lkml.org 
[lkml]   [2022]   [Nov]   [15]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
SubjectRe: [PATCH v4 3/3] btrfs: qgroup: fix sleep from invalid context bug in update_qgroup_limit_item()
From


On 2022/11/16 01:17, ChenXiaoSong wrote:
> Syzkaller reported BUG as follows:
>
> BUG: sleeping function called from invalid context at
> include/linux/sched/mm.h:274
> Call Trace:
> <TASK>
> dump_stack_lvl+0xcd/0x134
> __might_resched.cold+0x222/0x26b
> kmem_cache_alloc+0x2e7/0x3c0
> update_qgroup_limit_item+0xe1/0x390
> btrfs_qgroup_inherit+0x147b/0x1ee0
> create_subvol+0x4eb/0x1710
> btrfs_mksubvol+0xfe5/0x13f0
> __btrfs_ioctl_snap_create+0x2b0/0x430
> btrfs_ioctl_snap_create_v2+0x25a/0x520
> btrfs_ioctl+0x2a1c/0x5ce0
> __x64_sys_ioctl+0x193/0x200
> do_syscall_64+0x35/0x80
>
> Fix this by delaying the limit item updates until unlock the spin lock.
>
> Signed-off-by: ChenXiaoSong <chenxiaosong2@huawei.com>
> ---
> fs/btrfs/qgroup.c | 13 +++++++++----
> 1 file changed, 9 insertions(+), 4 deletions(-)
>
> diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c
> index ca609a70d067..f84507ca3b99 100644
> --- a/fs/btrfs/qgroup.c
> +++ b/fs/btrfs/qgroup.c
> @@ -2867,6 +2867,8 @@ int btrfs_qgroup_inherit(struct btrfs_trans_handle *trans, u64 srcid,
> bool need_rescan = false;
> u32 level_size = 0;
> u64 nums;
> + bool update_limit = false;
> + int err;
>
> /*
> * There are only two callers of this function.
> @@ -2957,10 +2959,7 @@ int btrfs_qgroup_inherit(struct btrfs_trans_handle *trans, u64 srcid,
> dstgroup->max_excl = inherit->lim.max_excl;
> dstgroup->rsv_rfer = inherit->lim.rsv_rfer;
> dstgroup->rsv_excl = inherit->lim.rsv_excl;
> -
> - ret = btrfs_update_quoto_limit(trans, dstgroup, fs_info);
> - if (ret)
> - goto unlock;
> + update_limit = true;

Nope, just call qgroup_dirty() for @dstgroup.

Thanks,
Qu
> }
>
> if (srcid) {
> @@ -2987,6 +2986,7 @@ int btrfs_qgroup_inherit(struct btrfs_trans_handle *trans, u64 srcid,
> dstgroup->max_excl = srcgroup->max_excl;
> dstgroup->rsv_rfer = srcgroup->rsv_rfer;
> dstgroup->rsv_excl = srcgroup->rsv_excl;
> + update_limit = false;
>
> qgroup_dirty(fs_info, dstgroup);
> qgroup_dirty(fs_info, srcgroup);
> @@ -3055,6 +3055,11 @@ int btrfs_qgroup_inherit(struct btrfs_trans_handle *trans, u64 srcid,
>
> unlock:
> spin_unlock(&fs_info->qgroup_lock);
> + if (update_limit) {
> + err = btrfs_update_quoto_limit(trans, dstgroup, fs_info);
> + if (err)
> + ret = err;
> + }
> if (!ret)
> ret = btrfs_sysfs_add_one_qgroup(fs_info, dstgroup);
> out:

\
 
 \ /
  Last update: 2022-11-15 23:52    [W:0.092 / U:2.116 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site