Commit Graph

89321 Commits

Author SHA1 Message Date
Jan Kara
d4d40e1219 quota: Properly annotate i_dquot arrays with __rcu
[ Upstream commit ccb49011bb ]

Dquots pointed to from i_dquot arrays in inodes are protected by
dquot_srcu. Annotate them as such and change .get_dquots callback to
return properly annotated pointer to make sparse happy.

Fixes: b9ba6f94b2 ("quota: remove dqptr_sem")
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-03-26 18:17:03 -04:00
Jan Kara
4772b81037 quota: Fix rcu annotations of inode dquot pointers
[ Upstream commit 179b8c97eb ]

Dquot pointers in i_dquot array in the inode are protected by
dquot_srcu. Annotate the array pointers with __rcu, perform the locked
dereferences with srcu_dereference_check() instead of plain reads, and
set the array elements with rcu_assign_pointer().

Fixes: b9ba6f94b2 ("quota: remove dqptr_sem")
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202402061900.rTuYDlo6-lkp@intel.com/
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-03-26 18:17:03 -04:00
Wang Jianjian
6afc9f4434 quota: Fix potential NULL pointer dereference
[ Upstream commit d0aa72604f ]

Below race may cause NULL pointer dereference

P1					P2
dquot_free_inode			quota_off
					  drop_dquot_ref
					   remove_dquot_ref
					   dquots = i_dquot(inode)
  dquots = i_dquot(inode)
  srcu_read_lock
  dquots[cnt]) != NULL (1)
					     dquots[type] = NULL (2)
  spin_lock(&dquots[cnt]->dq_dqb_lock) (3)
   ....

If dquot_free_inode(or other routines) checks inode's quota pointers (1)
before quota_off sets it to NULL(2) and use it (3) after that, NULL pointer
dereference will be triggered.

So let's fix it by using a temporary pointer to avoid this issue.

Signed-off-by: Wang Jianjian <wangjianjian3@huawei.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Message-Id: <20240202081852.2514092-1-wangjianjian3@huawei.com>
Stable-dep-of: 179b8c97eb ("quota: Fix rcu annotations of inode dquot pointers")
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-03-26 18:17:03 -04:00
Baokun Li
b50efb417c erofs: fix lockdep false positives on initializing erofs_pseudo_mnt
[ Upstream commit 0f28be64d1 ]

Lockdep reported the following issue when mounting erofs with a domain_id:

============================================
WARNING: possible recursive locking detected
6.8.0-rc7-xfstests #521 Not tainted
--------------------------------------------
mount/396 is trying to acquire lock:
ffff907a8aaaa0e0 (&type->s_umount_key#50/1){+.+.}-{3:3},
						at: alloc_super+0xe3/0x3d0

but task is already holding lock:
ffff907a8aaa90e0 (&type->s_umount_key#50/1){+.+.}-{3:3},
						at: alloc_super+0xe3/0x3d0

other info that might help us debug this:
 Possible unsafe locking scenario:

       CPU0
       ----
  lock(&type->s_umount_key#50/1);
  lock(&type->s_umount_key#50/1);

 *** DEADLOCK ***

 May be due to missing lock nesting notation

2 locks held by mount/396:
 #0: ffff907a8aaa90e0 (&type->s_umount_key#50/1){+.+.}-{3:3},
			at: alloc_super+0xe3/0x3d0
 #1: ffffffffc00e6f28 (erofs_domain_list_lock){+.+.}-{3:3},
			at: erofs_fscache_register_fs+0x3d/0x270 [erofs]

stack backtrace:
CPU: 1 PID: 396 Comm: mount Not tainted 6.8.0-rc7-xfstests #521
Call Trace:
 <TASK>
 dump_stack_lvl+0x64/0xb0
 validate_chain+0x5c4/0xa00
 __lock_acquire+0x6a9/0xd50
 lock_acquire+0xcd/0x2b0
 down_write_nested+0x45/0xd0
 alloc_super+0xe3/0x3d0
 sget_fc+0x62/0x2f0
 vfs_get_super+0x21/0x90
 vfs_get_tree+0x2c/0xf0
 fc_mount+0x12/0x40
 vfs_kern_mount.part.0+0x75/0x90
 kern_mount+0x24/0x40
 erofs_fscache_register_fs+0x1ef/0x270 [erofs]
 erofs_fc_fill_super+0x213/0x380 [erofs]

This is because the file_system_type of both erofs and the pseudo-mount
point of domain_id is erofs_fs_type, so two successive calls to
alloc_super() are considered to be using the same lock and trigger the
warning above.

Therefore add a nodev file_system_type called erofs_anon_fs_type in
fscache.c to silence this complaint. Because kern_mount() takes a
pointer to struct file_system_type, not its (string) name. So we don't
need to call register_filesystem(). In addition, call init_pseudo() in
erofs_anon_init_fs_context() as suggested by Al Viro, so that we can
remove erofs_fc_fill_pseudo_super(), erofs_fc_anon_get_tree(), and
erofs_anon_context_ops.

Suggested-by: Al Viro <viro@zeniv.linux.org.uk>
Fixes: a9849560c5 ("erofs: introduce a pseudo mnt to manage shared cookies")
Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-and-tested-by: Jingbo Xu <jefflexu@linux.alibaba.com>
Reviewed-by: Yang Erkun <yangerkun@huawei.com>
Link: https://lore.kernel.org/r/20240307101018.2021925-1-libaokun1@huawei.com
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-03-26 18:16:56 -04:00
Filipe Manana
ced63fffd6 btrfs: fix race when detecting delalloc ranges during fiemap
[ Upstream commit 978b63f746 ]

For fiemap we recently stopped locking the target extent range for the
whole duration of the fiemap call, in order to avoid a deadlock in a
scenario where the fiemap buffer happens to be a memory mapped range of
the same file. This use case is very unlikely to be useful in practice but
it may be triggered by fuzz testing (syzbot, etc).

This however introduced a race that makes us miss delalloc ranges for
file regions that are currently holes, so the caller of fiemap will not
be aware that there's data for some file regions. This can be quite
serious for some use cases - for example in coreutils versions before 9.0,
the cp program used fiemap to detect holes and data in the source file,
copying only regions with data (extents or delalloc) from the source file
to the destination file in order to preserve holes (see the documentation
for its --sparse command line option). This means that if cp was used
with a source file that had delalloc in a hole, the destination file could
end up without that data, which is effectively a data loss issue, if it
happened to hit the race described below.

The race happens like this:

1) Fiemap is called, without the FIEMAP_FLAG_SYNC flag, for a file that
   has delalloc in the file range [64M, 65M[, which is currently a hole;

2) Fiemap locks the inode in shared mode, then starts iterating the
   inode's subvolume tree searching for file extent items, without having
   the whole fiemap target range locked in the inode's io tree - the
   change introduced recently by commit b0ad381fa7 ("btrfs: fix
   deadlock with fiemap and extent locking"). It only locks ranges in
   the io tree when it finds a hole or prealloc extent since that
   commit;

3) Note that fiemap clones each leaf before using it, and this is to
   avoid deadlocks when locking a file range in the inode's io tree and
   the fiemap buffer is memory mapped to some file, because writing
   to the page with btrfs_page_mkwrite() will wait on any ordered extent
   for the page's range and the ordered extent needs to lock the range
   and may need to modify the same leaf, therefore leading to a deadlock
   on the leaf;

4) While iterating the file extent items in the cloned leaf before
   finding the hole in the range [64M, 65M[, the delalloc in that range
   is flushed and its ordered extent completes - meaning the corresponding
   file extent item is in the inode's subvolume tree, but not present in
   the cloned leaf that fiemap is iterating over;

5) When fiemap finds the hole in the [64M, 65M[ range by seeing the gap in
   the cloned leaf (or a file extent item with disk_bytenr == 0 in case
   the NO_HOLES feature is not enabled), it will lock that file range in
   the inode's io tree and then search for delalloc by checking for the
   EXTENT_DELALLOC bit in the io tree for that range and ordered extents
   (with btrfs_find_delalloc_in_range()). But it finds nothing since the
   delalloc in that range was already flushed and the ordered extent
   completed and is gone - as a result fiemap will not report that there's
   delalloc or an extent for the range [64M, 65M[, so user space will be
   mislead into thinking that there's a hole in that range.

