectors)
> sectors = raid10_sync_request(mddev, j, &skipped)
> if (!md_bitmap_start_sync(..., &sync_blocks))
> // md_bitmap_start_sync set sync_blocks to 0
> return sync_blocks + sectors_skippe;
> // sectors = 0;
> j += sectors;
> // j never change
>
> Root cause is that commit 301867b1c168 ("md/raid10: check
> slab-out-of-bounds in md_bitmap_get_counter") return early from
> md_bitmap_get_counter(), without setting returned blocks.
>
> Fix this problem by always set returned blocks from
> md_bitmap_get_counter"(), as it used to be.
>
> Noted that this patch just fix the softlockup problem in kernel, the
> case that bitmap size doesn't match array size still need to be fixed.
>
> Fixes: 301867b1c168 ("md/raid10: check slab-out-of-bounds in md_bitmap_get_counter")
> Reported-and-tested-by: Nigel Croxon <ncroxon@redhat.com>
> Closes: https://lore.kernel.org/all/71ba5272-ab07-43ba-8232-d2da642acb4e@redhat.com/
> Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Applied to md-6.10. Thanks!
Song
prev parent reply other threads:[~2024-04-23 22:29 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-22 6:58 [PATCH -next] md: fix resync softlockup when bitmap size is less than array size Yu Kuai
2024-04-23 7:15 ` Yu Kuai
2024-04-23 22:29 ` Song Liu [this message]
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