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linux/fs/erofs
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Gao Xiang 2f44013e39 erofs: fix pcluster use-after-free on UP platforms 
During stress testing with CONFIG_SMP disabled, KASAN reports as below:

==================================================================
BUG: KASAN: use-after-free in __mutex_lock+0xe5/0xc30
Read of size 8 at addr ffff8881094223f8 by task stress/7789

CPU: 0 PID: 7789 Comm: stress Not tainted 6.0.0-rc1-00002-g0d53d2e882f9 #3
Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011
Call Trace:
 <TASK>
..
 __mutex_lock+0xe5/0xc30
..
 z_erofs_do_read_page+0x8ce/0x1560
..
 z_erofs_readahead+0x31c/0x580
..
Freed by task 7787
 kasan_save_stack+0x1e/0x40
 kasan_set_track+0x20/0x30
 kasan_set_free_info+0x20/0x40
 __kasan_slab_free+0x10c/0x190
 kmem_cache_free+0xed/0x380
 rcu_core+0x3d5/0xc90
 __do_softirq+0x12d/0x389

Last potentially related work creation:
 kasan_save_stack+0x1e/0x40
 __kasan_record_aux_stack+0x97/0xb0
 call_rcu+0x3d/0x3f0
 erofs_shrink_workstation+0x11f/0x210
 erofs_shrink_scan+0xdc/0x170
 shrink_slab.constprop.0+0x296/0x530
 drop_slab+0x1c/0x70
 drop_caches_sysctl_handler+0x70/0x80
 proc_sys_call_handler+0x20a/0x2f0
 vfs_write+0x555/0x6c0
 ksys_write+0xbe/0x160
 do_syscall_64+0x3b/0x90

The root cause is that erofs_workgroup_unfreeze() doesn't reset to
orig_val thus it causes a race that the pcluster reuses unexpectedly
before freeing.

Since UP platforms are quite rare now, such path becomes unnecessary.
Let's drop such specific-designed path directly instead.

Fixes: 73f5c66df3 ("staging: erofs: fix `erofs_workgroup_{try_to_freeze, unfreeze}'")
Reviewed-by: Yue Hu <huyue2@coolpad.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Link: https://lore.kernel.org/r/20220902045710.109530-1-hsiangkao@linux.alibaba.com
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
2022-09-05 23:23:30 +08:00
..
compress.h erofs: introduce multi-reference pclusters (fully-referenced) 2022-07-22 21:44:27 +08:00
data.c erofs: get rid of erofs_prepare_dio() helper 2022-07-22 21:46:03 +08:00
decompressor_lzma.c erofs: wake up all waiters after z_erofs_lzma_head ready 2022-07-09 06:32:29 +08:00
decompressor.c erofs: introduce multi-reference pclusters (fully-referenced) 2022-07-22 21:44:27 +08:00
dir.c erofs: update ctx->pos for every emitted dirent 2022-07-31 22:26:29 +08:00
erofs_fs.h erofs: scan devices from device table 2022-05-18 00:11:21 +08:00
fscache.c erofs: fix error return code in erofs_fscache_{meta_,}read_folio 2022-09-05 23:21:15 +08:00
inode.c erofs: leave compressed inodes unsupported in fscache mode for now 2022-05-29 15:34:54 +08:00
internal.h erofs: fix pcluster use-after-free on UP platforms 2022-09-05 23:23:30 +08:00
Kconfig erofs: register fscache volume 2022-05-18 00:11:19 +08:00
Makefile erofs: register fscache volume 2022-05-18 00:11:19 +08:00
namei.c erofs: make filesystem exportable 2022-05-17 23:48:54 +08:00
pcpubuf.c erofs: get rid of ->lru usage 2021-10-25 08:22:59 +08:00
super.c dax: introduce holder for dax_device 2022-07-17 17:14:30 -07:00
sysfs.c erofs: add 'fsid' mount option 2022-05-18 00:11:21 +08:00
tagptr.h erofs: clean up file headers & footers 2021-06-08 00:41:24 +08:00
utils.c mm: shrinkers: provide shrinkers with names 2022-07-03 18:08:40 -07:00
xattr.c erofs: use meta buffers for xattr operations 2022-01-04 23:47:08 +08:00
xattr.h erofs: use meta buffers for xattr operations 2022-01-04 23:47:08 +08:00
zdata.c erofs: introduce multi-reference pclusters (fully-referenced) 2022-07-22 21:44:27 +08:00
zdata.h erofs: introduce multi-reference pclusters (fully-referenced) 2022-07-22 21:44:27 +08:00
zmap.c erofs: avoid the potentially wrong m_plen for big pcluster 2022-09-05 23:22:01 +08:00