This could actually be sporadically triggered with test case generic/094
from fstests, which reports a missing extent/delalloc range like this:

#  generic/094 2s ... - output mismatch (see /home/fdmanana/git/hub/xfstests/results//generic/094.out.bad)
#      --- tests/generic/094.out	2020-06-10 19:29:03.830519425 +0100
#      +++ /home/fdmanana/git/hub/xfstests/results//generic/094.out.bad	2024-02-28 11:00:00.381071525 +0000
#      @@ -1,3 +1,9 @@
#       QA output created by 094
#       fiemap run with sync
#       fiemap run without sync
#      +ERROR: couldn't find extent at 7
#      +map is 'HHDDHPPDPHPH'
#      +logical: [       5..       6] phys:   301517..  301518 flags: 0x800 tot: 2
#      +logical: [       8..       8] phys:   301520..  301520 flags: 0x800 tot: 1
#      ...
#      (Run 'diff -u /home/fdmanana/git/hub/xfstests/tests/generic/094.out /home/fdmanana/git/hub/xfstests/results//generic/094.out.bad'  to see the entire diff)

So in order to fix this, while still avoiding deadlocks in the case where
the fiemap buffer is memory mapped to the same file, change fiemap to work
like the following:

1) Always lock the whole range in the inode's io tree before starting to
   iterate the inode's subvolume tree searching for file extent items,
   just like we did before commit b0ad381fa7 ("btrfs: fix deadlock with
   fiemap and extent locking");

2) Now instead of writing to the fiemap buffer every time we have an extent
   to report, write instead to a temporary buffer (1 page), and when that
   buffer becomes full, stop iterating the file extent items, unlock the
   range in the io tree, release the search path, submit all the entries
   kept in that buffer to the fiemap buffer, and then resume the search
   for file extent items after locking again the remainder of the range in
   the io tree.

   The buffer having a size of a page, allows for 146 entries in a system
   with 4K pages. This is a large enough value to have a good performance
   by avoiding too many restarts of the search for file extent items.
   In other words this preserves the huge performance gains made in the
   last two years to fiemap, while avoiding the deadlocks in case the
   fiemap buffer is memory mapped to the same file (useless in practice,
   but possible and exercised by fuzz testing and syzbot).

Fixes: b0ad381fa7 ("btrfs: fix deadlock with fiemap and extent locking")
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-03-26 18:16:51 -04:00
Kees Cook
340682ed19 pstore: inode: Only d_invalidate() is needed
[ Upstream commit a43e0fc5e9 ]

Unloading a modular pstore backend with records in pstorefs would
trigger the dput() double-drop warning:

  WARNING: CPU: 0 PID: 2569 at fs/dcache.c:762 dput.part.0+0x3f3/0x410

Using the combo of d_drop()/dput() (as mentioned in
Documentation/filesystems/vfs.rst) isn't the right approach here, and
leads to the reference counting problem seen above. Use d_invalidate()
and update the code to not bother checking for error codes that can
never happen.

Suggested-by: Alexander Viro <viro@zeniv.linux.org.uk>
Fixes: 609e28bb13 ("pstore: Remove filesystem records when backend is unregistered")
Signed-off-by: Kees Cook <keescook@chromium.org>
2024-03-26 18:16:49 -04:00
Gabriel Krisman Bertazi
f3254829bd ovl: Always reject mounting over case-insensitive directories
[ Upstream commit 2824083db7 ]

overlayfs relies on the filesystem setting DCACHE_OP_HASH or
DCACHE_OP_COMPARE to reject mounting over case-insensitive directories.

Since commit bb9cd9106b ("fscrypt: Have filesystems handle their
d_ops"), we set ->d_op through a hook in ->d_lookup, which
means the root dentry won't have them, causing the mount to accidentally
succeed.

In v6.7-rc7, the following sequence will succeed to mount, but any
dentry other than the root dentry will be a "weird" dentry to ovl and
fail with EREMOTE.

  mkfs.ext4 -O casefold lower.img
  mount -O loop lower.img lower
  mount -t overlay -o lowerdir=lower,upperdir=upper,workdir=work ovl /mnt

Mounting on a subdirectory fails, as expected, because DCACHE_OP_HASH
and DCACHE_OP_COMPARE are properly set by ->lookup.

Fix by explicitly rejecting superblocks that allow case-insensitive
dentries. Yes, this will be solved when we move d_op configuration back
to ->s_d_op. Yet, we better have an explicit fix to avoid messing up
again.

While there, re-sort the entries to have more descriptive error messages
first.

Fixes: bb9cd9106b ("fscrypt: Have filesystems handle their d_ops")
Acked-by: Amir Goldstein <amir73il@gmail.com>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Link: https://lore.kernel.org/r/20240221171412.10710-2-krisman@suse.de
Signed-off-by: Gabriel Krisman Bertazi <krisman@suse.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-03-26 18:16:28 -04:00
Arnd Bergmann
c4c1b96bb8 fs/select: rework stack allocation hack for clang
[ Upstream commit ddb9fd7a54 ]

A while ago, we changed the way that select() and poll() preallocate
a temporary buffer just under the size of the static warning limit of
1024 bytes, as clang was frequently going slightly above that limit.

The warnings have recently returned and I took another look. As it turns
out, clang is not actually inherently worse at reserving stack space,
it just happens to inline do_select() into core_sys_select(), while gcc
never inlines it.

Annotate do_select() to never be inlined and in turn remove the special
case for the allocation size. This should give the same behavior for
both clang and gcc all the time and once more avoids those warnings.

Fixes: ad312f95d4 ("fs/select: avoid clang stack usage warning")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/20240216202352.2492798-1-arnd@kernel.org
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Andi Kleen <ak@linux.intel.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-03-26 18:16:27 -04:00
Randy Dunlap
0951b0a09e fs/hfsplus: use better @opf description
[ Upstream commit cf12445dae ]

Use a more descriptive explanation of the @opf function parameter,
more in line with <linux/blk_types.h>.

Fixes: 02105f18a2 ("fs/hfsplus: wrapper.c: fix kernel-doc warnings")
Suggested-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Link: https://lore.kernel.org/r/20240210050606.9182-1-rdunlap@infradead.org
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-03-26 18:16:27 -04:00
Bart Van Assche
038cc4a508 fs: Fix rw_hint validation
[ Upstream commit ec16b147a5 ]

Reject values that are valid rw_hints after truncation but not before
truncation by passing an untruncated value to rw_hint_valid().

Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Kanchan Joshi <joshi.k@samsung.com>
Cc: Jeff Layton <jlayton@kernel.org>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Fixes: 5657cb0797 ("fs/fcntl: use copy_to/from_user() for u64 types")
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20240202203926.2478590-2-bvanassche@acm.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-03-26 18:16:26 -04:00
Christoph Hellwig
fc6391de33 iomap: clear the per-folio dirty bits on all writeback failures
[ Upstream commit 7ea1d9b4a8 ]

write_cache_pages always clear the page dirty bit before calling into the
file systems, and leaves folios with a writeback failure without the
dirty bit after return.  We also clear the per-block writeback bits for
writeback failures unless no I/O has submitted, which will leave the
folio in an inconsistent state where it doesn't have the folio dirty,
but one or more per-block dirty bits.  This seems to be due the place
where the iomap_clear_range_dirty call was inserted into the existing
not very clearly structured code when adding per-block dirty bit support
and not actually intentional.  Switch to always clearing the dirty on
writeback failure.

