seq_read() is a nasty piece of work, not to mention buggy.
It has (I think) an old bug which allows unprivileged userspace to read
beyond the end of m->buf.
I was getting these:
BUG: KASAN: slab-out-of-bounds in seq_read+0xcd2/0x1480 at addr ffff880116889880
Read of size 2713 by task trinity-c2/1329
CPU: 2 PID: 1329 Comm: trinity-c2 Not tainted 4.8.0-rc1+ #96
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.9.3-0-ge2fc41e-prebuilt.qemu-project.org 04/01/2014
Call Trace:
kasan_object_err+0x1c/0x80
kasan_report_error+0x2cb/0x7e0
kasan_report+0x4e/0x80
check_memory_region+0x13e/0x1a0
kasan_check_read+0x11/0x20
seq_read+0xcd2/0x1480
proc_reg_read+0x10b/0x260
do_loop_readv_writev.part.5+0x140/0x2c0
do_readv_writev+0x589/0x860
vfs_readv+0x7b/0xd0
do_readv+0xd8/0x2c0
SyS_readv+0xb/0x10
do_syscall_64+0x1b3/0x4b0
entry_SYSCALL64_slow_path+0x25/0x25
Object at ffff880116889100, in cache kmalloc-4096 size: 4096
Allocated:
PID = 1329
save_stack_trace+0x26/0x80
save_stack+0x46/0xd0
kasan_kmalloc+0xad/0xe0
__kmalloc+0x1aa/0x4a0
seq_buf_alloc+0x35/0x40
seq_read+0x7d8/0x1480
proc_reg_read+0x10b/0x260
do_loop_readv_writev.part.5+0x140/0x2c0
do_readv_writev+0x589/0x860
vfs_readv+0x7b/0xd0
do_readv+0xd8/0x2c0
SyS_readv+0xb/0x10
do_syscall_64+0x1b3/0x4b0
return_from_SYSCALL_64+0x0/0x6a
Freed:
PID = 0
(stack is not available)
Memory state around the buggy address:
ffff88011688a000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff88011688a080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88011688a100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
^
ffff88011688a180: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff88011688a200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
Disabling lock debugging due to kernel taint
This seems to be the same thing that Dave Jones was seeing here:
https://lkml.org/lkml/2016/8/12/334
There are multiple issues here:
1) If we enter the function with a non-empty buffer, there is an attempt
to flush it. But it was not clearing m->from after doing so, which
means that if we try to do this flush twice in a row without any call
to traverse() in between, we are going to be reading from the wrong
place -- the splat above, fixed by this patch.
2) If there's a short write to userspace because of page faults, the
buffer may already contain multiple lines (i.e. pos has advanced by
more than 1), but we don't save the progress that was made so the
next call will output what we've already returned previously. Since
that is a much less serious issue (and I have a headache after
staring at seq_read() for the past 8 hours), I'll leave that for now.
Link: http://lkml.kernel.org/r/1471447270-32093-1-git-send-email-vegard.nossum@oracle.com
Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
Reported-by: Dave Jones <davej@codemonkey.org.uk>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull UBIFS fixes from Richard Weinberger:
"This pull requests contains fixes for two issues in UBI and UBIFS:
- wrong UBIFS assertion.
- a UBIFS xattr regression"
* tag 'upstream-4.8-rc4' of git://git.infradead.org/linux-ubifs:
ubifs: Fix xattr generic handler usage
ubifs: Fix assertion in layout_in_gaps()
Pull f2fs fixes from Jaegeuk Kim:
- fsmark regression
- i_size race condition
- wrong conditions in f2fs_move_file_range
* tag 'for-f2fs-v4.8-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs:
f2fs: avoid potential deadlock in f2fs_move_file_range
f2fs: allow copying file range only in between regular files
Revert "f2fs: move i_size_write in f2fs_write_end"
Revert "f2fs: use percpu_rw_semaphore"
An assertion in layout_in_gaps() verifies that the gap_lebs pointer is
below the maximum bound. When computing this maximum bound the idx_lebs
count is multiplied by sizeof(int), while C pointers arithmetic does take
into account the size of the pointed elements implicitly already. Remove
the multiplication to fix the assertion.
Fixes: 1e51764a3c ("UBIFS: add new flash file system")
Cc: <stable@vger.kernel.org>
Signed-off-by: Vincent Stehlé <vincent.stehle@intel.com>
Cc: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
Pull xfs and iomap fixes from Dave Chinner:
"Changes in this update:
Regression fixes for XFS changes introduce in 4.8-rc1:
- buffer IO accounting assert failure
- ENOSPC block accounting reservation issue
- DAX IO path page cache invalidation fix
- rmapbt on-disk block count in agf
- correct classification of rmap block type when updating AGFL.
