linux-stable.git/fs/fuse, branch v4.19.78 Linux kernel stable tree fuse: fix deadlock with aio poll and fuse_iqueue::waitq.lock 2019-10-05T11:10:13+00:00 Eric Biggers ebiggers@google.com 2019-09-09T03:15:18+00:00 5bead06b3443c784637d454c5c64a3bd05752cf4 [ Upstream commit 76e43c8ccaa35c30d5df853013561145a0f750a5 ] When IOCB_CMD_POLL is used on the FUSE device, aio_poll() disables IRQs and takes kioctx::ctx_lock, then fuse_iqueue::waitq.lock. This may have to wait for fuse_iqueue::waitq.lock to be released by one of many places that take it with IRQs enabled. Since the IRQ handler may take kioctx::ctx_lock, lockdep reports that a deadlock is possible. Fix it by protecting the state of struct fuse_iqueue with a separate spinlock, and only accessing fuse_iqueue::waitq using the versions of the waitqueue functions which do IRQ-safe locking internally. Reproducer: #include <fcntl.h> #include <stdio.h> #include <sys/mount.h> #include <sys/stat.h> #include <sys/syscall.h> #include <unistd.h> #include <linux/aio_abi.h> int main() { char opts[128]; int fd = open("/dev/fuse", O_RDWR); aio_context_t ctx = 0; struct iocb cb = { .aio_lio_opcode = IOCB_CMD_POLL, .aio_fildes = fd }; struct iocb *cbp = &cb; sprintf(opts, "fd=%d,rootmode=040000,user_id=0,group_id=0", fd); mkdir("mnt", 0700); mount("foo", "mnt", "fuse", 0, opts); syscall(__NR_io_setup, 1, &ctx); syscall(__NR_io_submit, ctx, 1, &cbp); } Beginning of lockdep output: ===================================================== WARNING: SOFTIRQ-safe -> SOFTIRQ-unsafe lock order detected 5.3.0-rc5 #9 Not tainted ----------------------------------------------------- syz_fuse/135 [HC0[0]:SC0[0]:HE0:SE1] is trying to acquire: 000000003590ceda (&fiq->waitq){+.+.}, at: spin_lock include/linux/spinlock.h:338 [inline] 000000003590ceda (&fiq->waitq){+.+.}, at: aio_poll fs/aio.c:1751 [inline] 000000003590ceda (&fiq->waitq){+.+.}, at: __io_submit_one.constprop.0+0x203/0x5b0 fs/aio.c:1825 and this task is already holding: 0000000075037284 (&(&ctx->ctx_lock)->rlock){..-.}, at: spin_lock_irq include/linux/spinlock.h:363 [inline] 0000000075037284 (&(&ctx->ctx_lock)->rlock){..-.}, at: aio_poll fs/aio.c:1749 [inline] 0000000075037284 (&(&ctx->ctx_lock)->rlock){..-.}, at: __io_submit_one.constprop.0+0x1f4/0x5b0 fs/aio.c:1825 which would create a new lock dependency: (&(&ctx->ctx_lock)->rlock){..-.} -> (&fiq->waitq){+.+.} but this new dependency connects a SOFTIRQ-irq-safe lock: (&(&ctx->ctx_lock)->rlock){..-.} [...] Reported-by: syzbot+af05535bb79520f95431@syzkaller.appspotmail.com Reported-by: syzbot+d86c4426a01f60feddc7@syzkaller.appspotmail.com Fixes: bfe4037e722e ("aio: implement IOCB_CMD_POLL") Cc: <stable@vger.kernel.org> # v4.19+ Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
[ Upstream commit 76e43c8ccaa35c30d5df853013561145a0f750a5 ]

When IOCB_CMD_POLL is used on the FUSE device, aio_poll() disables IRQs
and takes kioctx::ctx_lock, then fuse_iqueue::waitq.lock.

This may have to wait for fuse_iqueue::waitq.lock to be released by one
of many places that take it with IRQs enabled.  Since the IRQ handler
may take kioctx::ctx_lock, lockdep reports that a deadlock is possible.

