A while ago Vasily reported that it is possible to set a large number of
xattrs on inodes of filesystems that make use of the simple xattr
infrastructure. This includes all kernfs-based filesystems that support
xattrs (e.g., cgroupfs and tmpfs). Both cgroupfs and tmpfs can be
mounted by unprivileged users in unprivileged containers and root in an
unprivileged container can set an unrestricted number of security.*
xattrs and privileged users can also set unlimited trusted.* xattrs. As
there are apparently users that have a fairly large number of xattrs we
should scale a bit better. Other xattrs such as user.* are restricted
for kernfs-based instances to a fairly limited number.
Using a simple linked list protected by a spinlock used for set, get,
and list operations doesn't scale well if users use a lot of xattrs even
if it's not a crazy number. There's no need to bring in the big guns
like rhashtables or rw semaphores for this. An rbtree with a rwlock, or
limited rcu semanics and seqlock is enough.
It scales within the constraints we are working in. By far the most
common operation is getting an xattr. Setting xattrs should be a
moderately rare operation. And listxattr() often only happens when
copying xattrs between files or together with the contents to a new
file. Holding a lock across listxattr() is unproblematic because it
doesn't list the values of xattrs. It can only be used to list the names
of all xattrs set on a file. And the number of xattr names that can be
listed with listxattr() is limited to XATTR_LIST_MAX aka 65536 bytes. If
a larger buffer is passed then vfs_listxattr() caps it to XATTR_LIST_MAX
and if more xattr names are found it will return -E2BIG. In short, the
maximum amount of memory that can be retrieved via listxattr() is
limited.
Of course, the API is broken as documented on xattr(7) already. In the
future we might want to address this but for now this is the world we
live in and have lived for a long time. But it does indeed mean that
once an application goes over XATTR_LIST_MAX limit of xattrs set on an
inode it isn't possible to copy the file and include its xattrs in the
copy unless the caller knows all xattrs or limits the copy of the xattrs
to important ones it knows by name (At least for tmpfs, and kernfs-based
filesystems. Other filesystems might provide ways of achieving this.).
Bonus of this port to rbtree+rwlock is that we shrink the memory
consumption for users of the simple xattr infrastructure.
Also add proper kernel documentation to all the functions.
A big thanks to Paul for his comments.
Cc: Vasily Averin <vvs@openvz.org>
Cc: "Paul E. McKenney" <paulmck@kernel.org>
Acked-by: Roman Gushchin <roman.gushchin@linux.dev>
Acked-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Pull misc hotfixes from Andrew Morton:
"22 hotfixes.
Eight are cc:stable and the remainder address issues which were
introduced post-6.0 or which aren't considered serious enough to
justify a -stable backport"
* tag 'mm-hotfixes-stable-2022-11-11' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (22 commits)
docs: kmsan: fix formatting of "Example report"
mm/damon/dbgfs: check if rm_contexts input is for a real context
maple_tree: don't set a new maximum on the node when not reusing nodes
maple_tree: fix depth tracking in maple_state
arch/x86/mm/hugetlbpage.c: pud_huge() returns 0 when using 2-level paging
fs: fix leaked psi pressure state
nilfs2: fix use-after-free bug of ns_writer on remount
x86/traps: avoid KMSAN bugs originating from handle_bug()
kmsan: make sure PREEMPT_RT is off
Kconfig.debug: ensure early check for KMSAN in CONFIG_KMSAN_WARN
x86/uaccess: instrument copy_from_user_nmi()
kmsan: core: kmsan_in_runtime() should return true in NMI context
mm: hugetlb_vmemmap: include missing linux/moduleparam.h
mm/shmem: use page_mapping() to detect page cache for uffd continue
mm/memremap.c: map FS_DAX device memory as decrypted
Partly revert "mm/thp: carry over dirty bit when thp splits on pmd"
nilfs2: fix deadlock in nilfs_count_free_blocks()
mm/mmap: fix memory leak in mmap_region()
hugetlbfs: don't delete error page from pagecache
maple_tree: reorganize testing to restore module testing
...