Fixes: 4ce02c6797 ("iomap: Add per-block dirty state tracking to improve performance")
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20231207072710.176093-2-hch@lst.de
Signed-off-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-03-26 18:16:26 -04:00
Nikita Zhandarovich
bf9ec1b24a do_sys_name_to_handle(): use kzalloc() to fix kernel-infoleak
[ Upstream commit 3948abaa4e ]

syzbot identified a kernel information leak vulnerability in
do_sys_name_to_handle() and issued the following report [1].

[1]
"BUG: KMSAN: kernel-infoleak in instrument_copy_to_user include/linux/instrumented.h:114 [inline]
BUG: KMSAN: kernel-infoleak in _copy_to_user+0xbc/0x100 lib/usercopy.c:40
 instrument_copy_to_user include/linux/instrumented.h:114 [inline]
 _copy_to_user+0xbc/0x100 lib/usercopy.c:40
 copy_to_user include/linux/uaccess.h:191 [inline]
 do_sys_name_to_handle fs/fhandle.c:73 [inline]
 __do_sys_name_to_handle_at fs/fhandle.c:112 [inline]
 __se_sys_name_to_handle_at+0x949/0xb10 fs/fhandle.c:94
 __x64_sys_name_to_handle_at+0xe4/0x140 fs/fhandle.c:94
 ...

Uninit was created at:
 slab_post_alloc_hook+0x129/0xa70 mm/slab.h:768
 slab_alloc_node mm/slub.c:3478 [inline]
 __kmem_cache_alloc_node+0x5c9/0x970 mm/slub.c:3517
 __do_kmalloc_node mm/slab_common.c:1006 [inline]
 __kmalloc+0x121/0x3c0 mm/slab_common.c:1020
 kmalloc include/linux/slab.h:604 [inline]
 do_sys_name_to_handle fs/fhandle.c:39 [inline]
 __do_sys_name_to_handle_at fs/fhandle.c:112 [inline]
 __se_sys_name_to_handle_at+0x441/0xb10 fs/fhandle.c:94
 __x64_sys_name_to_handle_at+0xe4/0x140 fs/fhandle.c:94
 ...

Bytes 18-19 of 20 are uninitialized
Memory access of size 20 starts at ffff888128a46380
Data copied to user address 0000000020000240"

Per Chuck Lever's suggestion, use kzalloc() instead of kmalloc() to
solve the problem.

Fixes: 990d6c2d7a ("vfs: Add name to file handle conversion support")
Suggested-by: Chuck Lever III <chuck.lever@oracle.com>
Reported-and-tested-by: <syzbot+09b349b3066c2e0b1e96@syzkaller.appspotmail.com>
Signed-off-by: Nikita Zhandarovich <n.zhandarovich@fintech.ru>
Link: https://lore.kernel.org/r/20240119153906.4367-1-n.zhandarovich@fintech.ru
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-03-26 18:16:25 -04:00
Linus Torvalds
d0e88885b8 Changes since last update:
- Fix a KMSAN uninit-value issue triggered by a crafted image;
 
  - Fix VMA alignment for memory mapped files on THP.
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Merge tag 'erofs-for-6.8-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/xiang/erofs

Pull erofs fixes from Gao Xiang:
 "The main one is a KMSAN fix which addresses an issue introduced in
  this cycle so it'd be much better to fix before releasing, and the
  remaining one fixes VMA alignment for THP.

  Summary:

   - Fix a KMSAN uninit-value issue triggered by a crafted image

   - Fix VMA alignment for memory mapped files on THP"

* tag 'erofs-for-6.8-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/xiang/erofs:
  erofs: apply proper VMA alignment for memory mapped files on THP
  erofs: fix uninitialized page cache reported by KMSAN
2024-03-07 09:31:47 -08:00
Gao Xiang
4127caee89 erofs: apply proper VMA alignment for memory mapped files on THP
There are mainly two reasons that thp_get_unmapped_area() should be
used for EROFS as other filesystems:

 - It's needed to enable PMD mappings as a FSDAX filesystem, see
   commit 74d2fad133 ("thp, dax: add thp_get_unmapped_area for pmd
   mappings");

 - It's useful together with large folios and
   CONFIG_READ_ONLY_THP_FOR_FS which enable THPs for mmapped files
   (e.g. shared libraries) even without FSDAX.  See commit 1854bc6e24
   ("mm/readahead: Align file mappings for non-DAX").

Fixes: 06252e9ce0 ("erofs: dax support for non-tailpacking regular file")
Fixes: ce529cc25b ("erofs: enable large folios for iomap mode")
Fixes: e6687b8922 ("erofs: enable large folios for fscache mode")
Reviewed-by: Jingbo Xu <jefflexu@linux.alibaba.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Link: https://lore.kernel.org/r/20240306053138.2240206-1-hsiangkao@linux.alibaba.com
2024-03-07 10:21:10 +08:00
Gao Xiang
893e5e9b73 erofs: fix uninitialized page cache reported by KMSAN
syzbot reports a KMSAN reproducer [1] which generates a crafted
filesystem image and causes IMA to read uninitialized page cache.

Later, (rq->outputsize > rq->inputsize) will be formally supported
after either large uncompressed pclusters (> block size) or big
lclusters are landed.  However, currently there is no way to generate
such filesystems by using mkfs.erofs.

Thus, let's mark this condition as unsupported for now.

[1] https://lore.kernel.org/r/0000000000002be12a0611ca7ff8@google.com

Reported-and-tested-by: syzbot+7bc44a489f0ef0670bd5@syzkaller.appspotmail.com
Fixes: 1ca0152014 ("erofs: refine z_erofs_transform_plain() for sub-page block support")
Reviewed-by: Sandeep Dhavale <dhavale@google.com>
Reviewed-by: Yue Hu <huyue2@coolpad.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Link: https://lore.kernel.org/r/20240304035339.425857-1-hsiangkao@linux.alibaba.com
2024-03-07 10:21:00 +08:00
Linus Torvalds
a50026bdb8
iov_iter: get rid of 'copy_mc' flag
This flag is only set by one single user: the magical core dumping code
that looks up user pages one by one, and then writes them out using
their kernel addresses (by using a BVEC_ITER).

That actually ends up being a huge problem, because while we do use
copy_mc_to_kernel() for this case and it is able to handle the possible
machine checks involved, nothing else is really ready to handle the
failures caused by the machine check.

In particular, as reported by Tong Tiangen, we don't actually support
fault_in_iov_iter_readable() on a machine check area.

As a result, the usual logic for writing things to a file under a
filesystem lock, which involves doing a copy with page faults disabled
and then if that fails trying to fault pages in without holding the
locks with fault_in_iov_iter_readable() does not work at all.

We could decide to always just make the MC copy "succeed" (and filling
the destination with zeroes), and that would then create a core dump
file that just ignores any machine checks.

But honestly, this single special case has been problematic before, and
means that all the normal iov_iter code ends up slightly more complex
and slower.

See for example commit c9eec08bac ("iov_iter: Don't deal with
iter->copy_mc in memcpy_from_iter_mc()") where David Howells
re-organized the code just to avoid having to check the 'copy_mc' flags
inside the inner iov_iter loops.