Fix it by protecting the state of struct fuse_iqueue with a separate
spinlock, and only accessing fuse_iqueue::waitq using the versions of
the waitqueue functions which do IRQ-safe locking internally.

Reproducer:

	#include <fcntl.h>
	#include <stdio.h>
	#include <sys/mount.h>
	#include <sys/stat.h>
	#include <sys/syscall.h>
	#include <unistd.h>
	#include <linux/aio_abi.h>

	int main()
	{
		char opts[128];
		int fd = open("/dev/fuse", O_RDWR);
		aio_context_t ctx = 0;
		struct iocb cb = { .aio_lio_opcode = IOCB_CMD_POLL, .aio_fildes = fd };
		struct iocb *cbp = &cb;

		sprintf(opts, "fd=%d,rootmode=040000,user_id=0,group_id=0", fd);
		mkdir("mnt", 0700);
		mount("foo",  "mnt", "fuse", 0, opts);
		syscall(__NR_io_setup, 1, &ctx);
		syscall(__NR_io_submit, ctx, 1, &cbp);
	}

Beginning of lockdep output:

	=====================================================
	WARNING: SOFTIRQ-safe -> SOFTIRQ-unsafe lock order detected
	5.3.0-rc5 #9 Not tainted
	-----------------------------------------------------
	syz_fuse/135 [HC0[0]:SC0[0]:HE0:SE1] is trying to acquire:
	000000003590ceda (&fiq->waitq){+.+.}, at: spin_lock include/linux/spinlock.h:338 [inline]
	000000003590ceda (&fiq->waitq){+.+.}, at: aio_poll fs/aio.c:1751 [inline]
	000000003590ceda (&fiq->waitq){+.+.}, at: __io_submit_one.constprop.0+0x203/0x5b0 fs/aio.c:1825

	and this task is already holding:
	0000000075037284 (&(&ctx->ctx_lock)->rlock){..-.}, at: spin_lock_irq include/linux/spinlock.h:363 [inline]
	0000000075037284 (&(&ctx->ctx_lock)->rlock){..-.}, at: aio_poll fs/aio.c:1749 [inline]
	0000000075037284 (&(&ctx->ctx_lock)->rlock){..-.}, at: __io_submit_one.constprop.0+0x1f4/0x5b0 fs/aio.c:1825
	which would create a new lock dependency:
	 (&(&ctx->ctx_lock)->rlock){..-.} -> (&fiq->waitq){+.+.}

	but this new dependency connects a SOFTIRQ-irq-safe lock:
	 (&(&ctx->ctx_lock)->rlock){..-.}

	[...]

Reported-by: syzbot+af05535bb79520f95431@syzkaller.appspotmail.com
Reported-by: syzbot+d86c4426a01f60feddc7@syzkaller.appspotmail.com
Fixes: bfe4037e722e ("aio: implement IOCB_CMD_POLL")
Cc: <stable@vger.kernel.org> # v4.19+
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
fuse: fix missing unlock_page in fuse_writepage() 2019-10-05T11:10:04+00:00 Vasily Averin vvs@virtuozzo.com 2019-09-13T15:17:11+00:00 ad41162974c6b7914ef63dca6a9c9c3002050d2e commit d5880c7a8620290a6c90ced7a0e8bd0ad9419601 upstream. unlock_page() was missing in case of an already in-flight write against the same page. Signed-off-by: Vasily Averin <vvs@virtuozzo.com> Fixes: ff17be086477 ("fuse: writepage: skip already in flight") Cc: <stable@vger.kernel.org> # v3.13 Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit d5880c7a8620290a6c90ced7a0e8bd0ad9419601 upstream.

unlock_page() was missing in case of an already in-flight write against the
same page.

Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
Fixes: ff17be086477 ("fuse: writepage: skip already in flight")
Cc: <stable@vger.kernel.org> # v3.13
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
fuse: retrieve: cap requested size to negotiated max_write 2019-06-15T09:54:07+00:00 Kirill Smelkov kirr@nexedi.com 2019-03-27T10:15:19+00:00 ae35c325d8fda01844dc5ec64bcc1a9c9208e155 [ Upstream commit 7640682e67b33cab8628729afec8ca92b851394f ] FUSE filesystem server and kernel client negotiate during initialization phase, what should be the maximum write size the client will ever issue. Correspondingly the filesystem server then queues sys_read calls to read requests with buffer capacity large enough to carry request header + that max_write bytes. A filesystem server is free to set its max_write in anywhere in the range between [1*page, fc->max_pages*page]. In particular go-fuse[2] sets max_write by default as 64K, wheres default fc->max_pages corresponds to 128K. Libfuse also allows users to configure max_write, but by default presets it to possible maximum. If max_write is < fc->max_pages*page, and in NOTIFY_RETRIEVE handler we allow to retrieve more than max_write bytes, corresponding prepared NOTIFY_REPLY will be thrown away by fuse_dev_do_read, because the filesystem server, in full correspondence with server/client contract, will be only queuing sys_read with ~max_write buffer capacity, and fuse_dev_do_read throws away requests that cannot fit into server request buffer. In turn the filesystem server could get stuck waiting indefinitely for NOTIFY_REPLY since NOTIFY_RETRIEVE handler returned OK which is understood by clients as that NOTIFY_REPLY was queued and will be sent back. Cap requested size to negotiate max_write to avoid the problem. This aligns with the way NOTIFY_RETRIEVE handler works, which already unconditionally caps requested retrieve size to fuse_conn->max_pages. This way it should not hurt NOTIFY_RETRIEVE semantic if we return less data than was originally requested. Please see [1] for context where the problem of stuck filesystem was hit for real, how the situation was traced and for more involving patch that did not make it into the tree. [1] https://marc.info/?l=linux-fsdevel&m=155057023600853&w=2 [2] https://github.com/hanwen/go-fuse Signed-off-by: Kirill Smelkov <kirr@nexedi.com> Cc: Han-Wen Nienhuys <hanwen@google.com> Cc: Jakob Unterwurzacher <jakobunt@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 7640682e67b33cab8628729afec8ca92b851394f ]

FUSE filesystem server and kernel client negotiate during initialization
phase, what should be the maximum write size the client will ever issue.
Correspondingly the filesystem server then queues sys_read calls to read
requests with buffer capacity large enough to carry request header + that
max_write bytes. A filesystem server is free to set its max_write in
anywhere in the range between [1*page, fc->max_pages*page]. In particular
go-fuse[2] sets max_write by default as 64K, wheres default fc->max_pages
corresponds to 128K. Libfuse also allows users to configure max_write, but
by default presets it to possible maximum.

If max_write is < fc->max_pages*page, and in NOTIFY_RETRIEVE handler we
allow to retrieve more than max_write bytes, corresponding prepared
NOTIFY_REPLY will be thrown away by fuse_dev_do_read, because the
filesystem server, in full correspondence with server/client contract, will
be only queuing sys_read with ~max_write buffer capacity, and
fuse_dev_do_read throws away requests that cannot fit into server request
buffer. In turn the filesystem server could get stuck waiting indefinitely
for NOTIFY_REPLY since NOTIFY_RETRIEVE handler returned OK which is
understood by clients as that NOTIFY_REPLY was queued and will be sent
back.

Cap requested size to negotiate max_write to avoid the problem.  This
aligns with the way NOTIFY_RETRIEVE handler works, which already
unconditionally caps requested retrieve size to fuse_conn->max_pages.  This
way it should not hurt NOTIFY_RETRIEVE semantic if we return less data than
was originally requested.

Please see [1] for context where the problem of stuck filesystem was hit
for real, how the situation was traced and for more involving patch that
did not make it into the tree.