Pull nfsd fixes from Chuck Lever:
- Fix an export leak
- Fix a potential tracepoint crash
* tag 'nfsd-6.1-4' of git://git.kernel.org/pub/scm/linux/kernel/git/cel/linux:
nfsd: put the export reference in nfsd4_verify_deleg_dentry
nfsd: fix use-after-free in nfsd_file_do_acquire tracepoint
Pull UDF fix from Jan Kara:
"Fix a possible memory corruption with UDF"
* tag 'fixes_for_v6.1-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs:
udf: Fix a slab-out-of-bounds write bug in udf_find_entry()
If the tlink setup failed, lost to put the connections, then
the module refcnt leak since the cifsd kthread not exit.
Also leak the fscache info, and for next mount with fsc, it will
print the follow errors:
CIFS: Cache volume key already in use (cifs,127.0.0.1:445,TEST)
Let's check the result of tlink setup, and do some cleanup.
Fixes: 56c762eb9b ("cifs: Refactor out cifs_mount()")
Reviewed-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Signed-off-by: Zhang Xiaoxu <zhangxiaoxu5@huawei.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Some minor modifications to flush_merge and related parameters:
1.The FLUSH_MERGE opt is set by default only in non-ro mode.
2.When ro and merge are set at the same time, an error is reported.
3.Display noflush_merge mount opt.
Suggested-by: Chao Yu <chao@kernel.org>
Signed-off-by: Yangtao Li <frank.li@vivo.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Wei Chen reports a kernel bug as blew:
INFO: task syz-executor.0:29056 blocked for more than 143 seconds.
Not tainted 5.15.0-rc5 #1
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.0 state:D stack:14632 pid:29056 ppid: 6574 flags:0x00000004
Call Trace:
__schedule+0x4a1/0x1720
schedule+0x36/0xe0
rwsem_down_write_slowpath+0x322/0x7a0
fscrypt_ioctl_set_policy+0x11f/0x2a0
__f2fs_ioctl+0x1a9f/0x5780
f2fs_ioctl+0x89/0x3a0
__x64_sys_ioctl+0xe8/0x140
do_syscall_64+0x34/0xb0
entry_SYSCALL_64_after_hwframe+0x44/0xae
Eric did some investigation on this issue, quoted from reply of Eric:
"Well, the quality of this bug report has a lot to be desired (not on
upstream kernel, reproducer is full of totally irrelevant stuff, not
sent to the mailing list of the filesystem whose disk image is being
fuzzed, etc.). But what is going on is that f2fs_empty_dir() doesn't
consider the case of a directory with an extremely large i_size on a
malicious disk image.
Specifically, the reproducer mounts an f2fs image with a directory
that has an i_size of 14814520042850357248, then calls
FS_IOC_SET_ENCRYPTION_POLICY on it.
That results in a call to f2fs_empty_dir() to check whether the
directory is empty. f2fs_empty_dir() then iterates through all
3616826182336513 blocks the directory allegedly contains to check
whether any contain anything. i_rwsem is held during this, so
anything else that tries to take it will hang."
In order to solve this issue, let's use f2fs_get_next_page_offset()
to speed up iteration by skipping holes for all below functions:
- f2fs_empty_dir
- f2fs_readdir
- find_in_level
The way why we can speed up iteration was described in
'commit 3cf4574705 ("f2fs: introduce get_next_page_offset to speed
up SEEK_DATA")'.
Meanwhile, in f2fs_empty_dir(), let's use f2fs_find_data_page()
instead f2fs_get_lock_data_page(), due to i_rwsem was held in
caller of f2fs_empty_dir(), there shouldn't be any races, so it's
fine to not lock dentry page during lookuping dirents in the page.
Link: https://lore.kernel.org/lkml/536944df-a0ae-1dd8-148f-510b476e1347@kernel.org/T/
Reported-by: Wei Chen <harperchen1110@gmail.com>
Cc: Eric Biggers <ebiggers@google.com>
Signed-off-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
We need to make sure i_size doesn't change until atomic write commit is
successful and restore it when commit is failed.
