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| author | Anand Jain <anand.jain@oracle.com> | 2018-02-24 19:43:56 +0800 |
|---|---|---|
| committer | David Sterba <dsterba@suse.com> | 2018-03-26 15:09:34 +0200 |
| commit | acf18c56fdcb952a06650282192e3b4ca1855c5e (patch) | |
| tree | 4f6374052f8dab9a9b800e6c37b506d519627d2f /fs | |
| parent | eceff22a8067fa5f587d1bab0eb66503d33b7164 (diff) | |
| download | linux-acf18c56fdcb952a06650282192e3b4ca1855c5e.tar.bz2 | |
btrfs: fix null pointer deref when target device is missing
The replace target device can be missing when mounted with -o degraded,
but we wont allocate a missing btrfs_device to it. So check the device
before accessing.
BUG: unable to handle kernel NULL pointer dereference at 00000000000000b0
IP: btrfs_destroy_dev_replace_tgtdev+0x43/0xf0 [btrfs]
Call Trace:
btrfs_dev_replace_cancel+0x15f/0x180 [btrfs]
btrfs_ioctl+0x2216/0x2590 [btrfs]
do_vfs_ioctl+0x625/0x650
SyS_ioctl+0x4e/0x80
do_syscall_64+0x5d/0x160
entry_SYSCALL64_slow_path+0x25/0x25
This patch has been moved in front of patch "btrfs: log, when replace,
is canceled by the user" that could reproduce the crash if the system
reboots inside btrfs_dev_replace_start before the
btrfs_dev_replace_finishing call.
$ mkfs /dev/sda
$ mount /dev/sda mnt
$ btrfs replace start /dev/sda /dev/sdb
<insert reboot>
$ mount po degraded /dev/sdb mnt
<crash>
Signed-off-by: Anand Jain <anand.jain@oracle.com>
[ added reproducer description from mail ]
Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/btrfs/dev-replace.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/fs/btrfs/dev-replace.c b/fs/btrfs/dev-replace.c index dd717e204b5e..c523478b3de2 100644 --- a/fs/btrfs/dev-replace.c +++ b/fs/btrfs/dev-replace.c @@ -312,7 +312,7 @@ void btrfs_after_dev_replace_commit(struct btrfs_fs_info *fs_info) static char* btrfs_dev_name(struct btrfs_device *device) { - if (test_bit(BTRFS_DEV_STATE_MISSING, &device->dev_state)) + if (!device || test_bit(BTRFS_DEV_STATE_MISSING, &device->dev_state)) return "<missing disk>"; else return rcu_str_deref(device->name); |