lkml.org 
[lkml]   [2024]   [Apr]   [23]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH -next] md: fix resync softlockup when bitmap size is less than array size
From
Date
+CC Nigel

Sorry I forgot that.

在 2024/04/22 14:58, Yu Kuai 写道:
> 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>
> ---
> drivers/md/md-bitmap.c | 7 ++++---
> 1 file changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/md/md-bitmap.c b/drivers/md/md-bitmap.c
> index 059afc24c08b..f5b66d52cbe3 100644
> --- a/drivers/md/md-bitmap.c
> +++ b/drivers/md/md-bitmap.c
> @@ -1424,15 +1424,17 @@ __acquires(bitmap->lock)
> sector_t chunk = offset >> bitmap->chunkshift;
> unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
> unsigned long pageoff = (chunk & PAGE_COUNTER_MASK) << COUNTER_BYTE_SHIFT;
> - sector_t csize;
> + sector_t csize = ((sector_t)1) << bitmap->chunkshift;
> int err;
>
> +
> if (page >= bitmap->pages) {
> /*
> * This can happen if bitmap_start_sync goes beyond
> * End-of-device while looking for a whole page or
> * user set a huge number to sysfs bitmap_set_bits.
> */
> + *blocks = csize - (offset & (csize - 1));
> return NULL;
> }
> err = md_bitmap_checkpage(bitmap, page, create, 0);
> @@ -1441,8 +1443,7 @@ __acquires(bitmap->lock)
> bitmap->bp[page].map == NULL)
> csize = ((sector_t)1) << (bitmap->chunkshift +
> PAGE_COUNTER_SHIFT);
> - else
> - csize = ((sector_t)1) << bitmap->chunkshift;
> +
> *blocks = csize - (offset & (csize - 1));
>
> if (err < 0)
>


\
 
 \ /
  Last update: 2024-05-27 17:57    [W:0.032 / U:0.040 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site