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2024-02-25btrfs: port device access to fileChristian Brauner
Link: https://lore.kernel.org/r/20240123-vfs-bdev-file-v2-19-adbd023e19cc@kernel.org Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-02-25bcachefs: port block device access to fileChristian Brauner
Link: https://lore.kernel.org/r/20240123-vfs-bdev-file-v2-18-adbd023e19cc@kernel.org Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-02-25xfs: port block device access to filesChristian Brauner
Link: https://lore.kernel.org/r/20240123-vfs-bdev-file-v2-7-adbd023e19cc@kernel.org Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-02-25bdev: open block device as filesChristian Brauner
Add two new helpers to allow opening block devices as files. This is not the final infrastructure. This still opens the block device before opening a struct a file. Until we have removed all references to struct bdev_handle we can't switch the order: * Introduce blk_to_file_flags() to translate from block specific to flags usable to pen a new file. * Introduce bdev_file_open_by_{dev,path}(). * Introduce temporary sb_bdev_handle() helper to retrieve a struct bdev_handle from a block device file and update places that directly reference struct bdev_handle to rely on it. * Don't count block device openes against the number of open files. A bdev_file_open_by_{dev,path}() file is never installed into any file descriptor table. One idea that came to mind was to use kernel_tmpfile_open() which would require us to pass a path and it would then call do_dentry_open() going through the regular fops->open::blkdev_open() path. But then we're back to the problem of routing block specific flags such as BLK_OPEN_RESTRICT_WRITES through the open path and would have to waste FMODE_* flags every time we add a new one. With this we can avoid using a flag bit and we have more leeway in how we open block devices from bdev_open_by_{dev,path}(). Link: https://lore.kernel.org/r/20240123-vfs-bdev-file-v2-1-adbd023e19cc@kernel.org Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-02-25file: add alloc_file_pseudo_noaccount()Christian Brauner
When we open block devices as files we want to make sure to not charge them against the open file limit of the caller as that can cause spurious failures. Link: https://lore.kernel.org/r/20240123-vfs-bdev-file-v2-1-adbd023e19cc@kernel.org Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-02-25file: prepare for new helperChristian Brauner
In order to add a helper to open files that aren't accounted split alloc_file() and parts of alloc_file_pseudo() into helpers. One to prepare a path, another one to setup the file. Suggested-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20240129160241.GA2793@lst.de Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-02-25efivarfs: Drop 'duplicates' bool parameter on efivar_init()Ard Biesheuvel
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>
2024-02-25efivarfs: Drop redundant cleanup on fill_super() failureArd Biesheuvel
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>
2024-02-25efivarfs: Request at most 512 bytes for variable namesTim Schumacher
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>
2024-02-25ext4_get_link(): fix breakage in RCU modeAl Viro
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>
2024-02-25cifs_get_link(): bail out in unsafe caseAl Viro
->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>
2024-02-25fuse: fix UAF in rcu pathwalksAl Viro
->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>
2024-02-25procfs: make freeing proc_fs_info rcu-delayedAl Viro
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>
2024-02-25procfs: move dropping pde and pid from ->evict_inode() to ->free_inode()Al Viro
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>
2024-02-25nfs: fix UAF on pathwalk running into umountAl Viro
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>
2024-02-25nfs: make nfs_set_verifier() safe for use in RCU pathwalkAl Viro
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>
2024-02-25afs: fix __afs_break_callback() / afs_drop_open_mmap() raceAl Viro
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>
2024-02-25hfsplus: switch to rcu-delayed unloading of nls and freeing ->s_fs_infoAl Viro
->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>
2024-02-25exfat: move freeing sbi, upcase table and dropping nls into rcu-delayed helperAl Viro
