Checking buf->flags should be done before the pipe_buf_release() is called
on the pipe buffer, since releasing the buffer might modify the flags.
This is exactly what page_cache_pipe_buf_release() does, and which results
in the same VM_BUG_ON_PAGE(PageLRU(page)) that the original patch was
trying to fix.
Reported-by: Justin Forbes <jmforbes@linuxtx.org>
Fixes: 712a951025 ("fuse: fix page stealing")
Cc: <stable@vger.kernel.org> # v2.6.35
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
It is possible to trigger a crash by splicing anon pipe bufs to the fuse
device.
The reason for this is that anon_pipe_buf_release() will reuse buf->page if
the refcount is 1, but that page might have already been stolen and its
flags modified (e.g. PG_lru added).
This happens in the unlikely case of fuse_dev_splice_write() getting around
to calling pipe_buf_release() after a page has been stolen, added to the
page cache and removed from the page cache.
Fix by calling pipe_buf_release() right after the page was inserted into
the page cache. In this case the page has an elevated refcount so any
release function will know that the page isn't reusable.
Reported-by: Frank Dinoff <fdinoff@google.com>
Link: https://lore.kernel.org/r/CAAmZXrsGg2xsP1CK+cbuEMumtrqdvD-NKnWzhNcvn71RV3c1yw@mail.gmail.com/
Fixes: dd3bb14f44 ("fuse: support splice() writing to fuse device")
Cc: <stable@vger.kernel.org> # v2.6.35
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Extend the fuse_write_update_attr() helper to invalidate cached attributes
after a write.
This has already been done in all cases except in fuse_notify_store(), so
this is mostly a cleanup.
fuse_direct_write_iter() calls fuse_direct_IO() which already calls
fuse_write_update_attr(), so don't repeat that again in the former.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
This function already updates the attr_version in fuse_inode, regardless of
whether the size was changed or not.
Rename the helper to fuse_write_update_attr() to reflect the more generic
nature.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Due to the introduction of kmap_local_*, the storage of slots used for
short-term mapping has changed from per-CPU to per-thread. kmap_atomic()
disable preemption, while kmap_local_*() only disable migration.
There is no need to disable preemption in several kamp_atomic places used
in fuse.
Link: https://lwn.net/Articles/836144/
Signed-off-by: Peng Hao <flyingpeng@tencent.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
There is a potential race between fuse_read_interrupt() and
fuse_request_end().
TASK1
in fuse_read_interrupt(): delete req->intr_entry (while holding
fiq->lock)
TASK2
in fuse_request_end(): req->intr_entry is empty -> skip fiq->lock
wake up TASK3
TASK3
request is freed
TASK1
in fuse_read_interrupt(): dereference req->in.h.unique ***BAM***
Fix by always grabbing fiq->lock if the request was ever interrupted
(FR_INTERRUPTED set) thereby serializing with concurrent
fuse_read_interrupt() calls.
FR_INTERRUPTED is set before the request is queued on fiq->interrupts.
Dequeing the request is done with list_del_init() but FR_INTERRUPTED is not
cleared in this case.
Reported-by: lijiazi <lijiazi@xiaomi.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
A request could end up on the fpq->io list after fuse_abort_conn() has
reset fpq->connected and aborted requests on that list:
Thread-1 Thread-2
======== ========
->fuse_simple_request() ->shutdown
->__fuse_request_send()
->queue_request() ->fuse_abort_conn()
->fuse_dev_do_read() ->acquire(fpq->lock)
->wait_for(fpq->lock) ->set err to all req's in fpq->io
->release(fpq->lock)
->acquire(fpq->lock)
->add req to fpq->io
After the userspace copy is done the request will be ended, but
req->out.h.error will remain uninitialized. Also the copy might block
despite being already aborted.
Fix both issues by not allowing the request to be queued on the fpq->io
list after fuse_abort_conn() has processed this list.
Reported-by: Pradeep P V K <pragalla@codeaurora.org>
Fixes: fd22d62ed0 ("fuse: no fc->lock for iqueue parts")
Cc: <stable@vger.kernel.org> # v4.2
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Fix the "fuse: trying to steal weird page" warning.
Description from Johannes Weiner:
"Think of it as similar to PG_active. It's just another usage/heat
indicator of file and anon pages on the reclaim LRU that, unlike
PG_active, persists across deactivation and even reclaim (we store it in
the page cache / swapper cache tree until the page refaults).
So if fuse accepts pages that can legally have PG_active set,
PG_workingset is fine too."
Reported-by: Thomas Lindroth <thomas.lindroth@gmail.com>
Fixes: 1899ad18c6 ("mm: workingset: tell cache transitions from workingset thrashing")
Cc: <stable@vger.kernel.org> # v4.20
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
With commit f8425c9396 ("fuse: 32-bit user space ioctl compat for fuse
device") the matching constraints for the FUSE_DEV_IOC_CLONE ioctl command
are relaxed, limited to the testing of command type and number. As Arnd
noticed, this is wrong as it wouldn't ensure the correctness of the data
size or direction for the received FUSE device ioctl.
Fix by bringing back the comparison of the ioctl received by the FUSE
device to the originally generated FUSE_DEV_IOC_CLONE.
Fixes: f8425c9396 ("fuse: 32-bit user space ioctl compat for fuse device")
Reported-by: Arnd Bergmann <arnd@kernel.org>
Signed-off-by: Alessio Balsini <balsini@android.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
With a 64-bit kernel build the FUSE device cannot handle ioctl requests
coming from 32-bit user space. This is due to the ioctl command
translation that generates different command identifiers that thus cannot
be used for direct comparisons without proper manipulation.