So considering that we have exactly one user, and that one user is a
non-critical special case that doesn't actually ever trigger in real
life (Tong found this with manual error injection), the sane solution is
to just decide that the onus on handling the machine check lines on that
user instead.

Ergo, do the copy_mc_to_kernel() in the core dump logic itself, copying
the user data to a stable kernel page before writing it out.

Fixes: f1982740f5 ("iov_iter: Convert iterate*() to inline funcs")
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Tong Tiangen <tongtiangen@huawei.com>
Link: https://lore.kernel.org/r/20240305133336.3804360-1-tongtiangen@huawei.com
Link: https://lore.kernel.org/all/4e80924d-9c85-f13a-722a-6a5d2b1c225a@huawei.com/
Tested-by: David Howells <dhowells@redhat.com>
Reviewed-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Reported-by: Tong Tiangen <tongtiangen@huawei.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-03-06 10:52:12 +01:00
Bart Van Assche
961ebd1205 fs/aio: Check IOCB_AIO_RW before the struct aio_kiocb conversion
The first kiocb_set_cancel_fn() argument may point at a struct kiocb
that is not embedded inside struct aio_kiocb. With the current code,
depending on the compiler, the req->ki_ctx read happens either before
the IOCB_AIO_RW test or after that test. Move the req->ki_ctx read such
that it is guaranteed that the IOCB_AIO_RW test happens first.

Reported-by: Eric Biggers <ebiggers@kernel.org>
Cc: Benjamin LaHaise <ben@communityfibre.ca>
Cc: Eric Biggers <ebiggers@google.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Avi Kivity <avi@scylladb.com>
Cc: Sandeep Dhavale <dhavale@google.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: stable@vger.kernel.org
Fixes: b820de741a ("fs/aio: Restrict kiocb_set_cancel_fn() to I/O submitted via libaio")
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20240304235715.3790858-1-bvanassche@acm.org
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-03-05 10:40:58 +01:00
Bart Van Assche
28468cbed9 Revert "fs/aio: Make io_cancel() generate completions again"
Patch "fs/aio: Make io_cancel() generate completions again" is based on the
assumption that calling kiocb->ki_cancel() does not complete R/W requests.
This is incorrect: the two drivers that call kiocb_set_cancel_fn() callers
set a cancellation function that calls usb_ep_dequeue(). According to its
documentation, usb_ep_dequeue() calls the completion routine with status
-ECONNRESET. Hence this revert.

Cc: Benjamin LaHaise <ben@communityfibre.ca>
Cc: Eric Biggers <ebiggers@google.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Avi Kivity <avi@scylladb.com>
Cc: Sandeep Dhavale <dhavale@google.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: stable@vger.kernel.org
Reported-by: syzbot+b91eb2ed18f599dd3c31@syzkaller.appspotmail.com
Fixes: 54cbc058d8 ("fs/aio: Make io_cancel() generate completions again")
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20240304182945.3646109-1-bvanassche@acm.org
Acked-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-03-05 10:00:57 +01:00
Linus Torvalds
4640e2be39 Changes for 6.8-rc7:
* Drop experimental warning for FSDAX.
 
 Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>
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Merge tag 'xfs-6.8-fixes-4' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux

Pull xfs fix from Chandan Babu:
 "Drop experimental warning message when mounting an xfs filesystem on
  an fsdax device. We now consider xfs on fsdax to be stable"

* tag 'xfs-6.8-fixes-4' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux:
  xfs: drop experimental warning for FSDAX
2024-03-02 09:38:03 -08:00
Linus Torvalds
5870ba3dc6 A patch to catch up with mdsmap encoding rectification which ended up
being necessary after all to enable cluster upgrades from problematic
 v18.2.0 and v18.2.1 releases.
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Merge tag 'ceph-for-6.8-rc7' of https://github.com/ceph/ceph-client

Pull ceph fix from Ilya Dryomov:
 "Catch up with mdsmap encoding rectification which ended up being
  necessary after all to enable cluster upgrades from problematic
  v18.2.0 and v18.2.1 releases"

* tag 'ceph-for-6.8-rc7' of https://github.com/ceph/ceph-client:
  ceph: switch to corrected encoding of max_xattr_size in mdsmap
2024-03-01 12:34:23 -08:00
Linus Torvalds
7505aa147a for-6.8-rc6-tag
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Merge tag 'for-6.8-rc6-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux

Pull btrfs fixes from David Sterba:

 - fix freeing allocated id for anon dev when snapshot creation fails

 - fiemap fixes:
     - followup for a recent deadlock fix, ranges that fiemap can access
       can still race with ordered extent completion
     - make sure fiemap with SYNC flag does not race with writes

* tag 'for-6.8-rc6-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
  btrfs: fix double free of anonymous device after snapshot creation failure
  btrfs: ensure fiemap doesn't race with writes when FIEMAP_FLAG_SYNC is given
  btrfs: fix race between ordered extent completion and fiemap
2024-03-01 12:29:20 -08:00
Linus Torvalds
3aec97e0c7 Description for this pull request:
- Fix ftruncate failure when allocating non-contiguous clusters.
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Merge tag 'exfat-for-6.8-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/linkinjeon/exfat

Pull exfat fix from Namjae Jeon:

 - Fix ftruncate failure when allocating non-contiguous clusters

* tag 'exfat-for-6.8-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/linkinjeon/exfat:
  exfat: fix appending discontinuous clusters to empty file
2024-03-01 12:22:30 -08:00
Linus Torvalds
1678f8d85d vfs-6.8-rc7.fixes
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Merge tag 'vfs-6.8-rc7.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

Pull vfs fixes from Christian Brauner:
 "Two small fixes:

   - Fix an endless loop during afs directory iteration caused by not
     skipping silly-rename files correctly.

   - Fix reporting of completion events for aio causing leaks in
     userspace. This is based on the fix last week as it's now possible
     to recognize aio events submitted through the old aio interface"

* tag 'vfs-6.8-rc7.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
  fs/aio: Make io_cancel() generate completions again
  afs: Fix endless loop in directory parsing
2024-03-01 12:17:02 -08:00
Linus Torvalds
2bbb54ba1b EFI fixes for v6.8 #2
- Fix phys_addr_t size confusion in 32-bit capsule loader
 - Reduce maximum EFI variable name size to 512 to work around buggy
   firmware
 - Drop some redundant code from efivarfs while at it
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Merge tag 'efi-fixes-for-v6.8-2' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi

Pull EFI fixes from Ard Biesheuvel:
 "Only the EFI variable name size change is significant, and will be
  backported once it lands. The others are cleanup.

   - Fix phys_addr_t size confusion in 32-bit capsule loader

   - Reduce maximum EFI variable name size to 512 to work around buggy
     firmware

   - Drop some redundant code from efivarfs while at it"

* tag 'efi-fixes-for-v6.8-2' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi:
  efivarfs: Drop 'duplicates' bool parameter on efivar_init()
  efivarfs: Drop redundant cleanup on fill_super() failure
  efivarfs: Request at most 512 bytes for variable names
  efi/capsule-loader: fix incorrect allocation size
2024-03-01 11:40:29 -08:00
Filipe Manana
e2b54eaf28 btrfs: fix double free of anonymous device after snapshot creation failure
When creating a snapshot we may do a double free of an anonymous device
in case there's an error committing the transaction. The second free may
result in freeing an anonymous device number that was allocated by some
other subsystem in the kernel or another btrfs filesystem.