That stuff can be accessed by ->d_hash()/->d_compare(); as it is, we have a hard-to-hit UAF if rcu pathwalk manages to get into ->d_hash() on a filesystem that is in process of getting shut down. Besides, having nls and upcase table cleanup moved from ->put_super() towards the place where sbi is freed makes for simpler failure exits. Acked-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2024-02-25affs: free affs_sb_info with kfree_rcu()Al Viro
one of the flags in it is used by ->d_hash()/->d_compare() Reviewed-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2024-02-25rcu pathwalk: prevent bogus hard errors from may_lookup()Al Viro
If lazy call of ->permission() returns a hard error, check that try_to_unlazy() succeeds before returning it. That both makes life easier for ->permission() instances and closes the race in ENOTDIR handling - it is possible that positive d_can_lookup() seen in link_path_walk() applies to the state *after* unlink() + mkdir(), while nd->inode matches the state prior to that. Normally seeing e.g. EACCES from permission check in rcu pathwalk means that with some timings non-rcu pathwalk would've run into the same; however, running into a non-executable regular file in the middle of a pathname would not get to permission check - it would fail with ENOTDIR instead. Reviewed-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2024-02-25fs/super.c: don't drop ->s_user_ns until we free struct super_block itselfAl Viro
Avoids fun races in RCU pathwalk... Same goes for freeing LSM shite hanging off super_block's arse. Reviewed-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2024-02-24bcachefs: Fix check_snapshot() memcpyKent Overstreet
check_snapshot() copies the bch_snapshot to a temporary to easily handle older versions that don't have all the fields of the current version, but it lacked a min() to correctly handle keys newer and larger than the current version. Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2024-02-24bcachefs: Fix bch2_journal_flush_device_pins()Kent Overstreet
If a journal write errored, the list of devices it was written to could be empty - we're not supposed to mark an empty replicas list. Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2024-02-24bcachefs: fix iov_iter count underflow on sub-block dio readBrian Foster
bch2_direct_IO_read() checks the request offset and size for sector alignment and then falls through to a couple calculations to shrink the size of the request based on the inode size. The problem is that these checks round up to the fs block size, which runs the risk of underflowing iter->count if the block size happens to be large enough. This is triggered by fstest generic/361 with a 4k block size, which subsequently leads to a crash. To avoid this crash, check that the shorten length doesn't exceed the overall length of the iter. Fixes: Signed-off-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Su Yue <glass.su@suse.com> Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2024-02-24bcachefs: Fix BTREE_ITER_FILTER_SNAPSHOTS on inodes btreeKent Overstreet
If we're in FILTER_SNAPSHOTS mode and we start scanning a range of the keyspace where no keys are visible in the current snapshot, we have a problem - we'll scan for a very long time before scanning terminates. Awhile back, this was fixed for most cases with peek_upto() (and assertions that enforce that it's being used). But the fix missed the fact that the inodes btree is different - every key offset is in a different snapshot tree, not just the inode field. Fixes: Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2024-02-24bcachefs: Kill __GFP_NOFAIL in buffered read pathKent Overstreet
Recently, we fixed our __GFP_NOFAIL usage in the readahead path, but the easy one in read_single_folio() (where wa can return an error) was missed - oops. Fixes: Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2024-02-24bcachefs: fix backpointer_to_text() when dev does not existKent Overstreet
Fixes: Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2024-02-23fscrypt: shrink the size of struct fscrypt_inode_info slightlyEric Biggers
Shrink the size of struct fscrypt_inode_info by 8 bytes by packing the small fields into the 64 bits after ci_enc_key. Link: https://lore.kernel.org/r/20240224060103.91037-1-ebiggers@kernel.org Signed-off-by: Eric Biggers <ebiggers@google.com>
2024-02-23fscrypt: write CBC-CTS instead of CTS-CBCEric Biggers