Explicitly extract type and number from the ioctl command to enable 32-bit
user space compatibility on 64-bit kernel builds.
Signed-off-by: Alessio Balsini <balsini@android.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
We want to allow submounts for the same fuse_conn, but with different
superblocks so that each of the submounts has its own device ID. To do
so, we need to split all mount-specific information off of fuse_conn
into a new fuse_mount structure, so that multiple mounts can share a
single fuse_conn.
We need to take care only to perform connection-level actions once (i.e.
when the fuse_conn and thus the first fuse_mount are established, or
when the last fuse_mount and thus the fuse_conn are destroyed). For
example, fuse_sb_destroy() must invoke fuse_send_destroy() until the
last superblock is released.
To do so, we keep track of which fuse_mount is the root mount and
perform all fuse_conn-level actions only when this fuse_mount is
involved.
Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
With the last commit, all functions that handle some existing fuse_req
no longer need to be given the associated fuse_conn, because they can
get it from the fuse_req object.
Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Every fuse_req belongs to a fuse_conn. Right now, we always know which
fuse_conn that is based on the respective device, but we want to allow
multiple (sub)mounts per single connection, and then the corresponding
filesystem is not going to be so trivial to obtain.
Storing a pointer to the associated fuse_conn in every fuse_req will
allow us to trivially find any request's superblock (and thus
filesystem) even then.
Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
After unlock_request() pages from the ap->pages[] array may be put (e.g. by
aborting the connection) and the pages can be freed.
Prevent use after free by grabbing a reference to the page before calling
unlock_request().
The original patch was created by Pradeep P V K.
Reported-by: Pradeep P V K <ppvk@codeaurora.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Pull fuse updates from Miklos Szeredi:
- Fix a rare deadlock in virtiofs
- Fix st_blocks in writeback cache mode
- Fix wrong checks in splice move causing spurious warnings
- Fix a race between a GETATTR request and a FUSE_NOTIFY_INVAL_INODE
notification
- Use rb-tree instead of linear search for pages currently under
writeout by userspace
- Fix copy_file_range() inconsistencies
* tag 'fuse-update-5.8' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse:
fuse: copy_file_range should truncate cache
fuse: fix copy_file_range cache issues
fuse: optimize writepages search
fuse: update attr_version counter on fuse_notify_inval_inode()
fuse: don't check refcount after stealing page
fuse: fix weird page warning
fuse: use dump_page
virtiofs: do not use fuse_fill_super_common() for device installation
fuse: always allow query of st_dev
fuse: always flush dirty data on close(2)
fuse: invalidate inode attr in writeback cache mode
fuse: Update stale comment in queue_interrupt()
fuse: BUG_ON correction in fuse_dev_splice_write()
virtiofs: Add mount option and atime behavior to the doc
virtiofs: schedule blocking async replies in separate worker
Merge more updates from Andrew Morton:
"More mm/ work, plenty more to come
Subsystems affected by this patch series: slub, memcg, gup, kasan,
pagealloc, hugetlb, vmscan, tools, mempolicy, memblock, hugetlbfs,
thp, mmap, kconfig"
* akpm: (131 commits)
arm64: mm: use ARCH_HAS_DEBUG_WX instead of arch defined
x86: mm: use ARCH_HAS_DEBUG_WX instead of arch defined
riscv: support DEBUG_WX
mm: add DEBUG_WX support
drivers/base/memory.c: cache memory blocks in xarray to accelerate lookup
mm/thp: rename pmd_mknotpresent() as pmd_mkinvalid()
powerpc/mm: drop platform defined pmd_mknotpresent()
mm: thp: don't need to drain lru cache when splitting and mlocking THP
hugetlbfs: get unmapped area below TASK_UNMAPPED_BASE for hugetlbfs
sparc32: register memory occupied by kernel as memblock.memory
include/linux/memblock.h: fix minor typo and unclear comment
mm, mempolicy: fix up gup usage in lookup_node
tools/vm/page_owner_sort.c: filter out unneeded line
mm: swap: memcg: fix memcg stats for huge pages
mm: swap: fix vmstats for huge pages
mm: vmscan: limit the range of LRU type balancing
mm: vmscan: reclaim writepage is IO cost
mm: vmscan: determine anon/file pressure balance at the reclaim root
mm: balance LRU lists based on relative thrashing
mm: only count actual rotations as LRU reclaim cost
...
They're the same function, and for the purpose of all callers they are
equivalent to lru_cache_add().
[akpm@linux-foundation.org: fix it for local_lock changes]
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Rik van Riel <riel@surriel.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Link: http://lkml.kernel.org/r/20200520232525.798933-5-hannes@cmpxchg.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
And replace the arcane return value convention with a simple bool
where true means success and false means failure.
[AV: braino fix folded in]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
page_count() is unstable. Unless there has been an RCU grace period
between when the page was removed from the page cache and now, a
speculative reference may exist from the page cache.
Reported-by: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
When PageWaiters was added, updating this check was missed.
Reported-by: Nikolaus Rath <Nikolaus@rath.org>
Reported-by: Hugh Dickins <hughd@google.com>
Fixes: 6290602709 ("mm: add PageWaiters indicating tasks are waiting for a page bit")
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Instead of custom page dumping, use the standard helper.
Reported-by: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
