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a405c6f022
init_resync() inits mempool and sets conf->have_replacemnt at the beginning
of sync, close_sync() frees the mempool when sync is completed.
After [1] recovery might be skipped and init_resync() is called but
close_sync() is not. null-ptr-deref occurs with r10bio->dev[i].repl_bio.
The following is one way to reproduce the issue.
1) create a array, wait for resync to complete, mddev->recovery_cp is set
to MaxSector.
2) recovery is woken and it is skipped. conf->have_replacement is set to
0 in init_resync(). close_sync() not called.
3) some io errors and rdev A is set to WantReplacement.
4) a new device is added and set to A's replacement.
5) recovery is woken, A have replacement, but conf->have_replacemnt is
0. r10bio->dev[i].repl_bio will not be alloced and null-ptr-deref
occurs.
Fix it by not calling init_resync() if recovery skipped.
[1] commit 7e83ccbecd ("md/raid10: Allow skipping recovery when clean arrays are assembled")
Fixes: 7e83ccbecd ("md/raid10: Allow skipping recovery when clean arrays are assembled")
Cc: stable@vger.kernel.org
Signed-off-by: Li Nan <linan122@huawei.com>
Signed-off-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20230222041000.3341651-3-linan666@huaweicloud.com
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 Restructured Text 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.