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Yu Kuai
f0e729af2e
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 commit301867b1c1("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:301867b1c1("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> Link: https://lore.kernel.org/r/20240422065824.2516-1-yukuai1@huaweicloud.com Signed-off-by: Song Liu <song@kernel.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.