The steps that lead to this:

1) At ioctl.c:create_snapshot() we allocate an anonymous device number
   and assign it to pending_snapshot->anon_dev;

2) Then we call btrfs_commit_transaction() and end up at
   transaction.c:create_pending_snapshot();

3) There we call btrfs_get_new_fs_root() and pass it the anonymous device
   number stored in pending_snapshot->anon_dev;

4) btrfs_get_new_fs_root() frees that anonymous device number because
   btrfs_lookup_fs_root() returned a root - someone else did a lookup
   of the new root already, which could some task doing backref walking;

5) After that some error happens in the transaction commit path, and at
   ioctl.c:create_snapshot() we jump to the 'fail' label, and after
   that we free again the same anonymous device number, which in the
   meanwhile may have been reallocated somewhere else, because
   pending_snapshot->anon_dev still has the same value as in step 1.

Recently syzbot ran into this and reported the following trace:

  ------------[ cut here ]------------
  ida_free called for id=51 which is not allocated.
  WARNING: CPU: 1 PID: 31038 at lib/idr.c:525 ida_free+0x370/0x420 lib/idr.c:525
  Modules linked in:
  CPU: 1 PID: 31038 Comm: syz-executor.2 Not tainted 6.8.0-rc4-syzkaller-00410-gc02197fc9076 #0
  Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
  RIP: 0010:ida_free+0x370/0x420 lib/idr.c:525
  Code: 10 42 80 3c 28 (...)
  RSP: 0018:ffffc90015a67300 EFLAGS: 00010246
  RAX: be5130472f5dd000 RBX: 0000000000000033 RCX: 0000000000040000
  RDX: ffffc90009a7a000 RSI: 000000000003ffff RDI: 0000000000040000
  RBP: ffffc90015a673f0 R08: ffffffff81577992 R09: 1ffff92002b4cdb4
  R10: dffffc0000000000 R11: fffff52002b4cdb5 R12: 0000000000000246
  R13: dffffc0000000000 R14: ffffffff8e256b80 R15: 0000000000000246
  FS:  00007fca3f4b46c0(0000) GS:ffff8880b9500000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 00007f167a17b978 CR3: 000000001ed26000 CR4: 0000000000350ef0
  Call Trace:
   <TASK>
   btrfs_get_root_ref+0xa48/0xaf0 fs/btrfs/disk-io.c:1346
   create_pending_snapshot+0xff2/0x2bc0 fs/btrfs/transaction.c:1837
   create_pending_snapshots+0x195/0x1d0 fs/btrfs/transaction.c:1931
   btrfs_commit_transaction+0xf1c/0x3740 fs/btrfs/transaction.c:2404
   create_snapshot+0x507/0x880 fs/btrfs/ioctl.c:848
   btrfs_mksubvol+0x5d0/0x750 fs/btrfs/ioctl.c:998
   btrfs_mksnapshot+0xb5/0xf0 fs/btrfs/ioctl.c:1044
   __btrfs_ioctl_snap_create+0x387/0x4b0 fs/btrfs/ioctl.c:1306
   btrfs_ioctl_snap_create_v2+0x1ca/0x400 fs/btrfs/ioctl.c:1393
   btrfs_ioctl+0xa74/0xd40
   vfs_ioctl fs/ioctl.c:51 [inline]
   __do_sys_ioctl fs/ioctl.c:871 [inline]
   __se_sys_ioctl+0xfe/0x170 fs/ioctl.c:857
   do_syscall_64+0xfb/0x240
   entry_SYSCALL_64_after_hwframe+0x6f/0x77
  RIP: 0033:0x7fca3e67dda9
  Code: 28 00 00 00 (...)
  RSP: 002b:00007fca3f4b40c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
  RAX: ffffffffffffffda RBX: 00007fca3e7abf80 RCX: 00007fca3e67dda9
  RDX: 00000000200005c0 RSI: 0000000050009417 RDI: 0000000000000003
  RBP: 00007fca3e6ca47a R08: 0000000000000000 R09: 0000000000000000
  R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
  R13: 000000000000000b R14: 00007fca3e7abf80 R15: 00007fff6bf95658
   </TASK>

Where we get an explicit message where we attempt to free an anonymous
device number that is not currently allocated. It happens in a different
code path from the example below, at btrfs_get_root_ref(), so this change
may not fix the case triggered by syzbot.

To fix at least the code path from the example above, change
btrfs_get_root_ref() and its callers to receive a dev_t pointer argument
for the anonymous device number, so that in case it frees the number, it
also resets it to 0, so that up in the call chain we don't attempt to do
the double free.

CC: stable@vger.kernel.org # 5.10+
Link: https://lore.kernel.org/linux-btrfs/000000000000f673a1061202f630@google.com/
Fixes: e03ee2fe87 ("btrfs: do not ASSERT() if the newly created subvolume already got read")
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-02-29 22:34:11 +01:00
Filipe Manana
418b090277 btrfs: ensure fiemap doesn't race with writes when FIEMAP_FLAG_SYNC is given
When FIEMAP_FLAG_SYNC is given to fiemap the expectation is that that
are no concurrent writes and we get a stable view of the inode's extent
layout.

When the flag is given we flush all IO (and wait for ordered extents to
complete) and then lock the inode in shared mode, however that leaves open
the possibility that a write might happen right after the flushing and
before locking the inode. So fix this by flushing again after locking the
inode - we leave the initial flushing before locking the inode to avoid
holding the lock and blocking other RO operations while waiting for IO
and ordered extents to complete. The second flushing while holding the
inode's lock will most of the time do nothing or very little since the
time window for new writes to have happened is small.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-02-29 22:34:07 +01:00
Filipe Manana
a1a4a9ca77 btrfs: fix race between ordered extent completion and fiemap
For fiemap we recently stopped locking the target extent range for the
whole duration of the fiemap call, in order to avoid a deadlock in a
scenario where the fiemap buffer happens to be a memory mapped range of
the same file. This use case is very unlikely to be useful in practice but
it may be triggered by fuzz testing (syzbot, etc).

However by not locking the target extent range for the whole duration of
the fiemap call we can race with an ordered extent. This happens like
this:

1) The fiemap task finishes processing a file extent item that covers
   the file range [512K, 1M[, and that file extent item is the last item
   in the leaf currently being processed;

2) And ordered extent for the file range [768K, 2M[, in COW mode,
   completes (btrfs_finish_one_ordered()) and the file extent item
   covering the range [512K, 1M[ is trimmed to cover the range
   [512K, 768K[ and then a new file extent item for the range [768K, 2M[
   is inserted in the inode's subvolume tree;

3) The fiemap task calls fiemap_next_leaf_item(), which then calls
   btrfs_next_leaf() to find the next leaf / item. This finds that the
   the next key following the one we previously processed (its type is
   BTRFS_EXTENT_DATA_KEY and its offset is 512K), is the key corresponding
   to the new file extent item inserted by the ordered extent, which has
   a type of BTRFS_EXTENT_DATA_KEY and an offset of 768K;

4) Later the fiemap code ends up at emit_fiemap_extent() and triggers
   the warning:

      if (cache->offset + cache->len > offset) {
               WARN_ON(1);
               return -EINVAL;
      }

   Since we get 1M > 768K, because the previously emitted entry for the
   old extent covering the file range [512K, 1M[ ends at an offset that
   is greater than the new extent's start offset (768K). This makes fiemap
   fail with -EINVAL besides triggering the warning that produces a stack
   trace like the following:

     [1621.677651] ------------[ cut here ]------------
     [1621.677656] WARNING: CPU: 1 PID: 204366 at fs/btrfs/extent_io.c:2492 emit_fiemap_extent+0x84/0x90 [btrfs]
     [1621.677899] Modules linked in: btrfs blake2b_generic (...)
     [1621.677951] CPU: 1 PID: 204366 Comm: pool Not tainted 6.8.0-rc5-btrfs-next-151+ #1
     [1621.677954] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.2-0-gea1b7a073390-prebuilt.qemu.org 04/01/2014
     [1621.677956] RIP: 0010:emit_fiemap_extent+0x84/0x90 [btrfs]
     [1621.678033] Code: 2b 4c 89 63 (...)
     [1621.678035] RSP: 0018:ffffab16089ffd20 EFLAGS: 00010206
     [1621.678037] RAX: 00000000004fa000 RBX: ffffab16089ffe08 RCX: 0000000000009000
     [1621.678039] RDX: 00000000004f9000 RSI: 00000000004f1000 RDI: ffffab16089ffe90
     [1621.678040] RBP: 00000000004f9000 R08: 0000000000001000 R09: 0000000000000000
     [1621.678041] R10: 0000000000000000 R11: 0000000000001000 R12: 0000000041d78000
     [1621.678043] R13: 0000000000001000 R14: 0000000000000000 R15: ffff9434f0b17850
     [1621.678044] FS:  00007fa6e20006c0(0000) GS:ffff943bdfa40000(0000) knlGS:0000000000000000
     [1621.678046] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
     [1621.678048] CR2: 00007fa6b0801000 CR3: 000000012d404002 CR4: 0000000000370ef0
     [1621.678053] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
     [1621.678055] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
     [1621.678056] Call Trace:
     [1621.678074]  <TASK>
     [1621.678076]  ? __warn+0x80/0x130
     [1621.678082]  ? emit_fiemap_extent+0x84/0x90 [btrfs]
     [1621.678159]  ? report_bug+0x1f4/0x200
     [1621.678164]  ? handle_bug+0x42/0x70
     [1621.678167]  ? exc_invalid_op+0x14/0x70
     [1621.678170]  ? asm_exc_invalid_op+0x16/0x20
     [1621.678178]  ? emit_fiemap_extent+0x84/0x90 [btrfs]
     [1621.678253]  extent_fiemap+0x766/0xa30 [btrfs]
     [1621.678339]  btrfs_fiemap+0x45/0x80 [btrfs]
     [1621.678420]  do_vfs_ioctl+0x1e4/0x870
     [1621.678431]  __x64_sys_ioctl+0x6a/0xc0
     [1621.678434]  do_syscall_64+0x52/0x120
     [1621.678445]  entry_SYSCALL_64_after_hwframe+0x6e/0x76

There's also another case where before calling btrfs_next_leaf() we are
processing a hole or a prealloc extent and we had several delalloc ranges
within that hole or prealloc extent. In that case if the ordered extents
complete before we find the next key, we may end up finding an extent item
with an offset smaller than (or equals to) the offset in cache->offset.

So fix this by changing emit_fiemap_extent() to address these three
scenarios like this:

1) For the first case, steps listed above, adjust the length of the
   previously cached extent so that it does not overlap with the current
   extent, emit the previous one and cache the current file extent item;

2) For the second case where he had a hole or prealloc extent with
   multiple delalloc ranges inside the hole or prealloc extent's range,
   and the current file extent item has an offset that matches the offset
   in the fiemap cache, just discard what we have in the fiemap cache and
   assign the current file extent item to the cache, since it's more up
   to date;

3) For the third case where he had a hole or prealloc extent with
   multiple delalloc ranges inside the hole or prealloc extent's range
   and the offset of the file extent item we just found is smaller than
   what we have in the cache, just skip the current file extent item
   if its range end at or behind the cached extent's end, because we may
   have emitted (to the fiemap user space buffer) delalloc ranges that
   overlap with the current file extent item's range. If the file extent
   item's range goes beyond the end offset of the cached extent, just
   emit the cached extent and cache a subrange of the file extent item,
   that goes from the end offset of the cached extent to the end offset
   of the file extent item.

Dealing with those cases in those ways makes everything consistent by
reflecting the current state of file extent items in the btree and
without emitting extents that have overlapping ranges (which would be
confusing and violating expectations).

This issue could be triggered often with test case generic/561, and was
also hit and reported by Wang Yugui.

Reported-by: Wang Yugui <wangyugui@e16-tech.com>
Link: https://lore.kernel.org/linux-btrfs/20240223104619.701F.409509F4@e16-tech.com/
Fixes: b0ad381fa7 ("btrfs: fix deadlock with fiemap and extent locking")
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-02-29 22:34:04 +01:00
Bart Van Assche
54cbc058d8
fs/aio: Make io_cancel() generate completions again
The following patch accidentally removed the code for delivering
completions for cancelled reads and writes to user space: "[PATCH 04/33]
aio: remove retry-based AIO"
(https://lore.kernel.org/all/1363883754-27966-5-git-send-email-koverstreet@google.com/)
>From that patch:

-	if (kiocbIsCancelled(iocb)) {
-		ret = -EINTR;
-		aio_complete(iocb, ret, 0);
-		/* must not access the iocb after this */
-		goto out;
-	}

This leads to a leak in user space of a struct iocb. Hence this patch
that restores the code that reports to user space that a read or write
has been cancelled successfully.

Fixes: 41003a7bcf ("aio: remove retry-based AIO")
Cc: Christoph Hellwig <hch@lst.de>
Cc: Avi Kivity <avi@scylladb.com>
Cc: Sandeep Dhavale <dhavale@google.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: stable@vger.kernel.org
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20240215204739.2677806-3-bvanassche@acm.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-02-27 11:20:44 +01:00
David Howells
5f7a076466
afs: Fix endless loop in directory parsing
If a directory has a block with only ".__afsXXXX" files in it (from
uncompleted silly-rename), these .__afsXXXX files are skipped but without
advancing the file position in the dir_context.  This leads to
afs_dir_iterate() repeating the block again and again.

Fix this by making the code that skips the .__afsXXXX file also manually
advance the file position.

The symptoms are a soft lookup:

        watchdog: BUG: soft lockup - CPU#3 stuck for 52s! [check:5737]
        ...
        RIP: 0010:afs_dir_iterate_block+0x39/0x1fd
        ...
         ? watchdog_timer_fn+0x1a6/0x213
        ...
         ? asm_sysvec_apic_timer_interrupt+0x16/0x20
         ? afs_dir_iterate_block+0x39/0x1fd
         afs_dir_iterate+0x10a/0x148
         afs_readdir+0x30/0x4a
         iterate_dir+0x93/0xd3
         __do_sys_getdents64+0x6b/0xd4

This is almost certainly the actual fix for:

        https://bugzilla.kernel.org/show_bug.cgi?id=218496

Fixes: 57e9d49c54 ("afs: Hide silly-rename files from userspace")
Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://lore.kernel.org/r/786185.1708694102@warthog.procyon.org.uk
Reviewed-by: Marc Dionne <marc.dionne@auristor.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: Markus Suvanto <markus.suvanto@gmail.com>
cc: linux-afs@lists.infradead.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-02-27 11:20:43 +01:00
Shiyang Ruan
27c86d43bc xfs: drop experimental warning for FSDAX
FSDAX and reflink can work together now, let's drop this warning.