[1] https://marc.info/?l=linux-fsdevel&m=155057023600853&w=2
[2] https://github.com/hanwen/go-fuse

Signed-off-by: Kirill Smelkov <kirr@nexedi.com>
Cc: Han-Wen Nienhuys <hanwen@google.com>
Cc: Jakob Unterwurzacher <jakobunt@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
fuse: fallocate: fix return with locked inode 2019-06-11T10:20:51+00:00 Miklos Szeredi mszeredi@redhat.com 2019-05-27T09:42:07+00:00 a3b8b4ad6db7eea67a67eb88cc5f6e101f89dbc1 commit 35d6fcbb7c3e296a52136347346a698a35af3fda upstream. Do the proper cleanup in case the size check fails. Tested with xfstests:generic/228 Reported-by: kbuild test robot <lkp@intel.com> Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Fixes: 0cbade024ba5 ("fuse: honor RLIMIT_FSIZE in fuse_file_fallocate") Cc: Liu Bo <bo.liu@linux.alibaba.com> Cc: <stable@vger.kernel.org> # v3.5 Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 35d6fcbb7c3e296a52136347346a698a35af3fda upstream.

Do the proper cleanup in case the size check fails.

Tested with xfstests:generic/228

Reported-by: kbuild test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Fixes: 0cbade024ba5 ("fuse: honor RLIMIT_FSIZE in fuse_file_fallocate")
Cc: Liu Bo <bo.liu@linux.alibaba.com>
Cc: <stable@vger.kernel.org> # v3.5
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
fuse: Add FOPEN_STREAM to use stream_open() 2019-05-25T16:23:40+00:00 Kirill Smelkov kirr@nexedi.com 2019-04-24T07:13:57+00:00 fea685000caf196f676fc5a813599f63634c2c60 commit bbd84f33652f852ce5992d65db4d020aba21f882 upstream. Starting from commit 9c225f2655e3 ("vfs: atomic f_pos accesses as per POSIX") files opened even via nonseekable_open gate read and write via lock and do not allow them to be run simultaneously. This can create read vs write deadlock if a filesystem is trying to implement a socket-like file which is intended to be simultaneously used for both read and write from filesystem client. See commit 10dce8af3422 ("fs: stream_open - opener for stream-like files so that read and write can run simultaneously without deadlock") for details and e.g. commit 581d21a2d02a ("xenbus: fix deadlock on writes to /proc/xen/xenbus") for a similar deadlock example on /proc/xen/xenbus. To avoid such deadlock it was tempting to adjust fuse_finish_open to use stream_open instead of nonseekable_open on just FOPEN_NONSEEKABLE flags, but grepping through Debian codesearch shows users of FOPEN_NONSEEKABLE, and in particular GVFS which actually uses offset in its read and write handlers https://codesearch.debian.net/search?q=-%3Enonseekable+%3D https://gitlab.gnome.org/GNOME/gvfs/blob/1.40.0-6-gcbc54396/client/gvfsfusedaemon.c#L1080 https://gitlab.gnome.org/GNOME/gvfs/blob/1.40.0-6-gcbc54396/client/gvfsfusedaemon.c#L1247-1346 https://gitlab.gnome.org/GNOME/gvfs/blob/1.40.0-6-gcbc54396/client/gvfsfusedaemon.c#L1399-1481 so if we would do such a change it will break a real user. Add another flag (FOPEN_STREAM) for filesystem servers to indicate that the opened handler is having stream-like semantics; does not use file position and thus the kernel is free to issue simultaneous read and write request on opened file handle. This patch together with stream_open() should be added to stable kernels starting from v3.14+. This will allow to patch OSSPD and other FUSE filesystems that provide stream-like files to return FOPEN_STREAM | FOPEN_NONSEEKABLE in open handler and this way avoid the deadlock on all kernel versions. This should work because fuse_finish_open ignores unknown open flags returned from a filesystem and so passing FOPEN_STREAM to a kernel that is not aware of this flag cannot hurt. In turn the kernel that is not aware of FOPEN_STREAM will be < v3.14 where just FOPEN_NONSEEKABLE is sufficient to implement streams without read vs write deadlock. Cc: stable@vger.kernel.org # v3.14+ Signed-off-by: Kirill Smelkov <kirr@nexedi.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit bbd84f33652f852ce5992d65db4d020aba21f882 upstream.

