linux/fs/ubifs
Zhihao Cheng afd4270480 ubifs: Fix deadlock in concurrent rename whiteout and inode writeback
Following hung tasks:
[   77.028764] task:kworker/u8:4    state:D stack:    0 pid:  132
[   77.028820] Call Trace:
[   77.029027]  schedule+0x8c/0x1b0
[   77.029067]  mutex_lock+0x50/0x60
[   77.029074]  ubifs_write_inode+0x68/0x1f0 [ubifs]
[   77.029117]  __writeback_single_inode+0x43c/0x570
[   77.029128]  writeback_sb_inodes+0x259/0x740
[   77.029148]  wb_writeback+0x107/0x4d0
[   77.029163]  wb_workfn+0x162/0x7b0

[   92.390442] task:aa              state:D stack:    0 pid: 1506
[   92.390448] Call Trace:
[   92.390458]  schedule+0x8c/0x1b0
[   92.390461]  wb_wait_for_completion+0x82/0xd0
[   92.390469]  __writeback_inodes_sb_nr+0xb2/0x110
[   92.390472]  writeback_inodes_sb_nr+0x14/0x20
[   92.390476]  ubifs_budget_space+0x705/0xdd0 [ubifs]
[   92.390503]  do_rename.cold+0x7f/0x187 [ubifs]
[   92.390549]  ubifs_rename+0x8b/0x180 [ubifs]
[   92.390571]  vfs_rename+0xdb2/0x1170
[   92.390580]  do_renameat2+0x554/0x770

, are caused by concurrent rename whiteout and inode writeback processes:
	rename_whiteout(Thread 1)	        wb_workfn(Thread2)
ubifs_rename
  do_rename
    lock_4_inodes (Hold ui_mutex)
    ubifs_budget_space
      make_free_space
        shrink_liability
	  __writeback_inodes_sb_nr
	    bdi_split_work_to_wbs (Queue new wb work)
					      wb_do_writeback(wb work)
						__writeback_single_inode
					          ubifs_write_inode
					            LOCK(ui_mutex)
							   ↑
	      wb_wait_for_completion (Wait wb work) <-- deadlock!

Reproducer (Detail program in [Link]):
  1. SYS_renameat2("/mp/dir/file", "/mp/dir/whiteout", RENAME_WHITEOUT)
  2. Consume out of space before kernel(mdelay) doing budget for whiteout

Fix it by doing whiteout space budget before locking ubifs inodes.
BTW, it also fixes wrong goto tag 'out_release' in whiteout budget
error handling path(It should at least recover dir i_size and unlock
4 ubifs inodes).

Fixes: 9e0a1fff8d ("ubifs: Implement RENAME_WHITEOUT")
Link: https://bugzilla.kernel.org/show_bug.cgi?id=214733
Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
2022-01-09 21:33:25 +01:00
..
auth.c ubifs: Fix memleak in ubifs_init_authentication 2021-02-12 21:53:22 +01:00
budget.c ubifs: Limit the number of pages in shrink_liability 2019-08-22 17:25:33 +02:00
commit.c ubifs: Pass node length in all node dumping callers 2020-12-13 22:12:32 +01:00
compress.c ubifs: Add support for zstd compression. 2019-07-08 19:43:53 +02:00
crypto.c fscrypt: remove fscrypt_operations::max_namelen 2021-09-20 19:32:33 -07:00
debug.c ubifs: fix snprintf() checking 2021-06-18 22:04:47 +02:00
debug.h ubifs: ubifs_dump_sleb: Remove unused function 2020-12-13 22:12:38 +01:00
dir.c ubifs: Fix deadlock in concurrent rename whiteout and inode writeback 2022-01-09 21:33:25 +01:00
file.c ubifs: report correct st_size for encrypted symlinks 2021-07-25 20:01:07 -07:00
find.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 336 2019-06-05 17:37:07 +02:00
gc.c ubifs: read-only if LEB may always be taken in ubifs_garbage_collect 2021-12-23 22:30:38 +01:00
io.c ubifs: Export filesystem error counters 2021-12-23 20:23:42 +01:00
ioctl.c ubifs: convert to fileattr 2021-04-12 15:04:30 +02:00
journal.c ubifs: Fix spelling mistakes 2021-06-22 09:21:39 +02:00
Kconfig fscrypt: Allow modular crypto algorithms 2019-12-31 10:33:51 -06:00
key.h ubifs: allow both hash and disk name to be provided in no-key names 2020-01-22 14:49:56 -08:00
log.c ubifs: remove unnecessary check in ubifs_log_start_commit 2019-07-08 19:43:51 +02:00
lprops.c treewide: Use fallthrough pseudo-keyword 2020-08-23 17:36:59 -05:00
lpt_commit.c mm: remove the pgprot argument to __vmalloc 2020-06-02 10:59:11 -07:00
lpt.c ubifs: Fix the printing type of c->big_lpt 2020-12-13 21:57:10 +01:00
Makefile ubifs: Export filesystem error counters 2021-12-23 20:23:42 +01:00
master.c ubifs: Fix spelling mistakes 2021-06-22 09:21:39 +02:00
misc.c ubifs: Allow setting assert action as mount parameter 2018-08-15 00:25:21 +02:00
misc.h ubifs: misc.h: delete a duplicated word 2020-08-02 22:59:03 +02:00
orphan.c ubifs: Pass node length in all node dumping callers 2020-12-13 22:12:32 +01:00
recovery.c ubifs: Pass node length in all node dumping callers 2020-12-13 22:12:32 +01:00
replay.c ubifs: Fix spelling mistakes 2021-12-23 20:23:40 +01:00
sb.c ubifs: Default to zstd compression 2021-04-15 22:00:26 +02:00
scan.c ubifs: Pass node length in all node dumping callers 2020-12-13 22:12:32 +01:00
shrinker.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 336 2019-06-05 17:37:07 +02:00
super.c ubifs: Export filesystem error counters 2021-12-23 20:23:42 +01:00
sysfs.c ubifs: fix snprintf() length check 2021-12-23 22:08:19 +01:00
tnc_commit.c ubifs: Fix spelling mistakes 2021-06-22 09:21:39 +02:00
tnc_misc.c ubifs: Pass node length in all node dumping callers 2020-12-13 22:12:32 +01:00
tnc.c ubifs: Pass node length in all node dumping callers 2020-12-13 22:12:32 +01:00
ubifs-media.h ubifs: Add support for zstd compression. 2019-07-08 19:43:53 +02:00
ubifs.h ubifs: Export filesystem error counters 2021-12-23 20:23:42 +01:00
xattr.c ubifs: Remove ui_mutex in ubifs_xattr_get and change_xattr 2021-06-18 22:04:47 +02:00