- iomap support for attribute fork mapping
Regression fixes for iomap infrastructure in 4.8-rc1:
- fiemap: honor FIEMAP_FLAG_SYNC
- fiemap: implement FIEMAP_FLAG_XATTR support to fix XFS regression
- make mark_page_accessed and pagefault_disable usage consistent with
other IO paths"
* tag 'xfs-iomap-for-linus-4.8-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/dgc/linux-xfs:
xfs: remove OWN_AG rmap when allocating a block from the AGFL
xfs: (re-)implement FIEMAP_FLAG_XATTR
xfs: simplify xfs_file_iomap_begin
iomap: mark ->iomap_end as optional
iomap: prepare iomap_fiemap for attribute mappings
iomap: fiemap should honor the FIEMAP_FLAG_SYNC flag
iomap: remove superflous pagefault_disable from iomap_write_actor
iomap: remove superflous mark_page_accessed from iomap_write_actor
xfs: store rmapbt block count in the AGF
xfs: don't invalidate whole file on DAX read/write
xfs: fix bogus space reservation in xfs_iomap_write_allocate
xfs: don't assert fail on non-async buffers on ioacct decrement
Thread A Thread B
- inode_lock fileA
- inode_lock fileB
- inode_lock fileA
- inode_lock fileB
We may encounter above potential deadlock during moving file range in
concurrent scenario. This patch fixes the issue by using inode_trylock
instead.
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Only if two input files are regular files, we allow copying data in
range of them, otherwise, deny it.
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
This reverts commit a2ee0a3003.
When testing with generic/032 of xfstest suit, failure message will be
reported as below:
generic/032 8s ... [failed, exit status 1] - output mismatch (see results/generic/032.out.bad)
--- tests/generic/032.out 2015-01-11 16:52:27.643681072 +0800
+++ results/generic/032.out.bad 2016-08-06 13:44:43.861330500 +0800
@@ -1,5 +1,5 @@
QA output created by 032
-100 iterations
-0000000 cdcd cdcd cdcd cdcd cdcd cdcd cdcd cdcd
-*
-0100000
+1: [768..775]: unwritten
+Unwritten extents found!
...
(Run 'diff -u tests/generic/032.out results/generic/032.out.bad' to see the entire diff)
Ran: generic/032
Failures: generic/032
Failed 1 of 1 tests
In write_end(), we should update i_size of inode before unlock page,
otherwise, we will lose newly updated data in following race condition.
Thread A Thread B
- write_end
- unlock page
- writepages
- lock_page
- writepage
if page is out-of-range of file size,
we will skip writting the page.
- update i_size
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
LKP reported -36.3% regression of fsmark.files_per_sec due to this patch.
I've confirmed that fxmark [1] has also slight regression for DWAL.
[1] https://github.com/sslab-gatech/fxmark
This reverts commit ec795418c4.
Pull networking fixes from David Miller:
1) Buffers powersave frame test is reversed in cfg80211, fix from Felix
Fietkau.
2) Remove bogus WARN_ON in openvswitch, from Jarno Rajahalme.
3) Fix some tg3 ethtool logic bugs, and one that would cause no
interrupts to be generated when rx-coalescing is set to 0. From
Satish Baddipadige and Siva Reddy Kallam.
4) QLCNIC mailbox corruption and napi budget handling fix from Manish
Chopra.
5) Fix fib_trie logic when walking the trie during /proc/net/route
output than can access a stale node pointer. From David Forster.
6) Several sctp_diag fixes from Phil Sutter.
7) PAUSE frame handling fixes in mlxsw driver from Ido Schimmel.
8) Checksum fixup fixes in bpf from Daniel Borkmann.
9) Memork leaks in nfnetlink, from Liping Zhang.
10) Use after free in rxrpc, from David Howells.
11) Use after free in new skb_array code of macvtap driver, from Jason
Wang.
12) Calipso resource leak, from Colin Ian King.
13) mediatek bug fixes (missing stats sync init, etc.) from Sean Wang.
14) Fix bpf non-linear packet write helpers, from Daniel Borkmann.
15) Fix lockdep splats in macsec, from Sabrina Dubroca.
16) hv_netvsc bug fixes from Vitaly Kuznetsov, mostly to do with VF
handling.
17) Various tc-action bug fixes, from CONG Wang.
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (116 commits)
net_sched: allow flushing tc police actions
net_sched: unify the init logic for act_police
net_sched: convert tcf_exts from list to pointer array
net_sched: move tc offload macros to pkt_cls.h
net_sched: fix a typo in tc_for_each_action()
net_sched: remove an unnecessary list_del()
net_sched: remove the leftover cleanup_a()
mlxsw: spectrum: Allow packets to be trapped from any PG
mlxsw: spectrum: Unmap 802.1Q FID before destroying it
mlxsw: spectrum: Add missing rollbacks in error path
mlxsw: reg: Fix missing op field fill-up
mlxsw: spectrum: Trap loop-backed packets
mlxsw: spectrum: Add missing packet traps
mlxsw: spectrum: Mark port as active before registering it
mlxsw: spectrum: Create PVID vPort before registering netdevice
mlxsw: spectrum: Remove redundant errors from the code
mlxsw: spectrum: Don't return upon error in removal path
i40e: check for and deal with non-contiguous TCs
ixgbe: Re-enable ability to toggle VLAN filtering
ixgbe: Force VLNCTRL.VFE to be set in all VMDq paths
...