Calling CBC with ciphertext stealing "CBC-CTS" seems to be more common than calling it "CTS-CBC". E.g., CBC-CTS is used by OpenSSL, Crypto++, RFC3962, and RFC6803. The NIST SP800-38A addendum uses CBC-CS1, CBC-CS2, and CBC-CS3, distinguishing between different CTS conventions but similarly putting the CBC part first. In the interest of avoiding any idiosyncratic terminology, update the fscrypt documentation and the fscrypt_mode "friendly names" to align with the more common convention. Changing the "friendly names" only affects some log messages. The actual mode constants in the API are unchanged; those call it simply "CTS". Add a note to the documentation that clarifies that "CBC" and "CTS" in the API really mean CBC-ESSIV and CBC-CTS, respectively. Link: https://lore.kernel.org/r/20240224053550.44659-1-ebiggers@kernel.org Signed-off-by: Eric Biggers <ebiggers@google.com>
2024-02-24xfs: fix log recovery erroring out on refcount recovery failureDarrick J. Wong
Per the comment in the error case of xfs_reflink_recover_cow, zero out any error (after shutting down the log) so that we actually kill any new intent items that might have gotten logged by later recovery steps. Discovered by xfs/434, which few people actually seem to run. Fixes: 2c1e31ed5c88 ("xfs: place intent recovery under NOFS allocation context") Signed-off-by: "Darrick J. Wong" <djwong@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>
2024-02-23crash: split vmcoreinfo exporting code out from crash_core.cBaoquan He
Now move the relevant codes into separate files: kernel/crash_reserve.c, include/linux/crash_reserve.h. And add config item CRASH_RESERVE to control its enabling. And also update the old ifdeffery of CONFIG_CRASH_CORE, including of <linux/crash_core.h> and config item dependency on CRASH_CORE accordingly. And also do renaming as follows: - arch/xxx/kernel/{crash_core.c => vmcore_info.c} because they are only related to vmcoreinfo exporting on x86, arm64, riscv. And also Remove config item CRASH_CORE, and rely on CONFIG_KEXEC_CORE to decide if build in crash_core.c. [yang.lee@linux.alibaba.com: remove duplicated include in vmcore_info.c] Link: https://lkml.kernel.org/r/20240126005744.16561-1-yang.lee@linux.alibaba.com Link: https://lkml.kernel.org/r/20240124051254.67105-3-bhe@redhat.com Signed-off-by: Baoquan He <bhe@redhat.com> Signed-off-by: Yang Li <yang.lee@linux.alibaba.com> Acked-by: Hari Bathini <hbathini@linux.ibm.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: Pingfan Liu <piliu@redhat.com> Cc: Klara Modin <klarasmodin@gmail.com> Cc: Michael Kelley <mhklinux@outlook.com> Cc: Nathan Chancellor <nathan@kernel.org> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Yang Li <yang.lee@linux.alibaba.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-02-23exec: Delete unnecessary statements in remove_arg_zero()Li kunyu
'ret=0; ' In actual operation, the ret was not modified, so this sentence can be removed. Signed-off-by: Li kunyu <kunyu@nfschina.com> Link: https://lore.kernel.org/r/20240220052426.62018-1-kunyu@nfschina.com Signed-off-by: Kees Cook <keescook@chromium.org>
2024-02-23fuse: introduce FUSE_PASSTHROUGH capabilityAmir Goldstein
FUSE_PASSTHROUGH capability to passthrough FUSE operations to backing files will be made available with kernel config CONFIG_FUSE_PASSTHROUGH. When requesting FUSE_PASSTHROUGH, userspace needs to specify the max_stack_depth that is allowed for FUSE on top of backing files. Introduce the flag FOPEN_PASSTHROUGH and backing_id to fuse_open_out argument that can be used when replying to OPEN request, to setup passthrough of io operations on the fuse inode to a backing file. Introduce a refcounted fuse_backing object that will be used to associate an open backing file with a fuse inode. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2024-02-23fuse: factor out helper for FUSE_DEV_IOC_CLONEAmir Goldstein
In preparation to adding more fuse dev ioctls. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2024-02-23fuse: allow parallel dio writes with FUSE_DIRECT_IO_ALLOW_MMAPAmir Goldstein
Instead of denying caching mode on parallel dio open, deny caching open only while parallel dio are in-progress and wait for in-progress parallel dio writes before entering inode caching io mode. This allows executing parallel dio when inode is not in caching mode even if shared mmap is allowed, but no mmaps have been performed on the inode in question. An mmap on direct_io file now waits for all in-progress parallel dio writes to complete, so parallel dio writes together with FUSE_DIRECT_IO_ALLOW_MMAP is enabled by this commit. Signed-off-by: Bernd Schubert <bschubert@ddn.com> Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2024-02-23fuse: introduce inode io modesAmir Goldstein