Signed-off-by: Daeho Jeong <daehojeong@google.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
If block address is still alive, we should give a valid node block even after
shutdown. Otherwise, we can see zero data when reading out a file.
Cc: stable@vger.kernel.org
Fixes: 83a3bfdb5a ("f2fs: indicate shutdown f2fs to allow unmount successfully")
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
The current code provokes some kernel-doc warnings:
fs/ext2/dir.c:417: warning: This comment starts with '/**', but isn't a kernel-doc comment. Refer Documentation/doc-guide/kernel-doc.rst
Signed-off-by: Bo Liu <liubo03@inspur.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Jan Kara <jack@suse.cz>
jfs_mount_rw can call diUnmount and then diMount. These calls change the
imap pointer. Between these two calls there may be calls of function
jfs_lookup(). The jfs_lookup() function calls jfs_iget(), which, in turn
calls diRead(). The latter references the imap pointer. That may cause
diRead() to refer to a pointer freed in diUnmount(). This commit makes
the calls to diUnmount()/diMount() atomic so that nothing will read the
imap pointer until the whole remount is completed.
Signed-off-by: Oleg Kanatov <okanatov@gmail.com>
Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com>
When closing the block allocation map, an incorrect pointer
was NULL'ed. This commit fixes that.
Signed-off-by: Oleg Kanatov <okanatov@gmail.com>
Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com>
Some init function of cdev(like comedi) will call kobject_set_name()
before cdev_add(), but won't free the cdev.kobj.name or put the ref cnt
of cdev.kobj when cdev_add() failed. As the result, cdev.kobj.name will
be leaked.
Free the name of kobject in cdev_add() fail path to prevent memleak. With
this fix, the callers don't need to care about freeing the name of
kobject if cdev_add() fails.
unreferenced object 0xffff8881000fa8c0 (size 8):
comm "modprobe", pid 239, jiffies 4294905173 (age 51.308s)
hex dump (first 8 bytes):
63 6f 6d 65 64 69 00 ff comedi..
backtrace:
[<000000005f9878f7>] __kmalloc_node_track_caller+0x4c/0x1c0
[<000000000fd70302>] kstrdup+0x3f/0x70
[<000000009428bc33>] kstrdup_const+0x46/0x60
[<00000000ed50d9de>] kvasprintf_const+0xdb/0xf0
[<00000000b2766964>] kobject_set_name_vargs+0x3c/0xe0
[<00000000f2424ef7>] kobject_set_name+0x62/0x90
[<000000005d5a125b>] 0xffffffffa0013098
[<00000000f331e663>] do_one_initcall+0x7a/0x380
[<00000000aa7bac96>] do_init_module+0x5c/0x230
[<000000005fd72335>] load_module+0x227d/0x2420
[<00000000ad550cf1>] __do_sys_finit_module+0xd5/0x140
[<00000000069a60c5>] do_syscall_64+0x3f/0x90
[<00000000c5e0d521>] entry_SYSCALL_64_after_hwframe+0x63/0xcd
Suggested-by: Greg KH <gregkh@linuxfoundation.org>
Signed-off-by: Shang XiaoJing <shangxiaojing@huawei.com>
Link: https://lore.kernel.org/r/20221102072659.23671-1-shangxiaojing@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Pull btrfs fixes from David Sterba:
- revert memory optimization for scrub blocks, this misses errors in
2nd and following blocks
- add exception for ENOMEM as reason for transaction abort to not print
stack trace, syzbot has reported many
- zoned fixes:
- fix locking imbalance during scrub
- initialize zones for seeding device
- initialize zones for cloned device structures
- when looking up device, change assertion to a real check as some of
the search parameters can be passed by ioctl, reported by syzbot
- fix error pointer check in self tests
* tag 'for-6.1-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
btrfs: zoned: fix locking imbalance on scrub
btrfs: zoned: initialize device's zone info for seeding
btrfs: zoned: clone zoned device info when cloning a device
Revert "btrfs: scrub: use larger block size for data extent scrub"
btrfs: don't print stack trace when transaction is aborted due to ENOMEM
btrfs: selftests: fix wrong error check in btrfs_free_dummy_root()
btrfs: fix match incorrectly in dev_args_match_device
When erofs instance is remounted with fsid or domain_id mount option
specified, the original fsid and domain_id string pointer in sbi->opt
is directly overridden with the fsid and domain_id string in the new
fs_context, without freeing the original fsid and domain_id string.