Signed-off-by: Shiyang Ruan <ruansy.fnst@fujitsu.com>
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
Acked-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>
2024-02-27 09:53:30 +05:30
Linus Torvalds
b6c1f1ecb3 for-6.8-rc6-tag
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Merge tag 'for-6.8-rc6-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux

Pull btrfs fixes from David Sterba:
 "A  more fixes for recently reported or discovered problems:

   - fix corner case of send that would generate potentially large
     stream of zeros if there's a hole at the end of the file

   - fix chunk validation in zoned mode on conventional zones, it was
     possible to create chunks that would not be allowed on sequential
     zones

   - fix validation of dev-replace ioctl filenames

   - fix KCSAN warnings about access to block reserve struct members"

* tag 'for-6.8-rc6-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
  btrfs: fix data race at btrfs_use_block_rsv() when accessing block reserve
  btrfs: fix data races when accessing the reserved amount of block reserves
  btrfs: send: don't issue unnecessary zero writes for trailing hole
  btrfs: dev-replace: properly validate device names
  btrfs: zoned: don't skip block group profile checks on conventional zones
2024-02-26 11:00:54 -08:00
Xiubo Li
51d31149a8 ceph: switch to corrected encoding of max_xattr_size in mdsmap
The addition of bal_rank_mask with encoding version 17 was merged
into ceph.git in Oct 2022 and made it into v18.2.0 release normally.
A few months later, the much delayed addition of max_xattr_size got
merged, also with encoding version 17, placed before bal_rank_mask
in the encoding -- but it didn't make v18.2.0 release.

The way this ended up being resolved on the MDS side is that
bal_rank_mask will continue to be encoded in version 17 while
max_xattr_size is now encoded in version 18.  This does mean that
older kernels will misdecode version 17, but this is also true for
v18.2.0 and v18.2.1 clients in userspace.

The best we can do is backport this adjustment -- see ceph.git
commit 78abfeaff27fee343fb664db633de5b221699a73 for details.

[ idryomov: changelog ]

Cc: stable@vger.kernel.org
Link: https://tracker.ceph.com/issues/64440
Fixes: d93231a6bc ("ceph: prevent a client from exceeding the MDS maximum xattr size")
Signed-off-by: Xiubo Li <xiubli@redhat.com>
Reviewed-by: Patrick Donnelly <pdonnell@ibm.com>
Reviewed-by: Venky Shankar <vshankar@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2024-02-26 19:20:30 +01:00
Mark O'Donovan
c8e314624a fs/ntfs3: fix build without CONFIG_NTFS3_LZX_XPRESS
When CONFIG_NTFS3_LZX_XPRESS is not set then we get the following build
error:

  fs/ntfs3/frecord.c:2460:16: error: unused variable ‘i_size’

Signed-off-by: Mark O'Donovan <shiftee@posteo.net>
Fixes: 4fd6c08a16 ("fs/ntfs3: Use i_size_read and i_size_write")
Tested-by: Chris Clayton <chris2553@googlemail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2024-02-26 09:32:23 -08:00
Linus Torvalds
e231dbd452 bcachefs fixes for 6.8-rc6
Some more mostly boring fixes, but some not
 
 User reported ones:
  - the BTREE_ITER_FILTER_SNAPSHOTS one fixes a really nasty performance
    bug; user reported an unter initially taking 2 seconds and then ~2
    minutes
 
  - kill a __GFP_NOFAIL in the buffered read path; this was a leftover
    from the trickier fix to kill __GFP_NOFAIL in readahead, where we
    can't return errors (and have to silently truncate the read
    ourselves).
 
    bcachefs can't use GFP_NOFAIL for folio state unlike iomap based
    filesystems because our folio state is just barely too big, 2MB
    hugepages cause us to exceed the 2 page threshhold for GFP_NOFAIL.
 
    additionally, the flags argument was just buggy, we weren't supplying
    GFP_KERNEL previously (!).
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Merge tag 'bcachefs-2024-02-25' of https://evilpiepirate.org/git/bcachefs

Pull bcachefs fixes from Kent Overstreet:
 "Some more mostly boring fixes, but some not

  User reported ones:

   - the BTREE_ITER_FILTER_SNAPSHOTS one fixes a really nasty
     performance bug; user reported an untar initially taking two
     seconds and then ~2 minutes

   - kill a __GFP_NOFAIL in the buffered read path; this was a leftover
     from the trickier fix to kill __GFP_NOFAIL in readahead, where we
     can't return errors (and have to silently truncate the read
     ourselves).

     bcachefs can't use GFP_NOFAIL for folio state unlike iomap based
     filesystems because our folio state is just barely too big, 2MB
     hugepages cause us to exceed the 2 page threshhold for GFP_NOFAIL.

     additionally, the flags argument was just buggy, we weren't
     supplying GFP_KERNEL previously (!)"

* tag 'bcachefs-2024-02-25' of https://evilpiepirate.org/git/bcachefs:
  bcachefs: fix bch2_save_backtrace()
  bcachefs: Fix check_snapshot() memcpy
  bcachefs: Fix bch2_journal_flush_device_pins()
  bcachefs: fix iov_iter count underflow on sub-block dio read
  bcachefs: Fix BTREE_ITER_FILTER_SNAPSHOTS on inodes btree
  bcachefs: Kill __GFP_NOFAIL in buffered read path
  bcachefs: fix backpointer_to_text() when dev does not exist
2024-02-25 15:31:57 -08:00
Kent Overstreet
5197728f81 bcachefs: fix bch2_save_backtrace()
Missed a call in the previous fix.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2024-02-25 15:45:36 -05:00
Linus Torvalds
4ca0d9894f Change since last update:
- Fix page refcount leak when looking up specific inodes
    introduced by metabuf reworking.
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Merge tag 'erofs-for-6.8-rc6-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/xiang/erofs

Pull erofs fix from Gao Xiang:

 - Fix page refcount leak when looking up specific inodes
   introduced by metabuf reworking

* tag 'erofs-for-6.8-rc6-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/xiang/erofs:
  erofs: fix refcount on the metabuf used for inode lookup
2024-02-25 09:53:13 -08:00
Linus Torvalds
66a97c2ec9 We still have some races in filesystem methods when exposed to RCU
pathwalk.  This series is a result of code audit (the second round
 of it) and it should deal with most of that stuff.  Exceptions: ntfs3
 ->d_hash()/->d_compare() and ceph_d_revalidate().  Up to maintainers (a
 note for NTFS folks - when documentation says that a method may not block,
 it *does* imply that blocking allocations are to be avoided.  Really).
 
 Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Merge tag 'pull-fixes.pathwalk-rcu-2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull RCU pathwalk fixes from Al Viro:
 "We still have some races in filesystem methods when exposed to RCU
  pathwalk. This series is a result of code audit (the second round of
  it) and it should deal with most of that stuff.

  Still pending: ntfs3 ->d_hash()/->d_compare() and ceph_d_revalidate().
  Up to maintainers (a note for NTFS folks - when documentation says
  that a method may not block, it *does* imply that blocking allocations
  are to be avoided. Really)"

[ More explanations for people who aren't familiar with the vagaries of
  RCU path walking: most of it is hidden from filesystems, but if a
  filesystem actively participates in the low-level path walking it
  needs to make sure the fields involved in that walk are RCU-safe.

  That "actively participate in low-level path walking" includes things
  like having its own ->d_hash()/->d_compare() routines, or by having
  its own directory permission function that doesn't just use the common
  helpers.  Having a ->d_revalidate() function will also have this issue.

  Note that instead of making everything RCU safe you can also choose to
  abort the RCU pathwalk if your operation cannot be done safely under
  RCU, but that obviously comes with a performance penalty. One common
  pattern is to allow the simple cases under RCU, and abort only if you
  need to do something more complicated.