The fuse inode io mode is determined by the mode of its open files/mmaps and parallel dio opens and expressed in the value of fi->iocachectr: > 0 - caching io: files open in caching mode or mmap on direct_io file < 0 - parallel dio: direct io mode with parallel dio writes enabled == 0 - direct io: no files open in caching mode and no files mmaped Note that iocachectr value of 0 might become positive or negative, while non-parallel dio is getting processed. direct_io mmap uses page cache, so first mmap will mark the file as ff->io_opened and increment fi->iocachectr to enter the caching io mode. If the server opens the file in caching mode while it is already open for parallel dio or vice versa the open fails. This allows executing parallel dio when inode is not in caching mode and no mmaps have been performed on the inode in question. Signed-off-by: Bernd Schubert <bschubert@ddn.com> Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2024-02-23fuse: prepare for failing open responseAmir Goldstein
In preparation for inode io modes, a server open response could fail due to conflicting inode io modes. Allow returning an error from fuse_finish_open() and handle the error in the callers. fuse_finish_open() is used as the callback of finish_open(), so that FMODE_OPENED will not be set if fuse_finish_open() fails. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2024-02-23fuse: break up fuse_open_common()Amir Goldstein
fuse_open_common() has a lot of code relevant only for regular files and O_TRUNC in particular. Copy the little bit of remaining code into fuse_dir_open() and stop using this common helper for directory open. Also split out fuse_dir_finish_open() from fuse_finish_open() before we add inode io modes to fuse_finish_open(). Suggested-by: Miklos Szeredi <miklos@szeredi.hu> Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2024-02-23fuse: allocate ff->release_args only if release is neededAmir Goldstein
This removed the need to pass isdir argument to fuse_put_file(). Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2024-02-23fuse: factor out helper fuse_truncate_update_attr()Amir Goldstein
fuse_finish_open() is called from fuse_open_common() and from fuse_create_open(). In the latter case, the O_TRUNC flag is always cleared in finish_open()m before calling into fuse_finish_open(). Move the bits that update attribute cache post O_TRUNC open into a helper and call this helper from fuse_open_common() directly. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2024-02-23fuse: add fuse_dio_lock/unlock helper functionsBernd Schubert
So far this is just a helper to remove complex locking logic out of fuse_direct_write_iter. Especially needed by the next patch in the series to that adds the fuse inode cache IO mode and adds in even more locking complexity. Signed-off-by: Bernd Schubert <bschubert@ddn.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2024-02-23fuse: create helper function if DIO write needs exclusive lockBernd Schubert
This makes the code a bit easier to read and allows to more easily add more conditions when an exclusive lock is needed. Signed-off-by: Bernd Schubert <bschubert@ddn.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2024-02-23fuse: fix VM_MAYSHARE and direct_io_allow_mmapBernd Schubert
There were multiple issues with direct_io_allow_mmap: - fuse_link_write_file() was missing, resulting in warnings in fuse_write_file_get() and EIO from msync() - "vma->vm_ops = &fuse_file_vm_ops" was not set, but especially fuse_page_mkwrite is needed. The semantics of invalidate_inode_pages2() is so far not clearly defined in fuse_file_mmap. It dates back to commit 3121bfe76311 ("fuse: fix "direct_io" private mmap") Though, as direct_io_allow_mmap is a new feature, that was for MAP_PRIVATE only. As invalidate_inode_pages2() is calling into fuse_launder_folio() and writes out dirty pages, it should be safe to call invalidate_inode_pages2 for MAP_PRIVATE and MAP_SHARED as well. Cc: Hao Xu <howeyxu@tencent.com> Cc: stable@vger.kernel.org Fixes: e78662e818f9 ("fuse: add a new fuse init flag to relax restrictions in no cache mode") Signed-off-by: Bernd Schubert <bschubert@ddn.com> Reviewed-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2024-02-23virtiofs: emit uevents on filesystem eventsStefan Hajnoczi
Alyssa Ross <hi@alyssa.is> requested that virtiofs notifies userspace when filesytems become available. This can be used to detect when a filesystem with a given tag is hotplugged, for example. uevents allow userspace to detect changes without resorting to polling. The tag is included as a uevent property so it's easy for userspace to identify the filesystem in question even when the sysfs directory goes away during removal. Here are example uevents: # udevadm monitor -k -p KERNEL[111.113221] add /fs/virtiofs/2 (virtiofs) ACTION=add DEVPATH=/fs/virtiofs/2 SUBSYSTEM=virtiofs TAG=test KERNEL[165.527167] remove /fs/virtiofs/2 (virtiofs) ACTION=remove DEVPATH=/fs/virtiofs/2 SUBSYSTEM=virtiofs TAG=test Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2024-02-23virtiofs: export filesystem tags through sysfsStefan Hajnoczi