What's worse, when the new fsid and domain_id string is transferred to
sbi, they are not reset to NULL in fs_context, and thus they are freed
when remount finishes, while sbi is still referring to these strings.
Reconfiguration for fsid and domain_id seems unusual. Thus clarify this
restriction explicitly and dump a warning when users are attempting to
do this.
Besides, to fix the use-after-free issue, move fsid and domain_id from
erofs_mount_opts to outside.
Fixes: c6be2bd0a5 ("erofs: register fscache volume")
Fixes: 8b7adf1dff ("erofs: introduce fscache-based domain")
Signed-off-by: Jingbo Xu <jefflexu@linux.alibaba.com>
Reviewed-by: Jia Zhu <zhujia.zj@bytedance.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Link: https://lore.kernel.org/r/20221021023153.1330-1-jefflexu@linux.alibaba.com
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Syzbot reported a slab-out-of-bounds Write bug:
loop0: detected capacity change from 0 to 2048
==================================================================
BUG: KASAN: slab-out-of-bounds in udf_find_entry+0x8a5/0x14f0
fs/udf/namei.c:253
Write of size 105 at addr ffff8880123ff896 by task syz-executor323/3610
CPU: 0 PID: 3610 Comm: syz-executor323 Not tainted
6.1.0-rc2-syzkaller-00105-gb229b6ca5abb #0
Hardware name: Google Compute Engine/Google Compute Engine, BIOS
Google 10/11/2022
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x1b1/0x28e lib/dump_stack.c:106
print_address_description+0x74/0x340 mm/kasan/report.c:284
print_report+0x107/0x1f0 mm/kasan/report.c:395
kasan_report+0xcd/0x100 mm/kasan/report.c:495
kasan_check_range+0x2a7/0x2e0 mm/kasan/generic.c:189
memcpy+0x3c/0x60 mm/kasan/shadow.c:66
udf_find_entry+0x8a5/0x14f0 fs/udf/namei.c:253
udf_lookup+0xef/0x340 fs/udf/namei.c:309
lookup_open fs/namei.c:3391 [inline]
open_last_lookups fs/namei.c:3481 [inline]
path_openat+0x10e6/0x2df0 fs/namei.c:3710
do_filp_open+0x264/0x4f0 fs/namei.c:3740
do_sys_openat2+0x124/0x4e0 fs/open.c:1310
do_sys_open fs/open.c:1326 [inline]
__do_sys_creat fs/open.c:1402 [inline]
__se_sys_creat fs/open.c:1396 [inline]
__x64_sys_creat+0x11f/0x160 fs/open.c:1396
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7ffab0d164d9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89
f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01
f0 ff ff 73 01 c3 48 c7 c1 c0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffe1a7e6bb8 EFLAGS: 00000246 ORIG_RAX: 0000000000000055
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007ffab0d164d9
RDX: 00007ffab0d164d9 RSI: 0000000000000000 RDI: 0000000020000180
RBP: 00007ffab0cd5a10 R08: 0000000000000000 R09: 0000000000000000
R10: 00005555573552c0 R11: 0000000000000246 R12: 00007ffab0cd5aa0
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
</TASK>
Allocated by task 3610:
kasan_save_stack mm/kasan/common.c:45 [inline]
kasan_set_track+0x3d/0x60 mm/kasan/common.c:52
____kasan_kmalloc mm/kasan/common.c:371 [inline]
__kasan_kmalloc+0x97/0xb0 mm/kasan/common.c:380
kmalloc include/linux/slab.h:576 [inline]
udf_find_entry+0x7b6/0x14f0 fs/udf/namei.c:243
udf_lookup+0xef/0x340 fs/udf/namei.c:309
lookup_open fs/namei.c:3391 [inline]
open_last_lookups fs/namei.c:3481 [inline]
path_openat+0x10e6/0x2df0 fs/namei.c:3710
do_filp_open+0x264/0x4f0 fs/namei.c:3740
do_sys_openat2+0x124/0x4e0 fs/open.c:1310
do_sys_open fs/open.c:1326 [inline]
__do_sys_creat fs/open.c:1402 [inline]
__se_sys_creat fs/open.c:1396 [inline]
__x64_sys_creat+0x11f/0x160 fs/open.c:1396
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
