From: "Theodore Y. Ts'o" <tytso@mit.edu>
To: "zhangyi (F)" <yi.zhang@huawei.com>
Cc: linux-ext4@vger.kernel.org, jack@suse.com, adilger.kernel@dilger.ca
Subject: Re: [PATCH v2 1/7] ext4: clear buffer verified flag if read meta block from disk
Date: Thu, 8 Oct 2020 21:41:40 -0400 [thread overview]
Message-ID: <20201009014140.GA816148@mit.edu> (raw)
In-Reply-To: <20200924073337.861472-2-yi.zhang@huawei.com>
On Thu, Sep 24, 2020 at 03:33:31PM +0800, zhangyi (F) wrote:
> The metadata buffer is no longer trusted after we read it from disk
> again because it is not uptodate for some reasons (e.g. failed to write
> back). Otherwise we may get below memory corruption problem in
> ext4_ext_split()->memset() if we read stale data from the newly
> allocated extent block on disk which has been failed to async write
> out but miss verify again since the verified bit has already been set
> on the buffer.
>
> [ 29.774674] BUG: unable to handle kernel paging request at ffff88841949d000
> ...
> [ 29.783317] Oops: 0002 [#2] SMP
> [ 29.784219] R10: 00000000000f4240 R11: 0000000000002e28 R12: ffff88842fa1c800
> [ 29.784627] CPU: 1 PID: 126 Comm: kworker/u4:3 Tainted: G D W
> [ 29.785546] R13: ffffffff9cddcc20 R14: ffffffff9cddd420 R15: ffff88842fa1c2f8
> [ 29.786679] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),BIOS ?-20190727_0738364
> [ 29.787588] FS: 0000000000000000(0000) GS:ffff88842fa00000(0000) knlGS:0000000000000000
> [ 29.789288] Workqueue: writeback wb_workfn
> [ 29.790319] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [ 29.790321] (flush-8:0)
> [ 29.790844] CR2: 0000000000000008 CR3: 00000004234f2000 CR4: 00000000000006f0
> [ 29.791924] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> [ 29.792839] RIP: 0010:__memset+0x24/0x30
> [ 29.793739] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> [ 29.794256] Code: 90 90 90 90 90 90 0f 1f 44 00 00 49 89 f9 48 89 d1 83 e2 07 48 c1 e9 033
> [ 29.795161] Kernel panic - not syncing: Fatal exception in interrupt
> ...
> [ 29.808149] Call Trace:
> [ 29.808475] ext4_ext_insert_extent+0x102e/0x1be0
> [ 29.809085] ext4_ext_map_blocks+0xa89/0x1bb0
> [ 29.809652] ext4_map_blocks+0x290/0x8a0
> [ 29.809085] ext4_ext_map_blocks+0xa89/0x1bb0
> [ 29.809652] ext4_map_blocks+0x290/0x8a0
> [ 29.810161] ext4_writepages+0xc85/0x17c0
> ...
>
> Fix this by clearing buffer's verified bit if we read meta block from
> disk again.
>
> Signed-off-by: zhangyi (F) <yi.zhang@huawei.com>
> Cc: stable@vger.kernel.org
Thanks, applied.
- Ted
next prev parent reply other threads:[~2020-10-09 1:42 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-24 7:33 [PATCH v2 0/7] ext4: fix a memory corrupt problem zhangyi (F)
2020-09-24 7:33 ` [PATCH v2 1/7] ext4: clear buffer verified flag if read meta block from disk zhangyi (F)
2020-10-09 1:41 ` Theodore Y. Ts'o [this message]
2020-09-24 7:33 ` [PATCH v2 2/7] ext4: introduce new metadata buffer read helpers zhangyi (F)
2020-10-09 1:43 ` Theodore Y. Ts'o
2020-09-24 7:33 ` [PATCH v2 3/7] ext4: use common helpers in all places reading metadata buffers zhangyi (F)
2020-10-09 1:48 ` Theodore Y. Ts'o
2020-09-24 7:33 ` [PATCH v2 4/7] ext4: use ext4_buffer_uptodate() in __ext4_get_inode_loc() zhangyi (F)
2020-10-09 1:49 ` Theodore Y. Ts'o
2020-09-24 7:33 ` [PATCH v2 5/7] ext4: introduce ext4_sb_breadahead_unmovable() to replace sb_breadahead_unmovable() zhangyi (F)
2020-10-09 1:55 ` Theodore Y. Ts'o
2020-09-24 7:33 ` [PATCH v2 6/7] ext4: use ext4_sb_bread() instead of sb_bread() zhangyi (F)
2020-10-09 1:57 ` Theodore Y. Ts'o
2020-09-24 7:33 ` [PATCH v2 7/7] ext4: introduce ext4_sb_bread_unmovable() to replace sb_bread_unmovable() zhangyi (F)
2020-10-09 2:00 ` Theodore Y. Ts'o
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20201009014140.GA816148@mit.edu \
--to=tytso@mit.edu \
--cc=adilger.kernel@dilger.ca \
--cc=jack@suse.com \
--cc=linux-ext4@vger.kernel.org \
--cc=yi.zhang@huawei.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.