Starting from commit 9c225f2655e3 ("vfs: atomic f_pos accesses as per
POSIX") files opened even via nonseekable_open gate read and write via lock
and do not allow them to be run simultaneously. This can create read vs
write deadlock if a filesystem is trying to implement a socket-like file
which is intended to be simultaneously used for both read and write from
filesystem client.  See commit 10dce8af3422 ("fs: stream_open - opener for
stream-like files so that read and write can run simultaneously without
deadlock") for details and e.g. commit 581d21a2d02a ("xenbus: fix deadlock
on writes to /proc/xen/xenbus") for a similar deadlock example on
/proc/xen/xenbus.

To avoid such deadlock it was tempting to adjust fuse_finish_open to use
stream_open instead of nonseekable_open on just FOPEN_NONSEEKABLE flags,
but grepping through Debian codesearch shows users of FOPEN_NONSEEKABLE,
and in particular GVFS which actually uses offset in its read and write
handlers

	https://codesearch.debian.net/search?q=-%3Enonseekable+%3D
	https://gitlab.gnome.org/GNOME/gvfs/blob/1.40.0-6-gcbc54396/client/gvfsfusedaemon.c#L1080
	https://gitlab.gnome.org/GNOME/gvfs/blob/1.40.0-6-gcbc54396/client/gvfsfusedaemon.c#L1247-1346
	https://gitlab.gnome.org/GNOME/gvfs/blob/1.40.0-6-gcbc54396/client/gvfsfusedaemon.c#L1399-1481

so if we would do such a change it will break a real user.

Add another flag (FOPEN_STREAM) for filesystem servers to indicate that the
opened handler is having stream-like semantics; does not use file position
and thus the kernel is free to issue simultaneous read and write request on
opened file handle.

This patch together with stream_open() should be added to stable kernels
starting from v3.14+. This will allow to patch OSSPD and other FUSE
filesystems that provide stream-like files to return FOPEN_STREAM |
FOPEN_NONSEEKABLE in open handler and this way avoid the deadlock on all
kernel versions. This should work because fuse_finish_open ignores unknown
open flags returned from a filesystem and so passing FOPEN_STREAM to a
kernel that is not aware of this flag cannot hurt. In turn the kernel that
is not aware of FOPEN_STREAM will be < v3.14 where just FOPEN_NONSEEKABLE
is sufficient to implement streams without read vs write deadlock.

Cc: stable@vger.kernel.org # v3.14+
Signed-off-by: Kirill Smelkov <kirr@nexedi.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
fuse: honor RLIMIT_FSIZE in fuse_file_fallocate 2019-05-25T16:23:30+00:00 Liu Bo bo.liu@linux.alibaba.com 2019-04-17T20:04:41+00:00 979d2433b873cde6d2d360644754d16fe9c5481b commit 0cbade024ba501313da3b7e5dd2a188a6bc491b5 upstream. fstests generic/228 reported this failure that fuse fallocate does not honor what 'ulimit -f' has set. This adds the necessary inode_newsize_ok() check. Signed-off-by: Liu Bo <bo.liu@linux.alibaba.com> Fixes: 05ba1f082300 ("fuse: add FALLOCATE operation") Cc: <stable@vger.kernel.org> # v3.5 Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 0cbade024ba501313da3b7e5dd2a188a6bc491b5 upstream.

fstests generic/228 reported this failure that fuse fallocate does not
honor what 'ulimit -f' has set.

This adds the necessary inode_newsize_ok() check.

Signed-off-by: Liu Bo <bo.liu@linux.alibaba.com>
Fixes: 05ba1f082300 ("fuse: add FALLOCATE operation")
Cc: <stable@vger.kernel.org> # v3.5
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
fuse: fix writepages on 32bit 2019-05-25T16:23:30+00:00 Miklos Szeredi mszeredi@redhat.com 2019-04-24T15:05:06+00:00 a452f733f93e943d991fd98da1fda20e4cec77d1 commit 9de5be06d0a89ca97b5ab902694d42dfd2bb77d2 upstream. Writepage requests were cropped to i_size & 0xffffffff, which meant that mmaped writes to any file larger than 4G might be silently discarded. Fix by storing the file size in a properly sized variable (loff_t instead of size_t). Reported-by: Antonio SJ Musumeci <trapexit@spawn.link> Fixes: 6eaf4782eb09 ("fuse: writepages: crop secondary requests") Cc: <stable@vger.kernel.org> # v3.13 Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 9de5be06d0a89ca97b5ab902694d42dfd2bb77d2 upstream.