The buggy address belongs to the object at ffff8880123ff800
which belongs to the cache kmalloc-256 of size 256
The buggy address is located 150 bytes inside of
256-byte region [ffff8880123ff800, ffff8880123ff900)
The buggy address belongs to the physical page:
page:ffffea000048ff80 refcount:1 mapcount:0 mapping:0000000000000000
index:0x0 pfn:0x123fe
head:ffffea000048ff80 order:1 compound_mapcount:0 compound_pincount:0
flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000010200 ffffea00004b8500 dead000000000003 ffff888012041b40
raw: 0000000000000000 0000000080100010 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x0(),
pid 1, tgid 1 (swapper/0), ts 1841222404, free_ts 0
create_dummy_stack mm/page_owner.c:67 [inline]
register_early_stack+0x77/0xd0 mm/page_owner.c:83
init_page_owner+0x3a/0x731 mm/page_owner.c:93
kernel_init_freeable+0x41c/0x5d5 init/main.c:1629
kernel_init+0x19/0x2b0 init/main.c:1519
page_owner free stack trace missing
Memory state around the buggy address:
ffff8880123ff780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff8880123ff800: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff8880123ff880: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 06
^
ffff8880123ff900: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff8880123ff980: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================
Fix this by changing the memory size allocated for copy_name from
UDF_NAME_LEN(254) to UDF_NAME_LEN_CS0(255), because the total length
(lfi) of subsequent memcpy can be up to 255.
CC: stable@vger.kernel.org
Reported-by: syzbot+69c9fdccc6dd08961d34@syzkaller.appspotmail.com
Fixes: 066b9cded0 ("udf: Use separate buffer for copying split names")
Signed-off-by: ZhangPeng <zhangpeng362@huawei.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20221109013542.442790-1-zhangpeng362@huawei.com
Syzkaller reports a null-ptr-deref bug as follows:
======================================================
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
RIP: 0010:hugetlbfs_parse_param+0x1dd/0x8e0 fs/hugetlbfs/inode.c:1380
[...]
Call Trace:
<TASK>
vfs_parse_fs_param fs/fs_context.c:148 [inline]
vfs_parse_fs_param+0x1f9/0x3c0 fs/fs_context.c:129
vfs_parse_fs_string+0xdb/0x170 fs/fs_context.c:191
generic_parse_monolithic+0x16f/0x1f0 fs/fs_context.c:231
do_new_mount fs/namespace.c:3036 [inline]
path_mount+0x12de/0x1e20 fs/namespace.c:3370
do_mount fs/namespace.c:3383 [inline]
__do_sys_mount fs/namespace.c:3591 [inline]
__se_sys_mount fs/namespace.c:3568 [inline]
__x64_sys_mount+0x27f/0x300 fs/namespace.c:3568
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
[...]
</TASK>
======================================================
According to commit "vfs: parse: deal with zero length string value",
kernel will set the param->string to null pointer in vfs_parse_fs_string()
if fs string has zero length.
Yet the problem is that, hugetlbfs_parse_param() will dereference the
param->string, without checking whether it is a null pointer. To be more
specific, if hugetlbfs_parse_param() parses an illegal mount parameter,
such as "size=,", kernel will constructs struct fs_parameter with null
pointer in vfs_parse_fs_string(), then passes this struct fs_parameter to
hugetlbfs_parse_param(), which triggers the above null-ptr-deref bug.
This patch solves it by adding sanity check on param->string
in hugetlbfs_parse_param().
