btrfs-progs: Avoid double-free of fs_devices->list
I found the following patch is insufficient.
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commit
6e6b32ddf58db54f714d0f263c2589f4859e8b5e
Author: Adam Buchbinder <abuchbinder@google.com>
Date: Fri Jun 13 16:43:56 2014 -0700
btrfs-progs: Fix a use-after-free in the volumes code.
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"btrfs filesystem show <dev>" with this patch causes segmentation fault
if "<dev>" is a not-mounted Btrfs filesystem.
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Label: none uuid: <cut here>
Total devices 1 FS bytes used 112.00KiB
devid 1 size 59.12GiB used 2.04GiB path /dev/sdd1
Segmentation fault (core dumped)
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It's due to double-free of fs_devices->list as follows.
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cmd_show
-> list_del(&fs_devices->list) # 1st one.
-> btrfs_close_devices(fs_devices)
-> list_del(&fs_devices->list) # <- 2nd one introduced at
6e6b32dd.
Double-free happens here.
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First list_del() can safely be removed because fs_devices->list will be
deleted by second one, soon.
Signed-off-by: Satoru Takeuchi <takeuchi_satoru@jp.fujitsu.com>
Cc: Adam Buchbinder <abuchbinder@google.com>
Signed-off-by: David Sterba <dsterba@suse.cz>