2e6e518335
When we create a block group we add it to the rbtree of block groups before setting its ->space_info field (while it's NULL). This is problematic since other tasks can access the block group from the rbtree and attempt to use its ->space_info before it is set by btrfs_make_block_group(). This can happen for example when a concurrent fitrim ioctl operation is ongoing, which produces a trace like the following when CONFIG_DEBUG_PAGEALLOC is set. [11509.604369] BUG: unable to handle kernel NULL pointer dereference at 0000000000000018 [11509.606373] IP: [<ffffffff8107d675>] __lock_acquire+0xb4/0xf02 [11509.608179] PGD 2296a8067 PUD 22f4a2067 PMD 0 [11509.608179] Oops: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC [11509.608179] Modules linked in: btrfs crc32c_generic xor raid6_pq nfsd auth_rpcgss oid_registry nfs_acl nfs lockd grace fscache sunrpc loop fuse acpi_cpufreq processor i2c_piix4 psmou [11509.608179] CPU: 10 PID: 8538 Comm: fstrim Tainted: G W 4.0.0-rc5-btrfs-next-9+ #2 [11509.608179] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.7.5-0-ge51488c-20140602_164612-nilsson.home.kraxel.org 04/01/2014 [11509.608179] task: ffff88009f5c46d0 ti: ffff8801b3edc000 task.ti: ffff8801b3edc000 [11509.608179] RIP: 0010:[<ffffffff8107d675>] [<ffffffff8107d675>] __lock_acquire+0xb4/0xf02 [11509.608179] RSP: 0018:ffff8801b3edf9e8 EFLAGS: 00010002 [11509.608179] RAX: 0000000000000046 RBX: 0000000000000000 RCX: 0000000000000000 [11509.608179] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000018 [11509.608179] RBP: ffff8801b3edfaa8 R08: 0000000000000001 R09: 0000000000000000 [11509.608179] R10: 0000000000000000 R11: ffff88009f5c4f98 R12: 0000000000000000 [11509.608179] R13: 0000000000000000 R14: 0000000000000018 R15: ffff88009f5c46d0 [11509.608179] FS: 00007f280a10e840(0000) GS:ffff88023ed40000(0000) knlGS:0000000000000000 [11509.608179] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b [11509.608179] CR2: 0000000000000018 CR3: 00000002119bc000 CR4: 00000000000006e0 [11509.608179] Stack: [11509.608179] 0000000000000000 0000000000000000 0000000000000004 0000000000000000 [11509.608179] ffff880100000000 ffffffff00000000 0000000000000001 ffffffff00000000 [11509.608179] 0000000000000001 0000000000000000 ffff880100000000 00000000000006c4 [11509.608179] Call Trace: [11509.608179] [<ffffffff8107dc57>] ? __lock_acquire+0x696/0xf02 [11509.608179] [<ffffffff8107e806>] lock_acquire+0xa5/0x116 [11509.608179] [<ffffffffa04cc876>] ? do_trimming+0x51/0x145 [btrfs] [11509.608179] [<ffffffff81434f37>] _raw_spin_lock+0x34/0x44 [11509.608179] [<ffffffffa04cc876>] ? do_trimming+0x51/0x145 [btrfs] [11509.608179] [<ffffffffa04cc876>] do_trimming+0x51/0x145 [btrfs] [11509.608179] [<ffffffffa04cde7d>] btrfs_trim_block_group+0x201/0x491 [btrfs] [11509.608179] [<ffffffffa04849e2>] btrfs_trim_fs+0xe0/0x129 [btrfs] [11509.608179] [<ffffffffa04bb80a>] btrfs_ioctl_fitrim+0x138/0x167 [btrfs] [11509.608179] [<ffffffffa04c002f>] btrfs_ioctl+0x50d/0x21e8 [btrfs] [11509.608179] [<ffffffff81123bda>] ? might_fault+0x58/0xb5 [11509.608179] [<ffffffff81123bda>] ? might_fault+0x58/0xb5 [11509.608179] [<ffffffff81123bda>] ? might_fault+0x58/0xb5 [11509.608179] [<ffffffff81158050>] ? cp_new_stat+0x147/0x15e [11509.608179] [<ffffffff81163041>] do_vfs_ioctl+0x3c6/0x479 [11509.608179] [<ffffffff81158116>] ? SYSC_newfstat+0x25/0x2e [11509.608179] [<ffffffff81435b54>] ? ret_from_sys_call+0x1d/0x58 [11509.608179] [<ffffffff8116b915>] ? __fget_light+0x2d/0x4f [11509.608179] [<ffffffff8116314e>] SyS_ioctl+0x5a/0x7f [11509.608179] [<ffffffff81435b32>] system_call_fastpath+0x12/0x17 [11509.608179] Code: f4 01 00 0f 85 c0 00 00 00 48 c7 c1 f3 1f 7d 81 48 c7 c2 aa cb 7c 81 be fc 0b 00 00 eb 70 83 3d 61 eb 9c 00 00 0f 84 a5 00 00 00 <49> 81 3e 40 a3 2b 82 b8 00 00 00 [11509.608179] RIP [<ffffffff8107d675>] __lock_acquire+0xb4/0xf02 [11509.608179] RSP <ffff8801b3edf9e8> [11509.608179] CR2: 0000000000000018 [11509.608179] ---[ end trace 570a5c6769f0e49a ]--- Which corresponds to the following access in fs/btrfs/free-space-cache.c: static int do_trimming(struct btrfs_block_group_cache *block_group, u64 *total_trimmed, u64 start, u64 bytes, u64 reserved_start, u64 reserved_bytes, struct btrfs_trim_range *trim_entry) { struct btrfs_space_info *space_info = block_group->space_info; (...) spin_lock(&space_info->lock); ^^^^^ - block_group->space_info is NULL... Fix this by ensuring the block group's ->space_info is set before adding the block group to the rbtree. Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Chris Mason <clm@fb.com> |
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.. | ||
9p | ||
adfs | ||
affs | ||
afs | ||
autofs4 | ||
befs | ||
bfs | ||
btrfs | ||
cachefiles | ||
ceph | ||
cifs | ||
coda | ||
configfs | ||
cramfs | ||
debugfs | ||
devpts | ||
dlm | ||
ecryptfs | ||
efivarfs | ||
efs | ||
exofs | ||
exportfs | ||
ext2 | ||
ext3 | ||
ext4 | ||
f2fs | ||
fat | ||
freevxfs | ||
fscache | ||
fuse | ||
gfs2 | ||
hfs | ||
hfsplus | ||
hostfs | ||
hpfs | ||
hppfs | ||
hugetlbfs | ||
isofs | ||
jbd | ||
jbd2 | ||
jffs2 | ||
jfs | ||
kernfs | ||
lockd | ||
logfs | ||
minix | ||
ncpfs | ||
nfs | ||
nfs_common | ||
nfsd | ||
nilfs2 | ||
nls | ||
notify | ||
ntfs | ||
ocfs2 | ||
omfs | ||
openpromfs | ||
overlayfs | ||
proc | ||
pstore | ||
qnx4 | ||
qnx6 | ||
quota | ||
ramfs | ||
reiserfs | ||
romfs | ||
squashfs | ||
sysfs | ||
sysv | ||
tracefs | ||
ubifs | ||
udf | ||
ufs | ||
xfs | ||
aio.c | ||
anon_inodes.c | ||
attr.c | ||
bad_inode.c | ||
binfmt_aout.c | ||
binfmt_elf_fdpic.c | ||
binfmt_elf.c | ||
binfmt_em86.c | ||
binfmt_flat.c | ||
binfmt_misc.c | ||
binfmt_script.c | ||
block_dev.c | ||
buffer.c | ||
char_dev.c | ||
compat_binfmt_elf.c | ||
compat_ioctl.c | ||
compat.c | ||
coredump.c | ||
dax.c | ||
dcache.c | ||
dcookies.c | ||
direct-io.c | ||
drop_caches.c | ||
eventfd.c | ||
eventpoll.c | ||
exec.c | ||
fcntl.c | ||
fhandle.c | ||
file_table.c | ||
file.c | ||
filesystems.c | ||
fs_pin.c | ||
fs_struct.c | ||
fs-writeback.c | ||
inode.c | ||
internal.h | ||
ioctl.c | ||
Kconfig | ||
Kconfig.binfmt | ||
libfs.c | ||
locks.c | ||
Makefile | ||
mbcache.c | ||
mount.h | ||
mpage.c | ||
namei.c | ||
namespace.c | ||
no-block.c | ||
nsfs.c | ||
open.c | ||
pipe.c | ||
pnode.c | ||
pnode.h | ||
posix_acl.c | ||
proc_namespace.c | ||
read_write.c | ||
readdir.c | ||
select.c | ||
seq_file.c | ||
signalfd.c | ||
splice.c | ||
stack.c | ||
stat.c | ||
statfs.c | ||
super.c | ||
sync.c | ||
timerfd.c | ||
utimes.c | ||
xattr.c |