Link: https://lkml.kernel.org/r/20221020231609.4810-1-yin31149@gmail.com
Reported-by: syzbot+a3e6acd85ded5c16a709@syzkaller.appspotmail.com
Tested-by: syzbot+a3e6acd85ded5c16a709@syzkaller.appspotmail.com
Link: https://lore.kernel.org/all/0000000000005ad00405eb7148c6@google.com/
Signed-off-by: Hawkins Jiawei <yin31149@gmail.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Hawkins Jiawei <yin31149@gmail.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Ian Kent <raven@themaw.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
When psi annotations were added to to btrfs compression reads, the psi
state tracking over add_ra_bio_pages and btrfs_submit_compressed_read was
faulty. A pressure state, once entered, is never left. This results in
incorrectly elevated pressure, which triggers OOM kills.
pflags record the *previous* memstall state when we enter a new one. The
code tried to initialize pflags to 1, and then optimize the leave call
when we either didn't enter a memstall, or were already inside a nested
stall. However, there can be multiple PageWorkingset pages in the bio, at
which point it's that path itself that enters repeatedly and overwrites
pflags. This causes us to miss the exit.
Enter the stall only once if needed, then unwind correctly.
erofs has the same problem, fix that up too. And move the memstall exit
past submit_bio() to restore submit accounting originally added by
b8e24a9300 ("block: annotate refault stalls from IO submission").
Link: https://lkml.kernel.org/r/Y2UHRqthNUwuIQGS@cmpxchg.org
Fixes: 4088a47e78 ("btrfs: add manual PSI accounting for compressed reads")
Fixes: 99486c511f ("erofs: add manual PSI accounting for the compressed address space")
Fixes: 118f3663fb ("block: remove PSI accounting from the bio layer")
Link: https://lore.kernel.org/r/d20a0a85-e415-cf78-27f9-77dd7a94bc8d@leemhuis.info/
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reported-by: Thorsten Leemhuis <linux@leemhuis.info>
Tested-by: Thorsten Leemhuis <linux@leemhuis.info>
Cc: Chao Yu <chao@kernel.org>
Cc: Chris Mason <clm@fb.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Sterba <dsterba@suse.com>
Cc: Gao Xiang <xiang@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Josef Bacik <josef@toxicpanda.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
If a nilfs2 filesystem is downgraded to read-only due to metadata
corruption on disk and is remounted read/write, or if emergency read-only
remount is performed, detaching a log writer and synchronizing the
filesystem can be done at the same time.
In these cases, use-after-free of the log writer (hereinafter
nilfs->ns_writer) can happen as shown in the scenario below:
Task1 Task2
-------------------------------- ------------------------------
nilfs_construct_segment
nilfs_segctor_sync
init_wait
init_waitqueue_entry
add_wait_queue
schedule
nilfs_remount (R/W remount case)
nilfs_attach_log_writer
nilfs_detach_log_writer
nilfs_segctor_destroy
kfree
finish_wait
_raw_spin_lock_irqsave
__raw_spin_lock_irqsave
do_raw_spin_lock
debug_spin_lock_before <-- use-after-free
While Task1 is sleeping, nilfs->ns_writer is freed by Task2. After Task1
waked up, Task1 accesses nilfs->ns_writer which is already freed. This
scenario diagram is based on the Shigeru Yoshida's post [1].
This patch fixes the issue by not detaching nilfs->ns_writer on remount so
that this UAF race doesn't happen. Along with this change, this patch
also inserts a few necessary read-only checks with superblock instance
where only the ns_writer pointer was used to check if the filesystem is
read-only.