Writepage requests were cropped to i_size & 0xffffffff, which meant that
mmaped writes to any file larger than 4G might be silently discarded.

Fix by storing the file size in a properly sized variable (loff_t instead
of size_t).

Reported-by: Antonio SJ Musumeci <trapexit@spawn.link>
Fixes: 6eaf4782eb09 ("fuse: writepages: crop secondary requests")
Cc: <stable@vger.kernel.org> # v3.13
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
fs: prevent page refcount overflow in pipe_buf_get 2019-05-04T07:20:11+00:00 Matthew Wilcox willy@infradead.org 2019-04-05T21:02:10+00:00 0311ff82b70fa12e80d188635bff24029ec06ae1 commit 15fab63e1e57be9fdb5eec1bbc5916e9825e9acb upstream. Change pipe_buf_get() to return a bool indicating whether it succeeded in raising the refcount of the page (if the thing in the pipe is a page). This removes another mechanism for overflowing the page refcount. All callers converted to handle a failure. Reported-by: Jann Horn <jannh@google.com> Signed-off-by: Matthew Wilcox <willy@infradead.org> Cc: stable@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 15fab63e1e57be9fdb5eec1bbc5916e9825e9acb upstream.

Change pipe_buf_get() to return a bool indicating whether it succeeded
in raising the refcount of the page (if the thing in the pipe is a page).
This removes another mechanism for overflowing the page refcount.  All
callers converted to handle a failure.

Reported-by: Jann Horn <jannh@google.com>
Signed-off-by: Matthew Wilcox <willy@infradead.org>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
fuse: handle zero sized retrieve correctly 2019-02-12T18:47:24+00:00 Miklos Szeredi mszeredi@redhat.com 2019-01-16T09:27:59+00:00 6ccc9e1128e50e518ecdf9e1b120c735e40de25a commit 97e1532ef81acb31c30f9e75bf00306c33a77812 upstream. Dereferencing req->page_descs[0] will Oops if req->max_pages is zero. Reported-by: syzbot+c1e36d30ee3416289cc0@syzkaller.appspotmail.com Tested-by: syzbot+c1e36d30ee3416289cc0@syzkaller.appspotmail.com Fixes: b2430d7567a3 ("fuse: add per-page descriptor <offset, length> to fuse_req") Cc: <stable@vger.kernel.org> # v3.9 Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 97e1532ef81acb31c30f9e75bf00306c33a77812 upstream.

Dereferencing req->page_descs[0] will Oops if req->max_pages is zero.

Reported-by: syzbot+c1e36d30ee3416289cc0@syzkaller.appspotmail.com
Tested-by: syzbot+c1e36d30ee3416289cc0@syzkaller.appspotmail.com
Fixes: b2430d7567a3 ("fuse: add per-page descriptor <offset, length> to fuse_req")
Cc: <stable@vger.kernel.org> # v3.9
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
fuse: decrement NR_WRITEBACK_TEMP on the right page 2019-02-12T18:47:24+00:00 Miklos Szeredi mszeredi@redhat.com 2019-01-16T09:27:59+00:00 f99027ab63bee0cbbde549ff663aef8b1c1944b5 commit a2ebba824106dabe79937a9f29a875f837e1b6d4 upstream. NR_WRITEBACK_TEMP is accounted on the temporary page in the request, not the page cache page. Fixes: 8b284dc47291 ("fuse: writepages: handle same page rewrites") Cc: <stable@vger.kernel.org> # v3.13 Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit a2ebba824106dabe79937a9f29a875f837e1b6d4 upstream.

NR_WRITEBACK_TEMP is accounted on the temporary page in the request, not
the page cache page.

Fixes: 8b284dc47291 ("fuse: writepages: handle same page rewrites")
Cc: <stable@vger.kernel.org> # v3.13
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>