The virtiofs filesystem is mounted using a "tag" which is exported by the virtiofs device: # mount -t virtiofs <tag> /mnt The virtiofs driver knows about all the available tags but these are currently not exported to user space. People have asked for these tags to be exported to user space. Most recently Lennart Poettering has asked for it as he wants to scan the tags and mount virtiofs automatically in certain cases. https://gitlab.com/virtio-fs/virtiofsd/-/issues/128 This patch exports tags at /sys/fs/virtiofs/<N>/tag where N is the id of the virtiofs device. The filesystem tag can be obtained by reading this "tag" file. There is also a symlink at /sys/fs/virtiofs/<N>/device that points to the virtiofs device that exports this tag. This patch converts the existing struct virtio_fs into a full kobject. It already had a refcount so it's an easy change. The virtio_fs objects can then be exposed in a kset at /sys/fs/virtiofs/. Note that virtio_fs objects may live slightly longer than we wish for them to be exposed to userspace, so kobject_del() is called explicitly when the underlying virtio_device is removed. The virtio_fs object is freed when all references are dropped (e.g. active mounts) but disappears as soon as the virtiofs device is gone. Originally-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2024-02-23virtiofs: forbid newlines in tagsStefan Hajnoczi
Newlines in virtiofs tags are awkward for users and potential vectors for string injection attacks. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2024-02-23sysfs: Fix crash on empty group attributes arrayDan Williams
It turns out that arch/x86/events/intel/core.c makes use of "empty" attributes. static struct attribute *empty_attrs; __init int intel_pmu_init(void) { struct attribute **extra_skl_attr = &empty_attrs; struct attribute **extra_attr = &empty_attrs; struct attribute **td_attr = &empty_attrs; struct attribute **mem_attr = &empty_attrs; struct attribute **tsx_attr = &empty_attrs; ... That breaks the assumption __first_visible() that expects that if grp->attrs is set then grp->attrs[0] must also be set and results in backtraces like: BUG: kernel NULL pointer dereference, address: 00rnel mode #PF: error_code(0x0000) - not-present ] PREEMPT SMP NOPTI CPU: 1 PID: 1 Comm: swapper/IP: 0010:exra_is_visible+0x14/0x20 ? exc_page_fault+0x68/0x190 internal_create_groups+0x42/0xa0 pmu_dev_alloc+0xc0/0xe0 perf_event_sysfs_init+0x580000000000 ]--- RIP: 0010:exra_is_visible+0x14/0 Check for non-empty attributes array before calling is_visible(). Reported-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com> Closes: https://github.com/thesofproject/linux/pull/4799#issuecomment-1958537212 Fixes: 70317fd24b41 ("sysfs: Introduce a mechanism to hide static attribute_groups") Cc: Marc Herbert <marc.herbert@intel.com> Cc: Rafael J. Wysocki <rafael@kernel.org> Signed-off-by: Dan Williams <dan.j.williams@intel.com> Tested-by: Marc Herbert <marc.herbert@intel.com> Link: https://lore.kernel.org/r/170863445442.1479840.1818801787239831650.stgit@dwillia2-xfh.jf.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-02-22fat: fix uninitialized field in nostale filehandlesJan Kara
When fat_encode_fh_nostale() encodes file handle without a parent it stores only first 10 bytes of the file handle. However the length of the file handle must be a multiple of 4 so the file handle is actually 12 bytes long and the last two bytes remain uninitialized. This is not great at we potentially leak uninitialized information with the handle to userspace. Properly initialize the full handle length. Link: https://lkml.kernel.org/r/20240205122626.13701-1-jack@suse.cz Reported-by: syzbot+3ce5dea5b1539ff36769@syzkaller.appspotmail.com Fixes: ea3983ace6b7 ("fat: restructure export_operations") Signed-off-by: Jan Kara <jack@suse.cz> Acked-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> Cc: Amir Goldstein <amir73il@gmail.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-02-22nilfs2: convert cpfile to use kmap_localRyusuke Konishi
Convert all remaining usages of kmap_atomic in cpfile to kmap_local. Link: https://lkml.kernel.org/r/20240122140202.6950-16-konishi.ryusuke@gmail.com Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>