Link: https://syzkaller.appspot.com/bug?id=79a4c002e960419ca173d55e863bd09e8112df8b
Link: https://lkml.kernel.org/r/20221103141759.1836312-1-syoshida@redhat.com [1]
Link: https://lkml.kernel.org/r/20221104142959.28296-1-konishi.ryusuke@gmail.com
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Reported-by: syzbot+f816fa82f8783f7a02bb@syzkaller.appspotmail.com
Reported-by: Shigeru Yoshida <syoshida@redhat.com>
Tested-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
A semaphore deadlock can occur if nilfs_get_block() detects metadata
corruption while locating data blocks and a superblock writeback occurs at
the same time:
task 1 task 2
------ ------
* A file operation *
nilfs_truncate()
nilfs_get_block()
down_read(rwsem A) <--
nilfs_bmap_lookup_contig()
... generic_shutdown_super()
nilfs_put_super()
* Prepare to write superblock *
down_write(rwsem B) <--
nilfs_cleanup_super()
* Detect b-tree corruption * nilfs_set_log_cursor()
nilfs_bmap_convert_error() nilfs_count_free_blocks()
__nilfs_error() down_read(rwsem A) <--
nilfs_set_error()
down_write(rwsem B) <--
*** DEADLOCK ***
Here, nilfs_get_block() readlocks rwsem A (= NILFS_MDT(dat_inode)->mi_sem)
and then calls nilfs_bmap_lookup_contig(), but if it fails due to metadata
corruption, __nilfs_error() is called from nilfs_bmap_convert_error()
inside the lock section.
Since __nilfs_error() calls nilfs_set_error() unless the filesystem is
read-only and nilfs_set_error() attempts to writelock rwsem B (=
nilfs->ns_sem) to write back superblock exclusively, hierarchical lock
acquisition occurs in the order rwsem A -> rwsem B.
Now, if another task starts updating the superblock, it may writelock
rwsem B during the lock sequence above, and can deadlock trying to
readlock rwsem A in nilfs_count_free_blocks().
However, there is actually no need to take rwsem A in
nilfs_count_free_blocks() because it, within the lock section, only reads
a single integer data on a shared struct with
nilfs_sufile_get_ncleansegs(). This has been the case after commit
aa474a2201 ("nilfs2: add local variable to cache the number of clean
segments"), that is, even before this bug was introduced.
So, this resolves the deadlock problem by just not taking the semaphore in
nilfs_count_free_blocks().
Link: https://lkml.kernel.org/r/20221029044912.9139-1-konishi.ryusuke@gmail.com
Fixes: e828949e5b ("nilfs2: call nilfs_error inside bmap routines")
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Reported-by: syzbot+45d6ce7b7ad7ef455d03@syzkaller.appspotmail.com
Tested-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Cc: <stable@vger.kernel.org> [2.6.38+
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This change is very similar to the change that was made for shmem [1], and
it solves the same problem but for HugeTLBFS instead.
Currently, when poison is found in a HugeTLB page, the page is removed
from the page cache. That means that attempting to map or read that
hugepage in the future will result in a new hugepage being allocated
instead of notifying the user that the page was poisoned. As [1] states,
this is effectively memory corruption.
The fix is to leave the page in the page cache. If the user attempts to
use a poisoned HugeTLB page with a syscall, the syscall will fail with
EIO, the same error code that shmem uses. For attempts to map the page,
the thread will get a BUS_MCEERR_AR SIGBUS.
[1]: commit a760542666 ("mm: shmem: don't truncate page if memory failure happens")
Link: https://lkml.kernel.org/r/20221018200125.848471-1-jthoughton@google.com
Signed-off-by: James Houghton <jthoughton@google.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Tested-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: James Houghton <jthoughton@google.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
To not get the console spammed about WARN_ON() of invalid states in the
dlm midcomms hot path handling we switch to WARN_ON_ONCE() to get it
only once that there might be an issue with the midcomms state handling.
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
This patch will fix a small issue when printing out that
dlm_midcomms_start() failed to start and it was printing out that the
dlm subcomponent lowcomms was failed but lowcomms is behind the midcomms
layer.
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
This patch will catch a possible dlm_add_member() and delivers it to the
dlm recovery handling.
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
This patch drops additionally the sock_mutex when there is a sending
message burst. Since we have acknowledge handling we free sending
buffers only when we receive an ack back, but if we are stuck in
send_to_sock() looping because dlm sends a lot of messages and we never
leave the loop the sending buffer fill up very quickly. We can't receive
during this iteration because the sock_mutex is held. This patch will
unlock the sock_mutex so it should be possible to receive messages when
a burst of sending messages happens. This will allow to free up memory
because acks which are already received can be processed.
