2022-11-16 13:31:53

by ChenXiaoSong

Subject: [PATCH v6 2/2] btrfs: qgroup: fix sleep from invalid context bug in update_qgroup_limit_item()

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 calling qgroup_dirty() on @dstqgroup, and update limit item in
btrfs_run_qgroups() later.

Signed-off-by: ChenXiaoSong <[email protected]>
---
fs/btrfs/qgroup.c | 9 +--------
1 file changed, 1 insertion(+), 8 deletions(-)

diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c
index 9334c3157c22..b74105a10f16 100644
--- a/fs/btrfs/qgroup.c
+++ b/fs/btrfs/qgroup.c
@@ -2951,14 +2951,7 @@ int btrfs_qgroup_inherit(struct btrfs_trans_handle *trans, u64 srcid,
dstgroup->rsv_rfer = inherit->lim.rsv_rfer;
dstgroup->rsv_excl = inherit->lim.rsv_excl;

- ret = update_qgroup_limit_item(trans, dstgroup);
- if (ret) {
- qgroup_mark_inconsistent(fs_info);
- btrfs_info(fs_info,
- "unable to update quota limit for %llu",
- dstgroup->qgroupid);
- goto unlock;
- }
+ qgroup_dirty(fs_info, dstgroup);
}

if (srcid) {
--
2.31.1

2022-11-16 23:25:26

by Qu Wenruo

Subject: Re: [PATCH v6 2/2] btrfs: qgroup: fix sleep from invalid context bug in update_qgroup_limit_item()

On 2022/11/16 22:23, 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 calling qgroup_dirty() on @dstqgroup, and update limit item in
> btrfs_run_qgroups() later.
>
> Signed-off-by: ChenXiaoSong <[email protected]>

Reviewed-by: Qu Wenruo <[email protected]>

Thanks,
Qu
> ---
> fs/btrfs/qgroup.c | 9 +--------
> 1 file changed, 1 insertion(+), 8 deletions(-)
>
> diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c
> index 9334c3157c22..b74105a10f16 100644
> --- a/fs/btrfs/qgroup.c
> +++ b/fs/btrfs/qgroup.c
> @@ -2951,14 +2951,7 @@ int btrfs_qgroup_inherit(struct btrfs_trans_handle *trans, u64 srcid,
> dstgroup->rsv_rfer = inherit->lim.rsv_rfer;
> dstgroup->rsv_excl = inherit->lim.rsv_excl;
>
> - ret = update_qgroup_limit_item(trans, dstgroup);
> - if (ret) {
> - qgroup_mark_inconsistent(fs_info);
> - btrfs_info(fs_info,
> - "unable to update quota limit for %llu",
> - dstgroup->qgroupid);
> - goto unlock;
> - }
> + qgroup_dirty(fs_info, dstgroup);
> }
>
> if (srcid) {