  So not everything needs to be RCU-safe, and things like the inode etc
  that the VFS itself maintains obviously already are. But these fixes
  tend to be about properly RCU-delaying things like ->s_fs_info that
  are maintained by the filesystem and that got potentially released too
  early.   - Linus ]

* tag 'pull-fixes.pathwalk-rcu-2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  ext4_get_link(): fix breakage in RCU mode
  cifs_get_link(): bail out in unsafe case
  fuse: fix UAF in rcu pathwalks
  procfs: make freeing proc_fs_info rcu-delayed
  procfs: move dropping pde and pid from ->evict_inode() to ->free_inode()
  nfs: fix UAF on pathwalk running into umount
  nfs: make nfs_set_verifier() safe for use in RCU pathwalk
  afs: fix __afs_break_callback() / afs_drop_open_mmap() race
  hfsplus: switch to rcu-delayed unloading of nls and freeing ->s_fs_info
  exfat: move freeing sbi, upcase table and dropping nls into rcu-delayed helper
  affs: free affs_sb_info with kfree_rcu()
  rcu pathwalk: prevent bogus hard errors from may_lookup()
  fs/super.c: don't drop ->s_user_ns until we free struct super_block itself
2024-02-25 09:29:05 -08:00
Linus Torvalds
9b24349279 A couple of fixes - revert of regression from this cycle
and a fix for erofs failure exit breakage (had been there since
 way back).
 
 Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Merge tag 'pull-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull vfs fixes from Al Viro:
 "A couple of fixes - revert of regression from this cycle and a fix for
  erofs failure exit breakage (had been there since way back)"

* tag 'pull-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  erofs: fix handling kern_mount() failure
  Revert "get rid of DCACHE_GENOCIDE"
2024-02-25 09:17:15 -08:00
Ard Biesheuvel
2ce507f57b efivarfs: Drop 'duplicates' bool parameter on efivar_init()
The 'duplicates' bool argument is always true when efivar_init() is
called from its only caller so let's just drop it instead.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2024-02-25 09:43:39 +01:00
Ard Biesheuvel
9ca01c7adf efivarfs: Drop redundant cleanup on fill_super() failure
Al points out that kill_sb() will be called if efivarfs_fill_super()
fails and so there is no point in cleaning up the efivar entry list.

Reported-by: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2024-02-25 09:43:38 +01:00
Tim Schumacher
f45812cc23 efivarfs: Request at most 512 bytes for variable names
Work around a quirk in a few old (2011-ish) UEFI implementations, where
a call to `GetNextVariableName` with a buffer size larger than 512 bytes
will always return EFI_INVALID_PARAMETER.

There is some lore around EFI variable names being up to 1024 bytes in
size, but this has no basis in the UEFI specification, and the upper
bounds are typically platform specific, and apply to the entire variable
(name plus payload).

Given that Linux does not permit creating files with names longer than
NAME_MAX (255) bytes, 512 bytes (== 256 UTF-16 characters) is a
reasonable limit.

Cc: <stable@vger.kernel.org> # 6.1+
Signed-off-by: Tim Schumacher <timschumi@gmx.de>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2024-02-25 09:42:24 +01:00
Al Viro
9fa8e282c2 ext4_get_link(): fix breakage in RCU mode
1) errors from ext4_getblk() should not be propagated to caller
unless we are really sure that we would've gotten the same error
in non-RCU pathwalk.
2) we leak buffer_heads if ext4_getblk() is successful, but bh is
not uptodate.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2024-02-25 02:10:32 -05:00
Al Viro
0511fdb4a3 cifs_get_link(): bail out in unsafe case
->d_revalidate() bails out there, anyway.  It's not enough
to prevent getting into ->get_link() in RCU mode, but that
could happen only in a very contrieved setup.  Not worth
trying to do anything fancy here unless ->d_revalidate()
stops kicking out of RCU mode at least in some cases.

Reviewed-by: Christian Brauner <brauner@kernel.org>
Acked-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2024-02-25 02:10:32 -05:00
Al Viro
053fc4f755 fuse: fix UAF in rcu pathwalks
->permission(), ->get_link() and ->inode_get_acl() might dereference
->s_fs_info (and, in case of ->permission(), ->s_fs_info->fc->user_ns
as well) when called from rcu pathwalk.

Freeing ->s_fs_info->fc is rcu-delayed; we need to make freeing ->s_fs_info
and dropping ->user_ns rcu-delayed too.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2024-02-25 02:10:32 -05:00
Al Viro
e31f0a57ae procfs: make freeing proc_fs_info rcu-delayed
makes proc_pid_ns() safe from rcu pathwalk (put_pid_ns()
is still synchronous, but that's not a problem - it does
rcu-delay everything that needs to be)

Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2024-02-25 02:10:32 -05:00
Al Viro
47458802f6 procfs: move dropping pde and pid from ->evict_inode() to ->free_inode()
that keeps both around until struct inode is freed, making access
to them safe from rcu-pathwalk

Acked-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2024-02-25 02:10:32 -05:00
Al Viro
c1b967d03c nfs: fix UAF on pathwalk running into umount
NFS ->d_revalidate(), ->permission() and ->get_link() need to access
some parts of nfs_server when called in RCU mode:
	server->flags
	server->caps
	*(server->io_stats)
and, worst of all, call
	server->nfs_client->rpc_ops->have_delegation
(the last one - as NFS_PROTO(inode)->have_delegation()).  We really
don't want to RCU-delay the entire nfs_free_server() (it would have
to be done with schedule_work() from RCU callback, since it can't
be made to run from interrupt context), but actual freeing of
nfs_server and ->io_stats can be done via call_rcu() just fine.
nfs_client part is handled simply by making nfs_free_client() use
kfree_rcu().

Acked-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2024-02-25 02:10:32 -05:00
Al Viro
10a973fc4f nfs: make nfs_set_verifier() safe for use in RCU pathwalk
nfs_set_verifier() relies upon dentry being pinned; if that's
the case, grabbing ->d_lock stabilizes ->d_parent and guarantees
that ->d_parent points to a positive dentry.  For something
we'd run into in RCU mode that is *not* true - dentry might've
been through dentry_kill() just as we grabbed ->d_lock, with
its parent going through the same just as we get to into
nfs_set_verifier_locked().  It might get to detaching inode
(and zeroing ->d_inode) before nfs_set_verifier_locked() gets
to fetching that; we get an oops as the result.

That can happen in nfs{,4} ->d_revalidate(); the call chain in
question is nfs_set_verifier_locked() <- nfs_set_verifier() <-
nfs_lookup_revalidate_delegated() <- nfs{,4}_do_lookup_revalidate().
We have checked that the parent had been positive, but that's
done before we get to nfs_set_verifier() and it's possible for
memory pressure to pick our dentry as eviction candidate by that
time.  If that happens, back-to-back attempts to kill dentry and
its parent are quite normal.  Sure, in case of eviction we'll
fail the ->d_seq check in the caller, but we need to survive
until we return there...

Acked-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2024-02-25 02:10:31 -05:00
Al Viro
275655d320 afs: fix __afs_break_callback() / afs_drop_open_mmap() race
In __afs_break_callback() we might check ->cb_nr_mmap and if it's non-zero
do queue_work(&vnode->cb_work).  In afs_drop_open_mmap() we decrement
->cb_nr_mmap and do flush_work(&vnode->cb_work) if it reaches zero.

The trouble is, there's nothing to prevent __afs_break_callback() from
seeing ->cb_nr_mmap before the decrement and do queue_work() after both
the decrement and flush_work().  If that happens, we might be in trouble -
vnode might get freed before the queued work runs.

__afs_break_callback() is always done under ->cb_lock, so let's make
sure that ->cb_nr_mmap can change from non-zero to zero while holding
->cb_lock (the spinlock component of it - it's a seqlock and we don't
need to mess with the counter).

Acked-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2024-02-25 02:10:31 -05:00
Al Viro
af072cf683 hfsplus: switch to rcu-delayed unloading of nls and freeing ->s_fs_info
->d_hash() and ->d_compare() use those, so we need to delay freeing
them.

Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2024-02-25 02:10:31 -05:00