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
This patch removes the ls_remove_wait waitqueue handling. The current
handling tries to wait before a lookup is send out for a identically
resource name which is going to be removed. Hereby the remove message
should be send out before the new lookup message. The reason is that
after a lookup request and response will actually use the specific
remote rsb. A followed remove message would delete the rsb on the remote
side but it's still being used.
To reach a similar behaviour we simple send the remove message out while
the rsb lookup lock is held and the rsb is removed from the toss list.
Other find_rsb() calls would never have the change to get a rsb back to
live while a remove message will be send out (without holding the lock).
This behaviour requires a non-sleepable context which should be provided
now and might be the reason why it was not implemented so in the first
place.
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
This patch allows to give the use control about the allocation context
based on a per message basis. Currently all messages forced to be
created under GFP_NOFS context.
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
This patch will introducde a queue implementation for callbacks by using
the Linux lists. The current callback queue handling is implemented by a
static limit of 6 entries, see DLM_CALLBACKS_SIZE. The sequence number
inside the callback structure was used to see if the entries inside the
static entry is valid or not. We don't need any sequence numbers anymore
with a dynamic datastructure with grows and shrinks during runtime to
offer such functionality.
We assume that every callback will be delivered to the DLM user if once
queued. Therefore the callback flag DLM_CB_SKIP was dropped and the
check for skipping bast was moved before worker handling and not skip
while the callback worker executes. This will reduce unnecessary queues
of the callback worker.
All last callback saves are pointers now and don't need to copied over.
There is a reference counter for callback structures which will care
about to free the callback structures at the right time if they are not
referenced anymore.
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
This patch moves the debugging information of the last cast and bast
time when calling the last and bast function call.
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
There is no need to use a mutex in those hot path sections. We change it
to spin lock to serve callbacks more faster by not allowing schedule.
The locked sections will not be locked for a long time.
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
This patch converts the ls_cb_mutex mutex to a spinlock, there is no
sleepable context when this lock is held.
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
Instead of using list_entry() this patch moves to using the
list_first_entry() macro.
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
We should allow dlm_add_cb() to call queue_work() only after the
recovery queued pending for delayed lkbs. This patch will move the
switch LSFL_CB_DELAY after the delayed lkb work was processed.
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
This patch adds tracepoints for send and recv cases of dlm messages and
dlm rcom messages. In case of send and dlm message we add the dlm rsb
resource name this dlm messages belongs to. This has the advantage to
follow dlm messages on a per lock basis. In case of recv message the
resource name can be extracted by follow the send message sequence
number.
The dlm message DLM_MSG_PURGE doesn't belong to a lock request and will
not set the resource name in a dlm_message trace. The same for all rcom
messages.
There is additional handling required for this debugging functionality
which is tried to be small as possible. Also the midcomms layer gets
aware of lock resource names, for now this is required to make a
connection between sequence number and lock resource names. It is for
debugging purpose only.
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
To allow more than just dereferencing the inner header we directly point
to the inner dlm packet which allows us to dereference the header, rcom
or message structure.
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
This patch removes the send repeat remove handling. This handling is
there to repeatingly DLM_MSG_REMOVE messages in cases the dlm stack
thinks it was not received at the first time. In cases of message drops
this functionality is necessary, but since the DLM midcomms layer
guarantees there are no messages drops between cluster nodes this
feature became not strict necessary anymore. Due message
delays/processing it could be that two send_repeat_remove() are sent out
while the other should be still on it's way. We remove the repeat remove
handling because we are sure that the message cannot be dropped due
communication errors.
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
This patch fixes a race if we get two times an socket data ready event
while the listen connection worker is queued. Currently it will be
served only once but we need to do it (in this case twice) until we hit
-EAGAIN which tells us there is no pending accept going on.
This patch wraps an do while loop until we receive a return value which
is different than 0 as it was done before commit d11ccd451b ("fs: dlm:
listen socket out of connection hash").
Cc: stable@vger.kernel.org
Fixes: d11ccd451b ("fs: dlm: listen socket out of connection hash")
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