When we're really tight on space, xfs_alloc_ag_vextent_small() can
allocate a block from the AGFL and give it to the caller. Since the
caller is never the AGFL-fixing method, we must remove the OWN_AG
reverse mapping because it will clash with whatever rmap the caller
wants to set up. This bug was discovered by running generic/299
repeatedly.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Use a special read-only iomap_ops implementation to support fiemap on
the attr fork.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
We'll never get nimap == 0 for a successful return from xfs_bmapi_read,
so don't try to handle it.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
By bassing through an -ENOENT, similar to the old XFS implementation of
FIEMAP_FLAG_XATTR.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
[hch: split from a larger patch]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
The flag is checked as supported, but then we do an unconditional
sync of the file, regardless of whether the flag is set or not. Make
the sync conditional on having the FIEMAP_FLAG_SYNC flag set.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Chinner <david@fromorbit.com>
iov_iter_copy_from_user_atomic disables page faults internally, no need to
do it around the call. This also brings the iomap code in line with
the original filemap version.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
This catches up with commit 2457ae ("mm: non-atomically mark page
accessed during page cache allocation where possible"), which
moved the initial access marking into the pagecache allocator.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Track the number of blocks used for the rmapbt in the AGF. When we
get to the AG reservation code we need this counter to quickly
make our reservation during mount.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
When we do DAX IO, we try to invalidate the entire page cache held
on the file. This is incorrect as it will trash the entire mapping
tree that now tracks dirty state in exceptional entries in the radix
tree slots.
What we are trying to do is remove cached pages (e.g from reads
into holes) that sit in the radix tree over the range we are about
to write to. Hence we should just limit the invalidation to the
range we are about to overwrite.
Reported-by: Jan Kara <jack@suse.cz>
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Chinner <david@fromorbit.com>
The space reservations was without an explaination in commit
"Add error reporting calls in error paths that return EFSCORRUPTED"
back in 2003. There is no reason to reserve disk blocks in the
transaction when allocating blocks for delalloc space as we already
reserved the space when creating the delalloc extent.
With this fix we stop running out of the reserved pool in
generic/229, which has happened for long time with small blocksize
file systems, and has increased in severity with the new buffered
write path.
[ dchinner: we still need to pass the block reservation into
xfs_bmapi_write() to ensure we don't deadlock during AG selection.
See commit dbd5c8c ("xfs: pass total block res. as total
xfs_bmapi_write() parameter") for more details on why this is
necessary. ]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
The buffer I/O accounting mechanism tracks async buffers under I/O. As
an optimization, the buffer I/O count is incremented only once on the
first async I/O for a given hold cycle of a buffer and decremented once
the buffer is released to the LRU (or freed).
xfs_buf_ioacct_dec() has an ASSERT() check for an XBF_ASYNC buffer, but
we have one or two corner cases where a buffer can be submitted for I/O
multiple times via different methods in a single hold cycle. If an async
I/O occurs first, the I/O count is incremented. If a sync I/O occurs
before the hold count drops, XBF_ASYNC is cleared by the time the I/O
count is decremented.
Remove the async assert check from xfs_buf_ioacct_dec() as this is a
perfectly valid scenario. For the purposes of I/O accounting, we really
only care about the buffer async state at I/O submission time.
Discovered-and-analyzed-by: Dave Chinner <david@fromorbit.com>
Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Pull block fixes from Jens Axboe:
- an NVMe fix from Gabriel, fixing a suspend/resume issue on some
setups
- addition of a few missing entries in the block queue sysfs
documentation, from Joe
- a fix for a sparse shadow warning for the bvec iterator, from
Johannes
- a writeback deadlock involving raid issuing barriers, and not
flushing the plug when we wakeup the flusher threads. From
Konstantin
- a set of patches for the NVMe target/loop/rdma code, from Roland and
Sagi
* 'for-linus' of git://git.kernel.dk/linux-block:
bvec: avoid variable shadowing warning
doc: update block/queue-sysfs.txt entries
nvme: Suspend all queues before deletion
mm, writeback: flush plugged IO in wakeup_flusher_threads()
nvme-rdma: Remove unused includes
nvme-rdma: start async event handler after reconnecting to a controller
nvmet: Fix controller serial number inconsistency
nvmet-rdma: Don't use the inline buffer in order to avoid allocation for small reads
nvmet-rdma: Correctly handle RDMA device hot removal
nvme-rdma: Make sure to shutdown the controller if we can
nvme-loop: Remove duplicate call to nvme_remove_namespaces
nvme-rdma: Free the I/O tags when we delete the controller
nvme-rdma: Remove duplicate call to nvme_remove_namespaces
nvme-rdma: Fix device removal handling
nvme-rdma: Queue ns scanning after a sucessful reconnection
nvme-rdma: Don't leak uninitialized memory in connect request private data
Vegard Nossum
Linus Torvalds
Richard Weinberger
Vincent Stehlé
Chao Yu
Jaegeuk Kim
Dave Chinner
Darrick J. Wong
Christoph Hellwig
Dave Chinner
Brian Foster