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Message-ID: <af4bcfff-1522-e043-0ba0-46c7ed93c0af@huawei.com>
Date:   Fri, 24 Sep 2021 17:32:26 +0800
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Subject: Re: [PATCH 0/2] bugfix for read_extent_tree_block
To:     <tytso@mit.edu>, <jack@suse.cz>
CC:     <linux-ext4@vger.kernel.org>, <yukuai3@huawei.com>
References: <20210904044946.2102404-1-yangerkun@huawei.com>
From:   yangerkun <yangerkun@huawei.com>
In-Reply-To: <20210904044946.2102404-1-yangerkun@huawei.com>
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gently ping...

在 2021/9/4 12:49, yangerkun 写道:
> Our stress testcase with io error can trigger later OOB:
> 
>      [59898.282466] BUG: KASAN: slab-out-of-bounds in ext4_find_extent+0x2e4/0x480
>      ...
>      [59898.287162] Call Trace:
>      [59898.287575]  dump_stack+0x8b/0xb9
>      [59898.288070]  print_address_description+0x73/0x280
>      [59898.289903]  ext4_find_extent+0x2e4/0x480
>      [59898.290553]  ext4_ext_map_blocks+0x125/0x1470
>      [59898.295481]  ext4_map_blocks+0x5ee/0x940
>      [59898.315984]  ext4_mpage_readpages+0x63c/0xdb0
>      [59898.320231]  read_pages+0xe6/0x370
>      [59898.321589]  __do_page_cache_readahead+0x233/0x2a0
>      [59898.321594]  ondemand_readahead+0x157/0x450
>      [59898.321598]  generic_file_read_iter+0xcb2/0x1550
>      [59898.328828]  __vfs_read+0x233/0x360
>      [59898.328840]  vfs_read+0xa5/0x190
>      [59898.330126]  ksys_read+0xa5/0x150
>      [59898.331405]  do_syscall_64+0x6d/0x1f0
>      [59898.331418]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
> 
> It seem that a xattr block with verified confuse read_extent_tree_block.
> 
> The detail of the patch show us how to fix it.
> 
> yangerkun (2):
>    ext4: avoid recheck extent for EXT4_EX_FORCE_CACHE
>    ext4: check magic even the extent block bh is verified
> 
>   fs/ext4/extents.c | 25 ++++++++++++++++++-------
>   1 file changed, 18 insertions(+), 7 deletions(-)
>